{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T20:00:44Z","timestamp":1780430444915,"version":"3.54.1"},"reference-count":0,"publisher":"South African Medical Association NPC","license":[{"start":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T00:00:00Z","timestamp":1780358400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["S Afr Med J"],"abstract":"<jats:p>Background. Adverse events following COVID-19 vaccination have been studied extensively in recent years. However, there remains a paucity of data directly comparing adverse events among COVID-19 vaccinees and individuals with SARS-CoV-2 infection within the insured population in South Africa (SA). Moreover, the breadth of conditions assessed in this study exceeds that of most existing research, providing a unique perspective on potential immune-mediated outcomes. This study therefore contributes to a more comprehensive understanding of the risk-benefit profile of COVID-19 vaccination across different age groups.\nObjective. To evaluate the rate of adverse events occurring in COVID-19 vaccinees compared with individuals who have had SARS-CoV-2 infection.\nMethods. We conducted a retrospective cohort study, matching vaccinated individuals and those who have had a SARS-CoV-2 infection with comparable unexposed counterparts. Incident risk rates for 99 possible immune-mediated adverse events were compared between populations over a 42-day observation period to estimate relative risk ratios and confidence intervals. We used data from Discovery Health, a large managed care organisation in SA.\nResults. A total of 3 112 918 individuals aged \u226512 years who received a COVID-19 vaccination were included in the study, with an average of 76% successfully matched to a suitable comparator based on their risk profile. Additionally, 443 220 individuals with documented SARS-CoV-2 infection were analysed, with an average of 99.7% matched to an appropriate comparator. For recipients of the BNT162b2 vaccine, aged 12 - 17 years, we found an increased risk of lymphadenopathy and vertigo, compared with an increased risk of appendicitis, arrhythmia, encephalomyelitis, lymphadenopathy, myocarditis, seizure, syncope, type 1 diabetes and vertigo post SARS-CoV-2 infection. For those aged \u226518 years, we found no increased risk for any conditions post BNT162b2 vaccination. Additionally, no conditions post AD26.COV2.S vaccination had an increased risk for any age group. Post documented SARS-CoV-2 infection for persons in age groups 18 - 39, 40 - 59 and \u226560 years, we found an increased risk of acute kidney injury, anaemia, appendicitis, arrhythmia, axonal and neuronal neuropathy, cerebrovascular accident, deep-vein thrombosis, encephalomyelitis, endometriosis, eosinophilic oesophagitis, fibrosing alveolitis, glomerulonephritis, inflammatory bowel disease, intracranial haemorrhage, lymphadenopathy, myocardial infarction, myocarditis, myositis, pericarditis, pulmonary embolism, rheumatic fever, seizure, syncope, thrombocytopenia, type 1 diabetes, urticaria, vertigo, multiple sclerosis, cholangitis and\/or pancreatitis. Notably, not all conditions presented with an increased risk in each age group.\nConclusions. Across all age subgroups analysed, the risks associated with SARS-CoV-2 infection exceeded the increased risks following COVID-19 vaccination.<\/jats:p>","DOI":"10.7196\/samj.2026.v116i5.3941","type":"journal-article","created":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T19:01:13Z","timestamp":1780426873000},"page":"e3941","source":"Crossref","is-referenced-by-count":0,"title":["Analysis of adverse events following COVID-19 vaccination and infection: A retrospective, comparative cohort study using a claims database from Discovery Health, a managed care organisation in South Africa"],"prefix":"10.7196","author":[{"given":"K","family":"Bernhardt","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4300-9649","authenticated-orcid":false,"given":"S","family":"Collie","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D W C","family":"Jacobs","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P","family":"Mekgwe","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4649-1477","authenticated-orcid":false,"given":"G","family":"Gray","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2658-0723","authenticated-orcid":false,"given":"J","family":"Peter","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0755-4386","authenticated-orcid":false,"given":"L-G","family":"Bekker","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4425","published-online":{"date-parts":[[2026,6,2]]},"container-title":["South African Medical Journal"],"original-title":[],"link":[{"URL":"https:\/\/samajournals.co.za\/index.php\/samj\/article\/download\/3941\/1871","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/samajournals.co.za\/index.php\/samj\/article\/download\/3941\/1871","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T19:01:15Z","timestamp":1780426875000},"score":1,"resource":{"primary":{"URL":"https:\/\/samajournals.co.za\/index.php\/samj\/article\/view\/3941"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,2]]},"references-count":0,"URL":"https:\/\/doi.org\/10.7196\/samj.2026.v116i5.3941","relation":{},"ISSN":["2078-5135","0256-9574"],"issn-type":[{"value":"2078-5135","type":"electronic"},{"value":"0256-9574","type":"print"}],"subject":[],"published":{"date-parts":[[2026,6,2]]}}}