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A virus that shows no signs of disappearance, variants that are adept at bypassing the body’s defenses, and waves of infection two, maybe three times a year – this could be the future of Covid-19, which some scientists now fear.

The real problem is that the coronavirus has become more adept at reinfecting people. Currently, those infected with the first variant of Omicron report second infections with newer versions of the variant – BA.2 or BA2.12.1 in the United States, or BA.4 and BA.5 in South Africa.

The researchers said in interviews that these people could go on to have a third or fourth infection even this year. And some minor cuts may have symptoms that persist for months or years, a condition known as the long-term Covid.

“It seems likely to me that this is a long-term pattern,” said epidemiologist Juliet Pulliam of Stellenbosch University in South Africa.

“The virus will continue to evolve,” he added. “It’s likely that many people will get many, many reinfections in their lifetime.”

It’s difficult to quantify how often people are reinfected, partly because many infections are no longer reported. Dr. Pulliam and colleagues have collected enough data to say that the rate is low in South Africa. Higher than seen in previous variants with Omicron.

This shouldn’t have happened. At the beginning of the pandemic, experts thought that immunity from the vaccine or previous infection would prevent most re-infections.

The Omicron variant failed those hopes. Unlike previous variants, Omicron and its many descendants seem to have evolved to partially circumvent immunity. This leaves everyone – even those who have been vaccinated multiple times – vulnerable to multiple infections.

“If we manage it the way we currently do, most people will be infected with it at least a few times a year,” said Kristian Andersen, a virologist at the Scripps Research Institute in San Diego. “I’d be very surprised if he didn’t play like that.”

The new variants did not change the core benefit of the Covid vaccines. Most people who take three or even just two doses will not be sick enough to need medical care if they test positive for coronavirus. And a booster dose, like a previous match with virusseems to reduce the chance of re-infection – but not by much.

At the start of the pandemic, many experts based their coronavirus expectations on the viral enemy most familiar to them, influenza. They estimated that, as with the flu, a major epidemic could occur each year, most likely in the fall. The way to minimize its spread would be to vaccinate people before they arrive.

Instead, the coronavirus is behaving like four of its closely related cousins ​​that circulate throughout the year and cause the common cold. “We’ve seen people with multiple infections within a year,” said Jeffrey Shaman, an epidemiologist at Columbia University in New York, when studying cold coronaviruses.

If re-infection becomes the norm, the coronavirus “won’t be a winter thing a year,” he said, adding that “it won’t be a slight nuisance in terms of the amount of morbidity and mortality.” it causes.”

Re-infection with earlier variants, including Delta, did occur, but was relatively rare. However, Dr. In September, the rate of re-infections in South Africa rose and was markedly high by November, when the Omicron variant was identified, Pulliam said.

In South Africa, as well as in the United States, reinfections may seem all the more remarkable because many have been vaccinated or infected at least once by now.

Dr. “Perception magnifies what’s actually going on biologically,” Pulliam said. “There are just more people eligible for reinfection.”

The Omicron variant was sufficiently different from Delta and previous versions of the Delta virus, so some reinfection could be expected. Now, however, Omicron appears to be developing new forms that penetrate immune defenses with relatively little change to its genetic code.

“This actually came as a bit of a surprise to me,” said Alex Sigal, a virologist at the African Institute for Health Research. “I thought we would need a whole new species to get out of this. But actually, it looks like you weren’t.”

An infection with Omicron produces a weaker immune response that appears to diminish rapidly compared to infections with previous variants. While newer versions of the variant are closely related, they vary enough from an immune perspective to transmit infection with one. doesn’t go lots protection against others – and certainly not three or four months from now.

The good news, though, is that most people re-infected with new versions of Omicron will not become seriously ill. At least right now the virus hasn’t found a way to bypass the immune system completely.

Dr. “It’s probably that good for now,” Sigal said. “Great danger can come when the variant is completely different.”

Each infection can bring with it the possibility of prolonged Covid, a constellation of symptoms that can last for months or years. It is too early to know how often an Omicron infection leads to a prolonged Covid, especially in vaccinated people.

Other experts said that to keep up with the evolving virus, Covid vaccines need to be updated every year faster, if not more, than flu vaccines. Even an imperfect match with a new form of coronavirus would broaden immunity and provide some protection, they said.

Dr. “Every time we think we’ve gotten over it, every time we think we’ve got the upper hand, the virus is playing a trick on us,” Andersen said. “The way to get it under control is not ‘Let’s all get infected a few times a year and then hope for the best’.”