Thursday 21 October 2021

Pfizer releases trial data showing booster shot of its COVID-19 vaccine is 95.6% effective against infection

 Pfizer-BioNTech released data on Thursday showing a booster dose of their COVID-19 vaccine is highly effective against the virus, including the Delta variant.

Initial results from a Phase III trial of more than 10,000 participants aged 16 and older showed booster efficacy of 95.6 percent.

The study also found that the booster shot was found to be safe with no safety concerns or severe adverse events reported. 

Pfizer had said its two-shot vaccine's efficacy drops over time, citing a study that showed 84 percent effectiveness four months later after a peak of 96 percent - and said this is evidence that a booster is needed to sustain protection against Covid. 

New Phase III clinical trial data from Pfizer-BioNTech found that a booster dose of their COVID-19 vaccine was 95.6% effective against infection, up from 84% four months after two doses. Pictured: Shyrel Ritter, a certified nursing assistant at the Hebrew Home at Riverdale, receives her COVID-19 booster shot at her workplace in New York, October 8

New Phase III clinical trial data from Pfizer-BioNTech found that a booster dose of their COVID-19 vaccine was 95.6% effective against infection, up from 84% four months after two doses. Pictured: Shyrel Ritter, a certified nursing assistant at the Hebrew Home at Riverdale, receives her COVID-19 booster shot at her workplace in New York, October 8

Five cases of COVID-19 were detected in the booster group compared to 109 cases in the control group. Pictured: A vial of the Pfizer vaccine sitting n a table, October 15

Five cases of COVID-19 were detected in the booster group compared to 109 cases in the control group. Pictured: A vial of the Pfizer vaccine sitting n a table, October 15

'These results provide further evidence of the benefits of boosters as we aim to keep people well-protected against this disease,' said Pfizer CEO Albert Bourla in a statement.

'In addition to our efforts to increase global access and uptake among the unvaccinated, we believe boosters have a critical role to play in addressing the ongoing public health threat of this pandemic.

'We look forward to sharing these data with health authorities and working together to determine how they can be used to support the rollout of booster doses around the world.'

For the study, participants were split into two groups: half of whom received a 30 microgam (µg) booster - the same dose as that used for the two-dose vaccine - and the other half of whom received a placebo.


The median age of the participants was 53 years, with 55.5 percent of participants between 16 and 55 years, and 23.3 percent at 65 years or older. 

Researchers found five cases of COVID-19 in the booster group compared to 109 cases in the control group - a difference of 21.8-fold.

They say the findings suggest an efficacy of 95.6 percent against infection.  

'These important data add to the body of evidence suggesting that a booster dose of our vaccine can help protect a broad population of people from this virus and its variants,' said Dr Ugur Sahin, CEO and co-founder of BioNTech. 

'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.'


The companies said they would submit detailed results of the trial for peer-reviewed publication to the U.S. Food and Drug Administration (FDA), the European Medicines Agency and other regulatory agencies as soon as possible.

U.S. and EU regulators have already authorized a third dose of COVID-19 vaccines by Pfizer-BioNTech for patients with compromised immune systems who are likely to have weaker protection from the two-dose regimens.

Last month, the FDA also authorized a third dose for Americans aged 65 and older or those between ages 18 and 64 who are at high risk due to underlying conditions or their jobs.

This has since been expanded to allow fully vaccinated Americans to 'mix and match' Covid vaccines and booster shots.  

This means people can receive a Pfizer booster even if they initially received a Moderna or Johnson & Johnson vaccine.

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