(NewsNation Now) — The Centers for Disease Control and Prevention issued a warning for southern states about an emerging respiratory virus, and it’s not COVID-19.

Respiratory Syncytial Virus, or RSV, is not new, but it has taken a back seat to the pandemic in the public consciousness. The disease it causes is similar to COVID-19, but it results in a fraction of the deaths. The CDC says 14,000 Americans per year typically die from it.

Older adults, especially with chronic lung or heart disease or weakened immune systems, are at higher risk. They tend to think they have the flu. But, it can infect anyone.

“Infants can [get it], and young children can get bronchiolitis have difficulty breathing,” Dr. William Schaffner, Vanderbilt professor of preventative medicine and health policy, told NewsNation Friday. He says infants may reject food and then develop breathing difficulties.

Like the flu, RSV infected fewer Americans than normal in 2020, which experts credit to masks and social distancing to curb COVID-19.

But also like the flu, this is not the typical time of year for RSV to spike.

“It’s rather curious because it’s the wrong season, if you will, for RSV,” Schaffner said. “But nonetheless, we’re alerting people getting doctors when they see patients with these symptoms, to test to find out exactly what the illness is. And of course, we want to distinguish it from COVID.”

He recommends avoiding people who are sneezing or coughing because the disease spreads in droplets. COVID-19 is believed to spread like an aerosol spray that can go further, especially in indoor settings.

“You can give certain [RSV] treatments to very young infants who are quite sick,” Schaffner said. “But for the most part, it’s symptomatic treatment and staying away from others so you don’t catch it at home or elsewhere.”