Ômicron: Preliminary study shows that variant causes more Covid reinfections

A study produced by scientists in South Africa found that the omicron variant of the coronavirus may “escape” part of the immunity acquired by people who have already had Covid-19. Researchers detected an increase in the number of people who caught the disease more than once.

The research is a quick and not definitive analysis, but it reinforces the concern about the high number of mutations that this new variant has.

It is also unclear, for now, how this potential discovery affects the protection acquired through vaccines.

A week after the new variant was named omicron, the world is still trying to understand the scale of this new threat. But now a complex puzzle is beginning to be put together.

We already know that the strain has undergone several mutations, and authorities in South Africa have warned that it is causing an increase in cases in the country.

The last piece of this puzzle is figuring out what the probability is that someone who has had Covid-19 will catch the omicron.

Cases of infection by the variant have already been detected in more than 30 countries, including Brazil.

Scientists analyzed nearly 36,000 suspected reinfections in South Africa to look for changes in reinfection rates (who catches twice or more) during the pandemic.

The data show that there was no increased risk of reinfection during waves caused by the beta or delta variants, although laboratory studies suggest that they also had the potential to evade some immunity.

Now, however, scientists are detecting an increase in reinfections in the country. Although genetic sequencing analyzes have not been done in all patients to prove that they are in fact infected with the omicron variant, the data suggest that the variant is the driving force behind the increase in cases, according to the authors.

The study, which has not been formally reviewed by other scientists, estimates that omicrons may be two to three times more likely to cause a reinfection than earlier variants.

“These findings suggest that the omicron is partially driven by an increased ability to infect previously infected individuals,” says Juliet Pulliam, a professor at Stellenbosch University and one of the study’s researchers.

However, this is still just one piece of the puzzle.

There are doubts about the extent to which decreased immunity is a risk factor and to what extent the variant would be able to generate an exponential increase in cases.

Also, this was a quick review. More data will be collected over time. The fact that South Africa is home to a high rate of people infected with HIV – a virus that damages the immune system – also makes it more difficult to interpret the results collected in the country in relation to the rest of the world.

Laboratory studies on the ability of antibodies to attack the virus are expected to be released next week.

This Thursday (2), a study by the National Institute of Communicable Diseases in South Africa also found that omicron is more likely to cause reinfections, compared to the delta and beta variants, but these cases seem to be accompanied by mild symptoms .

“We believe that the number of cases will grow exponentially in all provinces (in South Africa)”, said, at a press conference with the WHO, scientist Anne von Gottberg, from the institute. “But we believe that vaccines will still protect against a more serious condition of the disease.”

In South Africa, only 24% of people are fully vaccinated. The researchers said their findings could have “important implications” for other countries with high levels of natural immunity to infections.

Researcher Juliet Pulliam emphasized that the team “cannot make any judgments about whether the omicron variant also prevents vaccine-derived immunity” because they lacked these data.

This makes it more difficult to understand what would happen in countries like the United Kingdom and Brazil, which not only vaccinated many more people, but are already applying booster doses.

“This scientific paper shows that omicron may be able to overcome natural and likely vaccine-induced immunity to a significant degree. The degree of this is not yet clear, although it is doubtful whether this represents a complete overcoming,” says Paul Hunter, professor of Medicine at the University of East Anglia, UK.

The vast majority of scientists say that while vaccines are not completely effective in stopping Covid infection, the main function of vaccination is to prevent contagion from more severe versions of the disease and slow down the rate at which the coronavirus spreads among people. .

However, the omicron variant can still cause problems. If the strain is capable of causing a sudden big wave of new infections, it could again affect care in hospitals, which can become crowded.

It is still too early to know if this will actually happen, as hospitals tend to be under more pressure weeks after infections start.

South Africa has a relatively young population, which means the Covid wave may seem less severe in the country than in regions with an older population.