Making Sense of Covid Changes

As we approach the third year of the pandemic, the coronavirus continues to make life difficult — and confusing. Official guidance on masks, testing and isolation change as new variants emerge, and a stream of case numbers turns us into armchair epidemiologists, trying to figure out how risky it is to attend a New Year’s Eve party.

If the past few weeks have left you dizzy, you’re not alone. In today’s newsletter we’ll explain some recent developments and take stock as we head into 2022.

New isolation rules

The C.D.C. this week shortened its recommended isolation period, saying that people who are infected can re-enter society after five days if they don’t have symptoms or if their symptoms are resolving. The guidance adds that people should wear a mask for five days after that.

The change came about, officials said, because studies have found that a majority of transmission happens in the first five days of an infection. It also allows companies to bring back workers in half the time.

Delta Air Lines, which had urged the C.D.C. to adopt the change, welcomed the news, as did officials in the food and retail industries. In New York City, a vital subway line shut down yesterday because so many workers were out sick. Shops and restaurants have temporarily closed across Europe.

Dr. Ashish Jha called the new guidance “reasonable,” as long as people follow the rule that they leave isolation only if they are asymptomatic. But Jha added that he would have required a negative rapid test before leaving isolation.

Many public health experts had a harsher reaction to the new rules, particularly the decision to omit testing. Angela Rasmussen, a virologist at the University of Saskatchewan, called it “reckless and, frankly, stupid.”

Dr. Rochelle Walensky, the C.D.C. director, told CNN that the guidance “had a lot to do with what we thought people would be able to tolerate.” She estimated that less than a third of people who should have isolated in the past had done so; the new rules, she said, were meant to encourage people to stay in when they were “maximally infectious.”

Experts also noted that the guidelines make no distinction between vaccinated and unvaccinated people who test positive, despite the unvaccinated facing far greater risks.

“The C.D.C. should develop further guidelines, right now, that allow for those who are vaccinated and boostered to leave isolation as soon as possible after they have gotten negative results repeatedly with antigen tests,” Dr. Aaron E. Carroll, the chief health officer for Indiana University, wrote in The Times. And, he added, the Biden administration should do “everything possible to make such antigen tests freely and easily available.”

Severe cases

It’s too early to be sure of Omicron’s effect on hospitalizations and deaths. But health officials say the early data offers some cautiously positive signs.

Walensky said yesterday that cases had increased by around 60 percent over the past week and hospitalizations had risen by 14 percent. While hospitalizations tend to lag cases, she noted, the pattern is similar to countries that have had the variant for longer, like South Africa and Britain.

Take the two states below as an example. New York has been one of the hardest-hit states in the current wave, and Florida was hit hard this summer by Delta. In each, hospitalizations haven’t yet reached the levels of last winter’s peaks, despite cases rising past that mark. (Look up your state here.)

“The pattern and disparity between cases and hospitalizations strongly suggest that there will be a lower hospitalization-to-case ratio when the situation becomes more clear,” Dr. Anthony Fauci said yesterday.

It’s not clear that Omicron’s severity is the main cause of the split between cases and hospitalizations, though, as a year’s worth of vaccinations and infections have strengthened the country’s resistance to the virus.

Omicron and Delta

Over the past few weeks, we’ve been talking a lot about Omicron, which is the dominant variant in the U.S. and many other countries. But Delta, the variant that came to prominence in the summer, is still here.

South African scientists are hoping that there’s some good news: People who have recovered from an infection with Omicron may be able to fend off Delta, according to a small early study. (The reverse is most likely not true: Delta antibodies seem to offer little protection against Omicron.)

If the theory holds, Omicron may eventually overwhelm Delta, Carl Zimmer explained in The Times. And if Omicron is indeed less severe, its takeover could mean that fewer people get seriously ill or die.

But that doesn’t mean that Omicron will be the only variant for years to come, Carl wrote: “Once people gain immunity to Omicron, natural selection may favor mutations that produce a new variant that can evade that immunity.”

Something else to know about Omicron versus earlier variants: The incubation period seems to be shorter. It may take three days for people to develop symptoms, become contagious and test positive, compared with four to six days with Delta.

New Year’s Eve

All of this could have you asking whether to gather with friends or family members for New Year’s Eve tomorrow. Many public health experts agree that you can celebrate with your favorite people as long as you’re taking precautions.

To help you make a decision and gauge the level of risk, The Times has this quiz.

More on the virus:

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This was the year TikTok’s biggest stars — Charli D’Amelio, Addison Rae, Chase Hudson and others — made their jump to more traditional channels like reality TV, music, movies and memoirs.

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“Throughout many of these projects, what you sense is the offscreen number-crunchers hoping to hang potential franchises on the heads and necks of these young people, who are less fully formed creative thinkers than fan-aggregation platforms in desperate need of content,” Jon Caramanica writes in The Times. Read his piece on the future of TikTok stardom. — Sanam Yar, a Morning writer

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