https://www.selleckchem.com/products/cx-5461.html COVID-19 mRNA vaccines were shown to be highly efficacious in preventing the disease in randomized controlled trials; nonetheless, evidence on the real-world effectiveness of this vaccine is limited. Study objective was to evaluate the effectiveness of BNT162b2 vaccine in preventing SARS-CoV-2 infection and COVID-19-related hospitalization and mortality. This historical cohort study included members of a large health provider in Israel that were vaccinated with at least one dose of BNT162b2. The primary outcome was incidence rate of a SARS-CoV-2 infection confirmed with rt-PCR, between 7 to 27 days after second dose (protection-period), as compared to days 1 to 7 after the first dose, where no protection by the vaccine is assumed (reference-period). Data of 1,178,597 individuals vaccinated with BNT162b2 were analyzed (mean age 47.7 years [SD=18.1], 48.4% males) of whom 872,454 (74.0%) reached the protection period. Overall, 4514 infections occurred during the reference period compared to 728 during the protection period, yielding a weighted mean daily incidence of 54.8 per 100,000 (95%CI 26.1-115.0 per 100,000) and 5.4 per 100,000 (95%CI 3.5-8.4 per 100,000), respectively. The vaccine effectiveness in preventing infection was 90% (95%CI79%- 95%) and 94% (95%CI88%-97%) against COVID-19. Among immunosuppressed patients, vaccine effectiveness against infection was 71% (95%CI37%-87%). The adjusted hazard ratios for hospitalization in those infected were 0.82 (95%CI0.36-1.88), 0.45 (95%CI0.23-0.90), and 0.56 (95%CI0.36-0.89) in the age groups 16-44, 45-64 and 75 and above, respectively. The effectiveness of the BNT162b2 vaccine is comparable to the one reported in the phase III clinical trial. The effectiveness of the BNT162b2 vaccine is comparable to the one reported in the phase III clinical trial. As the U.S. population ages, the prevalence of disability and functional limitations, and demand for long-term services and