COVID Vaccine Probably Hours Remaining
The FDA’s Vaccine Advisory Group spent yesterday afternoon discussing the results of Pfizer and BioNTech’s COVID vaccine studies. In the end, they voted yes to the question of whether the available science suggests that the benefits of the vaccine outweigh the risks. The FDA is expected to move quickly to issue an Emergency Use Authorization (EUA) for the vaccine; after originally scheduled to complete the order by Saturday, it could be as early as tonight, according to the New York Times .
Does this mean the vaccine is approved?
Not yet. Yes, we are probably a few days away from the EUA, but probably still a few months before full approval. EUA is a temporary permit. This means the vaccine is allowed to be administered in a public health emergency. Over time, the EUA may be canceled or revised.
Full approval, in the sense that we usually mean when we say a vaccine or drug is “approved,” involves a little more bureaucracy, including factory inspections, and the FDA is likely to want more data on long-term efficacy and safety in different population groups.
What happens next?
Usually, a “yes” from the advisory group does not guarantee anything, but the FDA said in a press release today that it “will work quickly to finalize and approve emergency use.” In other words, it’s getting closer.
The vaccine manufacturer, as well as the federal and state governments, are already working with hospitals and vaccine providers. In other words, the hospital near you probably already has a space-age thermos full of doses of COVID vaccine. Once they receive the information, they will be ready to start giving out injections.
The whole process has a chance to repeat itself again next week when the FDA panel meets on Thursday the 18th to discuss the EUA for the Moderna vaccine.
Who will get the first shots?
This decision is made at several levels. First, the CDC has a committee called ACIP that makes recommendations on vaccines. They have already indicated that they expect healthcare professionals and nursing home residents to be first in line .
This committee will meet today and then again this weekend following the issuance of the EUA. (You can tune in and listen to these meetings here if you like.) Their previous discussions were about the COVID vaccine in general; today they will be reviewing the Pfizer / BioNTech vaccine, in particular, taking into account all the latest test data .
The ACIP sets guidelines, and the federal government allocates doses between vaccine jurisdictions (each state is usually one vaccine jurisdiction), but the states themselves have the final say on how to allocate their vaccine doses.
What questions still remain?
There are so many. What we do know is that the Pfizer / BioNTech vaccine, which is an mRNA vaccine, has been effective in protecting people in trials against the coronavirus. Participants 16 years of age and older were followed for an average of two months after the second dose (the vaccine is a two-dose regimen) with no serious side effects or safety issues.
If you would like to know more about safety and efficacy, an article was published yesterday in the New England Journal of Medicine describing the results of the Phase 3 study. Or, if you prefer, you can read it as an FDA white paper that includes some additional background information about the agency process. …
In principle, everything looks good in the study. We just don’t know very much about what was not in the study. Some of the important questions:
Does this vaccine prevent asymptomatic infections?
A case of COVID as determined in the study was accompanied by at least one symptom followed by a positive PCR result. So we know that the vaccine is effective in preventing people from getting sick , but we don’t know if it stops them from getting infected . (Pfizer said human studies are now underway to answer this question, and that animal studies have shown that it does prevent infection.)
Stopping asymptomatic transmission is critical to the development of herd immunity. If vaccinated people cannot become infected and cannot transmit the disease to others, then vaccinating enough of the population will stop the spread of COVID. The few people who cannot or will not be vaccinated will still be partially protected just because the virus cannot spread easily.
But if a vaccine allows people to become infected and only prevents the virus from causing serious illness, we are looking at a different scenario. Then the vaccine will protect people, but not society. The coronavirus will continue to rage, but it will be more difficult to kill vaccinated people.
Will this vaccine be safe for children?
The study started with only adult subjects, and then 16 and 17 year olds were added. They were doing well, but there were only about 150 of them in the study population of about 40,000. Some of the advisory group members were concerned that children might not respond to the vaccine as much as adults, given that on rare occasions their immune systems respond in strange and deadly ways to COVID itself .
A Pfizer spokesman said the company had received enough safety data from 16-17 year olds for them to start studying the vaccine in 12-15 year olds. If it turns out to be safe and effective in this group, they will continue to study it closely in children aged 5 to 11, and then try to eventually try it in young children. But this whole process can take from months to years.
Is this vaccine safe for pregnant women?
Pregnant people were excluded from trials, which gave us the same -22 trick that often appears in new medical therapies: no one wants to experiment with pregnant people, so pregnant people have no choice but to take (or not take) approved a treatment that has not been studied in pregnancy.
It’s a delicate balance of risk and benefit. COVID may be more dangerous for pregnant women and their fetuses; but on the other hand, without data, how do we know if a vaccine is safe? A Pfizer spokesman said they are monitoring the outcome of pregnancies during the trial and that they are conducting animal experiments that should provide more information. They’ll get results soon.
What happened to these severe allergic reactions in the UK?
Earlier this week, the vaccine received the UK equivalent of EUA, and on the first day of vaccination, two people developed severe allergic reactions to the vaccine. Both had a history of severe allergies, although it is unclear from initial reports what they were allergic to or why they responded to the vaccine. The UK currently recommends against giving the vaccine to people with a history of anaphylaxis and anyone with an allergy serious enough to carry epipen with them.
Pfizer / BioNTech tests did not find anything like this; they ruled out everyone who had an allergic reaction to the vaccines or their ingredients, but not people who are allergic in general. These two cases in the UK may turn out to be coincidences, but serious problems for people with allergies can arise. We don’t know yet.
The population of the real world will be different from people in trials.
There may well be more surprises like the allergy problem. We are also not aware of any group that was underrepresented in the studies. People with serious illnesses were included in the study only if their health was stable (for example, people living with HIV), but people at high risk of complications from COVID were those who could have a health condition that could be more serious than people who participated in the research.
We also don’t know if one dose can be nearly as good as two; the study tested only the two-dose regimen. We do not know how long the vaccine protection will last because only two months of follow-up data were included in the study. We are also likely to lose the ability to obtain data from long-term placebo-controlled trials, because when the vaccine becomes available to study participants, those in the placebo group should ethically receive it. Regulators seemed alarmed by this, but we live in a world of uncertainty and compromise. But so far so good. This article was updated at 1:19 pm ET on December 11 to reflect the latest changes in the release dates for the COVID EUA vaccine from Pfizer and the FDA’s BioNTech.