The coronavirus’ impact is hard to predict. Other viruses make it even harder

After two winters with significant COVID-19 spikes, public health experts warn that this year will likely follow the same trend, especially with the development of several new, highly contagious omicron subvariants.

And new public health variables — including COVID-19 vaccine booster doses, waning effectiveness of certain treatments such as monoclonal antibodies and unseasonably early increases in other respiratory illnesses — could again alter the already difficult to predict coronavirus landscape, for better or for worse.

Forecasting which variant will spike and when is particularly difficult this year, because fewer people are reporting their test results and more subvariants are emerging at once, said Dr. James Cutrell, an associate professor in the Department of Internal Medicine at UT Southwestern Medical Center.

“We’re not looking at just one variant, but we’re looking at this convergence of a cluster of variants that, in some ways, are kind of competing with each other,” Cutrell said. “So you don’t ever necessarily know in a particular geographic area which one is going to win out and become dominant.”

BQ.1 and BQ.1.1, two subvariants in the omicron family, are picking up speed, accounting for about 27% of U.S. cases in the week ending Oct. 29, according to the Centers for Disease Control and Prevention.

In Texas, subvariants BQ.1 and BF.7 each account for more than 5% of cases, while BA.4.6 represents more than 7% in the week ending Oct. 15. BA.5, which became dominant over the summer, still accounts for nearly 73% of cases, according to Department of State Health Services data.

COVID-19 hospitalizations have remained low since the peak of the original omicron strain in January, but it’s difficult to predict whether another subvariant will cause more severe illness.

The new bivalent COVID-19 booster, designed to fight both the original COVID-19 virus and the omicron strain, promises some protection, although it’s not yet known how effective the dose will be against new subvariants such as BQ.1 and BQ.1.1, said Catherine Troisi, infectious diseases epidemiologist with UTHealth Houston School of Public Health.

“They still are descended from omicron, so they’re not completely new, but they are already 27% of new infections, which means that they have some competitive advantage over the first omicron,” Troisi said. “We don’t know exactly how the boosters are going to work against these.”

Health experts also expressed concern about treatment options for patients who are at high risk for severe disease with COVID-19. The newest omicron subvariants appear better at evading monoclonal antibodies, which are lab-made antibodies that can help the body fight an infection.

“This is going to have a significant impact, particularly for the subset of patients who are immunocompromised, because I think the monoclonal antibodies have been a really important piece of our treatment,” Cutrell said. “When those patients get sick, being able to get the monoclonal antibodies quickly keeps them from getting sicker and ending up in the hospital.”

Other treatments, such as the antivirals Remdesivir and Paxlovid, are still effective, Cutrell said, but they come with their own challenges. Remdesivir is given through an IV, which can be difficult to organize for people who are outpatients. Paxlovid, which comes in the form of pills, can interact with other drugs taken by people who are immunocompromised.

Tracking the potential public health repercussions of a COVID-19 surge is made all the more difficult by the increasing number of cases of the flu and RSV.

Immunity against those viruses is particularly low after years of public health measures used to prevent the coronavirus, such as masking and social distancing. Cases of both respiratory illnesses started to spike earlier than normal, causing trouble for pediatric hospitals in particular.

The so-called “tridemic” of flu, RSV and COVID-19 all at once could again strain health care systems, even if this winter’s COVID-19 spike is milder than in past years.

“The flu is still not a fun thing to have,” said Erin Carlson, associate clinical professor and director of graduate public health programs at the University of Texas at Arlington. “Some people are in bed for several days or a week with it.”

And because the symptoms of the viruses are similar — each can come with a cough, congestion and a fever — it can be difficult to tell which illness a patient has.

“That introduces diagnostic challenges, because now someone’s coming into a clinic or into the hospital and you have to test for all three, you can’t necessarily rely on a negative COVID test,” Cutrell said.

Medical professionals recommend vaccinations as the most effective ways to fight both the flu and COVID-19. Both vaccines can be administered on the same day.