Every year vaccine researchers from around the globe meet with vaccine manufacturers to try and predict the top 3 strains of the flu virus to wreak havoc that year. The top three are then placed in flu vaccine shots. The nasal spray contains live but significantly weakened viruses, while the shot has dead viruses that can be directly injected into the bloodstream. According to the CDC, the vaccines are 70 to 90 percent effective against viruses with just those three strains.
Who should not get the vaccine?
Children younger than six months, people with past allergic reactions to vaccines should not take the vaccine. Because the vaccines are grown in chicken eggs, people who are allergic to chicken eggs should not get the shot either, as there is a 5-10% chance that members of this group will experience side effects such as having fevers and headaches. Only healthy persons between the ages of 10 and 50 are recommended to get the nasal vaccine.
In some rare cases, drugs such as flu vaccines can cause dystonia. Dystonia causes a neurological movement disorder in which sustained muscle contractions cause abnormal posture, twisting and repetitive movements. The disorder may be inherited or caused by a physical trauma, lead poisoning or a reaction to drugs, particularly neuroleptics.This video highlights the case of a girl who suffered some neurological damage and can only walk backwards after getting a flu shot.