Boston Celtics wing Josh Richardson, who has evaded questions about his vaccination status, tested positive for COVID-19 on Dec. 10. He missed only two games before registering the required negative tests on consecutive days and returning to practice five days later. Richardson played two more games, scoring a season-high 27 points on Saturday, before reentering the NBA's health and safety protocols on Sunday.

In between, six more Celtics entered protocols, including Grant Williams, a vice president in the players' union and vocal vaccine advocate. Players can return from a COVID-19 diagnosis after 10 days or two negative tests 24 hours apart. Unvaccinated players who are considered close contacts are also subject to seven days in health and safety protocols. The Celtics are not among the league's fully vaccinated teams.

If this feels like information overload, welcome to the pandemic. It is frustrating and flummoxing and filled with every emotion, but the NBA is showing us in real time a science-based path across a political divide.

Every question you have asked about COVID-19 over the past 21 months, the NBA has asked and often answered many times over, because its players are among the world's most traveled and tested people. They are also 97% vaccinated and 65% boosted among those eligible, far higher than national averages.

Yet, a quarter of the NBA's players have entered protocols this month. Half its teams have experienced COVID-19 outbreaks of four or more positive cases in December. Nine games have been postponed since Dec. 13, the Christmas Day schedule is in peril, and experts expect another surge to peak in mid-January.

That fuels discussion about variants, transmissibility and each vaccine's effectiveness against either. The NBA, like the rest of us, is left to wonder whether we can put a stop to the cyclical nature of this pandemic, when COVID-19 becomes endemic, and at what point asymptomatic players might be allowed to compete.

When a pandemic becomes endemic

We may not eradicate COVID-19, but an improvement from the current wild swings brought on by its mutations would be to stabilize it at a predictably low level. In theory, that requires vaccinations and natural infection or both to generate widespread immunity, only we are in a race against the virus' next mutation.

The NBA has been at the front of the pack in that race, but the league is no longer operating in a bubble.

"In terms of whether we can, in essence, treat this as endemic and people move on and we only test those who are symptomatic and deal with those, we're not quite there yet," NBA commissioner Adam Silver said on ESPN's "NBA Today" on Tuesday. "We're talking to lots of other organizations, doctors and scientists to figure out what the right thing to do is. We do think there's an opportunity to potentially lead here."

Ask the doctors. Do not expect the COVID-19 version of Michael Jordan's flu game anytime soon. Or ever.

"What I don't think we're going to see and would never want to see and would never say is OK is, if we have a player who tests positive on a rapid test, meaning they have a high and detectable load, meaning they could be shedding it and transmitting it to others, and you know that player is positive, it would be irresponsible, immoral and disgusting to send that player out onto a field or court with other people," Zach Binney, a sports epidemiologist at Georgia's Oxford College of Emory University, told Yahoo Sports.

"I definitely think that would be a bad idea, and I think everybody at this point would agree that's a bad idea. Maybe once we have gotten to a point where we've gone through, say, a full year, and it's clear that COVID is at its endemic level now, maybe you could revisit that, but certainly not right now.

"What I think is much more likely to happen is teams are going to dial back on testing protocols, and you are going to get people accidentally going out there. That's not ideal from an epidemiological perspective, but it's hard to criticize these leagues when a lot of other workplaces are creating a heck of a lot more danger. We don't want to fall into that trap of only focusing on the worst offenders, but pro sports teams have had some of the best protocols and some of the safest work environments in the entire country."

The thing about boosters

As the NFL opted out of regularly testing asymptomatic vaccinated but un-boosted players, the NBA added safety measures in the face of an Omicron variant that has proven thus far to be more contagious than its predecessors, even if early (and not fully substantiated) studies indicate it could also be less severe. (Keep in mind, a virus twice as contagious and half as severe can still result in more hospitalizations and deaths.)

Per the Center for Disease Control and Prevention's latest data from October, unvaccinated people were 20 times more likely to die from COVID-19 than fully vaccinated and boosted individuals. Science continues to demonstrate that vaccines bolster your defense against the virus exponentially, specifically the Pfizer and Moderna vaccines, and a third dose of either further increases your protection. The Johnson & Johnson vaccine, which 30% of NBA players received, has proven less effective, particularly against recent variants.

"Vaccines, and especially with the Omicron variant, boosters, remain the best weapon we have against COVID-19," Dr. John DiFiori, the NBA’s Director of Sports Medicine, told Yahoo Sports in an email response to questions on Wednesday evening. "They are certainly not perfect and people can still become infected, but they continue to perform well in preventing severe illness, including hospitalization and death."

NBA data has revealed "a very small number" of breakthrough cases among players and coaches who are at least two weeks from receiving a booster, following two doses of either mRNA vaccine, and the majority of them have been asymptomatic or mildly symptomatic, Silver said. NBA data often reflects the general U.S. population, and initial studies of Omicron have similarly shown that, while it is more contagious, even among vaccinated individuals, boosters have added a formidable layer of defense against severe cases.

"I would just say to our community, really to everyone, at least based on the data the NBA has, the boosters are highly effective," Silver said on ESPN, "and we're strongly encouraging everyone to get them."

"Data shows that people who are fully vaccinated and boosted by one of the mRNA vaccines are the most protected against COVID-19. For the Omicron variant, boosters are particularly important," said DiFiori. "We continue to work closely with the players' association to inform them about the latest information regarding vaccines and boosters, as well as all measures needed to maintain health and safety during the pandemic."

The players' association on Tuesday "committed to facilitating the delivery of booster shots to all eligible players, and the NBPA is strongly encouraging all our members to receive a booster as soon as possible."

Masks are also required of all players everywhere but the court. The NBA instituted gameday testing for eligible players who had not yet received booster shots on Dec. 17. Multiple positive cases trigger team-wide testing, and the league experienced three straight days of double-digit entries into health and safety protocols. On Sunday, those players will begin testing on game and practice days for at least two weeks, at which point the league will have more data about the transmissibility and severity of the Omicron variant.

"We are actively looking at shortening the amount of days that a player is out before he can return to the floor," said Silver, citing data that suggests boosted players may stop spreading the virus before 10 days.

The replacements

Teams can sign a replacement player to a 10-day contract for every player who tests positive at no cost to the salary cap. Teams with two positive cases must sign at least one replacement player. Three positive cases will require a second 10-day signee, and four or more cases necessitate a third. Protocols for unvaccinated players entering into the league effectively bar them from accepting these hardship contracts.

As positive cases began to mount across the roster, the Brooklyn Nets announced on Friday they planned to reintroduce an unvaccinated Kyrie Irving to the rotation for road games "after careful consideration of our current circumstances, including players missing games due to injuries and health and safety protocols."

Confounding, right? New York City's vaccine mandate still prevents Irving from participating in games at the Barclays Center, but the Nets altered course to allow an unvaccinated player to join their road ranks in an attempt to stem the tide against a wave of positive cases among vaccinated individuals on their team.

By Saturday, Irving had joined Kevin Durant, James Harden and seven more teammates in protocols.

A member of Brooklyn's front office, quarantining with COVID-19, texted Rolling Stone, "When Ky tested positive, it was meant to be. But also part of me was glad that it shut up the anti-vaxxed hailing him."

The Nets signed replacement players James Ennis and Shaquille Harrison to meet the required eight available players for Saturday's game and both saw action in a loss to the Orlando Magic. The NBA then announced the postponement of Brooklyn's next two games on Sunday. A third has since been postponed.

"If they're continuing to test, they're going to find a lot of cases because of how transmissible Omicron is," said Binney. "A lot of them are probably going to be asymptomatic or have pretty mild symptoms. That's the good news. But they're going to find that these players are going to go into protocol, and they're going to be held out. You may continue to get to the point, as we've already seen several times, of not having enough players to play a game and needing to postpone games. And I would expect that to continue."

Simplifying the response

Boston mandated vaccines for indoor events on Monday, joining New York, San Francisco and Los Angeles. Every TD Garden attendee and employee will be vaccinated and boosted by Feb. 15 — except for unvaccinated Celtics players, who will still be subject to the NBA's rigorous testing. The three other major cities make no such exemption for home teams, although unvaccinated visiting players are exempted.

It is easy to get lost trying to determine the logic in the small print, but the league's directive is fairly simple: Educate players on the benefits of vaccines, implement stricter guidelines for those who do not get vaccinated and increase testing at any sign of an outbreak. This is the science-based approach to limiting the spread of the virus, early diagnosis of positive cases and prevention of hospitalization or severe illness.

The NBA proposed a vaccine mandate that the NBPA rejected. Given Irving's spot on the nine-man executive committee, the players' union is unlikely to reverse its position, even as the league's 30-member Board of Player Representatives issued a statement on Tuesday "strongly encouraging" booster shots.

More than 25% of NBA players have tested positive for COVID-19 this season, which has raised a question on the fringes, even among their own membership: "Why are people with vaccines still getting COVID?"

Vaccines are not 100% effective, less so against Omicron, but study after study has shown unvaccinated people account for an overwhelming majority of hospitalizations. Severe breakthrough cases are possible among the vaccinated. Ask Philadelphia 76ers star Joel Embiid, who said of his recent bout with COVID-19, "I really thought I wasn’t going to make it. It was that bad." Still, he is more the exception than the rule.

Even in a small NBA sample size, the virus has proven more contagious among the 3% of unvaccinated players. Silver said "many of the 3% now have gotten COVID, so they have developed antibodies." Five of the six known unvaccinated players have contracted the virus this calendar year. The other has not played since 2020. Two have twice tested positive. Four more players who shared anti-vaccination views and three others who evaded direct questioning about their vaccination status have also tested positive this season.

The NBA does not disclose data regarding its unvaccinated population of roughly 15 players.

Where we go from here

Whether or not you consider the NBA's decision to push through its recent increased caseload strictly financially motivated, the league will still take a hit on Christmas, its signature day of the regular season. Five of the 10 teams scheduled to play on Saturday have multiple starters in protocols. The status of All-Stars Giannis Antetokounmpo, Luka Doncic, Durant, Irving and Trae Young remains in question.

The NBA confirmed its first case of Omicron last week, and it now accounts for 90% of the league's cases, according to Silver. Omicron became the dominant variant in the U.S. over a similar timeframe, accounting for 73% of cases during the week ending Dec. 18, up from 12.6% the previous week, the CDC reported.

So long as the NBA continues without pause (and Silver said, "Frankly, we're having trouble coming up with what the logic would be behind pausing right now"), the league is likely to continue seeing a spike in cases through the holidays and into January, just as the rest of the world is expected to see a similar surge.

The question is whether the NBA can navigate to the other side of another curve before its next signature date on Martin Luther King Jr. Day on Jan. 17. There is a chance. Because the league has already seen so many Omicron infections, and the players' association is taking steps toward boosting the 97% of its membership that is vaccinated, the NBA is building up considerable immunity against the dominant variant.

"If you've already had 25% of the league test positive this month, eventually the virus is going to run out of people to infect," said Binney. "That's not how we want to get there, but eventually that could happen."

If only the nation was almost fully vaccinated, two-thirds boosted among those eligible, taking additional safety measures, testing regularly and quarantining when necessary, fans packing NBA arenas might be able to survive the same real-time science lesson largely unscathed — rather than learning the hard way.

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Ben Rohrbach is a staff writer for Yahoo Sports. Have a tip? Email him at rohrbach_ben@yahoo.com or follow him on Twitter! Follow @brohrbach