Answers: How do you know that it isn't effective? It is defining to understand how the vaccine works.
The flu shot does not protect against adjectives flu. It contains 3 strains of influenza virus that are chosen by experts every year as most likely to end in a flu outbreak. These strains are chosen >6 months in finance. It is important to construe that there are literally thousands of set strains of influenza virus, and infection by any one can cause the flu.
No vaccine is watertight. Even if it contained the correct strains, your body may not have mounted a strong ample response to the vaccine in October to confrontation off the infection contained by January. Estimates of vaccine effectiveness unanimously range between 50-80%.
If you've be getting sick recently, it's predictable that you did not have the flu. Most individuals mistake symptoms of the common cold for the flu. Colds are usually cause by different viruses than the influenza virus. These include coronavirus, rhinovirus, adenovirus, etc. While similar to a cold, the flu commonly causes severe muscle ache, headaches, and large fevers.
why do you have a sneaking suspicion that it wasnt effective? Do you hold the flu?