How often can you be infected?

A virus that shows no signs of disappearing, variants that are adept at dodging the body’s defenses and waves of infections two, maybe three times a year — this may be the future of COVID -19, some scientists now fear.

The central problem is that the coronavirus has become more adept at reinfecting people. Already, those infected with the first omicron variant are reporting second infections with the newer versions of the variant — BA.2 or BA2.12.1 in the United States, or BA.4 and BA.5 in South Africa.

Those people may go on to have third or fourth infections, even within this year, researchers said. And some small fraction may have symptoms that persist for months or years, a condition known as long COVID.

“It seems likely to me that that’s going to sort of be a long-term pattern,” said Juliet Pulliam, an epidemiologist at Stellenbosch University in South Africa.

“The virus is going to keep evolving,” she added. “And there are probably going to be a lot of people getting many, many reinfections throughout their lives.”

It’s difficult to quantify how frequently people are reinfected, in part because many infections are now going unreported. Pulliam and her colleagues have collected enough data in South Africa to say that the rate is higher with omicron than seen with previous variants.

Earlier in the pandemic, experts thought that immunity from vaccination or previous infection would forestall reinfections.

The omicron variant dashed those hopes. Unlike previous variants, omicron and its many descendants seem to have evolved to partially dodge immunity. That leaves everyone vulnerable to multiple infections.