It’s shaping up to be an active influenza season this year. At the end of the year, infections are accelerating, and we just hit a 6% infection rate, which crashed through the national baseline of 3% infection. Quite a few people’s Christmas plans were interrupted by the flu. I know of one recent instance where a nurse went into work, even though they were not feeling well, infecting their coworkers! If you are not feeling well and have sick leave, stay home!* The most common strains circulating right now are Influenza A (H3N2). While having the flu is never fun, the CDC forecasted well, including H1N1, H3N2, and influenza B/Victoria lineage in the vaccine. If you have been vaccinated, it should give you some protection. If you are not vaccinated, there is still time.
The CDC has an excellent influenza tracker called Flu View interactive, where you can see recent influenza data. This makes public the influenza tests done nationwide. Influenza is one of many notifiable diseases that hospitals and our public health infrastructure track. Another useful resource is the National Wastewater Surveillance System. This screens wastewater for influenza, measles, SARS-CoV-2 (COVID), RSV, and Monkeypox. This serves as an early warning system for all sorts of illnesses. One advantage of testing wastewater is that health professionals don’t have to wait until someone comes to the doctor ill. They are constantly monitoring the water and will know right away when an illness starts increasing in a community. Incidence can vary considerably even within a region. Right now, the incidence of influenza in Wisconsin is low, but in my community, Dane County, the incidence is high, and in Rock County, just south of Dane, the incidence is very high. Knowing this information can help inform doctors and allow individuals to take precautions when viruses are spreading.
If you want to learn more about influenza, consider buying my book, Why Microbes Matter. It has a detailed chapter on influenza and other illnesses.
*By the way, employers, it is monumentally stupid and a really mean policy not to allow your employees sick leave. Chunyu, Volpin, and Zhu found that having paid sick leave increases worker productivity. Also, Vander Weerdt, Stoddard-Dare, and Derigne found that employees without paid sick leave are 1.5 times more likely to show up to work and get other employees and customers sick. Having paid sick leave helped with retention, job satisfaction, and decreased occupational injury, contagion, and death. If you don’t offer paid sick leave to your employees, you’re kinda foolish and a bad person.