Respiratory virus spreads in the southern US

A young boy inhaling medication with inhalation mask.
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Parts of the southern U.S. are seeing off-season spikes in a respiratory virus called RSV after the lifting of public health measures put into place to slow COVID-19 spread, public health experts warn. 

RSV, or respiratory syncytial virus, is typically more active in the fall and winter. This summer spike is a "deviation" from normal, according to a Centers for Disease Control and Prevention (CDC) advisory issued on June 10 for clinicians and health care workers. 

For most people, the virus causes a typical cold, but for vulnerable populations — older adults with chronic conditions, young children and infants — the virus can cause more severe illness. In fact, it's the most common cause of bronchiolitis (a lung infection) and pneumonia in children under 1 in the U.S., according to the CDC.

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The number of RSV cases declined rapidly in April 2020 in the U.S., when public health measures were put in place to combat COVID-19, and cases remained low until March 2021. But data reported to the National Respiratory and Enteric Virus Surveillance System now indicate that cases of RSV are rising in parts of the southern U.S., including the Carolinas, Florida and Texas. 

Similarly, RSV activity increased between typical activity seasons in Australia in late 2020 and South Africa in early 2021, according to the CDC.

In New South Wales, Australia, RSV typically peaks between April and June, but last year, the number of cases fell by more than 85% compared with the typical number, Live Science previously reported. After officials lifted COVID-19 restrictions in late December 2020, RSV cases spiked to 6,000 in two weeks (much higher than the few hundred cases reported in those weeks in a typical year).

Experts have warned for some time now that seasonal viruses, which nearly disappeared last year due to measures taken to combat COVID-19, may surge at unexpected times, Live Science previously reported. Less exposure to seasonal viruses last year may have left behind a slightly more vulnerable population.

"We're very concerned that as we start to loosen up restrictions on the public health measures that we will see many other viruses come back as well, and other illnesses that will start to spread as people are more open to being together without distancing and without wearing masks," Dr. Sara Goza, physician and former president of the American Academy of Pediatrics, told NPR's "All Things Considered." "We hope people will continue to wash their hands frequently and stay home if they're sick."

RSV typically spreads through direct exposure to respiratory droplets in coughs and sneezes and through contact with contaminated surfaces. The virus can cause symptoms such as a runny nose, sore throat, cough, headache, fatigue and fever. In infants and younger children, it can cause irritability, poor feeding or appetite, lethargy, apnea (pauses while breathing), fever, runny nose, cough, sneezing, fever and wheezing.

The CDC recommends that health care workers increase testing for RSV among patients who have symptoms of an acute respiratory illness but who test negative for COVID-19. 

Each year, RSV causes around 58,000 hospitalizations and 100 to 500 deaths among kids younger than 5, and 177,000 hospitalizations and 14,000 deaths in people 65 and older, according to the CDC.

Originally published on Live Science.

Yasemin Saplakoglu
Staff Writer

Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.