J Pharmacoepidemiol Risk Manage.  2021 Sep;13(2):62-69. 10.56142/2021.13.2.62.

Adverse Reactions after the Second Dose of ChAdOx1 COVID-19 Vaccine in H ealthcare Workers

• Kim HJ
• Kim HH
• Park S
• Yeom HJ
• Jang JY
• Park Gy
• Kang HR
• Kang DY

• KMID: 2534650
• DOI: http://doi.org/10.56142/2021.13.2.62

Abstract

Objective
The Seoul National University Hospital Drug Safety Monitoring Center performed a prospective survey regarding adverse reactions after the second dose of the adenovirus-vectored vaccine (ChAdOx1 nCoV-19) in healthcare workers. This survey was used to provide information about the frequency, onset, recovery time of the reactions and to compare the degree of intensity of the reactions after the first dose and second doses of the vaccine.
Methods
Healthcare workers (HCWs) received two doses of ChAdOx1 vaccine from March to June 2021 at a tertiary hospital.The recipients were asked to report adverse reactions through a mobile self-report questionnaire seven days after the second dose of the vaccine.
Results
A total of 6,840 HCWs received two doses of ChAdOx1 vaccine and 3,248 HCWs answered the self-report questionnaire. Among the 3,248 survey participants, only 600 (18.5%) reported to have experienced adverse reactions. The incidence of adverse reactions was significantly higher in females and in younger age groups. The most frequently reported symptoms were injection site pain, myalgia and arthralgia. The intensity of all adverse reactions was milder after the second dose compared to the first dose of the vaccine. Although most adverse reactions resolved within three days, neurologic, cardiac, vascular, and skin reactions lasted longer.
Conclusion
Females and younger age groups experienced more adverse reactions following the second dose of the ChAdOx1 vaccine and the intensity of all adverse reactions were milder after the second dose compared to the first.

Keyword

COVID-19; Vaccination; Adverse reaction; ChAdOx1