ArticlePLOS global public health2025
Active vaccine safety surveillance: Experience from a prospective cohort event monitoring study of COVID-19 vaccines in Kenya.
Article in PLOS global public health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- Most COVID-19 vaccine adverse events detected within 48 hours in Ethiopia: implications for cohort event monitoring efficiency in resource-limited settings.European journal of clinical pharmacology · 2026Article
- Quality and Timeliness of Pharmacovigilance Reporting in Malawi: A Cross-Sectional Analysis of Individual Case Safety Reports.Drug, healthcare and patient safety · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
15 authors.
Funding
Abstract
Although active vaccine safety surveillance (VSS) can complement passive VSS while overcoming the inherent limitations of spontaneous safety monitoring, it remains rare in sub-Saharan Africa. We conducted post-authorization active VSS of COVID-19 vaccines in Kilifi, Kenya using a cohort event monitoring study design. Participants were followed weekly over 13 weeks for adverse events. A subset was followed daily for one week for solicited systemic reactogenicity events (chills, fatigue, fever, headache, joint pain, malaise, muscle aches, nausea). The daily prevalence of reactogenicity events was compared to the 3-day pre-vaccine average using McNemar's test. The association of baseline characteristics with reactogenicity events was assessed using logistic regression. Between 28th September 2022 and 30th June 2023, 2,440 participants were enrolled into the cohort; 1,000 systematically sampled participants were included in the reactogenicity sub-study. Most were aged 17-39 years (1683; 69.0%) and were female (1895; 77.7%); 535 (28.2%) female participants were pregnant. The three most frequently reported reactogenicity events were fatigue (422; 44.1%), headache (370; 38.7%), and malaise (346; 36.2%); the proportion of severe events ranged from 2.3% (22; nausea) to 5.0% (48; malaise). Except for headache, the prevalence of systemic reactogenicity events was significantly higher in the first two days post-vaccination than pre-vaccination (p-values <0.05). The odds of reactogenicity events were higher among non-pregnant women (adjusted odds ratio [aOR] 1.81; 95% CI 1.28-2.55) and pregnant women (aOR 1.69; 1.03-2.78) than among men, and higher among Johnson & Johnson (aOR 2.05; 1.40-3.00) and Moderna (aOR 4.19; 2.34-7.51) vaccine recipients than among Pfizer vaccine recipients. The prevalence of pregnancy complications was 2.6% (95% CI 1.4-3.5%) against a background prevalence of 3-49%. Reactogenicity events following COVID-19 vaccination were generally non-severe and transient. There was no elevated risk of pregnancy-related complications. Addressing operational barriers is essential for enhancing the utility and feasibility of future active VSS.
Identifiers
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.