Omicron underscores are behind the rise in cases

Within a month, substrates BA.4 and BA.5 of ômicron began to represent 44% of the positive covid-19 samples in Brazil, according to a report by the Instituto Todos pela Saude (ITpS). The previous rate was only 10.4%. Therefore, he noted that the ITpS had increased the number of cases and hospitalizations.

According to the institute’s estimates, BA.4 and BA.5 will be the highest transmission this week and, during June and July, there will be a drop in positivity in tests and, consequently, in cases. After arriving in the country in May, two strains have already been identified in 198 municipalities in 12 states and the Federal District.

According to the World Health Organization (WHO), BA.4 and BA.5 carry a mutation that appears to be associated with increased transmissibility and immune escape — from previous infections or vaccines. Evidence from several countries, however, does not indicate that the severity of the cases has increased. Higher transmission is explained by the increased ability of the virus to bind to the human cell. This can also lead to a lower viral load that can lead to infection.

The average number of infections has risen by 114.8% in the last two weeks, according to data from the media consortium. On Thursday, the number was 37,191, which shows a return to levels seen in late March, but far from the peak of the “original” omicron, BA.1. The rise may be underestimated due to self-testing and reporting problems by states.

Advances in cases and subplots occur at a time when vaccination rates and cold temperatures are stagnant, when people tend to be indoors, closer to each other, and with the circulation of other worrying respiratory viruses. To prevent further hospitalizations and increased mortality, experts point out the need to boost immunization, especially in high-dose and pediatric doses, and to return mandatory masks indoors.


From March 1 to June 4, ITpS tested more than 123,800 RT PCR tests performed by private laboratories. About 90% of the samples are from the Southeast and Central West. The current positive rate is 38.9%.

Virologist Anderson Brito, an ITpS researcher, pointed out that the data do not come from sequencing, but from genotyping. They study the detection of the S gene in the virus, which makes it possible to determine the possible underlying omicron.

BA.1 arrived in the country in December. It replaced the Delta variant and dominated from January to February. Beginning in March, BA.2 gradually gained strength and reached its peak in mid-May, when BA.4 and BA.5 entered the scene. Brito explained that BA.4 and BA.5 have an evolutionary advantage over BA.2. Both have a greater ability to transmit and also to escape the immune response. “Until the middle of last month (with BA.2), we basically experienced a small wave because the number of cases has not increased so much.”


The wave of cases driven by the emphasis, he says, “serves as a warning.” However, Brito emphasized that there was a “positive point”. “South Africa was the first country to deal with all these sub-variants. And the last wave that ended a few days ago (driven by BA.4 and BA.5) was the shortest and had the least impact on public health,” he says. emphasizing. “This shows us a scenario that is not comparable to the waves we face.”

But the danger does not exist. “These two variants have been prevalent in Europe for the past two months. And they have been responsible for the new rise in cases, as well as in hospitalizations there,” says Raquel Stucchi, an infectious disease expert at the Brazilian Association of Infectious Diseases. He emphasizes that vaccination in subterranean vaccines is related to infection and mild cases. Immunizers continue to provide strong protection against harsh conditions.

But in order to do that, it is necessary to have the right level of antibodies, which raises the need for progress in the application of reinforcements. “In four to five months, especially in the immunocompromised population and among those over 50, there has already been a decline in antibodies.”

People who have not yet been immunized or who have not met their dosing schedule are also more vulnerable in this subterranean wave. “We know that deaths and STIs are 20 times more likely to occur in people who are not vaccinated or not fully vaccinated,” said Marcelo Otsuka, vice president of the Department of Pediatric Association of the São Paulo Pediatric Association (SPSP).

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