BNT162b2 Vaccine Booster and Mortality Due to Covid-19

Abstract

Background The emergence of the B.1.617.2 (delta) variant of severe acute respiratory syndrome coronavirus 2 and the reduced effectiveness over time of the BNT162b2 vaccine (Pfizer–BioNTech) led to a resurgence of coronavirus disease 2019 (Covid-19) cases in populations that had been vaccinated early. On July 30, 2021, the Israeli Ministry of Health approved the use of a third dose of BNT162b2 (booster) to cope with this resurgence. Evidence regarding the effectiveness of the booster in lowering mortality due to Covid-19 is still needed. Methods We obtained data for all members of Clalit Health Services who were 50 years of age or older at the start of the study and had received two doses of BNT162b2 at least 5 months earlier. The mortality due to Covid-19 among participants who received the booster during the study period (booster group) was compared with that among participants who did not receive the booster (nonbooster group). A Cox proportional-hazards regression model with time-dependent covariates was used to estimate the association of booster status with death due to Covid-19, with adjustment for sociodemographic factors and coexisting conditions. Results A total of 843,208 participants met the eligibility criteria, of whom 758,118 (90%) received the booster during the 54-day study period. Death due to Covid-19 occurred in 65 participants in the booster group (0.16 per 100,000 persons per day) and in 137 participants in the nonbooster group (2.98 per 100,000 persons per day). The adjusted hazard ratio for death due to Covid-19 in the booster group, as compared with the nonbooster group, was 0.10 (95% confidence interval, 0.07 to 0.14; P<0.001). Conclusions Participants who received a booster at least 5 months after a second dose of BNT162b2 had 90% lower mortality due to Covid-19 than participants who did not receive a booster.

Duration of immunity against COVID-19 after vaccination in Indian subcontinent

“…Based on their observation they administered a booster dose and demonstrated protection against COVID-19. 6,7 Our results suggest that enumerating antibody titres at 6 months especially in those with comorbidities would help in prioritizing such individuals for booster dosing…”

Comparative analysis of BNT162b2, mRNA-1273 and ChAdOx1 COVID-19 vaccine induced antibody responses and the 3rd BNT162b2 vaccine induced neutralizing antibodies against Delta and Omicron variants

“…However, the antibody levels decline, and the surveillance of vaccine effectiveness and the decline of immune responses highlighted the need for a vaccine booster doses in the first group of vaccinees who received the vaccine with a 3-week interval 7,8 . Initial studies have shown that a third dose of COVID-19 vaccines strongly boost the waning immune responses and on the population level reduce severe COVID-19-associated morbidity and mortality [9][10][11] . Decisions for the third vaccine dose have been further promoted by the emergence of new SARS-CoV-2 variants-of-concerns (VOCs).…”

SARS-CoV2 vaccine boosters for India

“…With the omicron variant rising in several countries, the demand for boosters has been increasing. Prior to the emergence of the omicron variant, countries with excellent vaccination programmes used data that indicated a waning of vaccine effectiveness against infection and symptomatic disease with the delta variant to make the case for booster doses for their populations [ 1 ], an approach that has been amplified with the new variant.…”

“…Data from Israel, which exclusively used the Pfizer vaccine showed initial very high levels of protection against death, severe disease, all symptomatic infection and all infection. This protection declined with time, particularly with the delta variant, prompting Israel to begin booster doses with the same vaccine in July 2021, raising protection to high levels again [ 1 ]. In the UK, data with both Astra Zeneca and Pfizer vaccine showed similar high initial protection but a decline of about 15% against severe disease over time with the delta variant [ 4 ].…”