Many people, including some health care practitioners are concerned about mercury and aluminum present in flu shots. This is not a new concern for those who are against flu shots, but it is relevant as the flu season approaches.

The major concern about mercury and aluminum present in flu shots arises from concerns about Alzheimer's and autism. Even among those people who are not against flu shots, some are against mercury and aluminum present in flu shots. Recently, New York State passed a law banning the preservative thimerosal from flu shots and other vaccines meant for children and pregnant women. Thimerosal is mercury based and is known to cause allergic reactions in many people. On top of that, mercury is a known neurotoxin, meaning that it damages nerve cells, and has been linked to autism.

New York State is not against flu shots. In recent years, New York City and other areas of New York have had problems obtaining enough flu vaccine for high risk citizens. The ban came after several studies linked an increase in cases of autism (a condition which is first noted in childhood and is characterized by deficits in communication and social interaction as well as language and learning impairments) to vaccines and flu shots containing thimerosal. Some health care professionals still maintain that the risk of complications from the flu are greater than the risks that may be associated with mercury and aluminum present in flu shots.

Some people are against flu shots, in general, because they or someone close to them had a reaction to the flu shot. Sometimes it is a mild reaction, such as a mild case of the flu. Sometimes it is a more serious condition that may be due to mercury and aluminum present in flu shots. Several people blame the onset of their Chronic Fatigue Syndrome on mercury and aluminum present in flu shots.

It is important to note that these cases are rare. While complications arising form the flu, particularly pneumonia, caused over 60,000 deaths in 2003 in the United States, there were only a few reported cases of complications arising from the flu shot and none of those were life threatening. People who are against flu shots in general focus on the rare, but severe reactions to the vaccine and on the mercury and aluminum present in flu shots. People who are not against flu shots focus on the number of deaths each year that are caused by the flu virus.