Respiratory illness levels are high in the United States for the first time this virus season, the Centers for Disease Control and Prevention said on Dec. 30.
Levels of influenza and respiratory syncytial virus (RSV) requiring health care are elevated in many parts of the country, the CDC said in the Tuesday update on its website.
“Seasonal influenza activity is elevated and continues to increase across the country,” the CDC stated. “RSV activity is elevated in many areas of the country with emergency department visits and hospitalizations increasing among children 0-4 years old.”
Emergency department visits due to influenza, commonly known as the flu, are high, up from moderate earlier in the month. Visits to emergency departments driven by RSV are now listed as moderate, up from low.
Visits because of COVID-19 are still described as low, in contrast. Those visits, though, are also increasing, according to the public health agency.
The virus season typically starts in the fall and runs through the winter.
During the season, changes in habits, such as people spending more time indoors and less time outdoors, contribute to higher virus activity.
The CDC said that it is not too late to receive vaccines and that people should talk to their health care providers about which vaccines are recommended for themselves and their families. The CDC recently scaled back its guidance for COVID-19 vaccination, has maintained its broad influenza vaccine recommendations, and says nearly all pregnant women, older adults, and infants should receive a vaccine or monoclonal antibody against RSV.
Advised steps to prevent infection also include frequent hand-washing and avoiding sick people.
Influenza is causing the most problems so far this season. In a separate update focused on the flu, the CDC said that 25.6 percent of specimens tested by laboratories and reported to the CDC for the week ending Dec. 20 tested positive for the flu, primarily for influenza type A, an increase from the prior week.
The CDC also said that 19,053 people were admitted to hospitals with influenza during the week ending Dec. 20, and that there have been an estimated 81,000 hospitalizations and 3,100 deaths from the flu so far this virus season.
A subvariant called clade K has been responsible for many flu cases in the country in recent weeks, according to CDC testing. Experts are not sure whether the strain is causing more severe disease in people than normal.
Flu cases in several states prompted officials to ban children from visiting hospitalized patients, in a bid to protect patients and staffers.
The CDC also said Tuesday that respiratory infections caused by a bacteria called Mycoplasma pneumoniae are higher than usual in some parts of the country. The infections are known as walking pneumonia and are generally mild, although they can be severe.
Preliminary reports of pertussis, or whooping cough, are down from late 2024, the agency said.