Version 1
: Received: 3 October 2023 / Approved: 4 October 2023 / Online: 4 October 2023 (09:31:38 CEST)
Version 2
: Received: 5 October 2023 / Approved: 5 October 2023 / Online: 7 October 2023 (03:27:13 CEST)
How to cite:
Katz, M.A.; Castro, M.Y.R.; Chakhunashvili, G.; Chitadze, N.; Ward, C.; McKnight, C.J.; Lucaccioni, H.; Finci, I.; Zardiashvili, T.; Pebody, R.; Kissling, E.; Sanodze, L. Primary Series COVID-19 Vaccine Effectiveness among Health Care Workers in the Country of Georgia, March–December 2021. Preprints2023, 2023100224. https://doi.org/10.20944/preprints202310.0224.v1
Katz, M.A.; Castro, M.Y.R.; Chakhunashvili, G.; Chitadze, N.; Ward, C.; McKnight, C.J.; Lucaccioni, H.; Finci, I.; Zardiashvili, T.; Pebody, R.; Kissling, E.; Sanodze, L. Primary Series COVID-19 Vaccine Effectiveness among Health Care Workers in the Country of Georgia, March–December 2021. Preprints 2023, 2023100224. https://doi.org/10.20944/preprints202310.0224.v1
Katz, M.A.; Castro, M.Y.R.; Chakhunashvili, G.; Chitadze, N.; Ward, C.; McKnight, C.J.; Lucaccioni, H.; Finci, I.; Zardiashvili, T.; Pebody, R.; Kissling, E.; Sanodze, L. Primary Series COVID-19 Vaccine Effectiveness among Health Care Workers in the Country of Georgia, March–December 2021. Preprints2023, 2023100224. https://doi.org/10.20944/preprints202310.0224.v1
APA Style
Katz, M.A., Castro, M.Y.R., Chakhunashvili, G., Chitadze, N., Ward, C., McKnight, C.J., Lucaccioni, H., Finci, I., Zardiashvili, T., Pebody, R., Kissling, E., & Sanodze, L. (2023). Primary Series COVID-19 Vaccine Effectiveness among Health Care Workers in the Country of Georgia, March–December 2021. Preprints. https://doi.org/10.20944/preprints202310.0224.v1
Chicago/Turabian Style
Katz, M.A., Esther Kissling and Lia Sanodze. 2023 "Primary Series COVID-19 Vaccine Effectiveness among Health Care Workers in the Country of Georgia, March–December 2021" Preprints. https://doi.org/10.20944/preprints202310.0224.v1
Abstract
Background
Healthcare workers (HCWs) have suffered considerable morbidity and mortality during the
COVID-19 pandemic. Few data on COVID-19 vaccine effectiveness (VE) are available from middle-income countries in Europe. We evaluated primary series COVID-19 VE against laboratory-confirmed
COVID-19 among HCWs in Georgia.
Methods
HCWs in six hospitals in Georgia were invited to enroll in a prospective cohort study conducted during March 19–December 5, 2021. Participants completed weekly symptom questionnaires.
Symptomatic HCWs were tested by RT-PCR and/or rapid antigen test (RAT), and participants were routinely tested for SARS-CoV-2 by RT-PCR or RAT, regardless of symptoms. Serology was collected at enrolment, and quarterly thereafter, and tested by electrochemiluminescence immunoassay for SARS-CoV-2 antibodies. We defined primary series vaccination as two doses of COVID-19
vaccine received ≥14 days before symptom onset. We estimated VE as (1-hazard ratio)*100 using a Cox proportional hazards model with vaccination status as a time-varying covariate. Estimates were adjusted by potential confounders that changed the VE estimate by more than 5%, according to the change-in-estimate approach.
Results
Overall, 1561/3849 (41%) eligible HCWs enrolled and were included in the analysis. The median age was 40 (IQR: 30-53), 1318 (84%) were female, and 1003 (64%) had laboratory evidence of prior SARS-Cov-2 infection. At enrolment, 1300 (83%) were unvaccinated; By study end, 1082 (62%) had completed a primary vaccine series (69% BNT162b2 (Pfizer-BioNTech); 22% BBIBP-CorV (Sinopharm); 9% other). During the study period, 191(12%) participants had a new PCR- or RAT-confirmed symptomatic SARS-CoV-2 infection. VEa gainst PCR- or RAT- confirmed symptomatic SARS-CoV-2 infection was 58 (95%CI: 41; 70) for all primary series vaccinations, 68% (95%CI: 51; 79) for BNT162b2, and 40% (95%CI: 1; 64) for BBIBP-CorV vaccines. Among previously infected HCWs, VE was 58% (95%CI: 11; 80). VE against medically attended COVID-19 was 52% (95%CI: 28; 68), and VE against hospitalization was 69% (95% CI: 36; 85). During the period of predominant Delta variant circulation (July-December 2021), VE against symptomatic COVID-19 was 52% (95%CI: 30; 66).
Conclusions
Primary series vaccination with BNT162b2 and BBIBP-CorV was effective at preventing
COVID-19 among HCWs, most of whom had previous infection, during a period of mainly Delta circulation. Our results support the utility of COVID-19 primary vaccine series, and the importance of increasing coverage, even among previously infected individuals.
Public Health and Healthcare, Public, Environmental and Occupational Health
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
