(189) Incidence of Adverse Events of Special Interest in The Pre-Covid and Active Covid ERA as Historical Comparators for Post-Marketing Safety Surveillance of SARS-CoV-2 Vaccines

Publication Number: 863

Background: For vaccines targeting SARS CoV-2, adverse events of special interest (AESI) are routinely monitored based on known or theoretical association with immunization or occurrence during wild type disease. Administrative data allow estimation of historical population-based incidence rates in large studies that are useful for assessment of potential safety signals. However, limited information is available regarding changes in incidence rates resulting from alterations in healthcare seeking behavior and COVID-19 infection disease itself.

Objectives: To estimate background incidence of AESI in the pre-COVID and active-COVID eras (prior to the distribution of SARS-CoV-2 vaccines).

Methods: This observational cohort study included 50 million individuals sampled from HealthVerity closed claims to mirror the 2019 US census age and sex distribution. A 1-year of insurance enrollment was required prior to cohort entry in at least one of two time periods: pre-COVID (01Dec2018-30Nov2019) and COVID era (01Dec2019-10Dec2020). The incidence rates of 37 AESI per 100,000 person-years and associated 95% CI were calculated among individuals with no diagnosis of the applicable condition during a clean period prior to cohort entry. Within each time period, estimates were stratified by age and sex.

Results: Among individuals sampled from HealthVerity, there were 26.9 million individuals included in the pre-COVID and 25.9 million individuals included in the COVID era cohorts. Median age was 47 years, and 52% of individuals were male. Estimated IR varied substantially across categories of age and gender. For approximately half (46%) of the AESI considered, COVID era incidence was reduced by at least 15% compared to the pre-COVID era. The incidence of anosmia was elevated in the COVID era vs. the pre-COVID era (149.84 vs 47.67). The incidence of other COVID-19 disease outcomes was not elevated: myocarditis (9.51 vs 9.97), pericarditis (19.24 vs 24.53), single organ cutaneous vasculitis (16.91 vs 21.93), and Chilblain-like lesions (3.95 vs 4.29).

Conclusions: Potentially consistent with decreases in healthcare utilization and other COVID-19 pandemic factors, evidence of depression in claims-based estimates of the incidence of nearly half of the AESI were identified in the COVID era. Anosmia was markedly elevated in the COVID era, and other AESI associated with COVID-19 were less impacted.