Characteristics and Comparison of Adverse Events of Coronavirus Disease 2019 Vaccines Reported to the United States Vaccine Adverse Event Reporting System Between 14 December 2020 and 8 October 2021.
Level 4 - case-series / case-control
Retrospective disproportionality analysis of a spontaneous passive surveillance database (VAERS)
PubMed 35449806 · doi:10.3389/fmed.2022.826327
What was done
A retrospective pharmacovigilance analysis examined adverse event (AE) reports submitted to the US Vaccine Adverse Event Reporting System (VAERS) between 14 December 2020 and 8 October 2021. The study analyzed AE outcomes (emergency room visits, hospitalization, prolongation of hospitalization, life-threatening events, disability, birth defect, and death) for the Pfizer-BioNTech, Moderna, and Janssen COVID-19 vaccines. Reporting odds ratios (RORs) and Breslow-Day statistics were used to compare reporting between COVID-19 and non-COVID vaccines, as well as between individual COVID-19 vaccines.
What was found
A total of 604,157 COVID-19 vaccine AE reports were analyzed (47.13% Moderna, 43.51% Pfizer-BioNTech, 9.12% Janssen). Overall, 12.56% of reports involved ER visits, 5.96% involved hospitalization, and 1.52% involved life-threatening events. There were 7,674 death reports (mean age 73 years), among which 2,025 individuals (26.39%) had hypertension and 1,237 (16.12%) had cancer. COVID-19 vaccines showed increased RORs for ER visits, hospitalization, and life-threatening events compared with non-COVID vaccines (exact numerical ROR values not reported in the abstract). Breslow-Day tests demonstrated reporting heterogeneity among the three COVID-19 vaccines across four serious outcomes: ER visits, hospitalization, life-threatening events, and disability.
Why it matters
The paper catalogs spontaneous adverse event signals during the first ten months of the US COVID-19 vaccination campaign across three authorized vaccines.
Limits
VAERS relies on passive, voluntary reporting that is subject to substantial reporting bias, underreporting, and stimulated reporting. Reports capture temporal associations rather than confirmed causal relationships. The abstract does not provide exact ROR effect sizes, confidence intervals, or total administered vaccine doses required to calculate true incidence rates.
Cited by
- supports More than half of the deaths reported in the VAERS system following COVID-19 vaccination occurred in individuals aged 50 and older.