About the H1N1 Flu Shot

What is in the H1N1 flu shot?

The H1N1 flu shot has two ingredients, an "antigen" and an "adjuvant". The antigen is the active ingredient that helps your body become immune to the H1N1 flu virus. The antigen is not a live virus, so will not make you sick with the H1N1 flu. The adjuvant in the H1N1 flu shot is made up of natural ingredients such as fish oil, water and vitamin E. Adjuvant is added to the H1N1 flu shot to boost the body's response to the vaccine. When adjuvant is added to vaccine, less active ingredient (i.e. antigen) is needed. That way we can produce more vaccine for everyone.

H1N1 Flu Vaccine Question and Answer Information Sheet

What is an adjuvant?

An "adjuvant" is added to vaccines so that less of the active ingredient (i.e. antigen) is required to boost the body's response to vaccine. The adjuvant in the H1N1 flu shot is made up of natural ingredients such as fish oil, water, and vitamin E.

What is the unadjuvanted H1N1 flu shot? Should pregnant women receive the adjuvanted or unadjuvanted vaccine?

There are two types of H1N1 vaccine approved by Health Canada for pregnant women: the adjuvanted H1N1 vaccine and the unadjuvanted (or non-adjuvanted) H1N1 vaccine. An adjuvant is a substance that helps stimulate the body's immune response. The adjuvant in the H1N1 vaccine is made up of natural ingredients such as fish oil, water, and vitamin E.

All evidence suggests that adjuvanted vaccines are just as safe as unadjuvanted vaccines; however the adjuvanted vaccine has not been specifically studied in pregnant women. That is why the WHO's Strategic Advisory Group of Experts (SAGE) has recommended that pregnant women receive non-adjuvanted vaccine if possible.

However, unadjuvanted vaccine won't be available in Canada until at least the second week of November. Given that influenza rates are rising in our community, it is recommended that pregnant women with pre-existing health conditions or who are more than 20 weeks pregnant be offered the adjuvanted vaccine that is available now. This advice is consistent with that given by the Society of Obstetricians and Gynaecologists of Canada. These pregnant women are at greater risk of complications from H1N1.

Is it true that there is mercury in the vaccine? How much mercury?

The H1N1 vaccine contains a small amount of thimerosal. Thimerosal is a form of mercury used in the H1N1 flu vaccine to stabilize it and maintain its quality during storage. Thimerosal is a different form of mercury than the mercury known to cause health problems. The amount in the H1N1 adjuvanted flu vaccine is much less than the daily limit recommended for environmental exposure to mercury. For example, there is significantly less mercury in the vaccine than you would find in a can of tuna fish.

Is the H1N1 flu virus vaccine safe?

Yes. Health Canada is responsible for approving vaccines. They have a strong regulatory process to ensure the vaccines are safe before they are given to the general public. Health Canada has done a review of both the vaccine and the adjuvant. The benefit of immunization - the prevention of serious illness and death - far outweighs any risk associated with being immunized.

Are there any side effects?

Side effects are expected to include: pain and swelling where the injection is given, tiredness, muscle and joint pain, and headaches. Children may have a mild fever, be tired and irritable and not want to eat.

As with the seasonal influenza vaccine, it is expected that most side effects will be mild, and that serious side effects will be very rare.

Will everyone receive the H1N1 vaccine at the same time?

The PHAC and MOHLTC will sequence the distribution of the H1N1 vaccine. This means that individuals at higher risk for getting the H1N1 flu virus will be immunized first.

The H1N1 flu shots will be given in two stages. The first shipments of the vaccine will be given to primary care providers (doctors) so they can immunize individuals who are at higher risk of getting complications from influenza. These include:

• People 65 and under with chronic conditions (e.g. diabetes, cancer)
• Children 6 months to under five years of age;
• People living in remote or isolated communities;
• Pregnant women;
• Health care workers; and
• Household contacts and care providers of persons at higher risk who cannot be immunized (e.g. children under 6 months) or may not respond to vaccines (e.g. those who are immune-compromised)

Primary care providers (doctors) will start giving these individuals the vaccine the week of October 26.

Starting the week of November 3, other individuals will be able to get the H1N1 flu shot. Not everyone who wants it may be able to get the H1N1 flu shot that week, as initial supplies are limited. Public Health will offer clinics from November to mid-December to ensure everyone who wants the vaccine can get it.

Will the annual flu shot protect individuals during a pandemic?

The regular seasonal flu shot will protect you against seasonal flu. This year's seasonal flu shot will not protect you against H1N1 flu virus. A separate vaccine is being developed to protect individuals again the H1N1 flu virus. It is recommended that all Ontarians get both the annual and H1N1 flu vaccines.

What are antivirals?

Antivirals are drugs used for the prevention and early treatment of influenza. Antivirals continue to be recommended at this time only for treatment of severe cases or those at higher risk of complications.