There may be a COVID-19 vaccine by the end of the year, but 'normality' may not come until end of 2021

A COVID-19 vaccine is likely to be authorized before the end of the year, but that doesn't mean you'll be able to throw away your mask anytime soon.

Rolling out a vaccine to everyone who wants one will take months in the U.S., not to mention the rest of the world.

And while vaccines are essential tools for fighting a pandemic like COVID-19, they don't fix everything.

"People shouldn't think of vaccines as the savior," said Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a professor of vaccinology at the Perelman School of Medicine at the University of Pennsylvania. "Vaccines are, along with hygienic measures, a way to get in control of this virus, but we need both. Vaccines are not going to be magical. ... You can't abandon one in favor of the other."

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How quickly life will get back to normal will depend on a number of factors, public health experts say, including the vaccine's effectiveness, how many people are willing to get it and how quickly, and how much the virus is still raging out of control. 

"There is an end to this," said Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases. But it will require effort on the part of the public to continue wearing masks, maintaining distance from others, avoiding crowds – and being willing to get a vaccine.

"If you have a very, very highly effective vaccine and we convince most of the people in the country to take the vaccine, we could get back to a degree of normality maybe by the end of 2021," Fauci said.

Even with a vaccine, patience is required

Even if a vaccine is approved this year, there won't be enough available to change the course of the pandemic for months, said Samuel Scarpino, an assistant professor at Northeastern University in Boston, who directs the school's Emergent Epidemics Lab.

Companies already have begun making hundreds of millions of doses of their candidate vaccines, anticipating approval (and ready to throw out those same doses if their vaccine doesn't prove safe or effective enough).

The government has promised a smooth rollout across the country, starting immediately after a thumbs-up from the U.S. Food and Drug Administration. Pfizer, which is producing the frontrunning vaccine candidate, has said it will ask later this month for FDA authorization. It's not clear how long the FDA will take to comb through the mountains of required paperwork, but many expect approval before the end of the year.  

Still, it will take a while before enough doses are delivered to a drug store or clinic convenient for the vast majority of Americans. Health care workers fighting COVID-19 will get first dibs on a vaccine, followed by first responders and the frail elderly. 

"We all want our lives back," said Dr. Mary Bassett, director of the FXB Center for Health and Human Rights at Harvard University and a former New York City Health Commissioner. "The vaccine won't achieve that because it can't be distributed widely enough, fast enough." 

Then there's the question of how many people will take a vaccine. There's a lot of hesitancy at the moment; the percentage of people saying they'd take a vaccine fell substantially from May to September.

Public health experts hope much of that hesitation will go away after a vaccine has been shown safe and effective and community leaders start baring their shoulders to get vaccinated themselves.

"There's a famous line in the vaccine world that says, 'Vaccines don't save people, but vaccinations do,'" said Dr. Rochelle Walensky, a professor at Harvard Medical School and an infectious disease physician at Massachusetts General Hospital, both in Boston.

Vaccine effectiveness is key

No vaccine works perfectly.

The FDA has said COVID-19 vaccines must work at least half the time to win approval – though early signs are that they will be much more effective than that.

In its first release of effectiveness data, the candidate vaccine made by Pfizer and BioNTech proved 90% effective against COVID-19.

But even if everyone got a vaccine that effective, 1 out of 10 people wouldn't be protected against COVID-19. And it's impossible to know for certain who is protected until an infection proves they're not.

That's why experts say that roughly 70% of the population will need to be vaccinated to provide so-called herd immunity – enough protection to interrupt the chain of transmission and protect the vast majority of people.

With measles, which is more contagious than COVID-19, that figure is about 90%, and there have been outbreaks in recent years in communities where the vaccination rate has fallen below that level.

Plus, it's not clear how long vaccine protection lasts.

Vaccine developers are hoping for at least one to two years. But a small number of people have already contracted COVID-19 a second time, and protection against the common cold, which often comes from a related coronavirus, lasts only about six months, studies have shown.

Vaccine experts have said they expect vaccines to provide longer protection than a natural infection, but it's too soon to know.

The possibility of a short period of protection from a natural infection also means the public is unlikely to achieve herd immunity from infections, experts said.

Despite its rapid spread in the spring, only about 10% of Americans had been exposed to the coronavirus by late summer. And without long-term protection, those who were infected will remain vulnerable and will have to continue wearing masks and taking other health precautions.

Herd immunity won't become a reality until vaccines can reach the majority of Americans who want them – which could take half a year or more.

Dr. Peter Hotez, pediatrician and dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, said recently he'd get a vaccine regardless of its effectiveness. Even if it isn't perfect, it could give him extra antibodies to fight off disease, said Hotez, noting that at age 62, he's in a higher-risk category.

"If it's not durable, at least I've got some level of neutralizing antibody on board and then can get boosted later," he said in a recent webinar. "To give yourself the best chance over the next year, you want some neutralizing antibodies and T cell responses in your body." 

Testing and behaviors are still important 

To really get out of this mess will require a combination of factors: vaccines, testing, behaviors – and patience.

With the epidemic running out of control in most of the United States, now is not the time to be waiting passively for a vaccine, Fauci and others have said.

The best weapons against COVID-19 remain mask wearing, social distancing, hand washing and avoiding crowds, such as at football games, weddings, graduations and even family gatherings.

"Those are the tools that we're going to use as a whole to get this pandemic under control," Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said in a call with state officials Monday. "We'll certainly look forward to a time when we're not required to keep up those precautions. But that day is certainly not now."

Contact Karen Weintraub at kweintraub@usatoday.com and Elizabeth Weise at eweise@usatoday.com

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