There’s been a lot of paranoia about influenza, much of it justified. The 1918 pandemic killed as many as 30-50 million people worldwide, and 675,000 in the US. We don’t know for sure. But in an average non-pandemic year influenza kills between 3-49 thousand in the US. The figure I keep in mind is 35,000 a year, about the population of Bangor, our nearest city. So if that fear makes you get a flu shot, good.
Respiratory syncytial virus (RSV) season runs from approximately November through late February in this region and typically overlaps influenza. I was surprised recently to learn that RSV is deadly in adults, for many of the same reasons as influenza. According to the CDC, while infants and children are the most frequent concern, each year there are 177,000 hospitalizations and 14,000 deaths among adults older than 65.
Nearly half as many as flu? I find that surprising, but it seems plausible for a virus that targets the lower respiratory tract. Why isn’t this on the radar for these patients? Why don’t we routinely test older patients for RSV?
I talked to one of our hospitalists about this, and at first he was skeptical. “I don’t believe those numbers,” he said. “First of all, we don’t test for RSV. How does the CDC know?”
That’s a good point. The CDC admits on their website that it is difficult to estimate, since influenza and other viral agents are not often listed as a cause of death on death certificates. Laboratories don’t routinely test for RSV for a number of reasons. Most (if not all) of the rapid kits are insensitive to adult populations and have only been approved for pediatric patients. And there is no RSV vaccine, which may be another reason we don’t test. Treatment options for RSV are limited compared to influenza.
A local microbiologist working in a lab that routinely tests RSV as part of a respiratory panel shared numbers that suggest RSV is prevalent in older patients, along with influenza. In his opinion, the CDC figures are believable.
NEXT: Populations and Pathogens