Immunogenicity, Safety and Effectiveness of COVID-19 Pfizer-BioNTech (BNT162b2) mRNA Vaccination in Immunocompromised Adolescents and Young Adults: A systematic Review and Meta-Analyses (preprint)

People with weak immune systems are more likely to develop severe COVID-19, less likely to be included in vaccine controlled studies but more likely to be under-vaccinated. We review post-marketing studies to examine the immunogenicity, safety and effectiveness of BNT162b2 vaccine in immunocompromised adolescents and young adults (AYA). We searched more than three international databases from 2020 to 30 May 2022 and used the ROBINS-I for bias assessment. Random effect model was used to estimate pooled proportion, log RR, and mean difference. Egger's regression and Begg's rank correlation were used to examine publication bias. 47 full texts were reviewed, and nine were included. Conditions studied were rheumatic diseases, diabetes mellitus, Down syndrome, solid tumours, neurodisability, and cystic fibrosis. Eight studies used cohort designs and one used cross-sectional designs. Europe led most of the investigations. Most studies had unclear risk of bias and none could rule out selection bias, ascertainment bias, or selective outcome reporting. The overall estimated proportion of combined local and systemic reactions after the first BNT162b2 vaccination was 30%[95% CI: 17-42%] and slightly rose to 32% [95% CI: 19-44%] after the second dose. Rheumatic illnesses had the highest rate of AEFI (40%[95% CI: 16-65%]), while cystic fibrosis had the lowest (27%[95% CI: 17%-38%]). Hospitalizations for AEFIs were rare. Healthy controls exhibited higher levels of neutralizing antibodies and measured IgG than immunocompromised AYA, although pooled estimations did not demonstrate a statistically significant difference after primary dose. BNT162b2 is safe and effective in immunocompromised AYA, with no significant difference to healthy controls. However, current evidence is low to moderate due to high RoB. Our research advocates for improving methodology in studies including specific AYA population.

Community-based Case Studies of Vaccine Hesitancy and the COVID-19 Response in South Africa; The VaxScenes Study (preprint)

Background South Africa has reported more than half of all COVID-19 cases and deaths in Africa. The South African government has launched a large COVID-19 immunization campaign with the goal of reaching more than 40 million individuals. Nonetheless, certain international, largely internet-based surveys have shown a significant proportion of vaccine hesitancy in South Africa. This study aims to determine and co-create with local stakeholders a comprehensive understanding of vaccine hesitancy and opportunities to support the promotion of other COVID-19 health-promoting behaviours at community level. Methods and design A mixed-methods, multiple case-study design; informed by the socio-ecological model of behaviour change. Four socio-economically diverse communities across South Africa will be selected and data collection will take place concurrently through three iterative phases. Phase 1 will provide insights into community experiences of COVID-19 (response) through desktop mapping exercises, observations, in-depth interviews, and focus group discussions (FGDs) designed as expression sessions with local stakeholders. Phase 2 will explore the extent and drivers of community acceptance of COVID-19 vaccines. This phase will comprise a quantitative survey based on WHOs Behavioural and Social Drivers of Vaccination tool as well as further FGDs with community members. Phase 3 will involve cross-case study syntheses and presentation of findings to national role-players. Discussion This study will provide ground up, locally responsive, and timeous evidence on the factors influencing COVID-19 health-seeking behaviours to inform ongoing management and mitigation of COVID-19 in South Africa. It will also provide insights into the applicability of a novel vaccine hesitancy model in Africa.