Covid, WHO tracks evolution of XFG and NB.1.8.1 variants

The World Health Organization is keeping under observation several genetic lineages of SARS-CoV-2 currently in circulation, including those designated XFG and NB.1.8.1. This is reported by the website Pazienti.it, which describes the monitoring activity carried out by the organization.

Variant tracking is a routine practice of international epidemiological surveillance: every mutation of the virus is recorded and assessed to understand whether it changes anything significant compared with already known strains. According to the source, mutations can alter certain properties of the virus, such as the ability to partially evade the immune response developed through previous infections or vaccinations. This type of change, however, does not automatically translate into a new clinical picture: a virus’s ability to partly evade antibodies does not in itself indicate whether the disease it causes is more or less severe.

The same source cites a study conducted in the Netherlands, which reportedly found a reduction in the loss of taste and smell as a symptom of Covid-19: from 17% to 13% when comparing two successive epidemic waves. The available source does not specify the sample size, the exact period of data collection, or the method used to detect symptoms — elements that would be necessary to assess the robustness of this comparison. The figure should therefore be read as a preliminary indication, not as a consolidated conclusion about the evolution of symptoms linked to the new variants.

It should be noted that this account currently comes from a single source (Pazienti.it); it has not been possible to obtain independent confirmation of the details reported, nor to trace directly a World Health Organization statement describing the monitoring activity on the two viral lineages mentioned in the same terms.

At present, therefore, the verifiable information is limited to this: the WHO is tracking the evolution of several SARS-CoV-2 lineages, including XFG and NB.1.8.1, as part of its ongoing genomic surveillance activity.