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We have to wait longer than expected for coronavirus vaccine trial results – but that might be great news

Published Oct 28th, 2020 10:48AM EDT
Coronavirus Vaccine
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  • Coronavirus vaccine candidate maker Pfizer was expected to release early efficacy results for Phase 3 in mid-October, ahead of the presidential election.
  • That’s no longer the case, as the first efficacy data isn’t yet available.
  • Pfizer, which is blinded to the study, awaits conclusions from an independent data and safety monitoring board. The first results won’t be available until at least 32 of the 42,000 volunteers get infected with COVID-19.

One or more vaccines could help the world beat the novel coronavirus pandemic next year, and the officials involved with the development of these drugs keep saying they’re cautiously optimistic so far. A handful of drugs have reached the final phase of clinical testing. If these drugs prove to be both safe and effective, companies will move forward with emergency use authorization (EUA) procedures that will allow governments to start deploying the first COVID-19 vaccination campaigns.

Coronavirus vaccine campaigns have been intensely politicized in the second half of the year, with President Trump mentioning the imminent availability of vaccines as a development that will allow his administration to control the US outbreak. As that happened, the public became warier about vaccine safety, prompting FDA officials and execs from pharmaceutical companies to repeatedly state that vaccine research will not skirt the necessary steps. More recently, the FDA issued new EUA guidelines, asking vaccine makers to follow up with at least half of the volunteers in Phase 3 trials for at least two months after the final shot — most vaccines require two injections two or three weeks apart. This new provision effectively ended speculation that the first EUAs might come in time for the presidential election. And now, the only company with a vaccine candidate that had a theoretical chance of producing results before the election has confirmed the early data isn’t yet available.



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AstraZeneca/Oxford, Johnson & Johnson, Moderna, and Pfizer/BioNTech are the most advanced COVID-19 vaccine Phase 3 trials in the US right now. The first two were paused after safety incidents, and the FDA just cleared them to resume. The Oxford vaccine was on pause for well over a month, meaning its EUA application will also see delays. Johnson & Johnson has the largest study in the works but reached Phase 3 later than the other three, and the safety incident will probably set it back as well. Moderna said recently that it might have results at some point in late November, well after the election.

Pfizer remained the only company that could theoretically disclose Phase 3 results before November 3rd, although CEO Albert Bourla explained in a letter a few days ago that the company would not be able to seek EUA until late November, assuming its drug clears efficacy and safety requirements. But Pfizer was still expected to disclose some efficacy data this week, ahead of the election.

This is no longer the case, as Pfizer is still waiting for enough people to get infected before it can analyze results.

Pfizer confirmed on Tuesday that its interim efficacy analysis has not been conducted. As Stat points out, that’s both good news and bad news. The fact that Pfizer doesn’t have conclusions means that the vaccine has likely prevented more than 77% of covid cases. That’s according to investment bank Evercore ISI’s senior managing director Umer Raffat — the benchmark for success at this time is 77% efficacy.

But the bad news is that fewer volunteers are reporting COVID-19 infections, which means the study is progressing slower than desired. All Phase 3 vaccine trials for coronavirus need to have at least 30,000 volunteers. Pfizer has recruited more than 42,000 volunteers.

These people have been divided into two groups. One cohort will receive the drug in two doses, while the other group will get a placebo. All these volunteers will then go about their lives and they’ll all risk exposure to COVID-19. The volunteers, the researchers involved in the study, and Pfizer are all blinded. That means nobody knows whether a patient got the drug or the placebo, except for a few key people involved with the trial’s logistics and the data and safety monitoring board (DSMB).

The first analysis of the results will come when there has been a total of 32 confirmed COVID-19 across the entire 42,000-volunteer study. The results would be positive if only six or fewer people who got the vaccine get infected. The rest of the 26+ people would have to come from the placebo group.

The US is currently experiencing a massive surge of cases, with the pandemic having reached a higher peak last week than the previous record set in mid-July. That means there’s enough virus across the US for vaccine volunteers to risk exposure. The fact that Pfizer hasn’t received any data from the review board means that 32 people have not yet been infected. That’s not an indication that the vaccine is 100% effective — and the vaccines might not even block COVID-19 infections at all. Not to mention that the placebo group doesn’t have any protection. The lack of data is also an indication that volunteers are avoiding infection by practicing social distancing, wearing face masks, and using good hand hygiene.

Pfizer relies on the DSMB to deliver information about efficacy, and that information won’t be available until the first 32 volunteers get infected. The trial will continue until 150 volunteers have had COVID-19.

Bourla said on a conference call on Tuesday that he’s “cautiously optimistic” that the study will have positive results, adding that the results have nothing to do with the politics. “You never know until you have a study result,” the exec said. “Let’s all have the patience that is required for something so important for public health.”

He continued, “This is not going to be a Republican vaccine or a Democratic vaccine. This is going to be a vaccine for the citizens of the world. I hope that it is going to be effective.”

The full protocol for the Pfizer coronavirus vaccine trial is available at this link.

Chris Smith Senior Writer

Chris Smith has been covering consumer electronics ever since the iPhone revolutionized the industry in 2008. When he’s not writing about the most recent tech news for BGR, he brings his entertainment expertise to Marvel’s Cinematic Universe and other blockbuster franchises.

Outside of work, you’ll catch him streaming almost every new movie and TV show release as soon as it's available.