Accepted for/Published in: Journal of Medical Internet Research
Date Submitted: Mar 9, 2023
Open Peer Review Period: Mar 7, 2023 - May 2, 2023
Date Accepted: Mar 22, 2024
(closed for review but you can still tweet)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
App-based collection of real-world data on the COVID-19 pandemic and vaccines in Germany (eCOV): Prospective observational cohort study
ABSTRACT
Background:
The COVID-19 pandemic challenged health systems worldwide to collect data broadly, rapidly, and safely to better understand the SARS-CoV-2 virus and respond dynamically to new developments. As new variants might require new COVID-19 vaccines, adaptive and scalable study solutions are needed to test vaccine effectiveness (VE) and drug safety under real-world conditions.
Objective:
We investigated the feasibility of a digital study app to collect data on COVID-19 in Germany at a large scale with a focus on VE.
Methods:
In a digital prospective cohort study, we collected self-reported data between May 2021 and August 2022 to assess test positivity rates, COVID-19 incidences, suspected adverse events after COVID-19 vaccination, and VE. We used logistic regression models adjusted for confounders to estimate VE.
Results:
A total of 9,643 individuals participated in our study and reported an overall of 44,786 tests and 5,530 symptoms. 1,768 SARS-CoV-2-unvaccinated participants were compared with 3,464 participants who had received two doses of BNT162b2 from Pfizer–BioNTech and 1,167 participants who had received three doses of BNT162b2 and were not infected prior to last vaccination. Seven-day incidences and test-positive rates reflected the course of the pandemic in Germany when compared with official numbers of the national infectious disease surveillance system. Adverse events after vaccination were consistent with previously published research. The results suggested that VE against infections of any severity waned from 91.7% (95% CI [71.6 ; 97.6]) at week 4 to 38.2% (95% CI [24.9 ; 49.2]) at week 48 after the second dose of BNT162b2. A third vaccine dose of BNT162b2 restored VE to 67.9% (95%CI [51.0 ; 79.0]) after 4 weeks.
Conclusions:
We successfully tracked the course of the pandemic in the German population using self-reported data from a self-selected cohort. Calculation of COVID-19 real-world VE with self-reported data in our study app was feasible, but presented numerous challenges and potential biases that require further refinement for successful use as a digital public health tool. Clinical Trial: German Clinical Trials Registry, ID: DRKS00025169.
Citation
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Copyright
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