Covid-19 vaccine results from
Questions about production, distribution and, most importantly, the performance and capability of the shot itself still need to be answered, even if the numbers look highly promising, according to vaccine specialists. The Pfizer trial started less than four months ago, and how long the vaccine will confer protection and how many will benefit are almost complete unknowns for now.
“The key question still centers upon time,” said Michael Kinch, a drug development expert and associate vice chancellor at Washington University in St. Louis. “Will time tell us that the protection remains useful for the larger population?”
In a remarkable scientific feat -- achieved
The results were published in a press release, not a peer-reviewed journal study. Nonetheless, they
The likely success of the first vaccine in a large, late-stage trial raised hopes that others, like those developed by
The headline number of 90% reduction in symptomatic cases says little about what kind of cases are being prevented. Detail on how well the vaccine works in the elderly and other vulnerable groups who most need protection is yet to come.
About half the trial participants are elderly, and it’s possible to project from the current results that the efficacy among older people should be above 80%, BioNTech Chief Executive Officer
A shot that prevents serious disease would be important for relieving pressure on overloaded hospitals and emergency rooms. The current data analysis doesn’t include any severe cases, but they’re expected to occur as the study continues, Pfizer Senior Vice President William Gruber said.
It still may be difficult to accrue the five severe cases that the U.S.
Pfizer expects to have accumulated two months of safety data for people in the trial by next week. If there are no unforeseen problems, the company could apply for an emergency use authorization in the U.S. soon after that, potentially this month.
At that point, FDA’s internal reviewers will first pore over the safety, efficacy and manufacturing data. The agency also has promised a review by outside experts to increase public confidence in any vaccine authorized. A date for that hearing hasn’t been set yet.
If an emergency authorization is granted, a second committee of outside experts convened by the
All this means that even if Pfizer’s data hold up, it may be late December or even early January before a vaccine becomes available. At that point there might be around 50 million doses worldwide, enough for 25 million people.
In an interview late last month,
“Even if we got a positive readout and a pretty benign safety signal and an emergency use authorization is extended -- if that’s what ends up happening in the U.S. -- the quantity of the vaccine that will become available will still be limited,” he said.
The Warp Speed effort to develop and buy vaccines would have to achieve complete success -- with six of six successful -- for the U.S. to reach herd immunity by June, according to Airfinity Ltd., a London-based research firm. Failures and delays could stretch out the timeline for slowing the virus’s spread to 2023 or beyond.
Vaccines like Pfizer’s must be kept at ultra-cold temperatures, a challenge that will need to be overcome if the vaccine is to be made broadly available, according to experts.
Masks, Social Distancing
Rollout of any shots will take time, so masks, distancing and testing and contact tracing will still be vital, said Ohid Yaqub, a senior lecturer at the University of Sussex’s Science Policy Research Unit. President-elect Joe Biden also emphasized the need to continue such
It’s also important to continue watching those who received the vaccine for years. The messenger RNA technology used in the Pfizer/BioNTech vaccine has never been deployed in humans before.
“It will be crucial to track the safety and efficacy over the coming weeks and months,” said Kinch, the Washington University expert. “If nothing else, we have learned that we need to look to the long term.”
”A positive signal would be exciting,” Hatchett said, “but it certainly wouldn’t mean that the pandemic is about to be over.”
--With assistance from
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