key: cord-0705123-avfv6omk
authors: Muhsen, Khitam; Maimon, Nimrod; Mizrahi, Ami; Varticovschi, Baruch; Bodenheimer, Omri; Gelbshtein, Udi; Grotto, Itamar; Cohen, Dani; Dagan, Ron
title: Effects of BNT162b2 Covid-19 Vaccine Booster in Long-Term Care Facilities in Israel
date: 2021-12-22
journal: N Engl J Med
DOI: 10.1056/nejmc2117385
sha: ae93a3466d56bfd9166aaadb043d1b9d9cdafb99
doc_id: 705123
cord_uid: avfv6omk

nan

under 20 years of age. In this analysis, we calculated the weekly incidence of PCR-confirmed SARS-CoV-2 infection, hospitalization for severe Covid-19, and Covid-19-related death. Changes in incidence were analyzed with the use of Poisson regression models, as evaluated separately for each group and time period (weeks 26 to 30 before the booster campaign and weeks 31 to 36 after the booster campaign). We compared the rates during a calendar week of interest with the rates during the first week in each period. The relative reduction was calculated as 1 minus the incidence rate ratio times 100. In these analyses, a P value of less than 0.05 was considered to indicate statistical significance; P values were adjusted for multiplicity with the use of the Benjamini-Hochberg method. The study was approved by the ethics committee at Soroka University Medical Center.

The mean age of the residents of long-term care facilities was 81.8 years; 70.6% of the residents were women (Table S1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). During the prebooster period, the incidences of SARS-CoV-2 infection (Table S2) and hospitalization for severe Covid-19 (Table S3 ) increased in all the study groups ( Fig.  S1A and S1B). The BNT162b2 booster campaign in the long-term care facilities was characterized by a rapid implementation (Fig. 1A) . Figure 1B shows the proportion of all residents of longterm care facilities according to their immunestatus category and the time period. The uptake of the booster dose among persons who were 60 years of age or older in the general population was lower than that among the residents of long-term care facilities, and the uptake was lowest among persons in the younger age groups (Fig. 1C) .

During the booster period, the dynamics of Covid-19 incidence differed among the groups. Among the residents of long-term care facilities, significantly lower rates of SARS-CoV-2 infection and hospitalization for severe Covid-19 were observed starting at week 34 as compared with week 31 (the first week of the booster program). By week 36, the incidence rate ratio had reached 0.29 for overall infection and 0.20 for hospitalization, which corresponded to a relative rate reduction of 71% and 80%, respectively. Among persons who were 60 years of age or older in the general population, the decline after booster vaccination was of lower magnitude and was observed for all SARS-CoV-2 infections during weeks 35 and 36 only, with no significant decrease in the risk of hospitalization for severe disease. Among persons who were younger than 60 years of age, no significant decreases were observed in the incidence of either infection or hospitalization during the study period. Generally, mortality was higher among residents of long-term care facilities than among other groups. Rates of death varied widely during the booster period among the residents of long-term care facilities, with a decrease from 0.3 per 1000 population in week 34 to 0.1 per 1000 population in week 36. The rate of death continuously increased in the general population in the same age group, from 0.05 per 1000 population in week 31 to 0.1 per 1000 population in week 36 (Fig. S1C) .

In a previous study involving participants who were 60 years of age or older and had received two doses of the BNT162b2 vaccine at least 5 months earlier, the rates of confirmed Covid-19 and severe illness were substantially lower among those who had received a booster dose. 5 In the current study, after the initiation of an intensive BNT162b2 booster campaign with high vaccine uptake, we found a significant, rapid, and consistent reduction in the Covid-19 burden among persons in the same age group who were living in long-term care facilities. The reduction in the incidence of Covid-19 infection was delayed and of a lower magnitude among persons in the same age group in the general population during the booster period; among the younger age groups, no significant decreases were noted. Our results suggest the important reallife effects of the nationwide BNT162b2 vaccine booster program among residents in long-term care facilities. Panel A shows the daily number of new cases of SARS-CoV-2 infection, as confirmed on polymerasechain-reaction (PCR) assay, among 41,623 residents of Israeli long-term care facilities, along with the cumulative uptake of the BNT162b2 booster dose, from July 1 through September 11, 2021. The dashed line represents the moving average of infections. Panel B shows the changes in Covid-19 immune status among residents of long-term care facilities, according to the following categories: vaccination in process, unvaccinated and no previous Covid-19, vaccination with the second dose more than 5 months earlier, vaccination with the second dose within the past 5 months, booster vaccination 14 or more days earlier, recovered from Covid-19 and vaccinated (any number of doses), and recovered from Covid-19 and unvaccinated. Panel C shows the cumulative uptake of the BNT162b2 booster dose according to study group.

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Effectiveness of BNT162b2 mRNA COVID-19 vaccine against acquisitions of SARS-CoV-2 among health care workers in long-term care facilities: a prospective cohort study

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Correspondence Copyright © 2021 Massachusetts Medical Society

Drs. Muhsen