In the midst of flu vaccination season, I hear many patients refuse the flu shot because they don’t want to get the flu. But the truth is, the flu vaccine does not cause the flu.
The influenza vaccine is an inactivated vaccine, meaning that it does not contain an active virus. Inactive (or killed) vaccines contain viral particles which are grown in a culture and then killed , using such a method as heat or formaldehyde. However, the proteins of the virus are preserved enough that the immune system can recognize it and mount a response. An inactive pathogen cannot cause an infection because it does not contain the active, infectious component. Additionally, it no longer is capable of replicating, which is a key component in any infectious disease.
The intra-nasal flu vaccine is not a killed vaccine. It is an attenuated vaccine, meaning that it is weakened. They are additionally cold adapted and can only cause infection in cooler temperatures, such as within the nose. It cannot survive in warmer temperatures in other parts of the body, and thus cannot cause infection with the flu as well.
Although it is impossible for the flu vaccine to cause the flu given its nature, side effects are possible. The most common side effects include pain and redness at the site of injection. Because it provokes an immune response in the entire body like it does to any foreign body, it can cause generalized achiness and low-grade fever, which is usually very mild. These typically last 1-2 days. The intra-nasal vaccine can also cause runny nose, mild fever, chills, headache, fatigue and cough. Again, these side effects typical last 2 days or less.
No, the flu vaccine does not cause the flu but can cause side effects, which are mild. If you contrast that to actually being infected with the flu, vaccination makes sense. Typical flu symptoms include severe muscle and joint aches, pain around the eyes, fevers, chills, cough, headache, upper respiratory symptoms, diarrhea, vomiting, dizziness, malaise, and trouble breathing. People are typically very miserable and bed-bound. Compared to the side effects of the flu shot that last 1-2 days, the real flu can last up to 2 weeks.
The most important reason that we vaccine against the flu is not just to prevent illness, but to prevent the very real complications that can happen as a result of being infected. Typically, these complications occur in higher risk patients, such as the elderly, the very young and those suffering other chronic conditions. The flu can lead to pneumonia, either a viral pneumonia or a secondary bacterial pneumonia. This can be serious for anyone but it can also makes those afflicted with asthma, chronic obstructive pulmonary disease and other underlying chronic disease have exacerbation of those diseases. Blood sugars in diabetics may run out of control in those ill with the flu. Pregnant women may suffer preterm labor, miscarriage or stillbirth if they become sick with the flu while pregnant. More seriously, but less commonly, influenza can cause encephalitis and meningitis which can lead to death and permanent damage. And the most serious influenza complication of all: death.
While those at higher risk are more likely to suffer a complication from the flu, it can happen to anyone. Every year, previously healthy people die from the flu. There is no way to predict who will or won’t. While side effects from the vaccine may be uncomfortable, the disease itself is much more severe and the complications potentially deadly. Everyone should consider being vaccinated against influenza. Evidence shows it reduces hospitalizations and death. There are many myths surrounding flu shots, and vaccines in general, but vaccines have withstood the scientific rigors over decades of research around the globe. Vaccines clearly save lives. Did you get your flu shot yet?
Copyright secured by Digiprove © 2015 Linda Girgis, MD, FAAFP
