Safety Monitoring after the BNT162b2 COVID-19 Vaccine among Adults Aged 75 Years or Older.

ABSTRACT

BACKGROUND: Older adults are given high priority for coronavirus disease 2019 (COVID-19) vaccination; however, little is known about the safety of vaccines. This study was conducted to examine the safety of the COVID-19 vaccine for people who were ≥ 75 years of age, specifically those who first took two doses of the vaccine at the COVID-19 central vaccination center in South Korea. METHODS: Safety monitoring after the BNT162b2 vaccine was conducted in three ways for older adults who received the first dose of the vaccine at our center between April 5 and April 23, 2021. For immediate adverse reactions, every person who was vaccinated was observed for 15-30 minutes after injection at the center. For active surveillance, a telephone interview was conducted for stratified randomly sampled people after 7 days of each vaccination to enquire regarding types of adverse reactions they experienced, and its severity and duration. For passive surveillance, reported adverse event data were collected from the COVID-19 vaccine adverse event following immunization (AEFI) surveillance system-run by the Korea Disease Control and Prevention Agency (KDCA). The data were then reviewed. RESULTS: In total, 2,123 older adults received at least one vaccine dose during the study period. The frequency of acute adverse reactions that developed during the observed 15-30 minutes after injection was 8.5 cases per 1,000 doses. None of the reactions was assessed as acute allergic reactions to the vaccine and no cases required special treatment or drug administration. Overall, 638 people were followed up at least once by telephone interview 7 days post vaccination. The overall response rate was 82.3%. The rates of local reactions were 50.3% after the first dose and 45.2% after the second dose, and the rates of systemic reactions were 15.2% and 26.0%, respectively. During the study period, 23 medically attended adverse events (5.4 cases per 1,000 administered doses) were reported to the KDCA AEFI surveillance system. The most common symptoms of medically attended cases were nonspecific general weakness (26%) and dizziness (26%), followed by muscle pain (22%), headache (13%), fever (13%), and skin rash or urticaria (13%). Among them, there were five serious adverse events reported, which required hospitalization, including one death. However, most of them were not related to the vaccines. CONCLUSION: BNT162b2 vaccination was tolerable among adults who were ≥ 75 years of age.