As health experts warn about RSV infections in infants and toddlers, adults should know that they, too, can become severely ill from the virus.

Respiratory syncytial virus (RSV) is not always the mild respiratory illness people think it is but can lead to symptoms as serious as seen with influenza, according to an expert from Baylor College of Medicine in Houston.

The risks are particularly high for adults over 65 and those who have chronic lung disease, heart disease or diabetes, said Dr. Robert Atmar, a professor of infectious diseases at Baylor.

"One of the reasons that persons with these diseases are at higher risk is because of the underlying disease — the function of the heart, lungs and immune system are already compromised and less able to handle the stress associated with the infection," Atmar explained in a college news release.

Physicians have been seeing an increase in RSV cases since the end of September, different from the usual pattern of cases from October through March or April. Prevention measures taken during the pandemic likely disrupted RSV's typical pattern.

RSV is spread through contact with someone who is infected. Thorough hand washing and wearing masks can help prevent transmission.

Symptoms include cough, shortness of breath, runny nose and nasal congestion. Fever can occur. The virus can start out like a cold, as an upper respiratory illness, then move to the chest. Wheezing can be a symptom, especially for adults with a chronic lung disease, such as COPD or asthma.

The virus is more commonly recognized in children because of characteristic clinical findings such as bronchiolitis. Sensitive tests are available for pediatric cases.

While adults are not often tested for RSV, molecular diagnostics have become more available for use in adults in recent years, Atmar said.

No specific treatment exists for RSV. Atmar recommends treating symptoms, such as taking a decongestant for nasal congestion or cough syrups for a cough.

An RSV vaccine is being tested for pregnant women. By next year, there also may be a vaccine option for older adults, Atmar added.

"This is not necessarily just a mild infection in all adults. It can be a very serious infection, particularly in older adults and those who have chronic heart and lung disease or diabetes and it's for those reasons that vaccines are being developed for these at-risk persons. If those vaccines become available it's going to be important for those groups approved to take it, much like they take the flu vaccine," Atmar said.

"It's worth preventing if and when we have an effective vaccine available to do that, and we may have that within the next year or two," he noted.