An increase in a type of respiratory infection in young infants has caused the Centers for Disease Control and Prevention to say the disease has risen to epidemic levels, but some health experts say it’s the time of year that is the problem.
Respiratory syncytial virus, known as RSV, most commonly affects premature babies and children through the age of 2.
Results were positive for nearly 20 percent of the roughly 400 children tested at 30 California hospitals, according to the CDC. The agency considers any rate above 10 percent to be an epidemic.
The results — which included tests from San Francisco General Hospital and the UC San Francisco Mount Zion Campus — were from Nov. 20 through Dec. 4. The nationwide center, though, has not yet issued an epidemic warning in California.
At San Francisco General Hospital, as many as 10 cases of the virus have come through the outpatient clinics in the past few months, but there could be more.
“We’re not testing everyone,” hospital spokeswoman Rachel Kagan said. “We’re not flooded by RSV, but we are definitely seeing them.”
Health officials said the rise in infections is common for this time of year.
“We are in RSV season, and each year, there are typically RSV epidemics that occur between November and April,” said Dr. Stephen M. Parodi, chief of infectious diseases for Kaiser Permanente Northern California.
Kaiser is also seeing an increase in RSV cases throughout Northern California, Parodi said. Specific numbers of cases in Kaiser hospitals were not immediately available.
Kaiser Northern California includes hospitals in all Bay Area counties as well as Fresno, Sacramento and Roseville.
RSV infects the lungs and breathing passages in the body. A healthy adult will recover from the virus in up to two weeks, but infants and older adults can get the most severe cases.
RSV is the most common cause of bronchiolitis — an inflammation of the small airways in the lung — and pneumonia in children under 1 year of age, according to the CDC. In very young infants, irritability, decreased activity and breathing difficulties may be the only symptoms of infection.
There is no specific treatment for RSV infections.
Frequent hand-washing and wiping of hard surfaces with soap and water or disinfectant are ways to stop the spread of the virus, Parodi said.
“If you are sick,” he said, “it’s best to stay home from work or school to prevent others from being exposed to the virus.”