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1.
Cell ; 184(9): 2348-2361.e6, 2021 04 29.
Article in English | MEDLINE | ID: mdl-33730597

ABSTRACT

The race to produce vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began when the first sequence was published, and this forms the basis for vaccines currently deployed globally. Independent lineages of SARS-CoV-2 have recently been reported: UK, B.1.1.7; South Africa, B.1.351; and Brazil, P.1. These variants have multiple changes in the immunodominant spike protein that facilitates viral cell entry via the angiotensin-converting enzyme-2 (ACE2) receptor. Mutations in the receptor recognition site on the spike are of great concern for their potential for immune escape. Here, we describe a structure-function analysis of B.1.351 using a large cohort of convalescent and vaccinee serum samples. The receptor-binding domain mutations provide tighter ACE2 binding and widespread escape from monoclonal antibody neutralization largely driven by E484K, although K417N and N501Y act together against some important antibody classes. In a number of cases, it would appear that convalescent and some vaccine serum offers limited protection against this variant.


Subject(s)
COVID-19 Vaccines/blood , COVID-19 Vaccines/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , COVID-19/immunology , COVID-19/therapy , COVID-19/virology , Chlorocebus aethiops , Clinical Trials as Topic , HEK293 Cells , Humans , Immunization, Passive , Models, Molecular , Mutation/genetics , Neutralization Tests , Protein Binding , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Vero Cells , COVID-19 Serotherapy
2.
Cell ; 184(8): 2201-2211.e7, 2021 04 15.
Article in English | MEDLINE | ID: mdl-33743891

ABSTRACT

SARS-CoV-2 has caused over 2 million deaths in little over a year. Vaccines are being deployed at scale, aiming to generate responses against the virus spike. The scale of the pandemic and error-prone virus replication is leading to the appearance of mutant viruses and potentially escape from antibody responses. Variant B.1.1.7, now dominant in the UK, with increased transmission, harbors 9 amino acid changes in the spike, including N501Y in the ACE2 interacting surface. We examine the ability of B.1.1.7 to evade antibody responses elicited by natural SARS-CoV-2 infection or vaccination. We map the impact of N501Y by structure/function analysis of a large panel of well-characterized monoclonal antibodies. B.1.1.7 is harder to neutralize than parental virus, compromising neutralization by some members of a major class of public antibodies through light-chain contacts with residue 501. However, widespread escape from monoclonal antibodies or antibody responses generated by natural infection or vaccination was not observed.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , CHO Cells , COVID-19/epidemiology , Chlorocebus aethiops , Cricetulus , HEK293 Cells , Humans , Pandemics , Protein Binding , Structure-Activity Relationship , Vero Cells
3.
Cell ; 184(11): 2939-2954.e9, 2021 05 27.
Article in English | MEDLINE | ID: mdl-33852911

ABSTRACT

Terminating the SARS-CoV-2 pandemic relies upon pan-global vaccination. Current vaccines elicit neutralizing antibody responses to the virus spike derived from early isolates. However, new strains have emerged with multiple mutations, including P.1 from Brazil, B.1.351 from South Africa, and B.1.1.7 from the UK (12, 10, and 9 changes in the spike, respectively). All have mutations in the ACE2 binding site, with P.1 and B.1.351 having a virtually identical triplet (E484K, K417N/T, and N501Y), which we show confer similar increased affinity for ACE2. We show that, surprisingly, P.1 is significantly less resistant to naturally acquired or vaccine-induced antibody responses than B.1.351, suggesting that changes outside the receptor-binding domain (RBD) impact neutralization. Monoclonal antibody (mAb) 222 neutralizes all three variants despite interacting with two of the ACE2-binding site mutations. We explain this through structural analysis and use the 222 light chain to largely restore neutralization potency to a major class of public antibodies.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Binding Sites , COVID-19/therapy , COVID-19/virology , Cell Line , Humans , Immune Evasion , Immunization, Passive , Mutation , Protein Binding , Protein Domains , SARS-CoV-2/genetics , Sequence Deletion , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Vaccination , Vaccines/immunology , COVID-19 Serotherapy
4.
Cell ; 184(16): 4220-4236.e13, 2021 08 05.
Article in English | MEDLINE | ID: mdl-34242578

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has undergone progressive change, with variants conferring advantage rapidly becoming dominant lineages, e.g., B.1.617. With apparent increased transmissibility, variant B.1.617.2 has contributed to the current wave of infection ravaging the Indian subcontinent and has been designated a variant of concern in the United Kingdom. Here we study the ability of monoclonal antibodies and convalescent and vaccine sera to neutralize B.1.617.1 and B.1.617.2, complement this with structural analyses of Fab/receptor binding domain (RBD) complexes, and map the antigenic space of current variants. Neutralization of both viruses is reduced compared with ancestral Wuhan-related strains, but there is no evidence of widespread antibody escape as seen with B.1.351. However, B.1.351 and P.1 sera showed markedly more reduction in neutralization of B.1.617.2, suggesting that individuals infected previously by these variants may be more susceptible to reinfection by B.1.617.2. This observation provides important new insights for immunization policy with future variant vaccines in non-immune populations.


Subject(s)
Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antigen-Antibody Complex/chemistry , COVID-19/pathology , COVID-19/therapy , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Chlorocebus aethiops , Crystallography, X-Ray , Humans , Immunization, Passive , Neutralization Tests , Protein Domains/immunology , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Vero Cells , COVID-19 Serotherapy
5.
BMC Health Serv Res ; 24(1): 282, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38443896

ABSTRACT

BACKGROUND: Infertility is a major health issue worldwide, yet very few examples of interventions addressing infertility in the Global South have been documented to date. In The Gambia, West Africa, infertility is recognised as a burden and the health authorities have included it in several health policies and the new National Reproductive Health Strategy however, a detailed operationalisation plan for fertility care has not yet been established. Here, we aim to understand and document the factors that influence the implementation of fertility care in The Gambia. METHODS: We conducted 46 semi-structured interviews with policymakers, implementers, and health practitioners in both the public and private sectors from July to November 2021. The interviews were transcribed, anonymised and analysed with NVivo Pro version 1.6.1. The analysis was initially inductive, with themes arising from the coding categorised according to the WHO health systems building blocks framework. RESULTS: This study identified several barriers to a successful implementation of fertility care in The Gambia, including (i) a lack of routinely collected infertility data; (ii) an absence of financial protection mechanisms for patients, and/or a specific budget for infertility; (iii) limited cooperation between the public and private sectors in the provision of fertility care; and (iv) gaps in fertility care training among health practitioners. Conversely, enablers included: (i) strong national infertility leadership; and (ii) the integration of infertility care within public reproductive health services. CONCLUSION: The Gambian health system is not yet in the position to support a comprehensive fertility care package in its public health facilities. Several aspects of the implementation of fertility care must be considered in operationalising the health strategy including the systematic collection of infertility data, fertility awareness, and the provision of specialised fertility care training. Furthermore, a stronger partnership between the public and private sectors must be developed. Given the increasing availability of assisted reproductive technologies in the sub-Saharan Africa region, and the tendency to locate these technologies in the private sector, further research is needed to understand and identify the processes underlying the implementation of fertility care and to foster better integration with the existing health system.


Subject(s)
Fertility Preservation , Infertility , Humans , Gambia , Africa, Western , Infertility/therapy , Fertility
6.
Clin Exp Immunol ; 211(3): 280-287, 2023 03 24.
Article in English | MEDLINE | ID: mdl-36729167

ABSTRACT

The trajectory of immune responses following the primary dose series determines the decline in vaccine effectiveness over time. Here we report on maintenance of immune responses during the year following a two-dose schedule of ChAdOx1 nCoV-19/AZD1222, in the absence of infection, and also explore the decay of antibody after infection. Total spike-specific IgG antibody titres were lower with two low doses of ChAdOx1 nCoV-19 vaccines (two low doses) (P = 0.0006) than with 2 standard doses (the approved dose) or low dose followed by standard dose vaccines regimens. Longer intervals between first and second doses resulted in higher antibody titres (P < 0.0001); however, there was no evidence that the trajectory of antibody decay differed by interval or by vaccine dose, and the decay of IgG antibody titres followed a similar trajectory after a third dose of ChAdOx1 nCoV-19. Trends in post-infection samples were similar with an initial rapid decay in responses but good persistence of measurable responses thereafter. Extrapolation of antibody data, following two doses of ChAdOx1 nCov-19, demonstrates a slow rate of antibody decay with modelling, suggesting that antibody titres are well maintained for at least 2 years. These data suggest a persistent immune response after two doses of ChAdOx1 nCov-19 which will likely have a positive impact against serious disease and hospitalization.


Subject(s)
ChAdOx1 nCoV-19 , Immunoglobulin G , Humans , Follow-Up Studies , Randomized Controlled Trials as Topic , Immunity , Antibodies, Viral , Vaccination
7.
MMWR Morb Mortal Wkly Rep ; 72(9): 217-222, 2023 Mar 03.
Article in English | MEDLINE | ID: mdl-36862590

ABSTRACT

On July 26, 2022, a pediatric nephrologist alerted The Gambia's Ministry of Health (MoH) to a cluster of cases of acute kidney injury (AKI) among young children at the country's sole teaching hospital, and on August 23, 2022, MoH requested assistance from CDC. CDC epidemiologists arrived in The Gambia, a West African country, on September 16 to assist MoH in characterizing the illness, describing the epidemiology, and identifying potential causal factors and their sources. Investigators reviewed medical records and interviewed caregivers to characterize patients' symptoms and identify exposures. The preliminary investigation suggested that various contaminated syrup-based children's medications contributed to the AKI outbreak. During the investigation, MoH recalled implicated medications from a single international manufacturer. Continued efforts to strengthen pharmaceutical quality control and event-based public health surveillance are needed to help prevent future medication-related outbreaks.


Subject(s)
Acute Kidney Injury , Humans , Child , Child, Preschool , Gambia/epidemiology , Africa, Western , Acute Kidney Injury/chemically induced , Acute Kidney Injury/epidemiology , Pharmaceutical Preparations
8.
BMC Pregnancy Childbirth ; 23(1): 374, 2023 May 24.
Article in English | MEDLINE | ID: mdl-37226126

ABSTRACT

BACKGROUND: A barrier to achieving first trimester antenatal care (ANC) attendance in many countries has been the widespread cultural practice of not discussing pregnancies in the early stages. Motivations for concealing pregnancy bear further study, as the interventions necessary to encourage early ANC attendance may be more complicated than targeting infrastructural barriers to ANC attendance such as transportation, time, and cost. METHODS: Five focus groups with a total of 30 married, pregnant women were conducted to assess the feasibility of conducting a randomised controlled trial to evaluate the effectiveness of early initiation of physical activity and/or yoghurt consumption in reducing Gestational Diabetes Mellitus in pregnant women in The Gambia. Focus group transcripts were coded through a thematic analysis approach, assessing themes as they arose in relation to failure to attend early ANC. RESULTS: Two reasons for the concealment of pregnancies in the first trimester or ahead of a pregnancy's obvious visibility to others were given by focus group participants. These were 'pregnancy outside of marriage' and 'evil spirits and miscarriage.' Concealment on both grounds was motivated through specific worries and fears. In the case of a pregnancy outside of marriage, this was worry over social stigma and shame. Evil spirits were widely considered to be a cause of early miscarriage, and as such, women may choose to conceal their pregnancies in the early stages as a form of protection. CONCLUSION: Women's lived experiences of evil spirits have been under-explored in qualitative health research as they relate specifically to women's access to early antenatal care. Better understanding of how such sprits are experienced and why some women perceive themselves as vulnerable to related spiritual attacks may help healthcare workers or community health workers to identify in a timely manner the women most likely to fear such situations and spirits and subsequently conceal their pregnancies.


Subject(s)
Abortion, Spontaneous , Motivation , Female , Humans , Pregnancy , Gambia , Cognition , Community Health Workers
9.
BMC Womens Health ; 23(1): 660, 2023 12 09.
Article in English | MEDLINE | ID: mdl-38066506

ABSTRACT

BACKGROUND: Cervical cancer is the most common cancer and the leading cause of cancer-related death in Gambian women. The Gambian Ministry of Health is striving to improve access to screening, diagnostic, and treatment services for cervical cancer, but comprehensive data on currently available services is limited making it challenging to appropriately prioritize the ideal next steps for expanding care. This study aims to describe the current services available for the prevention, screening, and treatment of cervical cancer in The Gambia and provide suggestions for expanding geographic access to care. METHODS: A survey aimed at assessing the availability of key cervical cancer-related services was developed and then administered in person by research assistants to all secondary and tertiary health facilities (HFs) in The Gambia. ArcGIS Pro Software and 2020 LandScan population density raster were used to visualize and quantify geographic access to care. Survey results were compared with published targets outlined by the Gambian Ministry of Health in the "Strategic Plan for the Prevention and Control of Cervical Cancer in The Gambia: 2016-2020." RESULTS: One hundred and two HFs were surveyed including 12 hospitals, 3 major health centers, 56 minor health centers, and 31 medical centers/clinics. Seventy-eight of these HFs provided some form of cervical cancer-related service. HPV vaccination was available in all health regions. Two-thirds of the population lived within 10 km of a HF that offered screening for cervical cancer and half lived within 10 km of a HF that offered treatment for precancerous lesions. Ten HFs offered hysterectomy, but nine were located in the same region. Two HFs offered limited chemotherapy. Radiotherapy was not available. If all major health centers and hospitals started offering visual inspection with acetic acid and cryotherapy, 86.1% of the population would live within 25 km of a HF with both services. CONCLUSIONS: Geographic access to cervical cancer screening, and precancer treatment is relatively widespread across The Gambia, but targeted expansion in line with the country's "Strategic Plan" would improve access for central and eastern Gambia. The availability of treatment services for invasive cancer is limited, and establishing radiotherapy in the country should continue to be prioritized.


Subject(s)
Uterine Cervical Neoplasms , Humans , Female , Gambia , Uterine Cervical Neoplasms/therapy , Uterine Cervical Neoplasms/prevention & control , Early Detection of Cancer/methods , Population Density , Spatial Analysis
10.
Lancet ; 398(10304): 981-990, 2021 09 11.
Article in English | MEDLINE | ID: mdl-34480858

ABSTRACT

BACKGROUND: COVID-19 vaccine supply shortages are causing concerns about compromised immunity in some countries as the interval between the first and second dose becomes longer. Conversely, countries with no supply constraints are considering administering a third dose. We assessed the persistence of immunogenicity after a single dose of ChAdOx1 nCoV-19 (AZD1222), immunity after an extended interval (44-45 weeks) between the first and second dose, and response to a third dose as a booster given 28-38 weeks after the second dose. METHODS: In this substudy, volunteers aged 18-55 years who were enrolled in the phase 1/2 (COV001) controlled trial in the UK and had received either a single dose or two doses of 5 × 1010 viral particles were invited back for vaccination. Here we report the reactogenicity and immunogenicity of a delayed second dose (44-45 weeks after first dose) or a third dose of the vaccine (28-38 weeks after second dose). Data from volunteers aged 18-55 years who were enrolled in either the phase 1/2 (COV001) or phase 2/3 (COV002), single-blinded, randomised controlled trials of ChAdOx1 nCoV-19 and who had previously received a single dose or two doses of 5 × 1010 viral particles are used for comparison purposes. COV001 is registered with ClinicalTrials.gov, NCT04324606, and ISRCTN, 15281137, and COV002 is registered with ClinicalTrials.gov, NCT04400838, and ISRCTN, 15281137, and both are continuing but not recruiting. FINDINGS: Between March 11 and 21, 2021, 90 participants were enrolled in the third-dose boost substudy, of whom 80 (89%) were assessable for reactogenicity, 75 (83%) were assessable for evaluation of antibodies, and 15 (17%) were assessable for T-cells responses. The two-dose cohort comprised 321 participants who had reactogenicity data (with prime-boost interval of 8-12 weeks: 267 [83%] of 321; 15-25 weeks: 24 [7%]; or 44-45 weeks: 30 [9%]) and 261 who had immunogenicity data (interval of 8-12 weeks: 115 [44%] of 261; 15-25 weeks: 116 [44%]; and 44-45 weeks: 30 [11%]). 480 participants from the single-dose cohort were assessable for immunogenicity up to 44-45 weeks after vaccination. Antibody titres after a single dose measured approximately 320 days after vaccination remained higher than the titres measured at baseline (geometric mean titre of 66·00 ELISA units [EUs; 95% CI 47·83-91·08] vs 1·75 EUs [1·60-1·93]). 32 participants received a late second dose of vaccine 44-45 weeks after the first dose, of whom 30 were included in immunogenicity and reactogenicity analyses. Antibody titres were higher 28 days after vaccination in those with a longer interval between first and second dose than for those with a short interval (median total IgG titre: 923 EUs [IQR 525-1764] with an 8-12 week interval; 1860 EUs [917-4934] with a 15-25 week interval; and 3738 EUs [1824-6625] with a 44-45 week interval). Among participants who received a third dose of vaccine, antibody titres (measured in 73 [81%] participants for whom samples were available) were significantly higher 28 days after a third dose (median total IgG titre: 3746 EUs [IQR 2047-6420]) than 28 days after a second dose (median 1792 EUs [IQR 899-4634]; Wilcoxon signed rank test p=0·0043). T-cell responses were also boosted after a third dose (median response increased from 200 spot forming units [SFUs] per million peripheral blood mononuclear cells [PBMCs; IQR 127-389] immediately before the third dose to 399 SFUs per milion PBMCs [314-662] by day 28 after the third dose; Wilcoxon signed rank test p=0·012). Reactogenicity after a late second dose or a third dose was lower than reactogenicity after a first dose. INTERPRETATION: An extended interval before the second dose of ChAdOx1 nCoV-19 leads to increased antibody titres. A third dose of ChAdOx1 nCoV-19 induces antibodies to a level that correlates with high efficacy after second dose and boosts T-cell responses. FUNDING: UK Research and Innovation, Engineering and Physical Sciences Research Council, National Institute for Health Research, Coalition for Epidemic Preparedness Innovations, National Institute for Health Research Oxford Biomedical Research Centre, Chinese Academy of Medical Sciences Innovation Fund for Medical Science, Thames Valley and South Midlands NIHR Clinical Research Network, AstraZeneca, and Wellcome.


Subject(s)
COVID-19 Vaccines/administration & dosage , Immunogenicity, Vaccine/immunology , Randomized Controlled Trials as Topic , Vaccination , Adult , ChAdOx1 nCoV-19 , Female , Humans , Leukocytes, Mononuclear/immunology , Male , Middle Aged , Time Factors , United Kingdom
11.
Lancet ; 396(10267): 1979-1993, 2021 12 19.
Article in English | MEDLINE | ID: mdl-33220855

ABSTRACT

BACKGROUND: Older adults (aged ≥70 years) are at increased risk of severe disease and death if they develop COVID-19 and are therefore a priority for immunisation should an efficacious vaccine be developed. Immunogenicity of vaccines is often worse in older adults as a result of immunosenescence. We have reported the immunogenicity of a novel chimpanzee adenovirus-vectored vaccine, ChAdOx1 nCoV-19 (AZD1222), in young adults, and now describe the safety and immunogenicity of this vaccine in a wider range of participants, including adults aged 70 years and older. METHODS: In this report of the phase 2 component of a single-blind, randomised, controlled, phase 2/3 trial (COV002), healthy adults aged 18 years and older were enrolled at two UK clinical research facilities, in an age-escalation manner, into 18-55 years, 56-69 years, and 70 years and older immunogenicity subgroups. Participants were eligible if they did not have severe or uncontrolled medical comorbidities or a high frailty score (if aged ≥65 years). First, participants were recruited to a low-dose cohort, and within each age group, participants were randomly assigned to receive either intramuscular ChAdOx1 nCoV-19 (2·2 × 1010 virus particles) or a control vaccine, MenACWY, using block randomisation and stratified by age and dose group and study site, using the following ratios: in the 18-55 years group, 1:1 to either two doses of ChAdOx1 nCoV-19 or two doses of MenACWY; in the 56-69 years group, 3:1:3:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY; and in the 70 years and older, 5:1:5:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY. Prime-booster regimens were given 28 days apart. Participants were then recruited to the standard-dose cohort (3·5-6·5 × 1010 virus particles of ChAdOx1 nCoV-19) and the same randomisation procedures were followed, except the 18-55 years group was assigned in a 5:1 ratio to two doses of ChAdOx1 nCoV-19 or two doses of MenACWY. Participants and investigators, but not staff administering the vaccine, were masked to vaccine allocation. The specific objectives of this report were to assess the safety and humoral and cellular immunogenicity of a single-dose and two-dose schedule in adults older than 55 years. Humoral responses at baseline and after each vaccination until 1 year after the booster were assessed using an in-house standardised ELISA, a multiplex immunoassay, and a live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) microneutralisation assay (MNA80). Cellular responses were assessed using an ex-vivo IFN-γ enzyme-linked immunospot assay. The coprimary outcomes of the trial were efficacy, as measured by the number of cases of symptomatic, virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were by group allocation in participants who received the vaccine. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. This study is ongoing and is registered with ClinicalTrials.gov, NCT04400838, and ISRCTN, 15281137. FINDINGS: Between May 30 and Aug 8, 2020, 560 participants were enrolled: 160 aged 18-55 years (100 assigned to ChAdOx1 nCoV-19, 60 assigned to MenACWY), 160 aged 56-69 years (120 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY), and 240 aged 70 years and older (200 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY). Seven participants did not receive the boost dose of their assigned two-dose regimen, one participant received the incorrect vaccine, and three were excluded from immunogenicity analyses due to incorrectly labelled samples. 280 (50%) of 552 analysable participants were female. Local and systemic reactions were more common in participants given ChAdOx1 nCoV-19 than in those given the control vaccine, and similar in nature to those previously reported (injection-site pain, feeling feverish, muscle ache, headache), but were less common in older adults (aged ≥56 years) than younger adults. In those receiving two standard doses of ChAdOx1 nCoV-19, after the prime vaccination local reactions were reported in 43 (88%) of 49 participants in the 18-55 years group, 22 (73%) of 30 in the 56-69 years group, and 30 (61%) of 49 in the 70 years and older group, and systemic reactions in 42 (86%) participants in the 18-55 years group, 23 (77%) in the 56-69 years group, and 32 (65%) in the 70 years and older group. As of Oct 26, 2020, 13 serious adverse events occurred during the study period, none of which were considered to be related to either study vaccine. In participants who received two doses of vaccine, median anti-spike SARS-CoV-2 IgG responses 28 days after the boost dose were similar across the three age cohorts (standard-dose groups: 18-55 years, 20 713 arbitrary units [AU]/mL [IQR 13 898-33 550], n=39; 56-69 years, 16 170 AU/mL [10 233-40 353], n=26; and ≥70 years 17 561 AU/mL [9705-37 796], n=47; p=0·68). Neutralising antibody titres after a boost dose were similar across all age groups (median MNA80 at day 42 in the standard-dose groups: 18-55 years, 193 [IQR 113-238], n=39; 56-69 years, 144 [119-347], n=20; and ≥70 years, 161 [73-323], n=47; p=0·40). By 14 days after the boost dose, 208 (>99%) of 209 boosted participants had neutralising antibody responses. T-cell responses peaked at day 14 after a single standard dose of ChAdOx1 nCoV-19 (18-55 years: median 1187 spot-forming cells [SFCs] per million peripheral blood mononuclear cells [IQR 841-2428], n=24; 56-69 years: 797 SFCs [383-1817], n=29; and ≥70 years: 977 SFCs [458-1914], n=48). INTERPRETATION: ChAdOx1 nCoV-19 appears to be better tolerated in older adults than in younger adults and has similar immunogenicity across all age groups after a boost dose. Further assessment of the efficacy of this vaccine is warranted in all age groups and individuals with comorbidities. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midlands NIHR Clinical Research Network, and AstraZeneca.


Subject(s)
COVID-19 Vaccines/administration & dosage , Immunogenicity, Vaccine , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/pharmacology , ChAdOx1 nCoV-19 , Female , Humans , Immunization, Secondary/adverse effects , Immunoglobulin G/blood , Immunoglobulin G/drug effects , Male , Middle Aged , SARS-CoV-2/drug effects , Single-Blind Method , Young Adult
12.
BMC Health Serv Res ; 22(1): 1127, 2022 Sep 07.
Article in English | MEDLINE | ID: mdl-36071443

ABSTRACT

BACKGROUND: Infertility is a long-standing reproductive health issue, which affects both men and women worldwide and it is especially problematic in the Global South. In sub-Saharan Africa, understanding the current availability of diagnostic and treatment services for infertility is important because this could guide health systems to improve access to fertility care for all. Yet, few studies have explicitly started from a health system perspective to grasp the availability and integration of infertility services in sub-Saharan Africa. This quantitative study, the first in The Gambia, West Africa, examines the availability of infertility services in public and private facilities as part of a wider endeavour to improve fertility care policy and practice in the country. METHODS: A cross-sectional survey using Qualtrics was administered to 38 health facilities. The survey was carried out between March and August 2021 and involved closed-ended questions. Data analysis consisted of descriptive statistics and t-tests performed using SPSS version 26. RESULTS: A total of 25 facilities (66%) offered infertility services, of which 13 (52%) were public and 12 (47%) private. Although the availability of screening tests was similar between health institutions, most diagnostic and treatment services were available only in the private sector. Treatment services included: (i) ovarian stimulation (n = 16, 42%); (ii) reversal of tubal ligation and/or blockage (tuboplasty) (n = 4, 11%); and (iii) intrauterine insemination (n = 3, 8%). Assisted reproductive technologies such as IVF and ICSI were not available in public or private sectors. The Gambian health management information system lacked a dedicated space to capture data on infertility. Reported barriers to integration of infertility services in existing reproductive health services included a lack of specialised training, an absence of national guidance on infertility management, and a shortage of appropriate equipment, supplies, and medication. CONCLUSIONS: The availability of infertility services in The Gambia follows a trajectory that is similar to other SSA countries in which services are mostly obtainable through the private sector. Yet, access to private care is expensive and geographically restricted, which exacerbates inequalities in accessing fertility care for all. Improving the provision of infertility services in the public sector requires systematically capturing data on infertility and investing in the provision of a full-range fertility care package.


Subject(s)
Infertility , Private Facilities , Cross-Sectional Studies , Female , Gambia , Health Facilities , Humans , Infertility/diagnosis , Infertility/therapy , Male
13.
Emerg Infect Dis ; 27(8): 2064-2072, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34286683

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is evolving differently in Africa than in other regions. Africa has lower SARS-CoV-2 transmission rates and milder clinical manifestations. Detailed SARS-CoV-2 epidemiologic data are needed in Africa. We used publicly available data to calculate SARS-CoV-2 infections per 1,000 persons in The Gambia. We evaluated transmission rates among 1,366 employees of the Medical Research Council Unit The Gambia (MRCG), where systematic surveillance of symptomatic cases and contact tracing were implemented. By September 30, 2020, The Gambia had identified 3,579 SARS-CoV-2 cases, including 115 deaths; 67% of cases were identified in August. Among infections, MRCG staff accounted for 191 cases; all were asymptomatic or mild. The cumulative incidence rate among nonclinical MRCG staff was 124 infections/1,000 persons, which is >80-fold higher than estimates of diagnosed cases among the population. Systematic surveillance and seroepidemiologic surveys are needed to clarify the extent of SARS-CoV-2 transmission in Africa.


Subject(s)
COVID-19 , Africa , Gambia/epidemiology , Humans , Pandemics , SARS-CoV-2 , Seroepidemiologic Studies
14.
Lancet ; 396(10249): 467-478, 2020 08 15.
Article in English | MEDLINE | ID: mdl-32702298

ABSTRACT

BACKGROUND: The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be curtailed by vaccination. We assessed the safety, reactogenicity, and immunogenicity of a viral vectored coronavirus vaccine that expresses the spike protein of SARS-CoV-2. METHODS: We did a phase 1/2, single-blind, randomised controlled trial in five trial sites in the UK of a chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) expressing the SARS-CoV-2 spike protein compared with a meningococcal conjugate vaccine (MenACWY) as control. Healthy adults aged 18-55 years with no history of laboratory confirmed SARS-CoV-2 infection or of COVID-19-like symptoms were randomly assigned (1:1) to receive ChAdOx1 nCoV-19 at a dose of 5 × 1010 viral particles or MenACWY as a single intramuscular injection. A protocol amendment in two of the five sites allowed prophylactic paracetamol to be administered before vaccination. Ten participants assigned to a non-randomised, unblinded ChAdOx1 nCoV-19 prime-boost group received a two-dose schedule, with the booster vaccine administered 28 days after the first dose. Humoral responses at baseline and following vaccination were assessed using a standardised total IgG ELISA against trimeric SARS-CoV-2 spike protein, a muliplexed immunoassay, three live SARS-CoV-2 neutralisation assays (a 50% plaque reduction neutralisation assay [PRNT50]; a microneutralisation assay [MNA50, MNA80, and MNA90]; and Marburg VN), and a pseudovirus neutralisation assay. Cellular responses were assessed using an ex-vivo interferon-γ enzyme-linked immunospot assay. The co-primary outcomes are to assess efficacy, as measured by cases of symptomatic virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were done by group allocation in participants who received the vaccine. Safety was assessed over 28 days after vaccination. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. The study is ongoing, and was registered at ISRCTN, 15281137, and ClinicalTrials.gov, NCT04324606. FINDINGS: Between April 23 and May 21, 2020, 1077 participants were enrolled and assigned to receive either ChAdOx1 nCoV-19 (n=543) or MenACWY (n=534), ten of whom were enrolled in the non-randomised ChAdOx1 nCoV-19 prime-boost group. Local and systemic reactions were more common in the ChAdOx1 nCoV-19 group and many were reduced by use of prophylactic paracetamol, including pain, feeling feverish, chills, muscle ache, headache, and malaise (all p<0·05). There were no serious adverse events related to ChAdOx1 nCoV-19. In the ChAdOx1 nCoV-19 group, spike-specific T-cell responses peaked on day 14 (median 856 spot-forming cells per million peripheral blood mononuclear cells, IQR 493-1802; n=43). Anti-spike IgG responses rose by day 28 (median 157 ELISA units [EU], 96-317; n=127), and were boosted following a second dose (639 EU, 360-792; n=10). Neutralising antibody responses against SARS-CoV-2 were detected in 32 (91%) of 35 participants after a single dose when measured in MNA80 and in 35 (100%) participants when measured in PRNT50. After a booster dose, all participants had neutralising activity (nine of nine in MNA80 at day 42 and ten of ten in Marburg VN on day 56). Neutralising antibody responses correlated strongly with antibody levels measured by ELISA (R2=0·67 by Marburg VN; p<0·001). INTERPRETATION: ChAdOx1 nCoV-19 showed an acceptable safety profile, and homologous boosting increased antibody responses. These results, together with the induction of both humoral and cellular immune responses, support large-scale evaluation of this candidate vaccine in an ongoing phase 3 programme. FUNDING: UK Research and Innovation, Coalition for Epidemic Preparedness Innovations, National Institute for Health Research (NIHR), NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and the German Center for Infection Research (DZIF), Partner site Gießen-Marburg-Langen.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/prevention & control , Immunogenicity, Vaccine , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/adverse effects , Viral Vaccines/immunology , Acetaminophen/therapeutic use , Adenoviruses, Simian/genetics , Adult , Analgesics, Non-Narcotic/therapeutic use , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 , COVID-19 Vaccines , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Female , Genetic Vectors/administration & dosage , Humans , Immunization, Secondary , Immunoglobulin G/blood , Male , Pneumonia, Viral/drug therapy , SARS-CoV-2 , Single-Blind Method , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/immunology , United Kingdom , Viral Vaccines/administration & dosage
15.
BMC Health Serv Res ; 21(1): 943, 2021 Sep 09.
Article in English | MEDLINE | ID: mdl-34503503

ABSTRACT

BACKGROUND: The Gambia has one of the lowest survival rates for breast cancer in Africa. Contributing factors are late presentation, delays within the healthcare system, and decreased availability of resources. We aimed to characterize the capacity and geographic location of healthcare facilities in the country and calculate the proportion of the population with access to breast cancer care. METHODS: A facility-based assessment tool was administered to secondary and tertiary healthcare facilities and private medical centers and clinics in The Gambia. GPS coordinates were obtained, and proximity of service availability and population analysis were performed. Distance thresholds of 10, 20, and 45 km were chosen to determine access to screening, pathologic diagnosis, and surgical management. An additional population analysis was performed to observe the potential impact of targeted development of resources for breast cancer care. RESULTS: All 102 secondary and tertiary healthcare facilities and private medical centers and clinics in The Gambia were included. Breast cancer screening is mainly performed through clinical breast examination and is available in 52 facilities. Seven facilities provide pathologic diagnosis and surgical management of breast cancer. The proportion of the Gambian population with access to screening, pathologic diagnosis, and surgical management is 72, 53, and 62%, respectively. A hypothetical targeted expansion of resources would increase the covered population to 95, 62, and 84%. CONCLUSIONS: Almost half of the Gambian population does not have access to pathologic diagnosis and surgical management of breast cancer within the distance threshold utilized in the study. Mapping and population analysis can identify areas for targeted development of resources to increase access to breast cancer care.


Subject(s)
Breast Neoplasms , Breast Neoplasms/diagnosis , Breast Neoplasms/epidemiology , Breast Neoplasms/therapy , Cross-Sectional Studies , Early Detection of Cancer , Female , Gambia/epidemiology , Health Services Accessibility , Humans , Mass Screening
16.
BMC Infect Dis ; 19(1): 259, 2019 Mar 15.
Article in English | MEDLINE | ID: mdl-30876397

ABSTRACT

BACKGROUND: Infection with Hepatitis B virus (HBV) is a serious public health problem worldwide, with over 360 million carriers. Sixty million of these are resident in Sub-saharan Africa. Hepatitis B infection is the cause of Hepatocellular carcinoma (HCC), which is the second commonest cause of death from cancers among women in The Gambia. Vertical transmission is the commonest route of spread of Hepatitis B Virus in many endemic areas. The main aim of the study was to determine the sero-prevalence of Hepatitis B surface antigen (HBsAg) among pregnant women attending antenatal clinic at the Edward Francis Small Teaching Hospital, Banjul, The Gambia. METHODS: Four hundred and twenty six pregnant women were recruited from our antenatal clinics and tested for HBsAg. Serum Hepatitis B surface antigen (HBsAg) was tested using commercial rapid diagnostic Elisa kits at the point of care. RESULTS: A prevalence rate of 9.20% among all pregnant women studied was found. Women who were likely to have been vaccinated had a prevalence rate of 2.30% whiles those unlikely to have been vaccinated had a prevalence of 13.71%. There was a statistically significant difference between those likely to have been vaccinated and those unlikely to have been vaccinated. CONCLUSION: The prevalence of hepatitis B infection is very high among pregnant women at EFSTH as in the high endemic zone that is more than 8%. However the prevalence rate is lower than the national average of 15%. The prevalence is of moderate endemicity among the women who likely received vaccination during childhood. More interventions during pregnancy need to be undertaken if more successes are to be registered.


Subject(s)
Hepatitis B virus/isolation & purification , Hepatitis B/epidemiology , Pregnancy Complications, Infectious/epidemiology , Adolescent , Adult , Female , Gambia/epidemiology , Hepatitis B/blood , Hepatitis B Surface Antigens/blood , Hepatitis B virus/immunology , Humans , Pregnancy , Pregnancy Complications, Infectious/blood , Prenatal Care/statistics & numerical data , Seroepidemiologic Studies , Young Adult
17.
Expert Rev Proteomics ; 12(6): 607-21, 2015.
Article in English | MEDLINE | ID: mdl-26524107

ABSTRACT

Streptococcus pneumoniae is a major pathogen that is responsible for a variety of invasive diseases. The bacteria gain entry initially by establishing a carriage state in the nasopharynx from where they migrate to other sites in the body. The worldwide distribution of the bacteria and the severity of the diseases have led to a significant level of interest in the development of vaccines against the bacteria. Current vaccines, based on the bacterial polysaccharide, have a number of limitations including poor immunogenicity and limited effectiveness against all pneumococcal serotypes. There are many challenges in developing vaccines that will be effective against the diverse range of isolates and serotypes for this highly variable bacterial pathogen. This review considers how proteomic technologies have extended our understanding of the pathogenic mechanisms of nasopharyngeal colonization and disease development as well as the critical areas in developing protein-based vaccines.


Subject(s)
Proteome/immunology , Streptococcal Vaccines/immunology , Streptococcus pneumoniae/immunology , Bacterial Proteins/chemistry , Bacterial Proteins/immunology , Cell Wall/chemistry , Cell Wall/immunology , Proteome/chemistry , Streptococcal Vaccines/chemistry , Streptococcus pneumoniae/chemistry , Streptococcus pneumoniae/pathogenicity
18.
PLoS One ; 19(5): e0301700, 2024.
Article in English | MEDLINE | ID: mdl-38743724

ABSTRACT

INTRODUCTION: In the Global South, (in)fertility care is scarcely recognized as a priority, yet the government of The Gambia has recently included it as one of the key priorities in its reproductive health strategic plan. This inclusion appears to be the result of years of engagement between policy actors, academic researchers, and activists in the field of reproductive health and specifically of infertility. However, the operationalization of the strategic plan may be hampered by multiple factors. The research aims to identify and analyze challenges that may impede the effective implementation of the strategic plan, thereby providing policy action points and practical guidance into the operationalization of (in)fertility care in the context of The Gambia's health system. METHODS: This is a mixed-methods study with data from a survey and semi-structured interviews collected between 2020 and 2021 in The Gambia that were separately published. In this paper, we present the triangulation of quantitative and qualitative data using a convergence coding matrix to identify relevant policy action points. RESULTS: Six fertility care policy action points, driven by data, arose from the triangulation and interpretation process, specifically: (i) establishing and maintaining political commitment and national priority for fertility care; (ii) creating awareness and increasing the involvement of men in SRH and fertility; (iii) ensuring data-driven health policymaking; (iv) offering and regulating affordable IVF alternatives; (v) improving knowledge of and means for fertility care provision; and (vi) enhancing the collaboration among stakeholders and building links with the private healthcare sector. CONCLUSION: This study found the implementation of the fertility care-related activities in the reproductive health strategic plan may face challenges that require careful mitigation through a holistic approach. Such an approach conceptualizes infertility not just as a biomedical issue but as a broader one that incorporates educational and socio-emotional aspects, including male and (not only) female involvement in sexual and reproductive health. Moreover, it is supported by a comprehensive health management information system that includes capturing data on the demand for, and access to, infertility services in The Gambia health system.


Subject(s)
Health Policy , Humans , Gambia , Female , Male , Fertility , Reproductive Health , Infertility/therapy , Adult , Reproductive Health Services/organization & administration
19.
EClinicalMedicine ; 64: 102226, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37767194

ABSTRACT

Background: Hypertension is a major public health problem in sub-Saharan Africa with poor treatment coverage and high case-fatality rates. This requires assessment of healthcare performance to identify areas where intervention is most needed. To identify areas where health resources should be most efficiently targeted, we assessed the hypertension care cascade i.e., loss and retention across the various stages of care, in Gambian adults aged 35 years and above. Methods: This study was embedded within the nationally representative 2019 Gambia National Eye Health Survey of adults ≥35 years. We constructed a hypertension care cascade with four categories: prevalence of hypertension (defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, and/or current use of medication prescribed for hypertension); those aware of their diagnosis; those treated; and those with a controlled blood pressure (defined as blood pressure <140/90 mmHg). Analyses were age- and sex-standardised to the population structure of The Gambia. Logistic regression was used to assess the socio-demographic factors associated with prevalence, awareness, treatment and control of hypertension. Findings: Of 9171 participants with data for blood pressure, the prevalence of hypertension was 47.0%. Among people with hypertension, the prevalence of awareness was 54.7%, the prevalence of hypertension treatment was 32.5%, and prevalence of control was 10.0% with little difference between urban and rural residence. The cascade of care performance was better in women. However, there was no difference in achieving blood pressure control between men and women who were receiving treatment. Female sex, older age and higher body mass index were associated with higher hypertension awareness whilst having an occupation compared to being unemployed was associated with higher odds of being treated. Patients in the underweight category had higher odds of achieving blood pressure control. Interpretation: There is a high prevalence of hypertension and low performance of the health care system that impact on the hypertension care cascade among middle-aged and older adults in The Gambia. Addressing the full cascade will be paramount especially in reducing the mounting prevalence and improving diagnosis of patients with hypertension, where the greatest dividends will be gained. Funding: The Queen Elizabeth Diamond Jubilee Trust, Wellcome Trust.

20.
Lancet Glob Health ; 11(3): e414-e424, 2023 03.
Article in English | MEDLINE | ID: mdl-36796985

ABSTRACT

BACKGROUND: COVID-19, caused by SARS-CoV-2, is one of the deadliest pandemics of the past 100 years. Genomic sequencing has an important role in monitoring of the evolution of the virus, including the detection of new viral variants. We aimed to describe the genomic epidemiology of SARS-CoV-2 infections in The Gambia. METHODS: Nasopharyngeal or oropharyngeal swabs collected from people with suspected cases of COVID-19 and international travellers were tested for SARS-CoV-2 with standard RT-PCR methods. SARS-CoV-2-positive samples were sequenced according to standard library preparation and sequencing protocols. Bioinformatic analysis was done using ARTIC pipelines and Pangolin was used to assign lineages. To construct phylogenetic trees, sequences were first stratified into different COVID-19 waves (waves 1-4) and aligned. Clustering analysis was done and phylogenetic trees constructed. FINDINGS: Between March, 2020, and January, 2022, 11 911 confirmed cases of COVID-19 were recorded in The Gambia, and 1638 SARS-CoV-2 genomes were sequenced. Cases were broadly distributed into four waves, with more cases during the waves that coincided with the rainy season (July-October). Each wave occurred after the introduction of new viral variants or lineages, or both, generally those already established in Europe or in other African countries. Local transmission was higher during the first and third waves (ie, those that corresponded with the rainy season), in which the B.1.416 lineage and delta (AY.34.1) were dominant, respectively. The second wave was driven by the alpha and eta variants and the B.1.1.420 lineage. The fourth wave was driven by the omicron variant and was predominantly associated with the BA.1.1 lineage. INTERPRETATION: More cases of SARS-CoV-2 infection were recorded in The Gambia during peaks of the pandemic that coincided with the rainy season, in line with transmission patterns for other respiratory viruses. The introduction of new lineages or variants preceded epidemic waves, highlighting the importance of implementing well structured genomic surveillance at a national level to detect and monitor emerging and circulating variants. FUNDING: Medical Research Unit The Gambia at London School of Hygiene & Tropical Medicine, UK Research and Innovation, WHO.


Subject(s)
COVID-19 , Humans , Gambia/epidemiology , COVID-19/epidemiology , Phylogeny , SARS-CoV-2/genetics , Genomics
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