TY - JOUR T1 - Association of a Third Dose of BNT162b2 Vaccine With Incidence of SARS-CoV-2 Infection Among Health Care Workers in Israel. AU - Spitzer,Avishay, AU - Angel,Yoel, AU - Marudi,Or, AU - Zeltser,David, AU - Saiag,Esther, AU - Goldshmidt,Hanoch, AU - Goldiner,Ilana, AU - Stark,Moshe, AU - Halutz,Ora, AU - Gamzu,Ronni, AU - Slobodkin,Marina, AU - Amrami,Nadav, AU - Feigin,Eugene, AU - Elbaz,Meital, AU - Furman,Moran, AU - Bronstein,Yotam, AU - Chikly,Amanda, AU - Eshkol,Anna, AU - Furer,Victoria, AU - Mayer,Talia, AU - Meijer,Suzy, AU - Melloul,Ariel, AU - Mizrahi,Michal, AU - Yakubovsky,Michal, AU - Rosenberg,Dana, AU - Safir,Ari, AU - Spitzer,Liron, AU - Taleb,Eyal, AU - Elkayam,Ori, AU - Silberman,Adi, AU - Eviatar,Tali, AU - Elalouf,Ofir, AU - Levinson,Tal, AU - Pozyuchenko,Katia, AU - Itzhaki-Alfia,Ayelet, AU - Sprecher,Eli, AU - Ben-Ami,Ronen, AU - Henig,Oryan, PY - 2022/1/11/pubmed PY - 2022/2/2/medline PY - 2022/1/10/entrez SP - 341 EP - 349 JF - JAMA JO - JAMA VL - 327 IS - 4 N2 - Importance: Administration of a BNT162b2 booster dose (Pfizer-BioNTech) to fully vaccinated individuals aged 60 years and older was significantly associated with lower risk of SARS-CoV-2 infection and severe illness. Data are lacking on the effectiveness of booster doses for younger individuals and health care workers. Objective: To estimate the association of a BNT162b2 booster dose with SARS-CoV-2 infections among health care workers who were previously vaccinated with a 2-dose series of BNT162b2. Design, Setting, and Participants: This was a prospective cohort study conducted at a tertiary medical center in Tel Aviv, Israel. The study cohort included 1928 immunocompetent health care workers who were previously vaccinated with a 2-dose series of BNT162b2, and had enrolled between August 8 and 19, 2021, with final follow-up reported through September 20, 2021. Screening for SARS-CoV-2 infection was performed every 14 days. Anti-spike protein receptor binding domain IgG titers were determined at baseline and 1 month after enrollment. Cox regression with time-dependent analysis was used to estimate hazard ratios of SARS-CoV-2 infection between booster-immunized status and 2-dose vaccinated (booster-nonimmunized) status. Exposures: Vaccination with a booster dose of BNT162b2 vaccine. Main Outcomes and Measures: The primary outcome was SARS-CoV-2 infection, as confirmed by reverse transcriptase-polymerase chain reaction. Results: Among 1928 participants, the median age was 44 years (IQR, 36-52 years) and 1381 were women (71.6%). Participants completed the 2-dose vaccination series a median of 210 days (IQR, 205-213 days) before study enrollment. A total of 1650 participants (85.6%) received the booster dose. During a median follow-up of 39 days (IQR, 35-41 days), SARS-CoV-2 infection occurred in 44 participants (incidence rate, 60.2 per 100 000 person-days); 31 (70.5%) were symptomatic. Five SARS-CoV-2 infections occurred in booster-immunized participants and 39 in booster-nonimmunized participants (incidence rate, 12.8 vs 116 per 100 000 person-days, respectively). In a time-dependent Cox regression analysis, the adjusted hazard ratio of SARS-CoV-2 infection for booster-immunized vs booster-nonimmunized participants was 0.07 (95% CI, 0.02-0.20). Conclusions and Relevance: Among health care workers at a single center in Israel who were previously vaccinated with a 2-dose series of BNT162b2, administration of a booster dose compared with not receiving one was associated with a significantly lower rate of SARS-CoV-2 infection over a median of 39 days of follow-up. Ongoing surveillance is required to assess durability of the findings. SN - 1538-3598 UR - https://www.unboundmedicine.com/medline/citation/35006256/Association_of_a_Third_Dose_of_BNT162b2_Vaccine_With_Incidence_of_SARS_CoV_2_Infection_Among_Health_Care_Workers_in_Israel_ DB - PRIME DP - Unbound Medicine ER -