Safety evaluation of the single-dose Ad26.COV2.S vaccine among healthcare workers in the Sisonke study in South Africa: A phase 3b implementation trial

Exploring the adverse events of Oxford-AstraZeneca, Pfizer-BioNTech, Moderna, and Johnson and Johnson COVID-19 vaccination on Guillain-Barré Syndrome

The vaccination against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is an important public health strategy to prevent people from the pandemic. Vaccines are a game-changing tool, it is essential to understand the adverse events after COVID-19 vaccination. This study explored the adverse events of COVID-19 Vaccination Oxford-AstraZeneca, Pfizer-BioNTech, Moderna, Johnson and Johnson on Guillain-Barré Syndrome (GBS). In this study, initially 128 documents were identified from the databases, including Pub-Med, Web of Science-Clarivate Analytics, Scopus, and Google Scholar. The articles on COVID-19 vaccination and GBs were searched using the keywords "SARS-CoV-2, COVID-19, Vaccination, and Guillain Barré Syndrome, GBS", finally, 16 documents were included in the analysis and synthesis. After administering 1,680,042,214 doses of COVID-19 vaccines, 6177 cases were identified with 10.5 cases per million vaccine doses. A significant positive risk was found between COVID-19 vaccine administration and GBS with a risk rate of RR 1.97 (95% CI 1.26-3.08, p = 0.01). The mRNA vaccines were associated with 2076 cases, and 1,237,638,401 vaccine doses were linked with 4.47 GBS events per million vaccine doses. The first dose of the m-RNA vaccine was associated with 8.83 events per million doses compared to the second dose with 02 events per million doses. The viral-vector vaccine doses 193,535,249 were linked to 1630 GBS cases with 11.01 cases per million doses. The incidence of GBS after the first dose was 17.43 compared to 1.47 cases per million in the second dose of the viral-vector vaccine. The adverse events of the Oxford-AstraZeneca vaccine were linked to 1339 cases of GBS following 167,786,902 vaccine doses, with 14.2 cases per million doses. The Oxford-AstraZeneca vaccine significantly increased the risk of GBS RR: 2.96 (95% CI 2.51-3.48, p = 0.01). For the Pfizer-BioNTech vaccine, there were 7.20 cases per million doses of the vaccine, and no significant association was identified between the Pfizer-BioNTech vaccine and GBS incidence RR: 0.99 (95% CI 0.75-1.32, p = 0.96). Moderna vaccine was related with 419 cases of GBS after administering 420,420,909 doses, with 2.26 cases per million doses. However, Johnson and Johnson's vaccination was linked to 235 GBS after 60,256,913 doses of the vaccine with 8.80 cases per million doses. A significant association was seen between the risk of GBS and Ad.26.COV2. S vaccine, RR: 2.47 (95% CI 1.30-4.69, p < 0.01). Overall, a significant association was seen between the COVID-19 vaccines and the risk of GBS. The incidence of GBS was higher after the first dose compared to GBS cases per million in the second dose.

Factors associated with reactogenicity to an investigational HIV vaccine regimen in HIV vaccine trials network 702

BACKGROUND

Reactogenicity informs vaccine safety, and may influence vaccine uptake. We evaluated factors associated with reactogenicity in HVTN 702, a typical HIV vaccine efficacy trial with multiple doses and products.

METHODS

HVTN 702, a phase 2b/3 double-blind placebo-controlled trial, randomized 5404 African participants aged 18-35 years without HIV to placebo, or ALVAC-HIV (vCP2438) at months 0, 1 and ALVAC-HIV (vCP2438) + Bivalent Subtype C gp120/MF59 at months 3, 6, 12 and 18. Using multivariate logistic regression, we evaluated associations between reactogenicity with clinical, sociodemographic and laboratory variables.

RESULTS

More vaccine than placebo-recipients reported local symptoms (all p < 0.001), arthralgia (p = 0.008), chills (p = 0.012) and myalgia (p < 0.001). Reactogenicity was associated with female sex at birth (ORv = 2.50, ORp = 1.81, both p < 0.001) and geographic region. Amongst vaccine-recipients, each year of age was associated with 3 % increase in reactogenicity (OR = 1.03, p = 0.002).

CONCLUSION

Vaccine receipt, female sex at birth, older age, and region may affect reactogenicity.

Guillain-Barré syndrome and COVID-19 vaccination: a systematic review and meta-analysis

BACKGROUND

Case-reports/series and cohorts of Guillain-Barré syndrome (GBS) associated with COVID-19 vaccination have been reported.

METHODS

A systematic review and meta-analysis of cohort studies of GBS after COVID-19 vaccination was carried out. Incidence and incidence rate ratio for a number of vaccine doses and risk of GBS, also considering the specific vaccine technology, were calculated in a random-effects model.

RESULTS

Of 554 citations retrieved, 518 were discarded as irrelevant. We finally included 15 studies. The random effect model yielded, regardless of the vaccine technology, 1.25 (95%CI 0.21; 2.83) GBS cases per million of COVID-19 vaccine doses, 3.93 (2.54; 5.54) cases per million doses for adenovirus-vectored vaccines and 0.69 (0.38; 1.06) cases per million doses for mRNA vaccines. The GBS risk was 2.6 times increased with the first dose. Regardless of the vaccine technology, the GBS risk was not increased but disaggregating the data it was 2.37 (1.67; 3.36) times increased for adenovirus-vectored vaccines and 0.32 (0.23; 0.47) for mRNA vaccines. Mortality for GBS after vaccination was 0.10 per million doses and 4.6 per GBS cases.

CONCLUSIONS

Adenovirus-vectored vaccines showed a 2.4 times increased risk of GBS that was about seven times higher compared with mRNA-based vaccines. The decreased GBS risk associated with mRNA vaccines was possibly due to an elicited reduction of infections, including SARS-CoV-2, associated with GBS during the vaccination period. How adenovirus-vectored COVID-19 vaccines may trigger GBS is unclear and further studies should investigate the relationship between vaccine technologies and GBS risk.

Safety of a second homologous Ad26.COV2.S vaccine among healthcare workers in the phase 3b implementation Sisonke study in South Africa

The Sisonke 2 study provided a homologous boost at least 6 months after administration of the priming dose of Ad26.COV2.S for healthcare workers enrolled on the Sisonke phase 3b implementation study. Safety monitoring was via five reporting sources: (i.) self-report through a web-link; (ii.) paper-based case report forms; (iii.) a toll-free telephonic reporting line; (iv.) healthcare professionals-initiated reports; and (v.) active linkage with National Disease Databases. A total of 2350 adverse events were reported by 2117 of the 240 888 (0.88%) participants enrolled; 1625 of the 2350 reported events are reactogenicity events and 28 adverse events met seriousness criteria. No cases of thrombosis with thrombocytopaenia syndrome were reported; all adverse events including thromboembolic disorders occurred at a rate below the expected population rates apart from one case of Guillain Barre Syndrome and one case of portal vein thrombosis. The Sisonke 2 study demonstrates that two doses of Ad26.COV2.S is safe and well tolerated; and provides a feasible model for national pharmacovigilance strategies for low- and middle-income settings.

Safety of Janssen Ad26.COV.S and Astra Zeneca AZD1222 COVID-19 Vaccines among Mobile Phone Users in Malawi: Findings from a National Mobile-Based Syndromic Surveillance Survey, July 2021 to December 2021

The safety profiles of the Ad26.COV2.S and AZD1222 COVID-19 vaccines have not been described in the general population in Malawi. We present self-reported adverse events (AE) following the receipt of these vaccines in Malawi as part of a national syndromic surveillance survey. We conducted phone-based syndromic surveillance surveys among adults (≥18 years) with verbal consent. We used secure tablets through random digit dialing to select mobile phone numbers and collected data electronically. Survey questions included whether the respondent had received the COVID-19 vaccines, whether they had experienced any AE following vaccination, and the severity of the AE. We used multivariable analysis to identify factors associated with self-reported AE post-COVID-19 vaccination. A total of 11,924 (36.0%) out of 33,150 respondents reported receiving at least one dose of either Ad26.COV2.S or AZD1222 between July-December 2021; of those, 65.1% were female. About 49.2% of the vaccine recipients reported at least one AE, 90.6% of which were mild, and 2.6% were severe. Higher education level and concern about the safety of COVID-19 vaccines were associated with AE self-report (Adjusted Odds Ratio [AOR] 2.63 [95% CI 1.96-3.53] and 1.44, [95% CI 1.30-1.61], respectively), while male gender and older age were associated with reduced likelihood of AE self-report (AORs 0.81, [95% CI 0.75-0.88], 0.62 [95% CI 0.50-0.77], respectively). Ad26.COV2.S and AZD1222 vaccines are well-tolerated, with primarily mild and few severe AE among adults living in Malawi. Self-reporting of AE following COVID-19 vaccination is associated with gender, age, education, and concern about the safety of the vaccines. Recognizing these associations is key when designing and implementing COVID-19 vaccination communication messages to increase vaccination coverage.

Predictors of COVID-19 vaccine uptake among adults in South Africa: multimethod evidence from a population-based longitudinal study

BACKGROUND

COVID-19 vaccine coverage remains low in many low and middle-income countries despite widespread access. To understand the dynamic decision-making process around vaccination and provide evidence for future vaccine promotion campaigns, we identified predictors of COVID-19 vaccine uptake among South African adults, including those who did not believe in the vaccine's safety or efficacy.

METHODS

Data from two longitudinal telephone surveys in late 2021 and early 2022 of unvaccinated South African adults were used to model COVID-19 uptake. Predictors of interest informed by the theory of planned behaviour included vaccine attitudes and beliefs, social norms, perceived behavioural control and vaccine intentions. Responses to open-ended questions provided insights into key reasons for getting vaccinated.

RESULTS

Among panel participants (n=1772), 19% reported being vaccinated between Survey 1 and Survey 2. Vaccine uptake was greater among participants who reported wanting to get vaccinated 'as soon as possible' (+27 percentage points, p<0.01). Vaccine uptake was greater among participants who believed that the vaccine is effective in preventing COVID-19 infection and/or death (+12 percentage points, p<0.01) and lower among those who believed that the vaccine is unsafe (-9 percentage points, p<0.01). Among participants who did not believe the vaccine is safe, living with someone already vaccinated against COVID-19 increased vaccine uptake (+6 percentage points, p<0.05). At Survey 1, the intention to get vaccinated as soon as possible was positively associated with perceived risk of illness from COVID-19 (+9.2 percentage points, p<0.05), the belief that most people in their area had been vaccinated (+7.0 percentage points, p<0.05) and living with someone already vaccinated against COVID-19 (+6.6 percentage points, p<0.05).

CONCLUSION

Study findings underscore the predictive power of intentions and of beliefs about disease risk, vaccine safety and vaccine efficacy. Social proof interventions hold promise for increasing vaccination intentions and overcoming concerns about vaccine safety.

Safety and Efficacy of COVID-19 Vaccine in Africa: Systematic Review

Background

Coronavirus disease 2019 (COVID-19) pandemic scared the whole world at the end of 2019, which is a communicable respiratory disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In South Africa and other African countries, the COVID-19 vaccines were subsequently approved for emergency use by the respective national regulatory authorities. There is a paucity of aggregated data that revealed the safety and efficacy of COVID-19 vaccines in Africa.

Objective

The aim of this systematic review was to synthesize the literature on the safety and efficacy of the COVID-19 vaccine which was given in Africa.

Methods

A systematic search was conducted on Science Direct, PubMed, EMBASE, Google Scholar, CINAHL, Cochrane Library, and direct Google searches. Only studies written in English and published articles from 2019 to October 30, 2022, which comprise nine randomized clinical trials (RCT), and four different studies including a single-arm implementation trials, prospective study, retrospective cohort study, and test-negative designs were included.

Results

A total of 13 studies were included which contain 810,466 participants from Africa. Of these, 62.18% of the participants were female. The efficacy of COVID-19 vaccine in Africa ranges from 41.7% to 100%. Moreover, vaccine efficacy against COVID-19 variants ranges from -5.7% to 100%. In general, systemic and local adverse events following vaccination in most trials were reported with a similar pattern between the placebo and vaccine groups. Out of the total reported adverse events, most of them were mild to moderate, whereas a few were serious.

Conclusion

Almost all current COVID-19 vaccines appear to be safe for African study participants. Regarding efficacy, the protein subunit vaccine and mRNA vaccine exhibited high efficacy (100%) in this group of participants. However, Ad26. COV2.S and ChAdOx1 nCoV-19 COVID-19 vaccines are not effective against the delta variant and B.1.351 variant, respectively.

Vascular thrombosis after single dose Ad26.COV2.S vaccine in healthcare workers in South Africa: open label, single arm, phase 3B study (Sisonke study)

Objective

To assess the rates of vascular thrombotic adverse events in the first 35 days after one dose of the Ad26.COV2.S vaccine (Janssen/Johnson & Johnson) in healthcare workers in South Africa and to compare these rates with those observed in the general population.

Design

Open label, single arm, phase 3B study.

Setting

Sisonke study, South Africa, 17 February to 15 June 2021.

Participants

The Sisonke cohort of 477 234 healthcare workers, aged ≥18 years, who received one dose of the Ad26.COV2.S vaccine.

Main outcome measures

Observed rates of venous arterial thromboembolism and vaccine induced immune thrombocytopenia and thrombosis in individuals who were vaccinated, compared with expected rates, based on age and sex specific background rates from the Clinical Practice Research Datalink GOLD database (database of longitudinal routinely collected electronic health records from UK primary care practices using Vision general practice patient management software).

Results

Most of the study participants were women (74.9%) and median age was 42 years (interquartile range 33-51). Twenty nine (30.6 per 100 000 person years, 95% confidence interval 20.5 to 44.0) vascular thrombotic events occurred at a median of 14 days (7-29) after vaccination. Of these 29 participants, 93.1% were women, median age 46 (37-55) years, and 51.7% had comorbidities. The observed to expected ratios for cerebral venous sinus thrombosis with thrombocytopenia and pulmonary embolism with thrombocytopenia were 10.6 (95% confidence interval 0.3 to 58.8) and 1.2 (0.1 to 6.5), respectively. Because of the small number of adverse events and wide confidence intervals, no conclusions were drawn between these estimates and the expected incidence rates in the population.

Conclusions

Vaccine induced immune thrombocytopenia and thrombosis after one dose of the Ad26.COV2.S vaccine was found in only a few patients in this South African population of healthcare workers. These findings are reassuring if considered in terms of the beneficial effects of vaccination against covid-19 disease. These data support the continued use of this vaccine, but surveillance is recommended to identify other incidences of venous and arterial thromboembolism and to improve confidence in the data estimates.

Trial registration

ClinicalTrials.govNCT04838795.

Differential in-hospital mortality and intensive care treatment over time: Informing hospital pathways for modelling COVID-19 in South Africa

There are limited published data within sub-Saharan Africa describing hospital pathways of COVID-19 patients hospitalized. These data are crucial for the parameterisation of epidemiological and cost models, and for planning purposes for the region. We evaluated COVID-19 hospital admissions from the South African national hospital surveillance system (DATCOV) during the first three COVID-19 waves between May 2020 and August 2021. We describe probabilities and admission into intensive care units (ICU), mechanical ventilation, death, and lengths of stay (LOS) in non-ICU and ICU care in public and private sectors. A log-binomial model was used to quantify mortality risk, ICU treatment and mechanical ventilation between time periods, adjusting for age, sex, comorbidity, health sector and province. There were 342,700 COVID-19-related hospital admissions during the study period. Risk of ICU admission was 16% lower during wave periods (adjusted risk ratio (aRR) 0.84 [0.82-0.86]) compared to between-wave periods. Mechanical ventilation was more likely during a wave overall (aRR 1.18 [1.13-1.23]), but patterns between waves were inconsistent, while mortality risk in non-ICU and ICU were 39% (aRR 1.39 [1.35-1.43]) and 31% (aRR 1.31 [1.27-1.36]) higher during a wave, compared to between-wave periods, respectively. If patients had had the same probability of death during waves vs between-wave periods, we estimated approximately 24% [19%-30%] of deaths (19,600 [15,200-24,000]) would not have occurred over the study period. LOS differed by age (older patients stayed longer), ward type (ICU stays were longer than non-ICU) and death/recovery outcome (time to death was shorter in non-ICU); however, LOS remained similar between time periods. Healthcare capacity constraints as inferred by wave period have a large impact on in-hospital mortality. It is crucial for modelling health systems strain and budgets to consider how input parameters related to hospitalisation change during and between waves, especially in settings with severely constrained resources.