Leading Covid-19 vaccine candidate 90% effective in Phase 3 trial

  • First results shows initial evidence of ability to prevent Covid-19
  • The company's CEO says it's a critical milestone at a time when most needed
  • The Phase 3 trials are still ongoing worldwide

Pfizer said on Monday its experimental Covid-19 vaccine was more than 90% effective, a major victory in the fight against a pandemic that has killed more than a million people, battered the world's economy and upended daily life.

READ | Phase 3 of Covid-19 vaccine trial kicks off in South Africa

Pfizer and German partner BioNTech SE are the first drugmakers to release successful data from a large-scale clinical trial of a coronavirus vaccine. The companies said they have so far found no serious safety concerns and expect to seek US authorisation this month for emergency use of the vaccine.

If authorised, the number of doses will initially be limited and many questions remain, including how long the vaccine will provide protection. However, the news provides hope that other Covid-19 vaccines in development may also prove effective.

"Today is a great day for science and humanity," Albert Bourla, Pfizer's chairperson and chief executive, said.

"We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen."

Pfizer expects to seek broad US authorisation for emergency use of the vaccine for people aged 16 to 85. To do so, it will need two months of safety data from about half the study's 44 000 participants, which his expected late this month.

"I'm near ecstatic," Bill Gruber, one of Pfizer's top vaccine scientists, said in an interview. "This is a great day for public health and for the potential to get us all out of the circumstances we're now in."

1.3 billion doses

Pfizer and BioNTech have a $1.95bn contract with the US government to deliver 100 million vaccine doses beginning this year. They have also reached supply agreements with the European Union, the United Kingdom, Canada and Japan.

To save time, the companies began manufacturing the vaccine before they knew whether it would be effective. They now expect to produce up to 50 million doses, or enough to protect 25 million people this year.

Pfizer said it expects to produce up to 1.3 billion doses of the vaccine in 2021.

READ | Leading Covid-19 vaccine candidate to be manufactured in SA

The US pharmaceutical giant said the interim analysis was conducted after 94 participants in the trial developed Covid-19, examining how many of them had received the vaccine versus a placebo.

The company did not break down exactly how many of those who fell ill received the vaccine. Still, over 90% effectiveness implies that no more than 8 of the 94 people who caught Covid-19 had been given the vaccine, which was administered in two shots about three weeks apart.

The efficacy rate is well above the 50% effectiveness required by the US Food and Drug Administration for a coronavirus vaccine.

To confirm the efficacy rate, Pfizer said it would continue the trial until there are 164 Covid-19 cases among participants. Given the recent spike in US infection rates, that number could be reached by early December, Gruber said.

The data have yet to be peer-reviewed or published in a medical journal. Pfizer said it would do so once it has results from the entire trial.

Global race

The global race for a vaccine has seen wealthier countries forge multibillion-dollar supply deals with drugmakers like Pfizer, AstraZeneca Plc and Johnson & Johnson, raising questions over when middle income and poorer nations will get access to inoculations.

Dozens of drugmakers and research groups around the globe have been racing to develop vaccines against Covid-19, which on Sunday exceeded 50 million infections since the new coronavirus first emerged late last year in China.

The Pfizer and BioNTech vaccine uses messenger RNA (mRNA) technology, which relies on synthetic genes that can be generated and manufactured in weeks, and produced at scale more rapidly than conventional vaccines.

Moderna, whose vaccine candidate employs similar technology, is expected to report results from its large-scale trial later this month.

The mRNA technology is designed to trigger an immune response without using pathogens, such as actual virus particles.

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Image credit: Getty Images

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