How often can we get infected with the virus?

A virus that shows no signs of disappearing, variants that are experts at evading the body’s defenses, waves of infection two and even three times a year: scientists now fear that this is the future of Covid-19.

The main problem is that the coronavirus has become adept at re-infecting people. In fact, there are already people infected with the first omicron variant who have now contracted a newer version of this variant, such as BA. 2 or BA2.12.1 in the US or BA. 4 and BSc. 5 in South Africa.

Researchers interviewed indicated that those people with a second ummicron infection could become infected for the third or fourth time, even this year. And a small percentage of them may have persistent symptoms for months or years, which is known as “prolonged COVID”.

A disturbing hypothesis about the Corona virus

“In the long term, the disease is likely to follow this pattern,” says Juliette Pulliam, an epidemiologist at Stellenbosch University in South Africa.

“The virus will continue to evolve,” he adds. And there will likely be a lot of people who get reinfected again in their lifetime many times.”

It is difficult to determine the frequency of re-infections, in part because there are so many cases that people no longer report them. Dr. Pulliam and colleagues collected enough data in South Africa to say that with Omicron, the re-infection rate is higher than previous variables.

Variable change Omicron hopes

But it wasn’t supposed to be the case. At the start of the epidemic, experts believed that immunity from a vaccination or a previous infection would prevent most infections.

Alternative Omicron shattered that hope. In contrast to previous variants, the omicron and its prolific offspring appear to have evolved to partially bypass immunity. This leaves everyone, even those who have been vaccinated multiple times, susceptible to multiple infections.

“If we keep it running like it is now, most people will get infected at least twice a year,” says Kristian Andersen, a virologist at Scripps Research Institute, San Diego. I would be very surprised if the epidemic did not develop as well.

New variables do not change the usefulness of vaccines

The new variants do not in any way alter the essential benefit of the COVID vaccines. If they do become infected, most people who receive only three or even two doses will not develop a condition that requires it. healthcare. And each booster dose, like previous infection with the virus, appears to reduce the chance of re-infection, although not by much.

At the start of the pandemic, many experts based their predictions about the coronavirus on the common influenza, the most well-known viral enemy of science. They predicted that as with influenza, there could be major outbreaks each year, likely in the fall, and that the way to reduce its spread would be to vaccinate people before the seasonal wave arrived.

But the coronavirus’s behavior ended up being more similar to that of four of its closest cousins, those who spread and cause year-round colds. “When we studied common cold coronaviruses, we saw people with multiple infections in the same year,” says Jeffrey Shaman, an epidemiologist at Columbia University in New York.

Predictions about coronavirus cases

If re-infection turns out to be the norm, coronavirus “will not be something that happens once a year, during the winter,” says Shaman, “and it won’t be a minor nuisance in terms of the number of cases and deaths that do occur.”

Previous variants, including Delta, also produced re-infections, but they were very rare. But in September, the pace of re-infection in South Africa appeared to have improved, and in November, when the omicron variant was identified, it was remarkably high, Pulliam says.

In both South Africa and the United States, cases of infection could attract more attention because many of them have already been vaccinated or have been infected at least once.

“Perception multiplies what is already happening biologically,” says Pulliam. In that sense, the only thing that happens is that there are more people who can get infected again.”

Various variants, omicron and delta

The omicron variant was very different from delta, delta is very different from previous versions of the virus, and reinfections were expected to be few. But it now appears that the omicron variant is developing new ways to penetrate immune defenses. And without major modifications to its genetic code.

“This really surprised me a bit,” says Alex Segal, a virologist at the UCLA Research Institute. health from Africa. “I thought that to escape from this variant, completely new species should appear, but it seemed that it was not necessary….”

The problem is that, compared to previous variants, omicron infection produces a weaker immune response, which also appears to diminish rapidly. Although the newer versions of the variant are closely related, from an immunological perspective they differ enough to leave little protection against each other, and even less after three or four months.

Few cases of reinfection

But the good news is that most people who become infected again with new copies of omicron will not develop serious illness. At least for now, the virus hasn’t found a way to completely bypass the immune system.

“Right now, it’s the best we’ve got,” says Dr. Segal. The big danger is that a completely different species will emerge.”

Each new infection carries the risk of prolonged infection with the virus, a set of symptoms that can persist for months or years. It is still impossible to know what percentage of ómicron cases develop prolonged Covid-19, especially in previously vaccinated people.

Other experts say that to keep up with the virus’s evolution, Covid vaccines must be updated faster, even more often than the annual flu shots. They noted that although the new vaccine does not quite match the new variant of the coronavirus, it will still amplify immunity and provide some protection against the disease.

“Every time we think it’s all over and we think we’ve beaten it, the virus fools us,” says virologist Andersen. “We now know the way to control it is to not get infected several times a year and through your fingers and hopefully everything will go well.”

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