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How To Know When You Can Trust A COVID-19 Vaccine

If a COVID-19 vaccine went on the market before Election Day, Kamala Harris said she’s not sure she’d take it. And she’s not alone. In a recent poll, a majority of Americans — 62 percent — said they were worried that the Trump administration would pressure the Food and Drug Administration to release a vaccine before it’s ready, and 54 percent said they simply wouldn’t take that hypothetical vaccine at all, even if it were free.

Scientists around the world are currently undertaking one of the fastest vaccine-development programs in history, trying to get the novel coronavirus under control as quickly as humanly possible. But the vaccines being tested sit at a nexus of misinformation and mistrust. Between Trump’s apparent meddling in federal health agencies’ decision-making, skepticism about the seriousness of the disease, and long-standing culture wars around the safety of vaccines in general, it’s easy to find yourself floundering, unsure who you can trust.

So I spoke with a handful of people who really know how vaccines, clinical trials and COVID-19 work to find out how to know when it’s a good idea to get the vaccine. They offered these four pieces of advice.

Look for transparency in the data —
even if you don’t go through it yourself

Don’t get your COVID-19 vaccine advice from politicians or pharmaceutical companies, said William Schaffner, medical director of the National Foundation for Infectious Diseases and a professor at the Vanderbilt University School of Medicine. Instead, trust independent scientists and medical professionals — your doctor, for instance, or your state’s health commissioner.

But those people, in turn, need transparency from the drugmakers and government to be able to give informed advice. That means drug companies and the FDA should be disclosing not just trial data but also the standards they used to evaluate that data, their methods of analysis, and the reasoning behind any decisions they make about potential vaccines.

Being published in a peer-reviewed journal probably isn’t even enough transparency, said Peter Doshi, an associate editor at The BMJ (formerly the British Medical Journal) and a professor at the University of Maryland School of Pharmacy. “If the underlying data are not available, we shouldn’t consider these products as based in a scientific process that allowed clinicians and researchers to review the data themselves,” he wrote in an email. “There’s too much riding on the line.”

It’s not that you have to read interminable volumes of scientific data. The professionals can do that, and they’ll help your doctor form an educated opinion about whether the vaccine is a good idea for you personally.

The catch there is that some scientists think the necessary standards of transparency already aren’t being met. Eric Topol, a professor and executive vice president at Scripps Research, a nonprofit biomedical research institute, said there’s lots of information that could (and should) be available now but isn’t. Last week, Moderna and Pfizer did publish some key information about how their trials are designed — including the number of trial participants and the evidence that will be used to determine whether the vaccines are effective. Typically, Topol said, those things aren’t published until a clinical trial is over and the data is released. But extraordinary circumstances call for extraordinary transparency. “Rush without trust is bad math,” he said. In fact, Topol regards last week’s info dump as “a very good start” and would also like to see the companies release data on their trial charters, their full statistical analysis plans, and the identities of the scientists who will review the results.

Listen to the independent reviews
(with a caveat)

Every COVID-19 vaccine candidate will have to go through two separate independent review boards before it gets to you — one through the trial’s sponsoring institution and another through the FDA, said Sandra C. Quinn, a professor and chair of family science at the University of Maryland School of Public Health, who has served on institutional review boards for other clinical trials. She told me it’s the institutional review board that would have been responsible for flagging the problem with AstraZeneca’s vaccine earlier this month, which caused a temporary halt of the trial. Those boards offer a first look at the vaccines, and their recommendations are something we all should pay attention to.

However, Topol said, those boards can have their own incentives. “Each of the two trials we’re talking about [the Moderna and Pfizer vaccines] have an independent review board, but they have not published the rosters. So we don’t know how independent they are,” he said. “They get paid by the company and report to the company.” So knowing who these people are is an important part of knowing how much we can trust their judgment. Again, transparency is key.

Be highly skeptical of anything released before the end of the year

The clinical trials for the COVID-19 vaccine are happening with unprecedented speed — which is good. To get there, Schaffner said, the vaccines are being built on existing technology, scientists are working around the clock, and the vaccines are going through clinical trials at the same time the companies are ramping up production — that way, everything will be ready to go as soon as a vaccine gets the green light. Schaffner said it’s also likely that the FDA will approve the new vaccine under a faster process called an Emergency Use Authorization, rather than under the slower standard licensure system.

But there is such a thing as too speedy. Topol, who has worked on large clinical trials for nearly three decades, didn’t mince words: It would be impossible to have a properly vetted COVID-19 vaccine ready for public release before the general election — at least one that’s had any kind of real safety and efficacy testing. “Capital ‘i’ impossible,” he said. That’s because a trial can move only so fast. The most promising trials are still enrolling participants, and they have to wait two to four weeks between taking each of the two doses of the vaccine. By the time they finish enrolling people, you’re almost at the end of October, Topol said, and then you still have to give the trial time to see whether the vaccine even works. If the trials end too early, it’s easy to end up with a vaccine that’s much less effective than you think it is. February, or even January, would be a much more realistic time frame to get a vaccine that has met basic standards of trustworthiness, he said.

Trust the experts who are being straight with you about the limitations above everyone else

In terms of efficacy, the COVID-19 vaccine is not going to be like a measles shot, said Ali Moghtaderi, a professor of public health and management at George Washington University. Instead, we’re likely talking about something more like the flu vaccine — even if you get it, you won’t be perfectly protected.

How imperfect is the protection? Well, that’s still an open question, but the FDA has said it would require any vaccine to be at least 50 percent effective before approving it. But that still means that half the people who get the shot won’t be immune. Meanwhile, even on a realistic timeline for development, we’re likely talking about a situation where we don’t yet know all the potential side effects by the time the vaccine is released. Those are things the FDA will continue to monitor.

It’s critical that anyone talking to the public about the vaccine be honest about these limitations, Moghtaderi said. Both the government and the pharmaceutical companies have big conflicting interests in making sure a vaccine gets out quickly and gets used, so there’s a lot of incentive to overpromise or underinform in the pursuit of economic and political stability.

But whenever a vaccine is developed this quickly, issues that the clinical-trial process didn’t catch are only going to come up later — whether that’s problems of efficacy or of safety. If a side effect is rare enough, it might not become apparent until millions of people have taken the vaccine. Likewise, Doshi said, it’s probable that any COVID-19 vaccine would have different rates of efficacy and risk for different populations — older people, for example, might respond differently than young people. He’s watching closely to see who is being recruited for clinical trials. It would be a red flag, he said, if officials are heavily encouraging people who weren’t well represented in the trials to take the vaccine, or if there’s not public data on how effectiveness varied for different subgroups.

“I think at the end of the day … whatever comes out of this vaccine might have longer-term implication[s] for immunization in general,” Moghtaderi said. If the public decides this process wasn’t trustworthy, it will give ammunition to efforts to discredit all vaccines.

Maggie Koerth is a senior science writer for FiveThirtyEight.

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