Swine Flu Vaccine Dangers - Side Effects and Complications

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The Swine Flu Vaccine

The swine flu vaccine was manufactured in 2009 to combat a new strain of the influenza virus. The H1N1 influenza virus was different from the seasonal flu virus. It contained characteristics of a strain of the flu virus that were present in the pig population on farms. This is how the H1N1 virus became known as the swine flu virus.

The vaccine itself is similar to other vaccines. It contains components of the swine flu designed to activate the immune system of the body. Two forms of the vaccine were produced. The flu shot was administered via a needle, and it contained an inactivated form of the swine flu virus. A nasal spray was also manufactured, which contained a weakened but live swine flu virus.

Side Effects

One of the potential swine flu vaccine dangers is side effects. Depending on the type of vaccine administered, the side effects will be slightly different. The flu shot has a number of side effects, including soreness and redness at the injection site. Body aches, nausea, and a low grade fever are three more possible side effects of the flu shot.

The nasal spray has its own set of side effects. For children, the side effects include a runny nose, wheezing, fever, headaches, nausea, and vomiting. For adults, the side effects associated with the nasal spray include a runny nose, headaches, sore throat, and coughs.

Side effects usually become noticeable shortly after receiving the swine flu vaccine. Symptoms may last up to two days and then subside.

Allergies, Adjuvants, and Thimerosal

An allergic reaction is a rare but possible result of the swine flu vaccine. The vaccine was manufactured with chicken eggs. Those who are allergic to eggs should avoid the vaccine. An allergic reaction to any substance in the vaccine will probably occur within an hour of receiving the vaccine. If such a reaction occurs, it is recommended to see a doctor immediately.

None of the swine flu vaccines were produced with adjuvants, which are additional substances added to a vaccine designed to increase the immune response. The only adjuvant used in vaccines in the United States is aluminum gels or salts.

Another concern is the presence of thimerosal, a preservative used in certain swine flu preparations. It is included in multi-dose vials to prevent contamination. Single-dose vials and nasal sprays are not manufactured with thimerosal.

Possible Complications

Among the potential swine flu vaccine dangers, the development of Guillain-Barré Syndrome is the least likely. It is believed that 1 in 1 million people vaccinated for the swine flu may experience this disease. It is characterized by nerve cell damage, muscle weakness, and partial paralysis. Those with infections caused by the Campylobacter jejuni bacterium are more likely to develop Guillain-Barre Syndrome.


1. “General Questions and Answers on 2009 H1N1 Influenza Vaccine Safety.” Center for Disease Control and Prevention. https://www.cdc.gov/h1n1flu/vaccination/vaccine_safety_qa.htm

2. “Is the H1N1 Swine Flu Vaccine Safe?” WebMD. https://www.webmd.com/cold-and-flu/features/is-the-h1n1-swine-flu-vaccine-safe