Fort Worth physicians are seeing a spike in RSV infections among infants and toddlers this summer, an off-season increase that’s likely tied to the COVID-19 pandemic, experts say.
“We’ve had a huge outbreak here in Tarrant County,” the county’s public health director Vinny Taneja said during a commissioners court meeting Tuesday. “Other than supportive treatment, there’s not a cure that [health workers] can just give.”
In June, the U.S. Centers for Disease Control and Prevention issued a health advisory alerting health care workers to the increase in RSV cases throughout the southern U.S., and encouraging broader testing of the virus for patients who appear to have a respiratory illness but who test negative for SARS-CoV-2.
The virus causing the infections, respiratory syncytial virus, or RSV, causes nothing more than a cold in most healthy adults. But infections can cause serious illness and death in infants and young children, the immunocompromised, and people age 65 and older.
At Cook Children’s, physicians have seen a surprising increase in kids testing positive for RSV, said Dr. Mary Whitworth, the health system’s medical director for infectious diseases.
“Typically in the fall and in the winter we have RSV season and flu season,” Whitworth said. “This winter, we did not have either one.”
But starting in April, children with respiratory illnesses at Cook Children’s began testing positive for RSV, and the number of positive cases has continued to increase throughout the early summer months. In one week in late June, 94 kids tested positive for the virus, Whitworth said. During the same time period in previous years, there would typically be almost no kids testing positive for RSV.
“It’s happening at the wrong time of year, essentially,” Whitworth said.
RSV season usually peaks between mid-December and February. But during the 2020-21 season, the continued spread of the SARS-CoV-2 virus disrupted the normal seasons for influenza and RSV. In fall 2020, health providers braced for a “twindemic,” fearing that a joint surge of COVID-19 patients and patients sick with seasonal influenza would overwhelm hospitals.
Instead, the U.S. had almost no flu season to speak of, which experts say is almost certainly because of the pandemic, said Aubree Gordon, an RSV expert and associate professor at the University of Michigan.
Similarly, in the case of RSV, Gordon said there are theories but no definitive answer as to why RSV is circulating now, and why it’s more prevalent in Southern U.S. states like Texas.
The dearth of RSV cases throughout the peak of the COVID-19 pandemic could be because people were wearing masks, because children were staying home from schools and day cares and thus less able to spread the virus to their peers, or because of viral interference between SARS-CoV-2 and RSV.
“We don’t really know,” Gordon said.
Although the exact cause of the off-season outbreak is unclear, the phenomenon itself is not unusual, as past epidemics and pandemics have thrown other seasonal viral seasons out of whack. During the 2009 H1N1 flu pandemic, Gordon said, the timing of RSV season also shifted.
In a typical year, RSV causes about 58,000 hospitalizations and between 100 and 500 deaths for children younger than 5 years old, according to the CDC. For people age 65 and older, the virus causes 177,000 hospitalizations and about 14,000 deaths in a standard year.
Most people, including young children, will only suffer a mild illness from an RSV infection, according to the CDC, but some kids can develop bronchiolitis or pneumonia from the infection.
There is no RSV vaccine, and no proven treatments for serious infections.
The future of this off-season RSV outbreak is unclear, Whitworth said. Cases could continue to increase along the current trajectory, or unexpectedly drop off at some point this summer.
But Gordon and other experts say that if COVID-19 cases continue to stay relatively low in most parts of the U.S., adults and children throughout the country can expect a particularly intense fall and winter season when it comes to respiratory infections.
“I think what we’re going to see as the rates of SARS come down and as people start resuming normal life and stop wearing masks we’re going to see respiratory viruses pick up and particularly in the fall, during the typical respiratory virus season, it’s probably going to be pretty bad,” Gordon said. “Or at least, that’s the expectation.”