US grapples with spike in trio of respiratory viruses

US hospitals are under pressure as cases of three respiratory viruses – the flu, Covid-19, and RSV – are rising at the same time, and earlier than usual, experts said Friday.

Children are being hit hard by the respiratory syncytial virus (RSV), which causes the chest infection bronchiolitis in infants, and has spurred unusually high rates of hospitalisations in several countries around the world this season.

"We suspect that many children are being exposed to some respiratory viruses now for the first time having avoided these viruses during the height of the pandemic," said Jose Romero, director of the National Center for Immunization and Respiratory Diseases, at a press conference.

All three of the circulating respiratory viruses have similar symptoms, and even if most patients recover in a week or two, the very young and elderly are at risk of developing severe illness.

A surveillance system that tracks visits to outpatient medical providers and emergency departments for cold-like symptoms such as a fever or sore throat has shown "high" activity for this time of year, he said.

"We're seeing the highest influenza hospitalisation rates going back a decade."

He warned that if a child was struggling to breathe, had bluish lips, muscle pain and dehydration, it was crucial to take them to a doctor.

Experts say it is still difficult to say whether this year's influenza virus was causing worse illness than usual, but it has started circulating particularly early.

The US is still recording more than 270,000 cases of Covid-19 per week.

Hospitals in the mid-Atlantic states, New England, and Washington state are "currently experiencing significant strain," said Dawn O'Connell, assistant secretary at the US Department of Health and Human Services.

Vaccines are currently available for two of the circulating viruses, Covid-19 and the flu, however flu vaccination rates for children are below what they were prior to the pandemic.

Pfizer announced this week that it had positive results in a clinical trial for an RSV vaccine. Scientists and researchers have failed to find a successful vaccine for the virus over the past half a century.