President Donald Trump makes no secret he would like a COVID-19 vaccine to be available before the election. But it’s doubtful that will happen and, even after a vaccine wins FDA approval, there would be a long wait before it’s time to declare victory over the virus.
Dozens of vaccine candidates are in various testing stages around the world, with 11 in the last stage of preapproval clinical trials — including four in the U.S. One or more may prove safe and effective and enter the market in the coming months. What then?
Here are five things to consider in making vaccine dreams come true.
1. A vaccine is vital in fighting the virus, but it won’t be a quick pass back to our old lives.
Vaccines have helped rid the world of scourges like smallpox, but the process takes time and there are no guarantees. Until clinical trials have been completed on this first round of vaccine candidates, no one knows how effective they might prove to be.
The minimum requirement by the Food and Drug Administration for any COVID-19 vaccine is that it should at least prove 50% effective when compared with a placebo — that is, a neutral saline solution.
By comparison, the annual influenza vaccine ranges between 40% and 60% effective in preventing the illness, depending on the recipient and the season examined. In contrast, a full course of the measles vaccine is about 97% effective.
“It’s very unlikely that a first-generation vaccine will be something like a measles vaccine,” notes Dr. Amesh Adalja, a physician with expertise in infectious diseases and senior scholar at the Johns Hopkins University Center for Health Security.
2. After vaccines gain approval, the real-world evaluation ensues.
Vaccines undergo a protracted testing process involving thousands of subjects. They win FDA approval only after they demonstrate safety and meet at least the minimum standard of effectiveness. Monitoring continues after they hit the market; effectiveness and any rare side effects or safety issues become more apparent after millions of doses are given.
Hypothetically, let’s say the first new COVID vaccines prove 70% effective at preventing the disease. That would mean seven of every 10 people who roll up their sleeves will be protected, but three will not.
While that’s good news for those protected, questions remain about who is covered and who is still vulnerable. It’s possible, Adalja said, that the vaccine would reduce the severity of disease in the remaining three people, thereby helping cut hospitalizations and severe side effects.
But it’s also true that regulators are focused on whether a vaccine prevents disease. Some vaccines can keep you from getting sick without preventing infection, in which case you could still spread the virus even without exhibiting symptoms.
Mysteries remain, at least for now. Scientists don’t know how long the protection will last, for instance. Will protection fade, requiring annual shots, as with influenza? Or will it last for years?
Also, the COVID vaccine candidates are being tested only in adults so far. Most vaccine makers have delayed testing among children or pregnant and breastfeeding women, for example. That could mean an initial lag in safety and efficacy data for those groups, complicating vaccination efforts for children or even front-line health care workers, many of whom are women of childbearing age.
For all those reasons — “if you are looking for a magic wand, you won’t find one in vaccines,” said Dr. William Schaffner, a professor of preventive medicine and infectious disease at Vanderbilt University Medical Center in Nashville, Tennessee. “That said, vaccines will play a substantial role in reducing the epidemic.”
3. After a vaccine is approved, you still may need to wait awhile to get your shot.
Making vaccines is complicated. And so is distributing them. Vaccine makers say they are already producing vaccine in advance of knowing whether they will win…
Read More: 5 Things to Know About a COVID Vaccine: It Won’t Be a ‘Magic Wand’