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2 COVID-19 vaccine candidates may protect against the virus. Now what?

After months of clinical trials conducted at an unprecedented pace, two pharmaceutical companies in one week have released promising early data for a pair of vaccines designed to stop the coronavirus pandemic. But even as U.S. health officials predict that millions of Americans could begin to receive vaccinations as early as next month, more research must be done. Experts say we still need to know how much protection each vaccine candidate could generate, how long their immune response might last, and whether the other vaccines in development are successful.

One thing that could determine how quickly a vaccine is available to the public is an emergency use authorization from the Food and Drug Administration. Such a move is highly unusual. The U.S. has issued only one EUA for a vaccine, in 2005, to prevent members of the military and the public from becoming ill after inhaling anthrax.

So far, FDA has not granted an EUA to any coronavirus vaccine, but has set a benchmark at 50-percent efficacy — that is, a vaccine must work to protect patients at least half the time. These two vaccines produced by Pfizer and Moderna appear to exceed that benchmark by a wide margin. However, they have not been peer-reviewed or proven effective in a wider population. On a call with reporters Monday, National Institutes of Health Director Francis Collins said he anticipated that regulatory officials may approve both vaccines in the next few weeks.

On Friday, Pfizer said it would file a request for emergency use authorization from the FDA for its COVID-19 vaccine.

But even the millions of doses these two companies could produce would not be enough to fully inoculate the general population and snuff out the virus. So, researchers must also consider the toll that issuing an EUA will take on other ongoing vaccine trials, said Dr. Norman Baylor, president and CEO of Biologics Consulting and former director of the FDA’s Office of Vaccines Research and Review. If participants in ongoing trials choose to take the vaccines that receive early emergency approval, they may drop out of those trials, potentially making the path to approval take longer as scientists seek additional participants to get the data they need.

“The studies need to be completed, and if you start allowing dropouts from the placebo to get a vaccine under the EUA and that could confound the study,” Baylor said. “Would the study even be finished? Would the sponsors finish it?”

Both vaccine candidates producing such positive results (in early data) is better news than expected, said Dr. Ashish Jha, physician and dean of the Brown University School of Public Health. “Everything so far on the science and efficacy and safety of the vaccines are going better than I expected,” he said, adding that he expected to hear promising news about at least two more vaccine candidates before the end of the year.

While access to a vaccine may be close, a virus-driven humanitarian crisis is even closer. Roughly 250,000 Americans have died so far, and the country is facing the worst surge of coronavirus infections of the pandemic so far. More than 11 million people in this country are known to have been infected so far, according to Johns Hopkins University, and the U.S. still leads the world in both confirmed illness and death linked to the virus. While the U.S. enters “the worst” phase of this crisis, Jha said he expects the pandemic to persist for as long as another six months.

The goal of conducting extensive clinical trials that expand from a few dozen volunteers to tens of thousands of participants, as both companies have done, “is to mitigate risk and to lessen uncertainty.” But when more 1.3 million people have died worldwide from the virus, that drives an incredible urgency to stand up a vaccine. Much of the debate around issuing EUAs for the vaccines rests on the tension between the “sin of omission and the sin of commission,” said Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia. “We focus much more obviously on any side effects of vaccines,” he said, but not releasing a vaccine “is also doing something.”

On the heels of this unusually promising news about vaccines, Health and Human Services Secretary Alex Azar urged Americans to remember that getting inoculated against coronavirus is just one piece of a broader effort to lower devastatingly high case counts in the U.S. People must continue to wash their hands, wear a mask, watch their distance and avoid settings where they can’t take those precautions to prevent further spread of the virus, he said — in other words, the vaccine is no silver bullet. It won’t make the pandemic suddenly go away.. “Right now is not the time to let our guard down as we bridge to this optimistic day ahead,” he said.

What early data say about these vaccines

Last week, Pfizer announced it had produced a vaccine that could ramp up the immune system of participants with 90-percent effectiveness after two doses. Nearly 39,000 people received the full dose of the vaccine, with nearly a third of U.S. participants from non-white backgrounds — an important indicator for a virus that disproportionately infects or kills non-white Americans. On Wednesday, Pfizer said new data showed its vaccine candidate was 95-percent effective.

But physically getting that vaccine to people who need it will present huge logistical hurdles. To protect the vaccine’s viability, the company said it would ship the doses in ultra-cold storage at -94-degrees Fahrenheit, a temperature that prevents the protein molecules in the vaccine from breaking down, but is far colder than most conventional freezers. That condition has raised questions about how fragile the vaccine might be if administered in pharmacies or clinics, and whether it could survive in less resourced or more rural regions of the U.S.

More transparent data, including on how people responded to the vaccine during trials and also over time, also is needed to judge how effective the Pfizer vaccine is at promoting an immune response, said Offit, who called the announcement “science by press release” during a Nov. 10 call with reporters.

The Moderna vaccine can be stored at relatively warmer temperatures, as high as – 4 degrees Fahrenheit, boosting its potential for use across the country. For their trials, researchers enrolled more than 30,000 volunteers, with an aim of keeping the pool diverse. The vaccine was 94.5-percent effective in building an immune response in participants across two doses.

Many questions simply cannot yet be answered almost 11 months after this virus was first identified, Offit said. That includes how long these vaccines will protect you from getting infected. But Offit added that if a vaccine can prevent infection up to four months after someone was inoculated, you’re likely to have protection a little longer than that.

Safety data that monitors reported side effects is critical at this time, said Dr. Jesse Goodman, who formerly directed the FDA’s Center for Biologics Evaluation and Research and is a senior scholar with the O’Neill Institute for National and Global Health Law. Initially, Pfizer did not release safety data about adverse reactions to the vaccine, he said. In a released statement, company CEO Albert Bourla said the company looked forward to “sharing additional efficacy and safety data generated from thousands of participants in the coming weeks.”

Vaccine hesitancy and what’s next

With emergency approval from the FDA, manufacturers working with Moderna could produce 40 million doses to vaccinate 20 million people as early as by late December, according to Azar. In the United States, vulnerable populations, including seniors, first responders and health care workers, would be prioritized to receive the vaccine, he said Monday.

By summer 2021, the Moderna vaccine could possibly be available to the general population, according to Dr. Anthony Fauci, the nation’s top infectious disease expert who directs the National Institute of Allergy and Infectious Diseases. By the end of 2021, Moderna CEO Stéphane Bancel said, between 500 million and 1 billion doses would be globally available.

That would combine, theoretically, with Pfizer’s plans to produce 50 million doses to vaccinate 25 million people this year, Bourla told PBS NewsHour’s William Brangham. Over the course of next year, Pfizer aims to distribute 1.3 billion doses.

But even if there are enough doses, widespread immunity also depends on how many people are willing to roll up their sleeves. That willingness has been compromised amid messages from the White House that often conflict with public health guidance, experts say. In a Sept. 18 PBS NewsHour/NPR/Marist poll, 49 percent of Americans said they would get vaccinated against COVID-19 if available today. That was down from 60 percent in an August poll.

On Friday, during a White House Rose Garden ceremony recognizing the progress of Operation Warp Speed, President Donald Trump falsely took credit for the promising early data about the Pfizer vaccine and vowed his administration would never lock down the country against COVID-19. He also suggested that he would withhold vaccines from residents of New York, the latest threat he has lodged against his home state, which is led by Gov. Andrew Cuomo, a Democrat who has criticized the president for his pandemic response.

The Trump administration’s hostile approach to the incoming Biden administration also puts the American people in harm’s way, Jha said. So far, Trump has refused to concede that he lost the presidential election and obstructed transition efforts as President-elect Joe Biden prepares to take on a global pandemic.

“There’s a long way between having vaccines and getting people vaccinated,” Jha said. “That complexity is so much more difficult with what looks like a less than ideal transition happening between the Trump team and the Biden team.”

On Nov. 10 during a COVID-19 Vaccine Analysis Team call with reporters, Dr. Mary Bassett, director of the François-Xavier Bagnoud Center for Health and Human Rights at the Harvard T.H. Chan School of Public Health, said that people immediately want their lives back to how they once were, but said a “vaccine won’t achieve that because it won’t be distributed widely enough or fast enough.”

With Trump’s rhetoric, the perception of politics around the vaccine program gives people pause, said Bassett, who is also a former health commissioner for New York City. Despite the staid process of vetting vaccine candidates, the perception that vaccines are being rushed out for political purposes — in a program called Operation Warp Speed — can foster doubts. Even if there was the option to rapidly vaccinate Americans, Bassett said, “People have a really hard time with probability. They want zero risk.”