(NEXSTAR) – If you’re stuck at home with COVID-19 right now, you’re far from alone. The United States is experiencing another major surge in coronavirus cases, driven by two new types of the omicron variant.
BA.4 and BA.5, two highly contagious omicron subvariants, account for more than 90% of new cases nationwide, according to tracking by the Centers for Disease Control and Prevention.
There are several reasons why these two sub-variants – especially the dominant BA.5 – are spreading like wildfire and having such a big impact in the United States right now.
BA.4 and BA.5 are more sneaky
Early evidence suggests that BA.4 and BA.5 are no more contagious than the original omicron strain. However, they seem to be better at escaping prior immunity.
This means that people with some immunity – either to vaccines or to previous COVID infection – are still susceptible to BA.5 infection.
Additionally, it has been over six months since our last major national push of the first omicron variant. Those infected during this wave may have gained enhanced immunity, but that window has passed for most of us.
“The good news is that the vast majority of breakthrough infections are now ambulatory illnesses,” said Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital. “They don’t lead to the kind of serious illness that we saw earlier in the pandemic when no one was immune, which led to increased hospitalizations and deaths.”
People test at home, if at all
While you may feel like you know more people are catching COVID than ever before, the case rates tracked by public health departments don’t seem to reflect a massive increase. The New York Times in-depth COVID tracker shows an increase in new cases, but the latest curve is dwarfed by last winter’s surge.
Epidemiologists agree that COVID-19 cases are severely underestimated right now.
“With home testing, we’ve lost our ability to track reported cases,” said Dr. George Rutherford, an epidemiologist at the University of California, San Francisco.
When someone tests positive for the virus at home, that case often goes unreported to public health officials, leaving us with a hazier picture of how widely BA.5 has spread.
On top of that, milder symptoms mean fewer people can get tested. If they never test for the virus, they may continue to unknowingly spread it in the community.
COVID restrictions are gone
The initial wave of coronavirus cases – before we had any vaccines – triggered widespread restrictions, closures and masking requirements. The summer 2021 delta surge and last winter’s original omicron surge had more cautious localities and states reinstating mask mandates. Now there are almost no nationwide COVID-19 restrictions.
With less masking and more mixing, the virus can spread faster in a community.
The CDC recommends wearing a mask indoors if your county is experiencing a “high” level of COVID transmission. As of Tuesday, more than a third of US counties fell into this category. You can check your county’s status on the CDC map.