Respiratory virus activity remained low in the United States last week, with COVID levels continuing to decline, but respiratory syncytial virus (RSV) activity on the rise, especially in young children, the US Centers for Disease Control and Prevention (CDC) said in updates today.
Earlier this week, the CDC’s National Center for Immunization and Respiratory Diseases said though levels are low now, it anticipates rising levels, with peaks in respiratory disease activity often occurring between December and February.
“The holidays are coming, and large gatherings, travel, and more time indoors can mean more viruses spreading. Fortunately, we have tools to help us stay healthy so we can enjoy the time we spend with our families, friends, and neighbors,” the group said, urging health providers to get vaccinated and to encourage patients to do the same.
COVID indicators stay low amid variant shifts
For COVID, emergency department visits—considered an early indicator—are still at the minimal level and on a downward trend. Deaths also remain at a low level, with preliminary data showing reports of 250 deaths for the week ending November 9.
CDC’s wastewater tracking also shows SARS-CoV-2 detections remain at the low level, but are highest in the Midwest, followed by the West.
Surveillance from WastewaterSCAN, national wastewater monitoring system based at Stanford University in partnership with Emory University, also shows detections at low levels, with no up or down trend seen over the last 3 weeks. The same held true for other viruses the group tracks, including influenza A, influenza B, RSV, human metapneumovirus, and enterovirus D68.
In its latest variant proportion update, the CDC said the KP.3.1.1 variant levels declined further over the past 2 weeks, from 52% to 44%. Meanwhile, the proportion of XEC variant viruses rose from 26% to 38%.
What about pertussis and walking pneumonia?
Meanwhile, other respiratory pathogens are on the rise, including pertussis, which this year has shown a return to prepandemic levels. In its latest update yesterday, the CDC said preliminary data shows that six times as many cases have been reported in 2024 compared the same period in 2023.
Though Mycoplasma pneumoniae infection (“walking pneumonia”) isn’t a nationally notifiable condition, the CDC has reported a rise in activity, especially in young children, which it said differs from the usual pattern of the highest burden seen in older children and adolescents. CDC data show that ED visits for walking pneumonia rose steadily over the summer, peaking in kids ages 2 to 4 years old and those ages 5 to 17 years old in August.
CDC tracking of M pneumoniae resistance to macrolides shows that the level in the United States is about 10%, which is lower than the 28% seen globally. However, within the United States, limited data show that resistance levels are higher in the South and East and within clusters and outbreaks that occurred before the COVID pandemic.
