“Public confidence in the FDA has really been eroded because of the EUA on hydroxychloroquine and then the mess that they’ve made with serology tests,” said Nicole Lurie, an assistant secretary for preparedness and response at HHS during the Obama administration. “They’ve already got two strikes against them. The risk of the Trump administration eroding public confidence in our science agencies is just huge.”
The effects of such political calculus could extend beyond the coronavirus pandemic that has killed more than 112,000 in the United States so far, by reducing the public’s confidence in vaccination overall. Already, a quarter of Americans say they have little to no interest in receiving a coronavirus vaccine, according to a Reuters/Ipsos poll published last month. Roughly 36 percent of respondents said they would be less willing to take it if the president, who in the past has openly questioned the need for any vaccines, declared it safe.
The fastest vaccine ever developed, for mumps, took four years. Many experimental vaccines show promise in early human trials, which look at a shot’s safety and whether it prompts an immune response, but a significant chunk go on to flunk the broad final study of effectiveness known as a Phase III trial. Patients may produce antibodies in response to a dose of an experimental vaccine, but those are not always strong enough to protect against a disease.
Scores of potential shots to prevent HIV have fizzled in trials, for example, after producing antibodies that the virus can still evade. SARS-CoV-2 is a markedly different virus, but no vaccine for a coronavirus has ever been approved.
“You don’t know whether the immune response is predictive of protection. The only way to do that is to do an efficacy trial,” said Paul Offit, a University of Pennsylvania immunologist who co-developed a vaccine for rotavirus. Efficacy trials, also known as Phase III studies, typically enroll tens of thousands of people and take months to produce answers.
Offit and Emanuel penned an editorial in the New York Times last week expressing concern that Trump could hastily authorize a coronavirus vaccine as a so-called October surprise. (Michael Caputo, HHS assistant secretary for public affairs, called it a „lurid Resistance fantasy“ and accused the pair of „discrediting President Trump’s historic COVID response.“)
Despite the pitfalls of drug development, manufacturers of potential coronavirus vaccines are pushing to accelerate the development timeline. Rather than beginning with preliminary studies in animals, companies are conducting the tests concurrently with early human trials — which regulators have allowed because of the urgency of the situation.
Manufacturers are also merging clinical trials, which are typically done in three phases, and moving swiftly from one stage to another. Johnson & Johnson will begin testing its vaccine in people next month, in a study that will combine a Phase I safety trial and a Phase II efficacy trial. The company plans to start the final phase of testing, a Phase III trial, by September.
Another vaccine, made by Moderna Therapeutics, is heading into final human trials in July. And a candidate from AstraZeneca and the University of Oxford is hot on its heels. A dozen more candidates are progressing through laboratory tests and early studies in people.
But those trials can only be accelerated so much. Moderna plans to enroll 30,000 people in its Phase III studies, Fauci said — and signing them all up could take the rest of the year.
Scientists are also now considering sometimes controversial methods such as vaccinating healthy volunteers and then exposing them to the virus to see whether the vaccine works. That approach, known as a human challenge study, would need to be authorized by the FDA and overseen by an ethics committee.
Human challenge studies are tricky because scientists need to expose volunteers to just the right amount of the virus — too much, and the vaccine could fail; too little, and vaccine’s effectiveness could be overstated. But this type of study could fill in crucial data gaps if the U.S. outbreak shrinks before the first candidate vaccines enter Phase III trials in the fall.
Source: politico.com
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