Experts and armchair scientists alike are hopeful there will be a COVID-19 vaccine by the end of the year. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, is leader of their ranks. At a hearing with a House committee on Tuesday, Fauci said he is “cautiously optimistic” that the U.S. will have a vaccine by the end of the year or early 2021, a position he has made clear before.
Researchers are studying at least 10 candidate COVID-19 vaccines, according to a recent report from the medical journal The Lancet. At least one has shown promising results in animal models, Fauci said at the hearing. The studies are progressing at different paces, and one by Moderna Therapeutics will enter phase 3, the final phase of trials, in July. Phase 1 and phase 2 trials are conducted in smaller groups, mostly to ensure safety but also to test that the vaccine provokes an immune response. Phase 3 trials are tested in many participants to determine whether the vaccine actually works and to catch rare side effects. Fauci expects more vaccines will enter into phase 3 in the coming months.
Though the candidate vaccines seem promising, it’s impossible to tell at this stage whether they will work. “You can never guarantee at all the safety and efficacy of a vaccine until you actually test it in the field,” Fauci said. However, developing a vaccine for COVID-19 is a “when and not if.”
It takes an average of 10 years to develop a vaccine, according to the report in The Lancet. The record is four years. By Fauci’s prediction, the COVID-19 vaccine would take less than a year to develop from start to finish. This may be possible because large outbreaks speed up vaccine trials, decreasing the amount of time it takes to tell if a vaccine works, according to reporting from ProPublica.
Many experts are on board with Fauci’s optimism. Others are skeptics, such as George Yancopoulos, co-founder, president and chief scientific officer of Regeneron, a pharmaceutical company. “Most people don’t realize that successfully inventing and developing any new drug or vaccine is quantifiably among the hardest things that human beings try to do,” Yancopoulos told the New York Times. “The vast majority of efforts fail, with the F.D.A. only approving 20 to 50 new medicines a year. And each of the rare success stories usually occurs over many years, often a decade or two.”
Some experts wish that top officials would place less emphasis on predicting dates. “We are overpromising now, and I wish we wouldn’t do that,” William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt Medicine, told ProPublica. “I wish we would just say, ‘We’re working as hard as we can and we’ll get it to you whenever it’s finished, but we’ve got to do it right.’ And that would be a much more solid message.”
When a vaccine does come, it may not be available for everyone. Pregnant women and children probably won’t be included in the trials, so they may not be able to get the vaccine at first, according to ProPublica. And a vaccine doesn’t guarantee that recipients will be immune to COVID-19. Some may be, though others may develop a more mild course of the disease than they otherwise would. Experts also don’t know how long immunity will last or how often people will need to get re-vaccinated.
Trying to create a vaccine in such a short amount of time involves risks. However, Fauci said, vaccine companies are taking financial risks, not scientific or public safety risks. Some companies are planning on creating millions of vaccines before they know if they work. That way, once a vaccine gets the seal of approval, many will be available right away. But if the trials fail? All of those useless vaccines — and the money invested in them — will be worthless.