As Omicron keeps mutating, variant surveillance remains important

BA.4 and BA.5 caused more than 20% of new COVID-19 cases nationwide in the week ending June 11, according to CDC estimates.

This week, I had a new story published at TIME’s online news site, explaining what Omicron BA.4 and BA.5 could mean for COVID-19 trends in the U.S.

The story makes similar points to my FAQ post on these subvariants from earlier in June: basically, BA.4 and BA.5 have evolved to get around antibodies from a prior coronavirus infection or vaccination, and the U.S. is likely to see a lot of reinfections from these subvariants—even among people who already had BA.1 or BA.2 earlier this year. BA.2.12.1 has mutated in a similar way, leading experts to suspect that one of these subvariants (or all three) will dominate the next phase of the pandemic. 

When I talked to variant experts for my TIME story, I asked them for their thoughts on surveillance. “Is it getting harder to identify and track new linages like BA.4 and BA.5 as fewer people use PCR tests and more use at-home tests?” I asked. “What improvements or shifts would you like to see in surveillance?”

All three experts I spoke to had different perspectives, which I found interesting—and worth sharing in the COVID-19 Data Dispatch, since I wasn’t able to include this (somewhat wonkier) information in my TIME story.

Here’s what they said:

Marc Johnson, a microbiology and immunology professor at the University of Missouri who leads the state’s wastewater surveillance program, thinks that expanding wastewater monitoring is the way to go (though he admitted his bias, as someone who works in this area). “Sewershed monitoring is a really good way to track variants going forward,” he said. “It gives you a comprehensive view without costing you hundreds of thousands of dollars… or without having to sequence a thousand people.”

Shishi Luo, associate director of bioinformatics and infectious diseases at Helix (a genomics and viral surveillance company), is thinking about how to ensure her company consistently receives enough PCR test samples to get useful data from sequencing. At the moment, pharmacies and community testing sites are still providing enough samples that Helix has sufficient information to track variants, she said. But, anticipating that those numbers may dwindle, Helix is connecting with urgent care clinics and hospitals that do diagnostic testing. “I think those places will continue to collect samples and perform qPCR tests,” she said.

Paul Bieniasz, a professor at Rockefeller University who studies viral evolution, thinks that the current levels of surveillance are sufficient—at least, when it comes to policymaking and updating vaccines. “I would like to keep surveillance at a level such that such that we can have a pretty accurate picture about what’s going on,” he said. But he wants to prioritize “the really important things”: namely, understanding changes to vaccine effectiveness, which treatments to use, and identifying a new “major antigenic shift” like the one that produced Omicron as soon as it occurs.

“But it can always be better,” he said. “The more intense the surveillance, the more sensitive it is, and the earlier you detect things that might be of concern in the future.”

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