Most individuals will experience no side effects from the influenza vaccine. Less than one-third of those who receive the vaccine will have some soreness at the vaccination site, and about 5% to 10% will experience a headache or a mild fever. The most serious side effect that can occur after an influenza vaccination is an allergic reaction in individuals who have a severe allergy to eggs. For that reason, people who have an allergy to eggs should not receive the influenza vaccine.

The influenza vaccine is a killed virus vaccine containing three strains of influenza virus, two of Influenza A, and one of Influenza B. The strain components are changed annually based upon worldwide surveillance of circulating influenza strains.

No. Federal officials have contracted with a manufacturer to produce a small supply of human vaccine against H5N1 bird flu, and clinical trials are underway. The vaccine might not be effective if the H5N1 virus changes to a strain that more easily infects humans.

No. Although the capability does exist for scientists to produce vaccines against almost all known human flu viruses, the problem they face with the current threat is that they cannot predict the strain of any new hybrid mutations that may emerge. Once an outbreak occurs that is caused by a new strain, scientists will be able to rapidly identify the new virus and work towards creating a vaccine.

Influenza vaccines are designed to protect against specific viruses that have already been identified, so a pandemic vaccine cannot be produced until a new influenza virus emerges and starts to cause a significant number of human illnesses. A virus that could cause a pandemic would be very different from the seasonal flu viruses for which there is already vaccine.

Allergic reactions could occur after any vaccine. Pain or tenderness, swelling, or warmth at the injection site may occur in about 25 percent of people who receive the vaccine and last one to two days. About 3 percent of people will have muscle or joint aches, flu-like symptoms, fever, or chills. Tests of vaccine safety and effectiveness are not complete for children younger than 15, so preventing tick bites is the recommended alternative until a vaccine becomes available.

The influenza vaccine production process is long and complicated. Traditional influenza vaccine production for the U.S. relies on long-standing technology based on chicken eggs. This production technology is labor-intensive and takes 9 months from start to finish. The flu vaccine production process is further complicated by the fact that influenza virus strains continually evolve.

Influenza vaccine cannot prevent avian influenza as the vaccine was meant for human influenza. However, the vaccine can help reduce the chance of complications and hospitalization from human influenza; hence it is recommended for the elderly and patients with chronic illnesses. Influenza vaccine can also reduce the chance of genetic re-assortment and subsequent emergence of influenza strain with pandemic potential.

The meningococcal vaccine is safe and effective. As with all vaccines, there can be minor reactions, including pain and redness at the site of injection, lasting one to two days. You cannot get meningitis from the vaccine, because it is synthetic; there are no live bacteria in the vaccine.

Influenza vaccines are designed to protect against a specific virus, so a pandemic vaccine cannot be produced until a new pandemic influenza virus emerges and is identified. Even after a pandemic influenza virus has been identified, it could take at least 6 months to develop, test and produce vaccine.

Currently, Sanofi Pasteur and Medimmune have influenza vaccine production facilities in the United States, although only Sanofi Pasteur?s entire production process is based in this country. HHS has made the establishment and expansion of U.S.-based manufacturing facilities for influenza vaccine a key component of its strategy to improve the security of the influenza vaccine supply.

There are no commercial supplies of vaccine against pandemic influenza virus because the specific pandemic strain is not known in advance. It is impossible to develop a perfect match vaccine until a new influenza virus has shifted to human-to-human transmission and that strain has been identified and characterized so that a vaccine can be developed.

The influenza vaccine is very safe. The vaccine is a killed virus and CAN NOT cause influenza. If you become ill after being vaccinated it is just coincidence and is probably a "cold". with any vaccination, local reactions can occur. These include mild soreness, redness or swelling at the site. These may occur in about 1/4 of people who are vaccinated. Fever, headaches, loss of appetite or nausea, weakness and muscle pains occur infrequently. NOTE: The vaccine is grown in eggs.