The companies said in a press release that they would increase the size of the study to 44,000 participants from an initial recruitment target of 30,000 individuals.
The US Food and Drug Administration must approve the change before it takes effect.
“Companies expect a decisive readout on efficacy by the end of October,” the press release stated. The Pfizer and BioNTech studies are likely to be the first in the US to report efficacy data from Phase 3 trials.
Extending the test will likely make it easier for the company to demonstrate whether the vaccine is effective against SARS-CoV-2, which causes the virus Kovid-19. The companies also said that the change would allow the study to include a more diverse population. The companies said the study would now include teenagers as young as 16, people with stable HIV, and people with hepatitis C or hepatitis B.
The companies said the trial is expected to reach 30,000 patients by next week. Modern, which began its testing on the same day as Pfizer, said on 4 September that it was working to increase the diversity of trial participants in its study, “even if those efforts impact enrollment speed . ”
The Pfizer / BioNTech study may end sooner than modernity, even if both started on the same day, for other reasons, as well. Both vaccines require a second shot; Pfizer is given after three weeks, while Modern is given after four. Pfizer’s trial also begins to count the cases of Kovid-19 when participants receive their shots compared to the Modern Study.
But the Pfizer / BioNTech vaccine may also prove to be the most difficult of the experimental vaccines to deliver, should they prove effective. The vaccine should be stored at a temperature of -70 ° C.
With President Trump saying that there is political pressure to move a vaccine quickly, it may be available before Election Day. Last week, a number of drug manufacturers, including Pfizer, issued a resolution not to pursue a vaccine any sooner than would be reasonable from the results of their clinical trials.