Pfizer and BioNTech have said that their coronavirus vaccine may be more than 90% effective, after the two pharmaceutical firms released interim data from their ongoing large-scale trial.
Preliminary analysis, conducted by an independent data monitoring board, looked at 94 infections recorded so far in the vaccine’s phase 3 study, which has enrolled nearly 44,000 people in the US and five other countries.
Of those participants who were infected with COVID-19, it is currently unclear how many had received the vaccine versus those who had been given a placebo. The current efficacy rate, which is much better than most experts expected, implies that no more than eight volunteers will have been inoculated.
The data have yet to be peer-reviewed, and Pfizer said the initial protection rate might change by the time the study ends. The longevity of the immune response provoked by the mRNA-based vaccine also remains unknown.
However, the findings are the most promising indication to date that a vaccine will be effective in preventing disease among infected individuals, handing humanity a crucial tool in tackling the pandemic.
Pfizer and its German partner BioTech will continue with the phase 3 trial until 164 infections have been reported among volunteers - a figure that will give regulatory authorities a clearer idea of the vaccine’s efficacy.
This number is expected to be reached by early December in light of the rising US infection rates, Pfizer said.
The two companies said they have so far found no serious safety concerns and expect to seek US emergency use authorisation later this month.
Source: The Independent, 9 November 2020