Pfizer ends its Covid-19 vaccine trial with a 95% success rate

Final results from Pfizer Inc's Covid-19 vaccine trial showed its shot had a 95% success rate and two months of safety data, paving the way for the drugmaker to apply for an emergency US authorization within days, it said on Wednesday.

The vaccine’s efficacy rate, the highest of any candidate in late-stage clinical trials so far, pleased experts who had already said that interim results showing Pfizer’s shot was over 90% effective were very encouraging.

Pfizer said there were 170 cases of Covid-19 in its trial of more than 43,000 volunteers and only eight people with the disease had been given the shot rather than a placebo, meaning the vaccine had a 95% efficacy rate. Of the 10 people who developed severe Covid-19, one had received the vaccine.

“The data is very strong,” said Ian Jones, a professor of virology at Britain’s University of Reading. “It’s looking like a really contender.”

Pfizer said it expects the US Food and Drug Administration’s vaccine advisory committee to review and discuss the data in a public meeting that will likely be held in December.

The final analysis comes just a week after initial results from the trial showed the vaccine was more than 90% effective. Moderna Inc on Monday released preliminary data for its vaccine, showing 94.5% effectiveness.

The better-than-expected results from the two vaccines, both developed with new messenger RNA (mRNA) technology, have raised hopes for an end to a pandemic that has killed more than 1.3 million people and wreaked havoc upon economies and daily life.

However, while some groups such as healthcare workers will be prioritized in the United States for vaccinations this year, it will be months before large-scale rollouts begin.

Pfizer said the efficacy of the vaccine developed with German partner BioNTech was consistent across different age and ethnic groups, a sign that the immunization could be employed broadly around the world.

Efficacy in adults over 65 years, who are at particular risk from the virus, was over 94%.

Equity markets strengthened slightly on the Pfizer news. Europe's STOXX 600 and the U.S S&P 500 futures EScv1 both rose about 0.3% to hit highs for the day. The moves were small, however, compared with the jump when Pfizer first announced the vaccine was more than 90% effective on Nov. 9. The reaction in European government bonds and in currencies was muted.

Pfizer shares rose 3% in premarket trade while BioNTech’s US-listed shares jumped 8%.

Mild Side Effects

Pfizer said its vaccine, BNT162b2, was well-tolerated and that side effects were mostly mild to moderate, and cleared up quickly.

The only severe adverse event that affected more than 2% of those vaccinated was fatigue, which affected 3.7% of recipients after the second dose. Older adults tended to report fewer and milder adverse events.

Moderna named five categories of severe side effects experienced by at least 2% of those who received its vaccine. It listed fatigue at a frequency of 9.7%, muscle pain at 8.9%, joint pain at 5.2%, headache at 4.5%, pain at 4.1% and redness around the injection site at 2%.

Pfizer’s final results come as the virus is running rampant around the world, placing an enormous strain on healthcare systems with record numbers of new cases and hospitalizations.

The approach of winter in the northern hemisphere in tandem with the holiday season is expected to worsen case numbers as people spend more time indoors and have family gatherings.

“With hundreds of thousands of people around the globe infected every day, we urgently need to get a safe and effective vaccine to the world,” Pfizer CEO Albert Bourla said.

Pfizer and BioNTech also said they plan to submit the data to other regulatory agencies around the world and submit data from the study to a peer-reviewed scientific journal.

Pfizer reiterated that it expects to make as many as 50 million vaccine doses this year, enough to protect 25 million people, and then produce up to 1.3 billion doses in 2021.

Of the dozens of drugmakers and research groups racing to develop vaccines against Covid-19, the next data release will likely be from AstraZeneca Plc AZN.L with the University of Oxford in November or December. Johnson & Johnson JNJ.N says it is on track to deliver data this year.