Pfizer shares great news on COVID-19 vaccine booster dose
Pfizer and BioNTech on Thursday announced topline results from a Phase 3 randomized, controlled trial evaluating the efficacy and safety of a 30-µg booster dose of the Pfizer-BioNTech COVID-19 Vaccine in more than 10,000 individuals 16 years of age and older.
In the trial, a booster dose administered to individuals who previously received the Pfizer-BioNTech primary two-dose series restored vaccine protection against COVID-19 to the high levels achieved after the second dose, showing a relative vaccine efficacy of 95.6% when compared to those who did not receive a booster. These are the first efficacy results from any randomized, controlled COVID-19 vaccine booster trial.
Pfizer and BioNTech plan to submit detailed results from the trial for peer-reviewed publication. The companies also plan to share these data with the U.S. Food and Drug Administration, European Medicines Agency, and other regulatory agencies around the world as soon as possible.
The trial results come a day after the U.S. Food and Drug Administration authorized booster doses of the Covid-19 vaccines from Moderna and Johnson & Johnson and said Americans could choose a different shot from their original inoculation as a booster.
On September 22, 2021, the FDA authorised a booster dose of the Pfizer-BioNTech COVID-19 shot at least six months after the second dose for people aged 65 and older, adults (18-64) at high risk of severe COVID-19, and those (18-64) with frequent institutional or occupational exposure to SARS-CoV-2.
On October 20, 2021, a booster dose of the vaccine also was authorized for emergency use by the U.S. FDA in eligible individuals who have completed a primary vaccination with a different authorized COVID-19 vaccine. In addition, a booster dose of the vaccine is authorized in the European Union and other countries, with recommendations for populations varying based on local health authority guidance.
Dr Walid Gellad, a professor at University of Pittsburgh’s medical school, said there seems to be a benefit of having the third dose in the Delta wave for symptomatic COVID-19.
“I’m just still very curious if this is primarily in people who are much, much older. Because what we don’t want to do is run out and give boosters to 25-year-olds who had COVID before and got two doses of the vaccine, just based on this press release,” Reuters cited Gellad as saying.
“These results provide further evidence of the benefits of boosters as we aim to keep people well-protected against this disease,” said Albert Bourla, Chairman and Chief Executive Officer, Pfizer.
“Based on these findings we believe that, in addition to broad global access to vaccines for everyone, booster vaccinations could play an important role in sustaining pandemic containment and a return to normalcy," added Ugur Sahin, M.D., CEO and Co-Founder of BioNTech.
The companies said the median time between second dose and administration of the booster dose or placebo was approximately 11 months. Symptomatic COVID-19 occurrence was measured from at least 7 days after booster or placebo, with a median follow-up of 2.5 months. During the study period, there were 5 cases of COVID-19 in the booster group, and 109 cases in the non-boosted group.
The observed relative vaccine efficacy of 95.6% (95% CI: 89.3, 98.6) reflects the reduction in disease occurrence in the boosted group versus the non-boosted group in those without evidence of prior SARS-CoV-2 infection.
Median age of participants was 53 years, with 55.5% of participants between 16 and 55 years, and 23.3% of participants 65 years and older. Multiple subgroup analyses showed efficacy was consistent irrespective of age, sex, race, ethnicity, or comorbid conditions.
Protection across age groups of the Pfizer-BioNTech vaccine booster against COVID-19
Following administration to persons 60+ years of age, the booster vaccination campaign in Israel was gradually expanded to younger age groups who received a second dose >5 months earlier. Researchers are studying the booster effect on COVID-19 outcomes.
Researchers extracted data for the period July 30, 2021 to October 6, 2021 from the Israeli Ministry of Health database regarding 4,621,836 persons. They compared confirmed COVID-19 infections, severe illness, and death of those who received a booster ≥12 days earlier (booster group) with a nonbooster group.
In a secondary analysis, they compared the rates 3-7 days with ≥12 days after receiving the booster dose. They used Poisson regressions to estimate rate ratios after adjusting for possible confounding factors.
The results showed that
- confirmed infection rates were about 10-fold lower in the booster versus nonbooster group (ranging 8.8-17.6 across five age groups) and 4.8-11.2 fold lower in the secondary analysis.
- severe illness rates in the primary and secondary analysis were 18.7-fold (95% CI, 15.7-22.4) and 6.5-fold (95% CI, 5.1-8.3) lower for ages 60+, and
- 22.0-fold (95% CI, 10.3-47.0) and 3.2-fold (95% CI, 1.1-9.6) lower for ages 40-60.
- for ages 60+, COVID-19 associated death rates were 14.7-fold (95% CI, 9.4-23.1) lower in the primary analysis and
- 4.8-fold (95% CI, 2.8-8.2) lower in the secondary analysis.
Across all age groups, rates of confirmed infection and severe illness were substantially lower among those who received a booster dose of the BNT162b2 vaccine.
