If if isn’t a flu virus, then what is the cause?
Influenza is the term assigned to attack by certain rhino-viruses. Both rhino-virus and corona-virus are viruses, they depend on a host to replicate themselves.
Rhino-viruses are relatively simple. The RNA they replicate is shorter, and the container has a different shape, and different binding points to attach to cells in the host.
Even if the two viruses cause the same symptoms, a test for flu won't show presence of corona, and a test for corona won't show presence of flu.
CDC estimates that influenza has resulted in between 9 million - 45 million illnesses, between 140,000 - 810,000 hospitalizations and between 12,000 - 61,000 deaths annually since 2010.
There are a lot of garden variety virus that may not show up on an influenza test. We do a multiviral panel of some nearly 30 viruses when we test in hospital now which include the various influenzas. Where I work we’ve had type a and type b flu’s show up but we’ve had quite a bit of human metapneumovirus that is making a lot of seniors sick and is very transmittable to health care workers so we do droplate precautions. The virus makes people susceptible to bacteria that love to pour in after the fact. A person can go into general sepsis, organ failure and pneumonia very quickly especially if you are older.
The article is very narrow in scope focusing on the flu but there are other viruses that can give you a flu like illness and make one quite sick. That’s why the multipanel viral tests are important. Let’s not for get mono and hepatitis B as well.