A dangerous winter virus is still spreading nationwide – despite typically peaking in winter and fading by the end of March.
According to federal data, 7.5 percent of RSV tests are coming back positive, a significantly higher figure than the five percent rate seen at this time last year.
As such, multiple states have made the unprecedented decision to extend their RSV immunization period through at least April 30 as the virus season persists later than usual.
A map from the Centers for Disease Control and Prevention, based on wastewater surveillance data, highlights the states and regions where the virus is circulating most widely — and half the country now has moderate levels, with the Midwest and northern Plains emerging as clear hot zones.
States with the highest concentrations of RSV in wastewater samples – deemed high or very high – in late March include Michigan, Minnesota, South Dakota, Wyoming, Iowa, Kansas, Nebraska and Vermont.
Meanwhile, eight states have moderate levels of the virus in wastewater samples, such as California, Hawaii, Illinois, Louisiana, Nevada, New Mexico, Tennessee and West Virginia.
Most of the South, Southwest, and West Coast are in the clear, with more than 30 remaining states at very low or low levels, including Florida, Texas, Colorado, Oregon, Virginia, and Washington.
‘We’re seeing RSV continue to circulate around much of the US,’ Dr Robert Hopkins, medical director of the National Foundation for Infectious Diseases, told TODAY.com. ‘It is certainly later than we expect. The season is extending into the spring.’
For infants under eight months old, these typically mild infections can lead to serious complications like bronchiolitis — inflamed small airways — and pneumonia
Indeed, the CDC warned that because RSV activity began later than expected across the US, ‘this unusual timing means higher levels of RSV activity may continue into April in many regions.’
But, according to Hopkins, emergency room visits and hospitalizations are also starting to wane, but are still highest in kids under four.
Infants under eight months old are particularly vulnerable to complications of the typically mild respiratory infections, including bronchiolitis, or inflammation of the small airways in the lungs, and pneumonia, a lung infection.
‘Some of these children are sometimes on ventilators. And they can be on oxygen because they really can’t breathe with this virus,’ Dr Yvonne Maldonado, a pediatric infectious disease specialist at Stanford University told Wyoming Public Radio.
‘So it’s quite severe in the very young. Some of these babies develop chronic lung disease from this infection and can develop asthma.’
Approximately two to three out of every 100 infants younger than three months old end up in the hospital with RSV every year, and thousands of children have already been hospitalized this season.
Particularly in children five and under, the CDC estimates between 58,000 and 80,000 hospitalizations and 100 to 300 deaths.
A spokesperson from the Minnesota Department of Health’s Respiratory Disease Surveillance Unit, which is recording the season’s highest viral concentrations in wastewater, said: ‘RSV is currently driving more hospitalizations than influenza or COVID-19, but this year’s peak has been lower than the past two seasons.
‘Overall, RSV activity has gradually risen since November, and although we may be near the seasonal peak, sustained declines have not yet been observed.’
RSV is vaccine-preventable, and immunization is recommended for all infants born during or entering their first RSV season if their mother did not get the vaccine during pregnancy or if her vaccine status is unknown. Infants born less than 14 days after the mother got the shot should also receive a vaccine.
For children eight to 19 months old who are at high risk of disease due to chronic lung disease, prematurity, immunosuppression and cystic fibrosis, a second dose is recommended if they are about to enter their second RSV season.
When public health officials extend the immunization recommendation period, which typically runs from October to March, it allows doctors and hospitals to continue ordering RSV monoclonal antibody shots through the federal Vaccines for Children program for an extra month.
It also signals to hospitals and pediatricians to keep recommending and administering the shots to their vulnerable patients.
Nearly every state has extended the RSV immunization period through at least April 30, including New York, California, Texas, Illinois and Washington. The only exceptions are Florida, Hawaii, Oregon, Louisiana and Washington, DC, which have not extended the period.
Meanwhile, Missouri and Virginia are not following a blanket extension. Instead, they are leaving the decision to individual doctors and families.
Older adults who have increasingly weakened immune systems are also at a particularly high risk of severe complications due to RSV, which generally causes mild, cold-like symptoms in healthy adults.
According to the CDC, RSV causes 110,000 to 180,000 hospitalizations of adults ages 50 and older in the US. In seniors, RSV can cause severe lower respiratory tract illness, including pneumonia and bronchiolitis, often leading to hospitalization or death.
Only about 38 percent of adults 60 to 74 and 41.5 percent of adults 75 and up have received an RSV vaccine, though rates vary widely by state and demographic.
