The third dose of Pfizer-BioNTech vaccine against coronavirus disease (Covid-19) has shown 95.6% efficacy compared to those who did not receive a booster, according to the vaccine makers. Pfizer-BioNTech announced the results on Thursday from a Phase 3 trial evaluating the efficacy and safety of a 30-µg booster dose, the same dosage strength as those in the primary series, of the mRNA-based Pfizer-BioNTech Covid-19 Vaccine. 

“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 said in a statement.

More than 10,000 individuals who had completed the primary two-dose series of the Pfizer Covid-19 vaccine participated in the booster dose trial. Half of the trial participants received a 30-µg booster dose while the other half received a placebo. The researchers identified five Covid-19 cases in the booster dose group while 109 cases in the placebo group.

Citing multiple subgroup analyses, the study suggests that booster dose efficacy was consistent irrespective of age, sex, race, ethnicity, or comorbid conditions.

The US and German partners are the first to publish efficacy results from any randomized, controlled Covid-19 vaccine booster trial.

“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,” Bourla added.

Pfizer-BioNTech and Moderna Covid vaccines are at the centre of the immunisation programme in the United States to fight the pandemic.

The US Food and Drug Administration (FDA) has already authorised the third dose of Pfizer Covid vaccine for emergency use among individuals 65 years of age and older, all adults at high risk of severe Covid-19, and those with frequent institutional or occupational exposure to the virus.