gms | German Medical Science

Background and status of (inter)national research: The efficacy and safety of COVID-19 vaccines have been demonstrated in large randomized controlled trials. In addition, observational studies provide further important insights into the safety and efficacy of the vaccines under real-life conditions.

Research question and objective: In the CoVaKo safety study, we aim to assess reactogenicity and health problems after COVID-19 vaccination (= observation group) compared to other vaccinations like influenza or pneumococcal vaccination (= control group). The study focus is on health problems occurring within 18 weeks after vaccination and leading to medical consultation, medication intake, or sick-leave.

Method or hypothesis: In a longitudinal observational cohort study reactogenicity and safety of vaccinations were assessed 14 to 19 days, 40 to 45 days and 124 to 129 days after vaccination using web-based surveys. Recruitment of vaccinated participants commenced on April 17, 2021 in vaccination centres and primary care practices in Bavaria, Germany. Enrollment ended in April 2022. After a vaccination, individuals received a leaflet with information on the study and had the possibility to voluntarily register on a web-based platform (www.covako.org). Afterwards participants received the links to the surveys via E-Mail.

Results: Until March 2022, 17.177 participants registered for the study. The cohorts are as follows: prime vaccination: 9.624 persons received one of the mRNA vaccines, 3.491 persons received the vaccine ChAdOx1 and 237 persons received the Janssen vaccine; second vaccination: 11.665 persons received one of the mRNA vaccines and 627 persons received ChAdOx1. The control group comprises 571 subjects, thereof 76 % (n = 437) received the influenza vaccination. The study is currently being analysed. The final results will be available at the conference.

Discussion: The CoVaKo safety study will provide insights regarding reactogenicity and safety under real-world-conditions.

Practical implications: CoVaKo shows how an observational study can be conducted when facing dynamic changes as in COVID-19 vaccination strategies and under high workload in the health care system.

Appeal for practice (science and/or care) in one sentence: Systematic collection of data on vaccinations and vaccination adverse events is essential for patient care and health services research.

Funding: Sonstige Förderung