COVID-19 Booster Reduces Delta Variant Mortality by 90%

The emerging Omicron variant has recently dominated news cycles and public concern, but 95% of COVID-19 infections in the US are still caused by the Delta variant.

Luckily, an Israeli study published this week found that 3 doses of the Pfizer-BioNTech vaccine (2 initial doses and 1 “booster” dose at least 5 months later) reduce the risk of dying from the Delta variant by 90%.

The study consisted of 843000 Israelis who received an initial 2-dose series of Pfizer-BioNTech and were eligible for a booster vaccination. Of this cohort, approximately 758000 opted to receive a Pfizer-BioNTech booster.

The study ran from August-September 2021, during which Delta was the predominant COVID-19 strain in Israel. During this study period, 65 participants who received a third booster dose died, compared to 137 deaths in the non-booster group.

A second Israeli study of 4.7 million participants fully vaccinated with Pfizer-BioNTech found those who received a booster had a ten-fold reduction in COVID-19 infection. Additionally, resistance to Delta increased the longer the booster vaccine was in a person’s system.

Pfizer-BioNTech boosters were recently authorized for all US adults and adolescents 16-17 years of age.

On Wednesday, Pfizer-BioNTech released data showing 3 doses of their COVID-19 vaccine neutralized the Omicron variant. Omicron’s mutations are still 80% susceptible to Pfizer-BioNTech’s vaccine, and while 2 doses likely still protect against severe disease, a booster dose significantly increases resistance.

Notably, however, a third dose boosts antibody levels back to where they were before the emergence of Omicron. Pfizer-BioNTech is continuing to test the efficacy of 2 and 3 doses of its vaccine against the current and any subsequent variants.