As Flu and RSV Drop Omicron Subvariant Poses Unknown Threat

A flu and respiratory syncytial virus (RSV) season that began early and intensely already may have peaked, but other illnesses, including the XBB.1.5 omicron subvariant of the COVID-19 virus, remain threats.

That makes vaccinations crucial as these illnesses converge and as children return to school post-holidays, warns Peter Hotez, MD, dean of the National School of Tropical Medicine at Baylor College of Medicine. And physicians may have some headwinds to overcome as vaccine hesitancies persist.

The trio of influenza, RSV, and COVID-19 has been referred to as a tripledemic. With rates of four other pathogens – parainfluenza, metapneumovirus, rhinovirus, and pneumococcus – also spiking early this season, Dr. Hotez additionally warned of a “septa-demic” as patients approached the holiday season.

“Flu, RSV, rotavirus as well, those things will tend to peak in the winter – also, other respiratory virus pathogens like rhinovirus, metapneumovirus, pneumococcal illness, which is often a complication of those,” he said. “That, in itself, is not unusual. It’s the fact that it came on in such full force and so suddenly.”

Though flu and RSV rates have begun to taper, another spike remains possible, he adds.

The Centers for Disease Control and Prevention (CDC) estimates between Oct. 1, 2022 and Jan. 7, 2023, at least 16,000 Americans died of influenza. By comparison, CDC estimates 5,000 deaths associated with the flu for the entire 2021-22 season. Texas’ surveillance data indicate 2,646 pneumonia and influenza (P&I) deaths so far for the 2022-23 season, including nine pediatric deaths. There were 9,829 P&I deaths total for Texas’ 2021-22 season with no pediatric deaths reported.

Multiple theories could account for this season’s severity and early start, but it’s unclear which is in play or to what extent. “Immunity debt” – a potentially lower level of herd immunity due to masking and social distancing – could play a role but hasn’t been confirmed, Dr. Hotez says.   

Another unknown: the extent to which the XBB.1.5 subvariant will impact future respiratory illness rates, especially in Texas. In the Northeast, XBB.1.5 accounts for upwards of 70% of COVID-19 cases; as of this writing, the rate of XBB.1.5 in the region including Texas is about 25%, according to CDC. The World Health Organization has deemed this subvariant the most transmissible yet, making adequate precautions, such as masking, vaccinations, and staying home when sick, crucial.

Texas Department of State Health Services (DSHS) data show that only about one-quarter of Texans have been vaccinated with at least one booster dose, while CDC estimates about 10% of Texans have received the bivalent booster.

If public hesitancy toward COVID boosters is anything to go by, Dr. Hotez is worried respiratory illnesses along with other vaccine-preventable diseases could resurge.

Texas physicians already have seen skepticism about COVID vaccines overcome patients’ usually positive reception toward other routine vaccines.

For instance, data from DSHS’ annual reports of immunization status of students show that from the 2018-19 to the 2021-22 school year, the percent of students delinquent on their measles-mumps-rubella vaccines increased nearly 300%.

“I’m kind of holding my breath [that] because of all the anti-vaccine activism in Texas, we could start seeing measles outbreaks again,” Dr. Hotez said.

To help your patients stay up to date on recommended vaccines, check out these CDC resources and the Texas Medical Association’s Vaccines Defend What Matters

Last Updated On

January 18, 2023

Originally Published On

January 18, 2023

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