Detailed review of mortality reported following COVID-19 vaccination in Victoria, Australia: 2021-2023

The scale of the COVID-19 vaccine program, and appropriate focus on older individuals, emphasised monitoring of mortality as an important part of COVID-19 vaccine safety surveillance, noting many deaths temporally associated with vaccination may not be causally related. This cross-sectional study describes Victoria's vaccine safety service (SAEFVIC) process of reviewing mortality reports following COVID-19 vaccination, summarises report characteristics and identifies trends in mortality reporting.

Mortality cases reported to SAEFVIC following COVID-19 vaccination from 22 February 2021 to 22 February 2023 were included. Report characteristics, demographics, and cause of death information were described. Proportions of mortality reports per 100,000 vaccine doses administered were calculated, overall and stratified by age (<60 years, ≥60 years), sex, vaccine type and dose number. Rate ratios (RR) were used to compare proportions.

Reporting proportions were higher in the first three months of the vaccine program (3.98 per 100,000 doses), compared to the following 21 months (0.71 per 100,000 doses), RR:5.61, p < 0.001. Of 159 mortality reports included, 135/159 (84.9 %) were in individuals ≥60 years. Most individuals (121/159, 90.3 %) had comorbidities relevant to cause(s) of death, and 143/159 (89.9 %) were categorised as having a 'likely alternate' cause of death based on treating clinician/forensic assessment. For 11/159 (6.9 %) reports vaccine contribution to death could not be determined. Five deaths (0.03 per 100,000 doses administered), all publicly reported, were assessed by the national regulator as likely vaccine-associated.

Mortality reporting predominantly reflected the health status of the population receiving vaccines, vaccine administration patterns and contextual factors surrounding COVID-19 vaccines (including public concerns regarding serious adverse events of special interest), as well as extremely rare but fatal adverse events that were likely vaccine-associated. Jurisdictional vaccine safety services such as SAEFVIC play an important role in follow-up of mortality reports, supporting the work of national regulators, and thereby supporting vaccine safety surveillance and vaccine confidence more broadly.