Pfizer announced on Monday that an early analysis of its coronavirus vaccine trial suggested the vaccine was robustly effective in preventing Covid-19. The announcement didn’t come with many details so I don’t have many details to share except the following:
The Phase III Trial was conducted in the U.S. and has enrolled about 44,000 volunteers. About half of the participants were in the placebo group and about half were in the group that got the vaccine (with a booster a month later). The company said that almost all of the 94 persons in the trial that ended up contracting COVID-19 were in the placebo group. Statistically speaking, they said that the Phase III data (which has not been disclosed) suggests that the vaccine is 90% effective at preventing COVID-19. They also said that no serious adverse events were identified.
A couple of cautionary notes are that these results haven’t been released or published in a peer-reviewed journal article. Also, many of the participants in the Phase III trial haven’t been followed up for even a full 60 days yet (important for identifying adverse events).
There are 11 vaccines in late Phase III trials right now including 4 in the U.S. This Pfizer vaccine as well as Moderna’s candidate use a new Messenger RNA technology that has never before been used to create a vaccine. Both Moderna and Pfizer expect to submit full Phase III trial data in the coming weeks.
Here’s a link to one of my previous blog posts that discusses how vaccines are tested and approved.
