As coronavirus vaccination rates rise and the United States opens up after a lengthy pandemic, one of the emerging flashpoints involves elite sports.

The questions sports teams and leagues are facing are the same types of questions that are puzzling businesses, schools, shops and restaurants as the United States continues to open back up. But with world class athletes — young, healthy and, in some cases vaccinated — should the rules be different or more relaxed?

In recent weeks, at least two prominent athletes playing in the United States have tested positive for the coronavirus and were required, by league rules, to quarantine despite being involved in major events. Their vaccination status also became subject to debate.

In the National Basketball Association, Phoenix Suns star Chris Paul tested positive, sidelining him during the late stages of the playoffs. Paul has not discussed his vaccination status, but ESPN analyst Jalen Rose has reported that Paul has been vaccinated.

And Jon Rahm of the Professional Golfers Association was forced to withdraw from the Memorial Tournament, which he was easily leading, with just one round left. Rahm has said he was vaccinated, but not quite out of the two-week period after the final shot that marks full vaccination.

Rahm experienced no coronavirus symptoms, and only knew he tested positive because of PGA Tour rules that require testing for players not considered fully vaccinated.

“To all the people criticizing the PGA Tour, they shouldn’t,” Rahm said. “We are in a pandemic, and even though this virus has very different forms of attacking people, you never know what reaction you’re going to get. So PGA Tour did what they had to do … I’ve heard a lot of different theories: I should have played alone, I shouldn’t have — that’s nonsense. The rules are there, and it’s clear.”

Meanwhile, outside the United States, the coronavirus has spread among players at the Copa America soccer tournament in Brazil. In addition, officials are grappling with how to control the virus at the Olympics in Japan in July, since infections passed among participants could spark infection “brush fires” in their home countries once they return after the Games are over.

Here, we’ll take a closer look at the challenges that elite sports are trying to navigate at this point in the pandemic.

If you’re an athlete who is vaccinated, what are the risks from the coronavirus?

Scientists say that for fully vaccinated people, the risk of COVID-19 is significantly reduced, but not zero.

“All the vaccines produce several levels of immunity — a few antibodies that can block infection lead the way, followed by a range of antibodies and white blood cells that are very good at mopping up infections,” said Benjamin Neuman, a virologist at Texas A&M University. “Those front-line, infection-blocking antibodies are trying to hit a very small and difficult target, and sometimes miss. So not every vaccinated person starts with the same protection.”

However, even if a virus gets through and causes infection in a vaccinated person, “nearly everyone who has a normally functioning immune system will make enough other defenses to prevent serious illness,” Neuman said. “And new research shows that if a vaccinated person does become infected, the virus stimulates whatever anti-COVID immunity a person already has, to make even higher amounts of protective immunity.”

Athletes, given their younger ages and general state of health, should fare even better than the average in a “breakthrough infection” scenario, said Babak Javid, a professor of medicine at the University of California-San Francisco.

“Severe outcomes in this population, once they are immunized, should be vanishingly rare, Javid said. “High-quality data from the United Kingdom suggests that severe COVID-19 in fully immunized individuals is very rare, and even then, it is mostly confined to the elderly.”

Should athletes get vaccinated?

Unless there’s some known health reason not to, experts said they would strongly urge athletes, as well as almost anyone else, to get vaccinated.

“If anyone is going unvaccinated by choice into competitions where there will be close contact with other potentially unvaccinated people, that is a really bad idea,” Neuman said. “Play stupid games, win stupid prizes.”

There may be some variation in risk depending on the type of sport being played, Neuman said. Basketball features lengthy, close-up, person-to-person action, while golf doesn’t (and, in theory, could be made even more socially distanced through changes to the timing of play on the course).

Some experts go so far as to suggest that — at least for competitions within the United States, where vaccines are widely available for free — vaccinated athletes shouldn’t be punished for testing positive just to protect opponents who have chosen not to be vaccinated.

“If someone has been vaccinated with the extraordinarily safe and effective vaccines available in the U.S., their risk of getting seriously sick is almost non-existent, said Rebecca Wurtz, the director of public health administration and policy at the University of Minnesota School of Public Health. “So we don’t need to ‘protect’ someone who is vaccinated by testing them or the people around them.”

To Wurtz, “it is unfair to disqualify someone from attending, playing, or participating if they have been vaccinated even if they are shedding virus according to a positive test.”

How many precautions can safely be rolled back?

Some experts say that testing in elite sports may not be necessary any more.

“The CDC does not recommend asymptomatic testing after vaccination, since the chance for false positives or a low-level virus in the nose that can’t transmit or cause infection is high,” said Monica Gandhi, a professor of medicine at the University of California-San Francisco. “Unfortunately, many sports teams have still not adopted updated CDC guidance on testing protocols after vaccination and are seeing these test results of positivity that may lead to a player being out or a team not being able to play for concern of a positive test.”

However, other experts urged caution before phasing out testing, at least for now.

“People lie about their vaccination status,” said Arthur Caplan, director of the division of medical ethics at the New York University Grossman School of Medicine. “Some of them just got one shot, and one shot of a two-shot vaccine is not likely to work well against new variants.”

Caplan, who has advised the National Collegiate Athletic Association on coronavirus control practices, said the second-best course if mandatory vaccinations for athletes is impossible is to insist on public transparency.

“I don’t like it when someone’s waffling or saying it’s none of your business,” Caplan said. “Vaccination status isn’t personal in the middle of a pandemic. It may be for getting a shingles vaccine, because that doesn’t affect other people. But in a full-blown pandemic that’s already killed 600,000 Americans, you want to be transparent, not to mention that you want athletes to be role models.”

Caplan said that for now, it’s also wise to continue basic infection controls such as hand-washing and mask-wearing when coming into contact with the general public.

“We have to realize that the threat of the virus is not just to the athlete — it’s also (to) the support people, transportation workers and others,” Caplan said.

Should athletes be required to be vaccinated?

In an ideal world, experts said, mandatory vaccination would be desirable. “Any policy short of requiring vaccination is going to be much less effective than blanket vaccination,” Neuman said.

There’s also an imperative for the team owners and leagues: They have a lot of equity invested in the health of their players.

“If I were a team owner, I would protect my investment by requiring everyone to be vaccinated,” Wurtz said.

In the real world, however, it’s not so easy.

Federal law does allow companies to require employees to provide confirmation of vaccination, although some states have enacted laws that prevent this.

However, in the sports world, players typically belong to labor unions, so requirements on vaccination would likely need to be negotiated. (Paul, as it happens, is president of the NBA Player’s Association.)

“It’s important for a team owner to have a conversation with their players to get it right,” Caplan said. “It’s such a hot-wired issue.”

Ultimately, given the misconceptions about vaccine safety that are currently floating around, it’s important to establish two-way communications between players and management, Caplan said.

Caplan said that in his research, he’s found that vaccine hesitancy falls into several categories, each of which needs to be addressed on its own terms. Some female athletes are worried about the vaccines’ effect on fertility, he said, while other athletes are concerned about the long-term effects. Still others think they don’t need a vaccine if they’ve already become sick from the virus.

Through direct dialoguing, health professionals can address each of these concerns effectively, Caplan said.

“You want to address people’s fears,” he said. “You want to see it linked to an education campaign. Mandates work better when people are willing to go along.”