New variant: what is already known about the transmissibility of the Ômicron

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Since its discovery was announced on November 25, countries around the world have quickly mobilized to alleviate the impacts of the new Ômicron variant. The B.1.1.529 strain of the new coronavirus was first identified in Botswana, southern Africa, and was soon found in South Africa and Hong Kong.

In just a few days, more than 36 countries have already registered detections of the new variant, including Brazil, with a total of six cases, three in the state of São Paulo, two in the Federal District and one detected in Rio Grande do Sul.

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Currently, what intrigues scientists around the world are the level of transmissibility of the new variant and the effectiveness of vaccines against it.

According to the chief scientist of the World Health Organization (WHO), Soumya Swaminathan, the Ômicron variant of the coronavirus is very transmissible, but people should not panic.

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“How worried should we be? We need to be prepared and cautious, not panic, because we are in a different situation than a year ago,” said Swaminathan.

Chance of reinfection up to three times higher

An update of the study conducted in South Africa by Juliet Pulliam, director of the DSI-NRF South African Center of Excellence in Epidemiological Modeling and Analysis, was published on Friday (2) and points out that the chance of variant retransmission Ômicron is three times larger than other variants.

The research aims to examine whether the risk of SARS-CoV-2 reinfection has changed over time in South Africa, in the context of the emergence of Beta, Delta and Ômicron variants. And it shows that Ômicron is more likely to reinfect those who already had Covid-19.

The study was based on data collected by the South African healthcare system on an estimated 2.8 million confirmed coronavirus infections between March 2020 and November 27, 2021, including 35,670 suspected reinfections.

Focusing on the analysis of positive tests for Covid-19, the scientists observed a significant increase in supposed reinfections, which coincides with an increase in the Ômicron variant. Not all samples were sequenced, but the researchers say that there was no such trend with other variants in the country, which may indicate that the new strain could circumvent the immunity caused by a previous infection.

According to a post by Juliet Pulliam on Twitter, evidence of an increased risk of reinfection associated with the emergence of Ômicron suggests the evasion of immunity from the previous infection.

“We’ve seen a recent increase in the number of reinfections in individuals who already had multiple suspected infections by mid-November. The findings suggest that Ômicron’s selection advantage is, at least partially, driven by an increased ability to infect previously infected individuals. We do not have information on the vaccination status of individuals in our dataset and therefore we cannot assess whether Ômicron also prevents vaccine-derived immunity,” explains the study author.

She says two methods were used to monitor changes in the risk of reinfection.

“Both of these methods are responsible for the change in the strength of infection experienced by all individuals, and the increasing number of individuals eligible for reinfection over time,” said Juliet.

Recent research reiterates what many scientists have been saying: it is too early to assess the variant’s true potential, and further studies should provide more concise answers around Ômicron impacts.

“The next steps include quantifying the extent of Ômicron’s immune escape for natural and vaccine-derived immunity, as well as its transmissibility relative to other variants. Urgent data are also needed on the severity of disease associated with Ômicron infection, including in individuals with a history of prior infection,” the study concludes.

As this is a preliminary study, the material still needs to be reviewed by the scientific community.

A South African doctor, who was one of the first to suspect a different strain of coronavirus among her patients, said on Sunday (28) that the symptoms of the Ômicron variant were so far mild and could be treated at home.

Doctor Angelique Coetzee, a private physician and president of the Medical Association of South Africa, told Reuters that on November 18 she noticed seven patients in her clinic who had symptoms different from the Delta variant, although “very mild”.

“Most of them (doctors) are seeing very, very mild symptoms and none of them so far have referred patients for surgery. We have been able to treat these patients conservatively at home,” she said.

His experience so far shows that the variant is affecting people aged 40 and under. Almost half of the patients with Omicron symptoms she treated were not vaccinated.

Reference: CNN Brasil

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