Although COVID-19 positivity rates are up, there have been fewer coinfections with other respiratory viruses than expected, according to recent findings from Helix, a lab that assists the CDC with variant tracking.
Helix shared some of the latest observations from its COVID-19 and viral surveillance efforts in a Nov. 21 email, noting COVID-19 positivity rates are rising for the first time since July, with the highest growth in adults between 18 and 24.
"Given test positivity rates, we would have expected to see more coinfections with RSV or flu than are actually occurring," Helix said. "This is most likely because when someone is sick with one virus, they're not mingling with the broader community and so are less likely to catch another virus."
The coinfections that are occurring are mostly with RSV.
Two more observations from Helix's latest surveillance efforts:
1. A Helix graph indicates adults aged 18 to 24 have seen the highest growth in COVID-19 positivity. Among the group, the seven-day positivity average is between 25 and 30 percent, up from around 15 percent in mid-October. Nationwide, the seven-day average for test positivity was 8.5 percent as of Nov. 2, a 4 percent increase over the last 14 days, according to HHS data compiled by The New York Times. The positivity rate increases come as omicron subvariants BQ.1 and BQ.1.1 continue to grow, now accounting for nearly 50 percent of U.S. cases.
2. Overall, COVID-19 reinfections are up by about 2 percent to 4 percent, likely due to "waning immunity and increased variant diversity," the lab said. There has been a slight uptick in reinfections within 90 days since June. Still, the majority of reinfections overall still occur at least 180 days after original infection.