Healthy Living: Influenza
Amy Movius MD, October 15, 2019
As the seasons change, so do the viruses in our environment. There are many viruses that can cause "colds and flu" illnesses during the winter, but only influenza viruses cause the flu against which the "flu shot" is designed. This is because every year, influenza viruses cause serious illness and death in many people: last year in the US an estimated 42.9 million people got sick, 647,000 were hospitalized and 61,200 died from influenza. It is very contagious and can be easily transferred between people or even from a contaminated surface to people. Symptoms include cough, sore throat, fever and muscle aches. It can lead to unpleasant complications such as ear and sinus infections and outright dangerous complications such as pneumonia, heart or brain inflammation, and various organ dysfunction.
Flu season is generally considered to be between October and May, with peak season usually between December and February. It takes about 2 weeks for the full protection of the immunization from the shot to develop so getting it before peak season is best – the current recommendation is to get the shot in October.
The severity and strains of influenza viruses are constantly changing. Every year the shot is different based on the best predictions by the experts tracking these changes about what influenza viruses are likely to be circulating in the upcoming winter. This is one of the reasons the shot is never 100% effective against getting the flu. Also, the influenza viruses can continue to change or emerge even during the season. Despite these concerns, the shot can still be protective. Even if you get influenza despite receiving the vaccination it will very likely be less severe and shorter than if you were not vaccinated. A 2017 study in children showed that children with influenza who had received the vaccinations were much less likely to die from the infection than those who contracted influenza and were not vaccinated. These findings reinforce previous studies on adults.
There are groups at particular risk from influenza infection: the very young, the old, pregnant women, those with lung or heart problems and children with neurological disorders. The best protection for these individuals is to get the flu shot and for everyone around them to get the flu shot. Though some groups are at greater risk from complications or death from influenza, remember it can (and does) happen to anyone – including those in perfect health. It is recommended everyone over 6 months of age be vaccinated.
There are young babies and others who cannot receive the vaccine for certain reasons. Their only form of protection is "herd immunity" – meaning those of us who can be immunized getting immunized to reduce the amount of the virus in the community.
Lastly, the flu shot absolutely does not cause the influenza! There is no active virus contained in the vaccine. If you get sick after getting the shot it is likely from a different virus (not influenza) especially if the season hasn't hit yet. If you're unfortunate enough get influenza anyway, though you may feel crummy, you're risk of ending up in the hospital or dying is still greatly reduced.
To protect yourself and others even after receiving the shot, remember to frequently wash your hands and sneeze into the elbow rather than hands. "Social distancing" or keeping a couple feet between yourself and other people in gatherings, can also decrease transmission of virus. If you get influenza but are an otherwise healthy person – please stay home and take care of yourself! Influenza will generally run its course over days to a week or two. However, if you feel extremely sick you should seek medical attention promptly. If you get influenza but have chronic medical issues or are in a high-risk group OR live with somewhat at risk, call your provider to get antiviral medication. Sometimes this can be arranged without a clinic visit which risks spread in the waiting room.
2. US CDC- Influenza