The New England Journal of Medicine has just published the data sharing the high degree of protection of a third dose of the Pfizer-BioNTech mRNA coronavirus vaccine in Israel. The study included 1,137,804 individuals in the age 60 to 69, age 70 to 79, and age 80 to 89 populations during July 30 to August 31, 2021 who had 2 doses of the Pfizer-BioNTech vaccine at least 5 months before enrollment in the study and had not travelled abroad in the one month study period.
The authors report that at least 12 days after the booster dose, 11.3 times fewer infections were seen in the booster group than the non-boosted group. Those that received the booster dose also had a 19.5 times lower rate of severe illness than those that did not receive a third vaccine dose.
DOI: 10.1056/NEJMoa2114255
Figure 2. Reduction in Rate of Confirmed Infection in Booster Group as Compared with Nonbooster Group.
Shown is the factor reduction in the rate of confirmed infection among participants who received a third (booster) dose of the BNT162b2 vaccine as compared with those who did not receive a booster dose, according to the number of days after the administration of the booster dose. Because of wide confidence intervals, only days 1 through 25 are shown. The dashed horizontal line represents the level at which the booster dose provided no added protection. The 𝙸 bars represent 95% confidence intervals, which have not been corrected for multiplicity.
The authors summarize: “ Understanding the protection gained by a booster dose is critical for public health policy. On July 30, 2021, Israel was the first country in the world to make available a third dose of the BNT162b2 vaccine against Covid-19 to all persons who were 60 years of age or older and who had been vaccinated at least 5 months earlier. Since then, Israel has extended the booster program to the entire population. The results of such a policy are important for policymakers in countries that are exploring strategies to mitigate the pandemic. Our findings give clear indications of the effectiveness of a booster dose even against the currently dominant delta variant. Future studies will help determine the long-term effectiveness of the booster dose against current and emerging variants.”
Supplementary materials are available here.