A patient came to me with muscle aches, fever, severe fatigue and nasal congestion. I recognized the classic symptoms right away and tested her for flu, though it was still early September and I wasn’t expecting to see flu yet. I sent an electronic prescription for an anti-viral drug to her pharmacy and told her to start taking it. The flu test came back positive and she was bed-ridden for a week, and then slowly recovered.
This year promises to be a particularly bad flu season. We look to Australia to predict what will happen here, since their winter — flu season — is our summer. Australia was hit particularly hard this year; with more than 300,000 confirmed cases and a severe form of Influenza A H3N2 predominating.
Last year, also a bad flu season, there were more than 500,000 hospitalizations from flu in the U.S., with more than 50,000 deaths. This year looks like it could be worse.
The flu is a rapidly mutating virus because it is made up of a single strand of genetic material known as RNA (ribonucleic acid), which is not capable of repairing itself, so that the mutations are copied. This is why there are so many strains or subtypes of flu out in the community, and why we are not perfectly defended against this virus even when we take flu vaccine.
U.S. scientists determine the exact makeup of the yearly flu vaccine by looking to other countries where flu happens first, including Australia. The yearly flu vaccine generally covers four prevailing strains but is imperfect because it’s primarily made by culturing the flu virus in billions of hen’s eggs.
This process may take several months so that, by the time flu emerges here, it has frequently mutated to a subtype that isn’t a perfect match for the vaccine. Nevertheless, the flu shot is always worth getting for several reasons.
First, it decreases the amount of circulating flu virus. Second, it decreases the severity of flu, even if it isn’t completely effective in preventing it; if you have a milder case, your immune system is stronger and you are less likely to suffer a devastating complication, such as pneumonia or a heart attack.
There are two main proteins on the surface of the flu molecule: hemagglutinin and neuraminidase. Hemagglutinin, a spike-shaped protein, attaches the flu to the host cell and neuraminidase cleaves the flu off the cell when it is ready to jump to a neighboring cell. Flu drugs like, Tamiflu block neuraminidase, thereby decreasing its spread. Flu vaccines mainly target hemagglutinin.
Flu shots are made using inactivated (killed) flu viruses, so you cannot get the flu from a flu shot. A young baby or elderly person with chronic illness is less likely to get the flu if more people are immunized.
The future of fighting flu is to be found in the universal flu vaccine, which is being studied in National Institutes of Health-approved trials. Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases and one of the top experts in the country, told me in an interview that one promising candidate targets the stem rather than the surface of the hemagglutinin molecule. This is significant because the stalk is very similar from one flu molecule to the next.
A universal flu vaccine will change the game entirely. It will be used against most if not all strains — and it could be an effective defense against a "weaponized" bioengineered flu spread by terrorists, to which we otherwise would have zero immunity.
I look forward to a future where my patients aren’t healthy one minute and exhausted with a fever and muscle aches the next. The flu is a formidable foe and we need a formidable defense against it.
Marc Siegel M.D. is a professor of medicine and medical director at Doctor Radio at NYU Langone Health. He is a Fox News Medical Correspondent. Follow him on Twitter: @drmarcsiegel.