Tuesday, June 28, 2022

CDC Nowcast: BA.4/BA.5 Now More Than Half Of All Cases In The United States


As expected, the tag-team combo of Omicron BA.4 and BA.5 have eclipsed BA.2.12.1 as the dominant COVID variants in the country.  Both carry the L452R and F486V mutations in their viral spike protein which help them evade prior immunity (either from infection or vaccine, or both), but BA.5 continues to outperform BA.4 and will likely become the dominant strain.

BA.5 is already dominant in Denmark and in the UK, and while it doesn't appear to have caused more severe illness, its increased infectivity has sparked a rise in infections and hospitalizations in both nations. 

Everything we're seeing suggests that BA.5 (and BA.4) are more likely to evade prior immunity than earlier variants, meaning that even those who have (even recently) recovered from the virus - or have received their booster vaccination - may be at risk of infection.  

Vaccination (and boosters), along with prior infection, are still expected to reduce the severity of COVID illness, even if they provide relatively little protection against infection. 

As a result, we are starting to see more places recommend wearing face masks again, as an additional layer of protection against infection.

Given the limits of surveillance, testing, and genomic sequencing around the country, all of the following numbers should be viewed as rough estimates, and we may see further revisions to the data in the weeks ahead.

Given what we know about the often devastating effects of `long COVID', and recent evidence of risks to unborn children in the womb from maternal infection, and a report (Outcomes of SARS-CoV-2 Reinfection) suggesting that successive reinfections with COVID can lead to higher all-cause mortality, it makes sense not to trivialize the risks from COVID. 

Even though I'm fully vaccinated, and topped off with my 2nd booster this month, I'm continuing to wear a face mask in public, carry (and use) hand sanitizer, and avoid crowds when possible. 

Your mileage may vary. But for me, it seems well worth the hassle if it will reduce my chances of having a bad outcome.  And with influenza likely to return on top of COVID this fall, I don't expect to be changing my routine anytime soon.