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1.
Am J Epidemiol ; 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39191642

RESUMEN

Models of measles transmission can be used to identify areas of high risk to tailor immunization strategies. Estimates of spatial connectivity can be derived from data such as mobile phone records, however it is not clear how this maps to the movement of children who are more likely to be infected. Using travel surveys across two districts in Zambia and national mobile phone data, we compared estimates of out-of-district travel for the population captured in the mobile phone data and child-specific travel from travel surveys. We then evaluated the impact of unadjusted and adjusted connectivity measures on simulated measles virus introduction events across Zambia. The number of trips made by children from the travel survey was three to five times lower than the general population estimates from mobile phone data. This decreased the percentage of districts with measles virus introduction events from 78% when using unadjusted data to 51% - 64% following adjustment. Failure to account for age-specific heterogeneities in travel estimated from mobile phone data resulted in overestimating subnational areas at high risk of introduction events, which could divert mitigation efforts to districts that are at lower risk.

2.
Lancet ; 399(10332): 1336-1346, 2022 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-35367004

RESUMEN

Rubella is an acute illness caused by rubella virus and characterised by fever and rash. Although rubella is a clinically mild illness, primary rubella virus infection in early pregnancy can result in congenital rubella syndrome, which has serious medical and public health consequences. WHO estimates that approximately 100 000 congenital rubella syndrome cases occur per year. Rubella virus is transmitted through respiratory droplets and direct contact. 25-50% of people infected with rubella virus are asymptomatic. Clinical disease often results in mild, self-limited illness characterised by fever, a generalised erythematous maculopapular rash, and lymphadenopathy. Complications include arthralgia, arthritis, thrombocytopenic purpura, and encephalitis. Common presenting signs and symptoms of congenital rubella syndrome include cataracts, sensorineural hearing impairment, congenital heart disease, jaundice, purpura, hepatosplenomegaly, and microcephaly. Rubella and congenital rubella syndrome can be prevented by rubella-containing vaccines, which are commonly administered in combination with measles vaccine. Although global rubella vaccine coverage reached only 70% in 2020 global rubella eradiation remains an ambitious but achievable goal.


Asunto(s)
Síndrome de Rubéola Congénita , Rubéola (Sarampión Alemán) , Femenino , Humanos , Vacuna Antisarampión , Embarazo , Rubéola (Sarampión Alemán)/diagnóstico , Rubéola (Sarampión Alemán)/epidemiología , Rubéola (Sarampión Alemán)/prevención & control , Síndrome de Rubéola Congénita/diagnóstico , Síndrome de Rubéola Congénita/epidemiología , Síndrome de Rubéola Congénita/prevención & control , Vacuna contra la Rubéola , Virus de la Rubéola
3.
Lancet ; 397(10272): 398-408, 2021 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-33516338

RESUMEN

BACKGROUND: The past two decades have seen expansion of childhood vaccination programmes in low-income and middle-income countries (LMICs). We quantify the health impact of these programmes by estimating the deaths and disability-adjusted life-years (DALYs) averted by vaccination against ten pathogens in 98 LMICs between 2000 and 2030. METHODS: 16 independent research groups provided model-based disease burden estimates under a range of vaccination coverage scenarios for ten pathogens: hepatitis B virus, Haemophilus influenzae type B, human papillomavirus, Japanese encephalitis, measles, Neisseria meningitidis serogroup A, Streptococcus pneumoniae, rotavirus, rubella, and yellow fever. Using standardised demographic data and vaccine coverage, the impact of vaccination programmes was determined by comparing model estimates from a no-vaccination counterfactual scenario with those from a reported and projected vaccination scenario. We present deaths and DALYs averted between 2000 and 2030 by calendar year and by annual birth cohort. FINDINGS: We estimate that vaccination of the ten selected pathogens will have averted 69 million (95% credible interval 52-88) deaths between 2000 and 2030, of which 37 million (30-48) were averted between 2000 and 2019. From 2000 to 2019, this represents a 45% (36-58) reduction in deaths compared with the counterfactual scenario of no vaccination. Most of this impact is concentrated in a reduction in mortality among children younger than 5 years (57% reduction [52-66]), most notably from measles. Over the lifetime of birth cohorts born between 2000 and 2030, we predict that 120 million (93-150) deaths will be averted by vaccination, of which 58 million (39-76) are due to measles vaccination and 38 million (25-52) are due to hepatitis B vaccination. We estimate that increases in vaccine coverage and introductions of additional vaccines will result in a 72% (59-81) reduction in lifetime mortality in the 2019 birth cohort. INTERPRETATION: Increases in vaccine coverage and the introduction of new vaccines into LMICs have had a major impact in reducing mortality. These public health gains are predicted to increase in coming decades if progress in increasing coverage is sustained. FUNDING: Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation.


Asunto(s)
Control de Enfermedades Transmisibles , Enfermedades Transmisibles/mortalidad , Enfermedades Transmisibles/virología , Modelos Teóricos , Mortalidad/tendencias , Años de Vida Ajustados por Calidad de Vida , Vacunación , Preescolar , Control de Enfermedades Transmisibles/economía , Control de Enfermedades Transmisibles/estadística & datos numéricos , Enfermedades Transmisibles/economía , Análisis Costo-Beneficio , Países en Desarrollo , Femenino , Salud Global , Humanos , Programas de Inmunización , Masculino , Vacunación/economía , Vacunación/estadística & datos numéricos
4.
Pediatr Phys Ther ; 34(2): 221-228, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35184074

RESUMEN

PURPOSE: This needs assessment survey identifies the priorities of the clinical and research communities involved with the use of instrumented gait analysis (IGA) for a clinical practice guideline on IGA use with children with cerebral palsy (CP). METHODS: Thirteen Likert scale questions asked about the importance of topics related to IGA. Other questions addressed respondents' demographics, experience with IGA, patient populations, and gait laboratory characteristics. Several open-ended questions were included and analyzed. RESULTS: The survey was completed by 43 physical therapists and 53 non-physical therapists involved with IGA. More than 90% rated the following as critically or highly important: reliability and validity of IGA to identify gait pathology (94%); ability to longitudinally track gait pathology (93%); use in planning interventions (93%); use in evaluating outcomes (93%); and definition of IGA (90%). CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE: This needs assessment survey identified the topic priorities of clinicians and practitioners who use IGA for the management of children with CP. These results will guide the development of a clinical practice guideline on the use of IGA for the management of CP.


Asunto(s)
Parálisis Cerebral , Parálisis Cerebral/rehabilitación , Niño , Marcha , Análisis de la Marcha , Humanos , Inmunoglobulina A , Evaluación de Necesidades , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
5.
J Infect Dis ; 218(3): 355-364, 2018 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-29562334

RESUMEN

Background: Control efforts for measles and rubella are intensifying globally. It becomes increasingly important to identify and reach remaining susceptible populations as elimination is approached. Methods: Serological surveys for measles and rubella can potentially measure susceptibility directly, but their use remains rare. In this study, using simulations, we outline key subtleties in interpretation associated with the dynamic context of age-specific immunity, highlighting how the patterns of immunity predicted from disease surveillance and vaccination coverage data may be misleading. Results: High-quality representative serosurveys could provide a more accurate assessment of immunity if challenges of conducting, analyzing, and interpreting them are overcome. We frame the core disease control and elimination questions that could be addressed by improved serological tools, discussing challenges and suggesting approaches to increase the feasibility and sustainability of the tool. Conclusions: Accounting for the dynamical context, serosurveys could play a key role in efforts to achieve and sustain elimination.


Asunto(s)
Anticuerpos Antivirales/sangre , Erradicación de la Enfermedad/métodos , Transmisión de Enfermedad Infecciosa/prevención & control , Virus del Sarampión/inmunología , Sarampión/epidemiología , Virus de la Rubéola/inmunología , Rubéola (Sarampión Alemán)/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Simulación por Computador , Monitoreo Epidemiológico , Femenino , Humanos , Lactante , Control de Infecciones/métodos , Masculino , Sarampión/prevención & control , Persona de Mediana Edad , Modelos Estadísticos , Rubéola (Sarampión Alemán)/prevención & control , Estudios Seroepidemiológicos , Adulto Joven
6.
Am J Epidemiol ; 187(10): 2219-2226, 2018 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-29878051

RESUMEN

Madagascar reports few measles cases annually and high vaccination campaign coverage. However, the underlying age profile of immunity and risk of a measles outbreak is unknown. We conducted a nested serological survey, testing 1,005 serum samples (collected between November 2013 and December 2015 via Madagascar's febrile rash surveillance system) for measles immunoglobulin G antibody titers. We directly estimated the age profile of immunity and compared these estimates with indirect estimates based on a birth cohort model of vaccination coverage and natural infection. Combining these estimates of the age profile of immunity in the population with an age-structured model of transmission, we further predicted the risk of a measles outbreak and the impact of mitigation strategies designed around supplementary immunization activities. The direct and indirect estimates of age-specific seroprevalence show that current measles susceptibility is over 10%, and modeling suggests that Madagascar may be at risk of a major measles epidemic.


Asunto(s)
Inmunoglobulina G/inmunología , Sarampión/epidemiología , Rubéola (Sarampión Alemán)/epidemiología , Adolescente , Adulto , Distribución por Edad , Anticuerpos Antivirales , Niño , Preescolar , Brotes de Enfermedades , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Lactante , Madagascar/epidemiología , Masculino , Vacuna Antisarampión , Persona de Mediana Edad , Modelos Estadísticos , Estudios Seroepidemiológicos , Adulto Joven
7.
Epidemiol Infect ; 146(12): 1575-1583, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29860954

RESUMEN

Although measles incidence has reached historic lows in many parts of the world, the disease still causes substantial morbidity globally. Even where control programs have succeeded in driving measles locally extinct, unless vaccination coverage is maintained at extremely high levels, susceptible numbers may increase sufficiently to spark large outbreaks. Human mobility will drive potentially infectious contacts and interact with the landscape of susceptibility to determine the pattern of measles outbreaks. These interactions have proved difficult to characterise empirically. We explore the degree to which new sources of data combined with existing public health data can be used to evaluate the landscape of immunity and the role of spatial movement for measles introductions by retrospectively evaluating our ability to predict measles outbreaks in vaccinated populations. Using inferred spatial patterns of accumulation of susceptible individuals and travel data, we predicted the timing of epidemics in each district of Pakistan during a large measles outbreak in 2012-2013 with over 30 000 reported cases. We combined these data with mobility data extracted from over 40 million mobile phone subscribers during the same time frame in the country to quantify the role of connectivity in the spread of measles. We investigate how different approaches could contribute to targeting vaccination efforts to reach districts before outbreaks started. While some prediction was possible, accuracy was low and we discuss key uncertainties linked to existing data streams that impede such inference and detail what data might be necessary to robustly infer timing of epidemics.


Asunto(s)
Brotes de Enfermedades/prevención & control , Vacuna Antisarampión/administración & dosificación , Sarampión/epidemiología , Sarampión/prevención & control , Cobertura de Vacunación/estadística & datos numéricos , Susceptibilidad a Enfermedades , Femenino , Humanos , Programas de Inmunización , Incidencia , Lactante , Masculino , Modelos Estadísticos , Pakistán/epidemiología , Riesgo
8.
J Immunol ; 189(5): 2673-81, 2012 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-22855707

RESUMEN

The maintenance of adequate serum Ab levels following immunization has been identified as the most important mechanism for individual long-term protection against rapidly invading encapsulated bacteria. The mechanisms for maintaining adequate serum Ab levels and the relationship between Ag-specific memory B cells and Ab at steady state are poorly understood. We measured the frequency of circulating serogroup C meningococcal (MenC)-specific memory B cells in 250 healthy 6- to 12-y-old children 6 y following MenC conjugate vaccine priming, before a booster of a combined Haemophilus influenzae type b-MenC conjugate vaccine and then 1 wk, 1 mo, and 1 y after the booster. We investigated the relationship between circulating MenC-specific memory B cell frequencies and Ab at baseline and following the booster vaccine. We found very low frequencies of circulating MenC-specific memory B cells at steady state in primary school-aged children and little association with MenC IgG Ab levels. Following vaccination, there were robust memory B cell booster responses that, unlike Ab levels, were not dependent on age at priming with MenC. Measurement of B cell memory in peripheral blood does not predict steady state Ab levels nor the capacity to respond to a booster dose of MenC Ag.


Asunto(s)
Anticuerpos Antibacterianos/sangre , Subgrupos de Linfocitos B/inmunología , Inmunización Secundaria/métodos , Inmunoglobulina G/sangre , Memoria Inmunológica , Vacunas Meningococicas/administración & dosificación , Neisseria meningitidis Serogrupo C/inmunología , Factores de Edad , Anticuerpos Antibacterianos/biosíntesis , Subgrupos de Linfocitos B/microbiología , Niño , Ensayos Clínicos Fase IV como Asunto/métodos , Vacunas contra Haemophilus/administración & dosificación , Vacunas contra Haemophilus/inmunología , Humanos , Inmunoglobulina G/biosíntesis , Vacunas Meningococicas/inmunología , Vacunas Combinadas/administración & dosificación , Vacunas Combinadas/inmunología , Vacunas Conjugadas/administración & dosificación , Vacunas Conjugadas/inmunología
9.
Vaccines (Basel) ; 12(7)2024 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-39066451

RESUMEN

Measles elimination refers to the interruption of measles virus transmission in a defined geographic area (e.g., country or region) for 12 months or more, and measles eradication refers to the global interruption of measles virus transmission. Measles eradication was first discussed and debated in the late 1960's shortly after the licensure of measles vaccines. Most experts agree that measles meets criteria for disease eradication, but progress toward national and regional measles elimination has slowed. Several paths to measles eradication can be described, including an incremental path through country-wide and regional measles elimination and phased paths through endgame scenarios and strategies. Infectious disease dynamic modeling can help inform measles elimination and eradication strategies, and all paths would be greatly facilitated by innovative technologies such as microarray patches to improve vaccine access and demand, point-of-contact diagnostic tests to facilitate outbreak responses, and point-of-contact IgG tests to identify susceptible populations. A pragmatic approach to measles eradication would identify and realize the necessary preconditions and clearly articulate various endgame scenarios and strategies to achieve measles eradication with an intensified and coordinated global effort in a specified timeframe, i.e., to "go big and go fast". To encourage and promote deliberation among a broad array of stakeholders, we provide a brief historical background and key considerations for setting a measles eradication goal.

10.
Am J Trop Med Hyg ; 111(1): 121-128, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38772386

RESUMEN

Countries with moderate to high measles-containing vaccine coverage face challenges in reaching the remaining measles zero-dose children. There is growing interest in targeted vaccination activities to reach these children. We developed a framework for prioritizing districts for targeted measles and rubella supplementary immunization activities (SIAs) for Zambia in 2020, incorporating the use of the WHO's Measles Risk Assessment Tool (MRAT) and serosurveys. This framework was used to build a model comparing the cost of vaccinating one zero-dose child under three vaccination scenarios: standard nationwide SIA, targeted subnational SIA informed by MRAT, and targeted subnational SIA informed by both MRAT and measles seroprevalence data. In the last scenario, measles seroprevalence data are acquired via either a community-based serosurvey, residual blood samples from health facilities, or community-based IgG point-of-contact rapid diagnostic testing. The deterministic model found that the standard nationwide SIA is the least cost-efficient strategy at 13.75 USD per zero-dose child vaccinated. Targeted SIA informed by MRAT was the most cost-efficient at 7.63 USD per zero-dose child, assuming that routine immunization is just as effective as subnational SIA in reaching zero-dose children. Under similar conditions, a targeted subnational SIA informed by both MRAT and seroprevalence data resulted in 8.17-8.35 USD per zero-dose child vaccinated, suggesting that use of seroprevalence to inform SIA planning may not be as cost prohibitive as previously thought. Further refinement to the decision framework incorporating additional data may yield strategies to better target the zero-dose population in a financially feasible manner.


Asunto(s)
Vacuna Antisarampión , Sarampión , Humanos , Zambia/epidemiología , Sarampión/prevención & control , Sarampión/epidemiología , Sarampión/economía , Vacuna Antisarampión/economía , Vacuna Antisarampión/administración & dosificación , Vacuna Antisarampión/inmunología , Vacunación/economía , Vacunación/métodos , Estudios Seroepidemiológicos , Análisis Costo-Beneficio , Preescolar , Programas de Inmunización/economía , Lactante , Niño , Rubéola (Sarampión Alemán)/prevención & control , Rubéola (Sarampión Alemán)/epidemiología , Rubéola (Sarampión Alemán)/economía
11.
PLOS Glob Public Health ; 4(6): e0002985, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38941295

RESUMEN

Nested serosurveys within routine service delivery platforms such as planned supplemental immunization activities (SIAs) provide an opportunity to collect information that can be used to answer valuable questions on the effectiveness and efficiency of the delivery model to inform future activities. However, integrating research data collection in SIAs is rarely done due to concerns it will negatively impact the program. We conducted a serosurvey nested within the November 2020 measles-rubella SIA integrated with the Child Health Week activities in Zambia to evaluate this approach. In-depth interviews with the study teams and vaccination campaign staff at the vaccination sites were conducted. Recorded interviews were transcribed, transcripts were coded and then grouped into themes based on a process evaluation framework. A multi-methods analytical approach was used to assess the feasibility and acceptability of collecting dried blood spots from children during the SIA. This included a quantitative assessment of participant enrollment. The serosurvey successfully enrolled 90% of children from Child Health Week due to close coordination and teamwork between the vaccination teams and serosurvey team, in addition to substantial social mobilization efforts. Continually adjusting the sampling interval that was used to select eligible children allowed us to enroll throughout the SIA and capture a representative sample of children in attendance although it was challenging for the staff involved. As vaccination programs aim to tailor their approaches to reach the hardest-to-reach children, embedding research questions in SIAs will allow evaluation of the successes and challenges and compare alternative approaches. Lessons learned from this experience collecting data during an SIA can be applicable to future research activities embedded in SIAs or other delivery platforms.

12.
Vaccine ; 42(26): 126307, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39276622

RESUMEN

The World Health Organization's Immunization and Vaccines-related Implementation Research Advisory Committee (IVIR-AC) serves to independently review and evaluate vaccine-related research to maximize the potential impact of vaccination programs. From 28 June - 1 July 2024, IVIR-AC was convened for an ad hoc meeting to discuss new evidence on criteria for rubella vaccine introduction and the risk of congenital rubella syndrome. This report summarizes background information on rubella virus transmission and the burden of congenital rubella syndrome, meeting structure and presentations, proceedings, and recommendations.

13.
PLOS Glob Public Health ; 4(4): e0003072, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38683820

RESUMEN

Community-based serological studies are increasingly relied upon to measure disease burden, identify population immunity gaps, and guide control and elimination strategies; however, there is little understanding of the potential for and impact of sampling biases on outcomes of interest. As part of efforts to quantify measles immunity gaps in Zambia, a community-based serological survey using stratified multi-stage cluster sampling approach was conducted in Ndola and Choma districts in May-June 2022, enrolling 1245 individuals. We carried out a follow-up study among individuals missed from the sampling frame of the serosurvey in July-August 2022, enrolling 672 individuals. We assessed the potential for and impact of biases in the community-based serosurvey by i) estimating differences in characteristics of households and individuals included and excluded (77% vs 23% of households) from the sampling frame of the serosurvey and ii) evaluating the magnitude these differences make on healthcare-seeking behavior, vaccination coverage, and measles seroprevalence. We found that missed households were 20% smaller and 25% less likely to have children. Missed individuals resided in less wealthy households, had different distributions of sex and occupation, and were more likely to seek care at health facilities. Despite these differences, simulating a survey in which missed households were included in the sampling frame resulted in less than a 5% estimated bias in these outcomes. Although community-based studies are upheld as the gold standard study design in assessing immunity gaps and underlying community health characteristics, these findings underscore the fact that sampling biases can impact the results of even well-conducted community-based surveys. Results from these studies should be interpreted in the context of the study methodology and challenges faced during implementation, which include shortcomings in establishing accurate and up-to-date sampling frames. Failure to account for these shortcomings may result in biased estimates and detrimental effects on decision-making.

14.
PLoS One ; 19(3): e0297385, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38551928

RESUMEN

BACKGROUND: In alignment with the Measles and Rubella (MR) Strategic Elimination plan, India conducted a mass measles and rubella vaccination campaign across the country between 2017 and 2020 to provide a dose of MR containing vaccine to all children aged 9 months to 15 years. We estimated campaign vaccination coverage in five districts in India and assessed campaign awareness and factors associated with vaccination during the campaign to better understand reasons for not receiving the dose. METHODS AND FINDINGS: Community-based cross-sectional serosurveys were conducted in five districts of India among children aged 9 months to 15 years after the vaccination campaign. Campaign coverage was estimated based on home-based immunization record or caregiver recall. Campaign coverage was stratified by child- and household-level risk factors and descriptive analyses were performed to assess reasons for not receiving the campaign dose. Three thousand three hundred and fifty-seven children aged 9 months to 15 years at the time of the campaign were enrolled. Campaign coverage among children aged 9 months to 5 years documented or by recall ranged from 74.2% in Kanpur Nagar District to 90.4% in Dibrugarh District, Assam. Similar coverage was observed for older children. Caregiver awareness of the campaign varied from 88.3% in Hoshiarpur District, Punjab to 97.6% in Dibrugarh District, Assam, although 8% of children whose caregivers were aware of the campaign were not vaccinated during the campaign. Failure to receive the campaign dose was associated with urban settings, low maternal education, and lack of school attendance although the associations varied by district. CONCLUSION: Awareness of the MR vaccination campaign was high; however, campaign coverage varied by district and did not reach the elimination target of 95% coverage in any of the districts studied. Areas with lower coverage among younger children must be prioritized by strengthening the routine immunization programme and implementing strategies to identify and reach under-vaccinated children.


Asunto(s)
Sarampión , Rubéola (Sarampión Alemán) , Humanos , Lactante , Niño , Adolescente , Estudios Transversales , Sarampión/prevención & control , Rubéola (Sarampión Alemán)/prevención & control , Vacuna Antisarampión/uso terapéutico , Vacunación , Vacuna contra la Rubéola/uso terapéutico , India/epidemiología , Programas de Inmunización
15.
Am J Trop Med Hyg ; 2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39226906

RESUMEN

Multiplex-based serological surveillance is a valuable but underutilized tool to understand gaps in population-level exposure, susceptibility, and immunity to infectious diseases. Assays for which blood samples can be tested for antibodies against several pathogens simultaneously, such as multiplex bead immunoassays, can more efficiently integrate public health surveillance in low- and middle-income countries. On March 7-8, 2023 a group of experts representing research institutions, multilateral organizations, private industry, and country partners met to discuss experiences, identify challenges and solutions, and create a community of practice for integrated, multi-pathogen serosurveillance using multiplex bead assay technologies. Participants were divided into six working groups: 1) supply chain; 2) laboratory assays; 3) seroepidemiology; 4) data analytics; 5) sustainable implementation; and 6) use case scenarios. These working groups discussed experiences, challenges, solutions, and research needs to facilitate integrated, multi-pathogen serosurveillance for public health. Several solutions were proposed to address challenges that cut across working groups.

16.
Lancet Glob Health ; 12(4): e563-e571, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38485425

RESUMEN

BACKGROUND: There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered. METHODS: For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up. FINDINGS: We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]). INTERPRETATION: Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption. FUNDING: The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation. TRANSLATIONS: For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.


Asunto(s)
COVID-19 , Hepatitis B , Sarampión , Meningitis , Infecciones por Papillomavirus , Vacunas contra Papillomavirus , Rubéola (Sarampión Alemán) , Enfermedades Prevenibles por Vacunación , Fiebre Amarilla , Humanos , Infecciones por Papillomavirus/prevención & control , Pandemias , COVID-19/epidemiología , COVID-19/prevención & control , Vacunación , Inmunización , Hepatitis B/tratamiento farmacológico
17.
Vaccine ; 42(24): 126077, 2024 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-38960788

RESUMEN

BACKGROUND: India aims to eliminate rubella and congenital rubella syndrome (CRS) by 2023. We conducted serosurveys among pregnant women to monitor the trend of rubella immunity and estimate the CRS burden in India following a nationwide measles and rubella vaccination campaign. METHODS: We surveyed pregnant women at 13 sentinel sites across India from Aug to Oct 2022 to estimate seroprevalence of rubella IgG antibodies. Using age-specific seroprevalence data from serosurveys conducted during 2017/2019 (prior to and during the vaccination campaign) and 2022 surveys (after the vaccination campaign), we developed force of infection (FOI) models and estimated incidence and burden of CRS. RESULTS: In 2022, rubella seroprevalence was 85.2% (95% CI: 84.0, 86.2). Among 10 sites which participated in both rounds of serosurveys, the seroprevalence was not different between the two periods (pooled prevalence during 2017/2019: 83.5%, 95% CI: 82.1, 84.8; prevalence during 2022: 85.1%, 95% CI: 83.8, 86.3). The estimated annual incidence of CRS during 2017/2019 in India was 218.3 (95% CI: 209.7, 226.5) per 100, 000 livebirths, resulting in 47,120 (95% CI: 45,260, 48,875) cases of CRS every year. After measles-rubella (MR) vaccination campaign, the estimated incidence of CRS declined to 5.3 (95% CI: 0, 21.2) per 100,000 livebirths, resulting in 1141 (95% CI: 0, 4,569) cases of CRS during the post MR-vaccination campaign period. CONCLUSION: The incidence of CRS in India has substantially decreased following the nationwide MR vaccination campaign. About 15% of women in childbearing age in India lack immunity to rubella and hence susceptible to rubella infection. Since there are no routine rubella vaccination opportunities for this age group under the national immunization program, it is imperative to maintain high rates of rubella vaccination among children to prevent rubella virus exposure among women of childbearing age susceptible for rubella.


Asunto(s)
Anticuerpos Antivirales , Síndrome de Rubéola Congénita , Vacuna contra la Rubéola , Rubéola (Sarampión Alemán) , Humanos , Femenino , India/epidemiología , Síndrome de Rubéola Congénita/epidemiología , Síndrome de Rubéola Congénita/prevención & control , Estudios Seroepidemiológicos , Embarazo , Rubéola (Sarampión Alemán)/epidemiología , Rubéola (Sarampión Alemán)/prevención & control , Rubéola (Sarampión Alemán)/inmunología , Adulto , Adulto Joven , Adolescente , Anticuerpos Antivirales/sangre , Incidencia , Vacuna contra la Rubéola/inmunología , Vacuna contra la Rubéola/administración & dosificación , Programas de Inmunización , Prevalencia , Inmunoglobulina G/sangre , Vacunación , Complicaciones Infecciosas del Embarazo/epidemiología , Complicaciones Infecciosas del Embarazo/inmunología , Complicaciones Infecciosas del Embarazo/prevención & control , Virus de la Rubéola/inmunología
19.
AIDS Behav ; 17(7): 2352-66, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22677974

RESUMEN

Despite efforts to increase HIV testing in the African region, the proportion of men who report ever having been tested for HIV remains low. Research has focused on individual level determinants of women's testing however little is known about factors associated with men's testing behavior. This analysis investigates community influences on HIV testing among men ages 15-54, using Demographic and Health Survey (DHS) data from Chad, Ghana, Malawi, Nigeria, Tanzania, Uganda, Zambia, and Zimbabwe. Multilevel models were fitted in each country for the outcome of ever receiving an HIV test. After controlling for individual and household level factors, community level factors of demographics, economics, and behavior and knowledge remain significantly associated with HIV testing among men. The results of this analysis highlight the need to recognize the impact of community influences on men's HIV test seeking behavior, and to harness these community factors in the design of programs aimed at encouraging the uptake of HIV testing among men in Africa.


Asunto(s)
Serodiagnóstico del SIDA/estadística & datos numéricos , Comparación Transcultural , Países en Desarrollo , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Estado Civil/estadística & datos numéricos , Aceptación de la Atención de Salud/psicología , Aceptación de la Atención de Salud/estadística & datos numéricos , Características de la Residencia , Facilitación Social , Adolescente , Adulto , África , Infecciones por VIH/psicología , Infecciones por VIH/transmisión , Conocimientos, Actitudes y Práctica en Salud , Encuestas Epidemiológicas , Humanos , Masculino , Persona de Mediana Edad , Factores Socioeconómicos , Sexo Inseguro/psicología , Sexo Inseguro/estadística & datos numéricos , Adulto Joven
20.
AIDS Care ; 25(6): 784-92, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23215551

RESUMEN

Transactional sex, or the exchange of sex for material goods or money, is a risky sexual behavior that has been linked to HIV/AIDS and gender-based violence. Throughout sub-Saharan Africa, transactional sex remains a common practice, putting men and women at risk of HIV. However, little is known of how community environments shape men's participation in risky transactional sex. This analysis examines community-level influences on participation in risky transactional sex among sexually active men in three African countries (Malawi, Tanzania, and Nigeria). The analysis uses Demographic and Health Survey (DHS) data to examine the association between men's report of risky transactional sex and community characteristics including economic, gender norms, HIV behavior and knowledge, and demographic factors. The results show that men residing in communities with more female education and later age of first birth are less likely to report risky transactional sex, while men who live in communities where men report higher number of sexual partners are more likely to report risky transactional sex. While programmatic interventions should continue to improve women's status individually and relative to men, such efforts should be extended to recognize that many community and cultural influences also affect men's sexual behavior. Programs that understand, discuss, and challenge community factors that influence men's sexual behavior may be able to provide a more effective intervention resulting in opportunities for communities to initiate behavioral change.


Asunto(s)
Características de la Residencia , Asunción de Riesgos , Trabajo Sexual/estadística & datos numéricos , Conducta Sexual , Medio Social , Adolescente , Adulto , África del Sur del Sahara/epidemiología , Factores de Edad , Estudios Transversales , Economía , Escolaridad , Femenino , Humanos , Malaui/epidemiología , Masculino , Persona de Mediana Edad , Nigeria/epidemiología , Parejas Sexuales , Tanzanía/epidemiología , Violencia , Adulto Joven
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