XEC: everything that is known about the new variant of Covid-19

One new strain of the Covid-19 virus was detected in three Brazilian states: Rio de Janeiro, São Paulo and Santa Catarina. Call from XEC the lineage belongs to the variant Ômicron and was identified for the first time in Brazil by the Oswaldo Cruz Institute (IOC/Fiocruz), in samples from two patients diagnosed with Covid-19 in September.

According to Agência Brasil, the identification was carried out by the Laboratory of Respiratory Viruses, Exanthematics, Enteroviruses and Viral Emergencies of the IOC, which acts as a reference for Sars-CoV-2 with the Ministry of Health and the World Health Organization (WHO) .

XEC was classified by the World Health Organization (WHO) on September 24 as a variant under monitoring. This occurs when a strain presents mutations in the genome that are suspected of affecting the behavior of the virus and the first signs of a “growth advantage” are observed in relation to other variants in circulation.

What is the XEC lineage and how did it arise?

According to Fiocruz, analyzes indicate that XEC emerged through genetic recombination between previously circulating strains . This can happen when an individual is infected by two different viral strains simultaneously, which can lead to the mixing of the two pathogens’ genomes during the viral replication process.

According to the Foundation, the XEC genome contains excerpts from the genomes of the KS.1.1 and KP.3.3 lineages. “Viruses continually mutate, some more quickly, others more slowly. This lineage is a hybrid of these previous subvariants of Ômicron”, explains Emy Gouveia, infectious disease specialist at Hospital Israelita Albert Einstein.

In addition to Brazil, in which places has XEC already been detected?

According to data from Gisaid, at least 35 countries have identified the strain which totals more than 2,400 genetic sequences deposited on the platform until October 10th of this year.

The variant began to attract attention in June and July 2024, due to an increase in detections in Germany. In a short time, it spread across Europe, the Americas, Asia and Oceania. Also according to Gisaid, the variant is prevalent in Europe, where at least 13 nations have detected it.

In Brazil, the detection was made based on a surveillance strategy that expanded the sequencing of Sars-CoV-2 genomes in the capital of Rio de Janeiro between August and September, as explained by Fiocruz. The action was in partnership with the Municipal Health Department of Rio de Janeiro.

For three weeks, a nasal swab sample was collected to be sent to the IOC/Fiocruz Reference Laboratory in cases positive for Sars-CoV-2 diagnosed by rapid tests in basic health units. Although it indicated the presence of XEC, monitoring confirmed the predominance of the JN.1 lineage, the majority in Brazil since the end of last year.

What are the symptoms caused by the XEC variant?

There is still no data to indicate that the XEC variant causes more severe or different symptoms than previous variants. Therefore, it is likely to have similar manifestations to other strains, including high fever, sore throat, cough, headache and body aches, as well as fatigue.

Is the XEC variant more transmissible?

According to virologist Paola Resende, researcher at the Laboratory of Respiratory Viruses, Exanthematics, Enteroviruses and Viral Emergencies at the IOC, data from abroad indicate that XEC may be more transmissible than other strains. However, it is important to evaluate your behavior in Brazil.

“In other countries, this variant has shown signs of greater transmissibility, increasing the circulation of the virus. It is important to observe what will happen in Brazil. The impact of the arrival of this variant may not be the same here because the population’s immunological memory is different in each country, due to the lineages that have already circulated in the past”, explains Resende, who also works at the Fiocruz Genomic Network, in statement released by Fiocruz.

Is the XEC variant more serious?

The WHO has not classified the new strain as a variant of concern. However, it is still too early to make a full assessment of the severity of the variant.

“The way in which a new variant will impact a population depends on a series of factors, such as the population’s vaccination rate, which vaccines were administered and in what period,” says Gouveia.

Do current vaccines work against XEC?

Current vaccines against Covid-19 offer protection against Ômicron subvariants and, therefore, must protect against the XEC lineage. Infectious disease specialist William Schaffner, from Vanderbilt University Medical Center, in Tennessee, USA, told NewScientist portal The most up-to-date coronavirus vaccines are expected to protect against the new variant.

Gouveia also reinforces that the entire population must keep their vaccination record up to date, regardless of the circulating variants.

The most up-to-date version of the Covid-19 vaccine, SpikeVax, from the Moderna laboratory, is available in the Unified Health System (SUS). This is a monovalent vaccine that protects against the XBB 1.5 variant, a subtype of Ômicron.

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This content was originally published in XEC: everything that is known about the new variant of Covid-19 on the CNN Brasil website.

Source: CNN Brasil