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BA.2.86 "Pirola" update

Since we are in the middle of holiday and fall cold season, and we have a noticeable uptick in cases per the wastewater data and the increase in hospitalizations nationally, I have gotten a lot of questions about whether the increases in cases are due to the variant "Pirola" or BA.2.86.

This week the CDC posted a respiratory virus update on their website about BA.2.86 which received a lot of attention. This isn't actually a new variant. We started hearing about BA.2.86 spreading in other parts of the world back in the summer, but the proportion of infections attributed to this variant in the US had been very small. Recently, there have been enough cases of BA.2.86 detected that it started showing up on the CDC variant tracker November 11, and it has been increasing in prevalence over the past month. As of Monday, November 27, this variant now accounts for between 5-15% of currently circulating variants, with the highest proportions being seen in the NY/NJ area.

The reason people are paying attention to BA.2.86 is because this variant has over 30 mutations to the spike protein, relative to XBB.1.5, the variant that the fall 2023 boosters were targeted to.

Any time we see a variant with a lot of mutations, it is tracked closely because there is a concern that we will have potential for greater spread, more severe disease or that perhaps vaccines or treatments would not be as effective.

So, should we worry?

The WHO released a risk assessment on November 21 that shows the global prevalence of this variant is 8.9%, which similar to the prevalence in the US, even though it has been circulating elsewhere in the world for a few months longer. This is good news that suggests BA.2.86 is not likely to cause more disruption than any other currently circulating variant.

Additionally, from all available evidence, COVID-19 tests and treatments are effective against this variant, and the clinical symptoms do not seem to be different than other variants.

This variant, which is a descendent of Omicron BA.2, is likely not driving current increases in cases and hospitalizations because there are not enough cases yet for that. In the US, variants that descended from the Omicron XBB family, like EG.5 and HV.1 are still dominant. Cases will likely continue to rise in the next week due to Thanksgiving holiday gatherings last week.

The new 2023 COVID-19 vaccine specifically targets the XBB.1.5 virus, but data from the three vaccine manufacturers (Pfizer, Moderna and Novavax) presented to the FDA and CDC in September demonstrates that the antibodies from the new vaccines recognize and neutralize several newer circulating variants as well, including the XBB lineages and BA.2.86.

What is the recommendation?

Definitely go get any of the three new COVID-19 vaccines. Like the flu, COVID-19 is a disease caused by continually mutating viruses. It is really important to update your protection with vaccines for both the flu and covid-19 every fall so that if you do get sick, you can shift your case to the more mild end of the spectrum.

Also, we know how to do the things that prevent all respiratory viruses. In areas and times of increased transmission, we can wear masks indoors in public, make sure to wash our hands well, and seek out well ventilated areas for indoor activities (as many parts of the country are too cold to gather outside).


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