Indirect effectiveness of a novel SARS-COV-2 vaccine (SCB-2019) in unvaccinated household contacts in the Philippines: A cluster randomised analysis.

BACKGROUND: Though observational evidence supports indirect effects of SARS-CoV-2 vaccines, randomised experiments are lacking. To address this gap, the double-blinded, prospective follow-up of the household contacts (HHCs) of Philippine participants of the individually-randomised, placebo-controlled trial of the adjuvanted-subunit protein COVID-19 vaccine, SCB-2019, (EudraCT, 2020-004272-17; ClinicalTrials.gov, NCT04672395) was analyzed in a cluster-randomised fashion. METHODS: Over an eight-week period, HHCs were followed by rRT-PCR and paired rapid antibody tests (RATs) to detect symptomatic (SCI, primary) and all (ACI, secondary) SARS-CoV-2 infection. A standard analysis estimated the indirect effectiveness of SCB-2019 for each endpoint, excluding HHC RAT-positive at enrollment. A secondary analysis employed enzyme-linked immunosorbent assay (ELISA) results to correct for suspected bias. FINDINGS: SCB-2019 (N = 3470) and placebo (N = 3225) exposed HHCs contributed to at least one analysis. The standard analysis estimated that SCB-2019 reduced the risk of SCI by 83% (95% confidence/credible interval [CI: 32% to 96%), with no effect against ACI. The bias-corrected relative risk reduction was 97% (95% CI: 74% to 100%) for SCI and 79% (95% CI: 14% to 96%) for ACI, with an estimated one SARS-CoV-2 infection prevented per 4.8 households where one member received SCB-2019. INTERPRETATION: SCB-2019 demonstrated bias-corrected indirect effectiveness against SARS-CoV-2 infection among HHC, even at a modest coverage level in the household (approximately 25%). Further research into the indirect effects of SARS-CoV-2 vaccines is needed to optimize the impact of limited doses in low and middle-income settings.

Using Dried Blood Spots to Quantitatively Detect Anti-SARS-CoV-2 IgG Antibodies by ELISA: A Validation Study.

SARS-CoV-2 serological testing is useful to determine seroprevalence, epidemiological trends, and the extent of transmission. The collection and transport of serum samples can be logistically challenging, especially in remote underserved areas. Dried blood spots (DBSs) would allow easier sample collection and logistical handling compared with standard serum collection, particularly for extensive and repeated SARS-CoV-2 serosurveys. We evaluated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the IgG ELISA (Wantai, Beijing, China) using DBSs against sera for the quantitative detection of SARS-CoV-2 IgG antibody. The IgG ELISA was used to test paired sera and DBSs obtained from individuals with recent virologically confirmed COVID-19 illness and banked paired sera and DBSs collected before the COVID-19 pandemic. We found that 100/100 (100%) seropositive samples were positive using DBSs, and 193/194 (99%) seronegative samples were negative using DBSs. Compared with sera, the DBS method had a 100% sensitivity, 99% specificity, 99% PPV, and 100% NPV. Use of DBSs for SARS-CoV-2 household or population serosurveys may be considered in situations with limitations in sample collection, shipment, and storage.

Safety and immunogenicity of ChAdOx1 nCoV-19 (AZD1222) vaccine in adults in Kenya: a phase 1/2 single-blind, randomised controlled trial.

Background: There are limited data on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in African populations. Here we report the immunogenicity and safety of the ChAdOx1 nCoV-19 (AZD1222) vaccine from a phase 1/2 single-blind, randomised, controlled trial among adults in Kenya conducted as part of the early studies assessing vaccine performance in different geographical settings to inform Emergency Use Authorisation. Methods: We recruited and randomly assigned (1:1) 400 healthy adults aged ≥18 years in Kenya to receive ChAdOx1 nCoV-19 or control rabies vaccine, each as a two-dose schedule with a 3-month interval. The co-primary outcomes were safety, and immunogenicity assessed using total IgG enzyme-linked immunosorbent assay (ELISA) against SARS-CoV-2 spike protein 28 days after the second vaccination. Results: Between 28 th October 2020 and 19 th August 2021, 400 participants were enrolled and assigned to receive ChAdOx1 nCoV-19 (n=200) or rabies vaccine (n=200). Local and systemic adverse events were self-limiting and mild or moderate in nature. Three serious adverse events were reported but these were deemed unrelated to vaccination. The geometric mean anti-spike IgG titres 28 days after second dose vaccination were higher in the ChAdOx1 group (2773 ELISA units [EU], 95% CI 2447, 3142) than in the rabies vaccine group (61 EU, 95% CI 45, 81) and persisted over the 12 months follow-up. We did not identify any symptomatic infections or hospital admissions with respiratory illness and so vaccine efficacy against clinically apparent infection could not be measured. Vaccine efficacy against asymptomatic SARS-CoV-2 infection was 38.4% (95% CI -26.8%, 70.1%; p=0.188). Conclusions: The safety, immunogenicity and efficacy against asymptomatic infection of ChAdOx1 nCoV-19 among Kenyan adults was similar to that observed elsewhere in the world, but efficacy against symptomatic infection or severe disease could not be measured in this cohort. Pan-African Clinical Trials Registration: PACTR202005681895696 (11/05/2020).

Safety and immunogenicity of varied doses of R21/Matrix-M™ vaccine at three years follow-up: A phase 1b age de-escalation, dose-escalation trial in adults, children, and infants in Kilifi-Kenya.

Background: Falciparum malaria remains a global health problem. Two vaccines, based on the circumsporozoite antigen, are available. RTS, S/AS01 was recommended for use in 2021 following the advice of the World Health Organisation (WHO) Strategic Advisory Group of Experts (SAGE) on Immunization and WHO Malaria Policy Advisory Group (MPAG). It has since been pre-qualified in 2022 by the WHO. R21 is similar to RTS, S/AS01, and recently licensed in Nigeria, Ghana and Burkina Faso following Phase 3 trial results. Methods: We conducted a Phase 1b age de-escalation, dose escalation bridging study after a change in the manufacturing process for R21. We recruited healthy adults and children and used a three dose primary vaccination series with a booster dose at 1-2 years. Variable doses of R21 and adjuvant (Matrix-M ™) were administered at 10µgR21/50 µg Matrix-M™, 5µgR21/25µg Matrix-M™ and 5µgR21/50µg Matrix-M™ to 20 adults, 20 children, and 51 infants. Results: Self-limiting adverse events were reported relating to the injection site and mild systemic symptoms. Two serious adverse events were reported, neither linked to vaccination. High levels of IgG antibodies to the circumsporozoite antigen were induced, and geometric mean titres in infants, the target group, were 1.1 (0.9 to 1.3) EU/mL at day 0, 10175 (7724 to 13404) EU/mL at day 84 and (following a booster dose at day 421) 6792 (5310 to 8687) EU/mL at day 456. Conclusion: R21/Matrix-M™ is safe, and immunogenic when given at varied doses with the peak immune response seen in infants 28 days after a three dose primary vaccination series given four weeks apart. Antibody responses were restored 28 days after a 4 th dose given one year post a three dose primary series in the young children and infants. Registration: Clinicaltrials.gov (NCT03580824; 9 th of July 2018; Pan African Clinical Trials Registry (PACTR202105682956280; 17 th May 2021).

Community and Provider Perspectives on Addressing Unmet Need for Contraception: Key Findings from a Formative Phase Research in Kenya, South Africa and Zambia (2015-2016).

Unmet need for contraception remains a challenge especially in low and middle-income countries. Community participation or the -active involvement of affected populations in all stages of decision-making and implementation of policies, programs, and services‖ is a precondition for attaining the highest standard of health. Participation as a key component of rights and quality of care frameworks could increase met needs. However, it has been inadequately addressed in contraceptive programs. A qualitative, exploratory methodology that included focus group discussions and in-depth interviews with community members, healthcare providers, and other stakeholders were conducted to identify domains or key thematic areas of action through which stakeholders could be engaged. The study conducted in Kenya, South Africa, and Zambia explored knowledge and use of contraceptives, barriers and enablers to access, quality of care, and participatory practices. Thematic analysis was used, facilitated by NVivo (version 10 QSR International) with a single master codebook. Comparing the thematic areas that emerged from the county data, four domains were selected: quality of care, informed decision-making, acceptability, and accountability. These domains informed the theory of change of a participatory programme aiming to meet unmet needs. Identifying possible generalizable domains establishes measurable and comparable intermediate outcomes for participatory programs despite diverse African contexts.

Community and provider perspectives on addressing unmet need for contraception: key findings from a formative phase research in Kenya, south Africa and Zambia (2015-2016)

Unmet need for contraception remains a challenge especially in low and middle-income countries. Community participation or the ­active involvement of affected populations in all stages of decision-making and implementation of policies, programs, and services‖ is a precondition for attaining the highest standard of health. Participation as a key component of rights and quality of care frameworks could increase met needs. However, it has been inadequately addressed in contraceptive programs. A qualitative, exploratory methodology that included focus group discussions and in-depth interviews with community members, healthcare providers, and other stakeholders were conducted to identify domains or key thematic areas of action through which stakeholders could be engaged. The study conducted in Kenya, South Africa, and Zambia explored knowledge and use of contraceptives, barriers and enablers to access, quality of care, and participatory practices. Thematic analysis was used,facilitated by NVivo (version 10 QSR International) with a single master codebook. Comparing the thematic areas that emerged from the county data, four domains were selected: quality of care, informed decision-making, acceptability, and accountability. These domains informed the theory of change of a participatory programme aiming to meet unmet needs. Identifying possible generalizable domains establishes measurable and comparable intermediate outcomes for participatory programs despite diverse African contexts

Factors associated with late presentation of suspected tuberculosis cases to tuberculosis management facilities: The case in Dagoretti district, Nairobi, Kenya.

BACKGROUND: Tuberculosis is a highly contagious disease accounting for a high number of deaths in the developing countries; its control can be effectively achieved if individuals with the disease receive adequate and timely treatment. The objective of this study was to determine the factors associated with late presentation of suspects to tuberculosis management facilities in Dagoretti district in Nairobi, Kenya. METHOD: A cross sectional study was conducted on patients aged 18 years and above attending TB clinics in Dagoretti District, Nairobi Kenya. A total of 426 TB suspects were interviewed. The study covered 8 clinics in Dagoretti district. Analysis was done using SPSS version 16.0 and Epi info version 6, this included Chi Square for Bivariate analysis and Binary Logistic Regression for Multivariate Analysis. RESULTS: Out of the 426 tuberculosis suspects, 248 (58.2%) suspects had delayed in seeking medical care. In Bivariate analysis male gender (P = 0.039, O.R = 1.51; 95% Confidence Interval; 1.00- 2.27), level of education (Primary class 5-8) (P = 0.001, O.R= 2.06; 95% C.I 1.34-3.19) and place of first medical care (drug store) (P= 0.013, O.R = 1.63; 95% C.I 1.09-2.46) were all significantly associated with late presentation. After multivariate logistic regression, gender (P = 0,019, OR = 1.6), level of education (p = 0.029, OR = 1.26) and place of first medical care (P= 0.01 OR = 1.27), were found to be significantly associated with late presentation. CONCLUSION: This study shows that age, level of education and place of first medical care are the factors associated with late presentation of suspects to tuberculosis management facilities.