Fiocruz warns of possible increase in the XBB lineage of the coronavirus

The Fiocruz Genomic Network detected the reduction in the frequency of the BA.5 omicron lineage and its subvariants in the samples of the new coronavirus collected in December and believes that the reduction is related to a greater presence of the XBB lineages, which have caused great concern in the world.

In a note released this Friday afternoon (13), the foundation explains that, since mid-2022, the omicron lineage BA.5 and its subvariants, including BQ.1.1, was observed in practically 100% of the tests performed.

“This week, however, the Fiocruz Genomic Network detected a considerable increase in variants without the Spike_69/70del mutation in PCR tests carried out in December. Considering the global scenario of the diversity of Sars-CoV-2 variants, the researchers concluded that the increase of variants without this mutation may correspond to the XBB lineage”, says the entity.

The frequency of possible XBB lineages showed constant growth in December, going from less than 5% at the beginning of the month to 15% in the last week, according to Fiocruz.

The states in which the possible circulation of the XBB variant was detected were Rio de Janeiro, São Paulo, Minas Gerais, Espírito Santo, Bahia, Mato Grosso and Santa Catarina.

The information is worrying because one of the subvariants of XBB, XBB.1.5, was considered the most transmissible so far by the WHO (World Health Organization) and is responsible for the recent increase in cases in the United States.

In Brazil, genomic sequencing data detected two samples with the XBB.1.5 subvariant in São Paulo, and Fiocruz defends the importance of PCR analysis tools, such as the one performed now, for the early detection of changes in the virus circulation profile .

In this sense, the work would take place in two stages. First, with a faster analysis, by PCR, to verify the change in the frequency of the Omicron variant, and then, a more detailed study, through genetic sequencing, to confirm the circulation of the XBB variant.

“Therefore, it is clear the need to maintain networks for genomic surveillance of Sars-CoV-2 in the country, ensuring financial resources and the flow of samples to laboratories capable of producing the genomes and analyzing the data quickly”, defends in the note the Fiocruz researcher Tiago Gräf.