COVID cases rise in parts of U.S. as omicron subvariant spreads. What’s Idaho’s outlook?
After tens of thousands of COVID-19 cases constituted a surge in Idaho earlier this year, the incidence of the disease fell quickly in the Gem State, to some of the lowest metrics seen since the start of the pandemic.
But a new subvariant has fueled a rise in cases in other parts of the country, and Idaho’s public health agency is preparing for the possibility of another wave this spring — albeit a smaller one.
Called BA.2, the new iteration of the virus is a sublineage of the omicron variant, which caused Idaho to enter crisis standards of care for the second time in January.
BA.2 has several mutations that make it differ substantially from omicron. It is, in fact, about as different from omicron as omicron was from the delta variant, which caused Idaho’s first crisis standards of care crisis last year, said Dr. Kathryn Turner, Idaho’s deputy state epidemiologist.
What’s known about BA.2?
Though the new strain differs markedly from omicron and appears to be more transmissible, health leaders in Idaho are not concerned that it is more dangerous.
“It does appear to be more transmissible,” Turner said, citing research from Denmark and England that shows the new strain made infected people more likely to spread the virus to others in their household, and at a faster rate.
Despite that, BA.2 does not appear to be more virulent or more able to evade available vaccines.
Vaccine effectiveness took a hit from the omicron variant, but recent research has shown that the available vaccines are effective against the new strain. Research also indicates that natural antibodies developed from omicron should be effective against BA.2, which could apply to as much as 40% of Idahoans, Turner said.
Estimates elsewhere indicate that more than 50% of Americans were infected with omicron last winter.
“We’ve got a lot of protection in our communities right now,” Turner said. “At least those (people) that are healthy and have really strong immune systems and either responded well to the vaccine or to a mild or moderate infection.”
Evidence suggests that antivirals such as Paxlovid, molnupiravir and remdesivir remain highly effective against BA.2, as they were against BA.1, Turner said. Evusheld, another drug that can prevent symptomatic COVID-19, also remains effective, she added.
As with BA.1, some authorized drugs appear to be less effective against the sister strain. Earlier this month, regulators suspended the authorization of a monoclonal antibody treatment, sotrovimab, because it has been shown to be insufficiently effective against BA.2.
Is BA.2 in Idaho?
The Department of Health and Welfare has identified just 11 total cases of BA.2 in the state, Turner said. Ten of those were located in surveillance testing conducted during the last two weeks of March, while the first case was found in late January.
Idaho labs are unable to sequence every positive test in Idaho, meaning that sequenced cases make up only a sampling of the total number of positive PCR tests. Many residents also elect to take rapid at-home tests instead of PCR tests, which are usually not included in official case totals.
The BA.2 cases made up around 10% of the total cases that were sequenced during the last two weeks of March, with most of the remaining cases being BA.1, Turner said.
But peculiarities of the two related variants could indicate that a larger percentage of recent cases have been BA.2.
A quirk of the BA.1 variant meant that on PCR tests, the strain was often quickly visible because it looked different on test results than the delta variant did. But the BA.2 variant does not have this peculiarity, meaning it appears like delta cases did.
Turner said a “large proportion” of recent tests have appeared without the BA.1 quirk, meaning they are likely the BA.2 subvariant.
What should Idaho expect?
Despite elevated levels of immunity in Idaho, health officials expect a rise in cases from BA.2 that Turner described as “a little bump.”
Turner said widespread immunity — both from vaccination and infection — in Idaho should mean a less severe swell than what occurred earlier this year.
“We’re probably going to see an increase in cases, but I don’t think we’re going to see anything like what we saw in January,” Turner said. “But we are watching our colleagues in other states to see what their trend looks like.”
After hovering at an all-time low positivity rate of 1.5% for two weeks, Idaho’s rate slightly ticked up the week of March 27, to 1.8%, according to state data. The week of April 3, it rose to 1.9%. At Idaho hospitals, COVID in-patient numbers have fallen to levels not seen since the summer of 2020.
Idaho ranks 40th among the states in the proportion of recent surveillance testing that consists of BA.2 cases, Turner said, citing data from the Centers for Disease Control and Prevention.
Some parts of the country, most in the Northeast — New York, Rhode Island and Washington, D.C. — have seen major increases in new recorded cases since the beginning of March because of BA.2. Turner predicts Idaho is at least two or three weeks behind states that have seen large upticks.
On Monday, Philadelphia reinstituted an indoor mask mandate following a spike in cases.
Turner said the state will monitor whether certain groups appear to be more vulnerable to the BA.2 subvariant, which could cause the agency to alter its public health recommendations. But she also said precautions are based on “individual risk at this point.”
Young children remain ineligible for the COVID-19 vaccines, while others who are vaccinated could see their immunity wane without a booster.
Turner stressed that eligible Idahoans, regardless of prior infection, should get the booster doses they are eligible for “so that we can continue to keep our immunization rate really high.”
“We really want to make it stop getting transmitted,” she said.
This story was originally published April 14, 2022 at 4:30 PM.
