TY - JOUR
T1 - Early effectiveness of BNT162b2 Covid-19 vaccine in preventing SARS-CoV-2 infection in healthcare personnel in six Israeli hospitals (CoVEHPI)
AU - Katz, Mark A.
AU - Harlev, Efrat Bron
AU - Chazan, Bibiana
AU - Chowers, Michal
AU - Greenberg, David
AU - Peretz, Alon
AU - Tshori, Sagi
AU - Levy, Joseph
AU - Yacobi, Mili
AU - Hirsch, Avital
AU - Amichay, Doron
AU - Weinberger, Ronit
AU - Dor, Anat Ben
AU - Taraday, Elena Keren
AU - Reznik, Dana
AU - Chayat, Chen Barazani
AU - Sagas, Dana
AU - Zvi, Haim Ben
AU - Berdinstein, Rita
AU - Rashid, Gloria
AU - Avni, Yonat Shemer
AU - Mandelboim, Michal
AU - Zuckerman, Neta
AU - Rainy, Nir
AU - Akriv, Amichay
AU - Dagan, Noa
AU - Kepten, Eldad
AU - Barda, Noam
AU - Balicer, Ran D.
N1 - Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2022/1/24
Y1 - 2022/1/24
N2 - Background: Methodologically rigorous studies on Covid-19 vaccine effectiveness (VE) in preventing SARS-CoV-2 infection are critically needed to inform national and global policy on Covid-19 vaccine use. In Israel, healthcare personnel (HCP) were initially prioritized for Covid-19 vaccination, creating an ideal setting to evaluate early real-world VE in a closely monitored population. Methods: We conducted a prospective study among HCP in 6 hospitals to estimate the effectiveness of the BNT162b2 mRNA Covid-19 vaccine in preventing SARS-CoV-2 infection. Participants filled out weekly symptom questionnaires, provided weekly nasal specimens, and three serology samples – at enrollment, 30 days and 90 days. We estimated VE against PCR-confirmed SARS-CoV-2 infection using the Cox Proportional Hazards model and against a combined PCR/serology endpoint using Fisher's exact test. Results: Of the 1567 HCP enrolled between December 27, 2020 and February 15, 2021, 1250 previously uninfected participants were included in the primary analysis; 998 (79.8%) were vaccinated with their first dose prior to or at enrollment, all with Pfizer BNT162b2 mRNA vaccine. There were four PCR-positive events among vaccinated participants, and nine among unvaccinated participants. Adjusted two-dose VE against any PCR-confirmed infection was 94.5% (95% CI: 82.6%-98.2%); adjusted two-dose VE against a combined endpoint of PCR and seroconversion for a 60-day follow-up period was 94.5% (95% CI: 63.0%-99.0%). Five PCR-positive samples from study participants were sequenced; all were alpha variant. Conclusions: Our prospective VE study of HCP in Israel with rigorous weekly surveillance found very high VE for two doses of Pfizer BNT162b2 mRNA vaccine against SARS-CoV-2 infection in recently vaccinated HCP during a period of predominant alpha variant circulation. Funding: Clalit Health Services.
AB - Background: Methodologically rigorous studies on Covid-19 vaccine effectiveness (VE) in preventing SARS-CoV-2 infection are critically needed to inform national and global policy on Covid-19 vaccine use. In Israel, healthcare personnel (HCP) were initially prioritized for Covid-19 vaccination, creating an ideal setting to evaluate early real-world VE in a closely monitored population. Methods: We conducted a prospective study among HCP in 6 hospitals to estimate the effectiveness of the BNT162b2 mRNA Covid-19 vaccine in preventing SARS-CoV-2 infection. Participants filled out weekly symptom questionnaires, provided weekly nasal specimens, and three serology samples – at enrollment, 30 days and 90 days. We estimated VE against PCR-confirmed SARS-CoV-2 infection using the Cox Proportional Hazards model and against a combined PCR/serology endpoint using Fisher's exact test. Results: Of the 1567 HCP enrolled between December 27, 2020 and February 15, 2021, 1250 previously uninfected participants were included in the primary analysis; 998 (79.8%) were vaccinated with their first dose prior to or at enrollment, all with Pfizer BNT162b2 mRNA vaccine. There were four PCR-positive events among vaccinated participants, and nine among unvaccinated participants. Adjusted two-dose VE against any PCR-confirmed infection was 94.5% (95% CI: 82.6%-98.2%); adjusted two-dose VE against a combined endpoint of PCR and seroconversion for a 60-day follow-up period was 94.5% (95% CI: 63.0%-99.0%). Five PCR-positive samples from study participants were sequenced; all were alpha variant. Conclusions: Our prospective VE study of HCP in Israel with rigorous weekly surveillance found very high VE for two doses of Pfizer BNT162b2 mRNA vaccine against SARS-CoV-2 infection in recently vaccinated HCP during a period of predominant alpha variant circulation. Funding: Clalit Health Services.
UR - http://www.scopus.com/inward/record.url?scp=85121136797&partnerID=8YFLogxK
U2 - 10.1016/j.vaccine.2021.11.092
DO - 10.1016/j.vaccine.2021.11.092
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C2 - 34903372
AN - SCOPUS:85121136797
SN - 0264-410X
VL - 40
SP - 512
EP - 520
JO - Vaccine
JF - Vaccine
IS - 3
ER -