Covid-19 'FLiRT' variants: What you need to know

The relative calm in the US regarding Covid-19 could be disrupted by a new cluster of SARS-CoV-2 variants, collectively known as the "FLiRT" variants. These variants have emerged from the JN.1 lineage, responsible for a surge in Covid-19 cases last winter. The most notable among these, the KP.2 variant, represented approximately 25% of the newly sequenced cases in the last two weeks of April, according to data from the Centers for Disease Control and Prevention (CDC).
As per a report in the Time magazine, while other variants in the FLiRT family, like KP.1.1, have not yet spread widely in the US, the scientific community is vigilantly monitoring their progression.
Understanding the FLiRT Covid-19 variants
The "FLiRT" Covid-19 variants represent a group of SARS-CoV-2 mutations that are part of the Omicron family. These variants emerged from a lineage known as JN.1, which was responsible for a notable surge in COVID-19 cases during the previous winter season. The name "FLiRT" comes from the technical names of their specific mutations, where one includes the letters "F" and "L" and another includes "R" and "T."
Among the FLiRT variants, KP.2 has become particularly prominent. By the end of April, it accounted for about 25% of new sequenced cases in the United States, as reported by the US Centers for Disease Control and Prevention (CDC). Other variants within the FLiRT family, such as KP.1.1, have not yet spread as extensively.
The concern with the FLiRT variants lies in their potential to spread quickly, possibly causing diseases that could be more severe than previous strains or could partially evade the protection provided by existing vaccines. Research is ongoing to determine the characteristics of these variants, including their transmissibility and the severity of the illness they cause.
Should we be wary?
Two preliminary studies have highlighted concerns regarding the ability of the FLiRT variants to bypass the immune defense provided by vaccines:
A study from Japan indicated that the KP.2 variant might be less infectious than its predecessor, JN.1, but could still pose challenges due to its ability to partially evade vaccine-induced immunity.
Another study from researchers in China suggested similar findings, emphasizing the need for ongoing vaccine adjustments to keep pace with the evolving virus.
Dr Eric Topol, executive vice president at Scripps Research, mentioned in his newsletter that it's too early to predict whether the FLiRT variants will lead to a significant new wave of infections. Current indicators, such as minimal virus levels in US wastewater and declining hospitalizations and deaths since January, suggest a major surge might not be imminent. "It might be a 'wavelet,'" Topol suggested, indicating a minor increase in cases.
WHO recommendations
In response to these developments, the World Health Organization (WHO) has recommended that future Covid-19 vaccine formulations should be based on the JN.1 lineage, from which the FLiRT variants have evolved. This recommendation aims to ensure that the vaccines remain effective as the virus continues to mutate.
Despite the challenges posed by new variants, the fundamental public health advice remains consistent: it is crucial to stay up-to-date with Covid-19 vaccinations. The regular updating of vaccines, akin to the annual updates for flu shots, may become necessary to maintain high levels of protection against emerging variants.