Monitoring the BA.2.86 Variant: Insights into the Latest Developments and Global Impact

Jessy Lee
Nov 29, 2023
During the summer, concerns arose with the appearance of the BA.2.86 variant of COVID-19, colloquially named "pirola," owing to its numerous mutations. However, initial worries diminished as the variant exhibited minimal impact. Fast forward several months, and BA.2.86 is gaining prominence.
Monitoring the BA.2.86 Variant: Insights into the Latest Developments and Global Impact

During the summer, concerns arose with the appearance of the BA.2.86 variant of COVID-19, colloquially named "pirola," owing to its numerous mutations. However, initial worries diminished as the variant exhibited minimal impact. Fast forward several months, and BA.2.86 is gaining prominence.


In a Wednesday press conference, Maria Van Kerkhove of the World Health Organization (WHO) emphasized the need to monitor BA.2.86. While the strain appears to have a growth advantage, it does not seem to cause more severe disease.


In its recently released risk assessment, WHO categorized BA.2.86 as having a "low" global-level public health risk. The significant population immunity resulting from previous infections and vaccinations diminishes the likelihood of the variant imposing an additional burden on national public health systems.


Despite the overall low risk, WHO upgraded BA.2.86 to a "variant of interest," indicating changes that could impact virus transmission and a growth advantage over other strains. However, there is currently no evidence that BA.2.86 poses additional public health risks compared to other circulating omicron descendant lineages.


Estimates from the Centers for Disease Control and Prevention (CDC) suggest that BA.2.86 contributed to nearly 9% of recent COVID-19 cases in the U.S., a substantial increase from 1% in late October. Global estimates in early November showed a similar prevalence of nearly 9%, with a gradual rise reported worldwide.


The CDC cautioned that data on BA.2.86 is based on a relatively small number of sequences, urging careful interpretation. Nevertheless, expectations are that the updated vaccine will enhance protection against this variant, and existing COVID-19 tests and treatments are expected to remain effective.


Despite the increase in COVID-19 cases and hospitalizations in the U.S., the CDC clarified that BA.2.86 "does not appear to be driving" these upswings.