The data set offers a more complete view than the promising early results Pfizer shared Monday, November 9th (at the time, the drugmaker said the vaccine was more than 90% effective). Pfizer, and its partner BioNTech, now plan to apply to the Food and Drug Administration for emergency authorization to start producing and distributing the vaccine.
The trial consisted of about 44,000 volunteers, half of whom received the two-dose vaccine, while the other half received a placebo. Out of the 170 cases of Covid-19 that developed, 162 were in the placebo group, and the rest were in the vaccine group. There were 10 total cases of severe Covid-19, and nine of them came from the placebo group.
The trial also showed that the vaccine was consistently effective across age, race, and ethnicity groups, and was 94% effective in older people, who are most vulnerable to Covid-19. Although the side effects were minimal, about 3.7% of volunteers reported fatigue, while 2% reported a headache after receiving the second dose.
Akiko Iwasaki, an immunologist at Yale University, praised the results, especially among people who are 65 years or older. “We know from the influenza vaccine that it’s very difficult to achieve protection in this age group with vaccines,” she said.
Should the FDA approve the vaccine, Pfizer said it could have up to 50 million doses available by the end of the year, and 1.3 billion by the end of next year. But only half of its supply will go to the United States, so only about 12.5 million people here will have access to it. Per federal health officials, most doses will be given to health care workers or those who are most vulnerable.
The biggest hitch in Pfizer’s vaccine remains the fact that it must be stored at extremely cold temperatures of minus 94 degrees Fahrenheit. The company plans to ship it in special boxes packed with dry ice, where it will be able to stay for up to 15 days so long as the dry ice is replenished and the box isn’t opened more than a couple of times per day.
Pfizer’s bolstered results come days after another drugmaker, Moderna, announced that preliminary trials showed its Covid-19 vaccine was nearly 95% effective (that one can be refrigerated normally — and its development was funded in part by Dolly Parton). Both studies have yet to be peer-reviewed, but Pfizer plans to submit its results for review in a scientific journal soon. Additionally, Moderna still needs to wait until there are 151 cases of Covid-19 among its study patients before it can apply for FDA emergency authorization.