“I think there will be a vaccine that will initially be available sometime between November and December,” Robert Redfield, the director of the Centers for Disease Control and Prevention, said Wednesday. There were some caveats—there would be a ”very limited supply,” which would “have to be prioritized” for health care workers and high-risk folks. The public, said Redfield, might get this vaccine sometime next year. But still: a vaccine, available in November.
This is, in Trump Land, what passes for a conservative estimate. “We think we can probably have it sometime during the month of October,” the president told reporters earlier this month. Trump went as far as to call Redfield’s timeline “incorrect information, because a vaccine would really be ready sooner: “We’re ready to go immediately as the vaccine is announced, and it could be announced in October. It could be announced a little bit after October.”
It’s true that scientists and drug companies are working at a record-breaking clip to develop and manufacture a vaccine for the novel coronavirus. But it is not possible for us to have access to a vaccine this fall. At least—based on the information we have now about where candidates are in the research process—not one that has been proven safe and effective.
We could, maybe, physically have a vaccine by November. As the New York Times vaccine tracker notes, as of Friday afternoon there were nine vaccines in Phase 3 trials, the last major stage of data collection prior to a vaccine’s release to the public. This is the phase in which a large group of people get a vaccine to test its safety and efficacy. Five of these are not only in Phase 3 trials, but they have been approved for limited use in either China or Russia. While this is promising for our long-term vaccine potential, it is by no means enough evidence to suggest we’ll have a safe, effective vaccine before the end of the year. As the tracker also notes, “experts say the rushed process has serious risks.”
There are two main “serious risks,” and I’ve mentioned them a few times now: safety and efficacy. A vaccine that isn’t as effective as you’d hope means that more people than you expected get sick after getting the vaccine. It might fail to produce an immune response in some people, or the immune response could wear off too quickly. Evaluating the efficacy of a vaccine takes time because people have to get the vaccine (or a placebo shot) and then go about their lives where they may or may not encounter the virus, using the vaccine the way people will use it once it reaches a larger market. We are only just starting that process, which should take months—in normal times, years—now.
The second concern, around safety, is about whether the vaccine will produce some adverse reaction in a small fraction of people who get it. By Phase 3, the vaccine has been cleared for use in thousands of study participants, which means we already have a sense that it’s not going to turn out to be harmful to most people. We know that because it has already been tested on a few humans in Phase 1 and a few hundred or so humans in Phase 2. Phase 3 is necessary for seeing if there are bad side effects that happen in even a tiny fraction of the people who get a vaccine, say an allergic reaction, or an infection. It’s critically important because when a vaccine is distributed to an entire country, and planet, a tiny fraction represents an awful lot of people. “The concern is that if you jump too fast you might miss something,” says Daniel Salmon, director of Johns Hopkins Institute for Vaccine Safety. “Releasing a vaccine prior to Phase 3 trials is quite risky.”
It is possible for people to start using the vaccine prior to the completion of a Phase 3 trial if the CDC uses the Emergency Use Authorization on it. This same authorization was used earlier in the pandemic to usher hydroxychloroquine to patients because we thought it might help them recover faster, but it was quickly revoked when it became clear that the drug was not effective. The back-and-forth on hydroxychloroquine raised concerns about the whole process, particularly in how an EUA can be used for political aims.
Those concerns aside, there’s a whole different reason to be worried about EUA use for a vaccine. With therapeutic drugs, an EUA at least makes sense. If you’re dying of COVID-19, and there’s a drug that shows some clear promise but also might have some rare side effects, you might be willing to take the risk, explains Salmon. But EUAs have not been historically used for vaccines, because they’re given prophylactically to enormous populations. And if you’re healthy, taking the risk for a rare side effect (in exchange for a potentially unknown benefit) isn’t worth it. Plus, vaccines aren’t really an individual calculation. For vaccines to work—for a vaccine to be able to stop a disease from circulating in a population—we all have to take them as a group, which is why they have to be really, really safe.
Salmon, says it is hard to know what the EUA process would even look like for a vaccine. The point is that regulators require less data to approve a medicine via EUA than they do for a regular approval. But, “is that a little less? Is that a lot less?” asks Salmon. One limitation is how much data will even be available to analyze. Maria Elena Bottazzi, a virologist at Baylor College of Medicine who worked on a vaccine candidate that’s slated to start clinical trials soon, says, “There’s no way” that a clinical trial will have produced a substantial amount of data by November.* She points to the fact that one of the most promising candidates, a vaccine by Moderna, began its Phase 3 clinical trial in late July, with participants getting the vaccine on a rolling basis. At the time, Francis Collins, the director of the National Institutes of Health, called having a vaccine distributed by the end of 2020 “a stretch goal.” In mid-August, Collins criticized the trial for its poor recruitment of minorities, a clear hiccup in the process of gathering data. The trial is still in the process of recruiting participants, who each need to get two spaced-out doses of the vaccine. Then, of course, they need to go about their lives for a few months, to see if it protects against the coronavirus, and to see if they have adverse reactions. “You need time—there’s no way,” says Bottazzi, adding, “I don’t think they can do that evaluation with a very limited amount of data.”
We’re already poised to get a vaccine in a record amount of time, given that vaccines typically take a few years, at their fastest, to develop. There are already concessions to the process that will, if all goes well, help a COVID-19 vaccine obliterate previous records. The vaccines at the front of the race use new technology. Some of them are going through Phase 2 and Phase 3 of testing at the same time. The first vaccine, according to the Food and Drug Administration, will only need to be 50 percent effective and may well be a stopgap until something more effective comes out. It’s still impossible to say when we’ll have a vaccine, even with these leaps and concessions. As a New York Times piece on Moderna’s blueprint for Phase 3 makes clear, just because the company plans to look at the data in November or December doesn’t mean they’ll have enough information, at that point, to say whether it’s safe and effective. The company has benchmarks of how many people in the trial will need to get COVID in order to determine effectiveness, the Times explains, and it’s hard to predict when those will be met. And time to complete the trial aside—there’s no guarantee that it will be safe and effective.
It’s becoming a political strategy to suggest, to promise, that early data will tell us something solid and trustworthy about a vaccine. “I worry that the push from the White House is politicizing a very important scientific process that should not be rushed,” says Saskia Popescu, an infectious disease epidemiologist and infection preventionist. We’re essentially now counting on the FDA to do its job, and not bend scientific protocol under political pressure, in an era when public health institutions are bending scientific protocol under political pressure. (It’s worth noting that drug companies have some stake in this too, in not pushing out a vaccine that they can’t be confident in.) “We are very hopeful that those who are going to review the information are going to be very strict,” says Bottazzi. Anthony Fauci has been publicly expressing his faith that the FDA will do its job. Then again, it’s part of his job to not freak us out.
A rushed vaccine poses a risk not just in terms of rare side effects but in terms of the viability of a vaccine in general, given the importance of public participation. If something goes wrong with a vaccine in early rollout, it hands vaccine skeptics ammunition. Frankly, it could hand people without a previous inclination against vaccines an understandable reason to be skeptical of a COVID vaccine, even later, when it makes it out of Phase 3 trials. “Imagine you have to pull it out of the market,” says Bottazzi, of a hypothetical early vaccine. That could be damaging to public trust in vaccines, and to public health not just during the pandemic but for years to come.
Correction, Sept. 22, 2020: This article initially misstated that Maria Elena Bottazzi is a virologist at Baylor University. She does her research at Baylor College of Medicine.