Canada is currently facing a potential disruption in the lull of COVID-19 cases with the emergence of a new family of subvariants known as the FLiRT variants. These genetic cousins, originating from the JN.1 Omicron subvariant, are spreading nationwide, with one variant, KP.2, quickly gaining dominance in the country. The FLiRT variants are named as such due to specific mutations in their genetic makeup. The World Health Organization (WHO) has identified the KP.2 subvariant as a descendant lineage of JN.1 and stated that it began circulating globally in January. The emergence of KP.2 in Canada was first observed in February, and although data indicates it has a reproductive advantage, it has a diminished growth rate compared to previous variants.
While COVID-19 levels are currently low on average in Canada, experts such as infectious disease specialist Dr. Isaac Bogoch warn of a potential spike in cases with the emergence of the FLiRT variants, particularly KP.2. Bogoch notes that the mutation may be more adept at evading immunity, potentially leading to an increase in infections. However, he emphasizes that the severity of these infections is typically lower, especially among those who have been infected, vaccinated, or both. While the FLiRT variants may better evade immunity, the majority of the population is not immuno-naive, reducing the overall threat to healthy adults and children. Seniors and immunocompromised individuals remain at a higher risk.
Data on the FLiRT variants is still being analyzed, but symptoms appear to align closely with those of all Omicron variants. The COVID-19 vaccine currently available in Canada targets the XBB 1.5 Omicron subvariant, but experts believe it should still provide efficacy against the FLiRT variants. While young, healthy individuals who received their vaccine in the autumn likely won’t need another booster until fall 2024, older adults and immunocompromised individuals are advised to get the spring booster. The National Advisory Committee on Immunization (NACI) anticipates another surge in the fall and winter months and recommends preparing for updated vaccine formulations.
The WHO’s Technical Advisory Group on COVID-19 Vaccine Composition has recommended that future vaccine formulations include JN.1, and discussions on this are ongoing. Experts acknowledge the challenges of staying ahead of the virus due to its constant mutation, similar to the challenges faced with influenza vaccines. Despite the potential threat posed by the FLiRT variants, the current data indicates a lower infectivity rate compared to previous variants, offering some level of reassurance. However, ongoing monitoring and adaptation of vaccination strategies will be crucial in addressing the evolving landscape of COVID-19 in Canada and globally.
