As cold weather sets in, flu, RSV and COVID-19 are on the rise across the state, and public health officials are encouraging vaccines.

It is unclear what the surge in COVID-19 cases could look like this winter and whether it could rival past years, but there is no question the flu season will be severe, based on its transmission in the Southern Hemisphere, said Dr. Michelle Barron, senior medical director of infection prevention and control for UCHealth. Since early October, the flu has hospitalized 49 people statewide and respiratory syncytial virus, or RSV, a virus that hits children hardest, has resulted in 367 hospitalized cases in the Denver area, state health department data show. It is early for respiratory illnesses to be circulating so broadly, according to the state. 

US flu season off to a fast start as other viruses spread

Coronavirus hospitalizations are also up, with more than 218 people hospitalized with the illness statewide and more than 50 people hospitalized in Colorado Springs in the past two weeks. The numbers are still far shy of the major peaks of the last two winters.

However, a surge is likely, it is just unclear what that peak might look like, Barron said. 

A new variant of omicron could be a challenge for health care providers because early data suggests it is highly contagious like omicron and it has some properties of the delta variant, which makes patients more severely ill, Barron said. 

“Somebody asked me this summer what’s your nightmare – I said if there is love child of delta and omicron and this is kind of a love child of omicron and delta,” she said. 

At the same time, immunity against COVID-19 is waning because vaccines and naturally gained immunity wears off over time and interest in boosters has been low. 

As residents prepare for holiday travel, Barron urged getting vaccinated for both the flu and COVID-19. 

RSV cases, hospitalizations higher than usual across Colorado

“The time is now, it still takes two weeks for all these to be effective,” she said.

In El Paso County, 77,500 doses of the bivalent booster that provides better protection against omicron strains of the COVID-19 have been administered, said Dr. Bernadette Albanese, co-medical director of El Paso County Public Health. The county’s population is close to 740,000 people. 

The boosters are recommended for those at high risk of COVID, such as older adults and those with chronic health conditions, and people who have not received a vaccine or had the virus in the last four to six months, said Dr. Paul Mayer, co-medical director of El Paso County Public Health. 

“If people do get sick, we also want them to know that there are treatment options available that can help reduce severe outcomes,” he said. 

Testing can help residents get treatment more quickly and prevent hospitalization, experts said. 

Barron urged residents to make responsible decisions over the holidays and consider staying home if they are ill.

“The old and the very young can get very sick from all these diseases. … Please be thoughtful of your loved ones,” she said. 

Vaccines and boosters are available through many clinics and pharmacies.

A state COVID-19 booster clinic is ongoing at the 8 a.m. to 6 p.m. Monday through Saturday at The Citadel mall. To register, visit https://bit.ly/3DcpPaw.

COVID variants BQ.1/BQ.1.1 make up 35% of U.S. cases