In addition to the 2009 influenza A (H1N1) strain antigens, the vaccine also includes an adjuvant and a preservative.

The adjuvant is called AS03 and was developed by the company GSK, as part of the production of the vaccine against the influenza virus H5N1. This “oil in water” type adjuvant is composed of:

• tocopherol (vitamin E), a vitamin essential for the proper functioning of the body;
• squalene, a lipid produced naturally in the body. It is an essential intermediate in the manufacture of cholesterol and vitamin D.
• polysorbate 80, a product present in many vaccines and drugs in order to maintain homogeneity.

The adjuvant makes it possible to achieve substantial savings in the amount of antigen used, which facilitates the immunization of a large number of individuals as quickly as possible. The use of an adjuvant can also provide cross-protection against mutation of the viral antigen.

Adjuvants are not new. They have been used for several decades to stimulate the immune response to vaccines, but the use of adjuvants with influenza vaccines has not been previously approved in Canada. This is therefore a first in this case.

The vaccine also contains a mercury-based preservative called thimerosal (or thiomersal), which is used to prevent contamination of the vaccine with infectious agents from bacterial overgrowth. The common seasonal flu vaccine and most hepatitis B vaccines contain this stabilizer.

There are no reliable data on the safety of the adjuvanted vaccine in pregnant women and young children (6 months to 2 years). Nevertheless, the World Health Organization (WHO) considers that the administration of this vaccine is preferable to the absence of vaccination, since these two groups are particularly sensitive to complications in the event of contamination.

Quebec authorities have chosen to offer pregnant women a vaccine without adjuvant, as a precautionary measure. The small quantity of doses of unadjuvanted vaccines which is currently available does not, however, make it possible to offer this choice to all future mothers. It is therefore unnecessary to request it, even for young children. According to Canadian experts, who refer to preliminary clinical trials, there is no reason to believe that the adjuvanted vaccine will trigger any side effects – other than a higher risk of fever – in children aged 6 months to 3 years.

The unadjuvanted vaccine, which is generally recommended for pregnant women, contains 10 times more thimerosal than the adjuvanted vaccine, but according to the most recent scientific data, there is no evidence that women who received this vaccine have had an adjuvanted vaccine. miscarriage or given birth to a malformed child. The Dr de Wals, of the INSPQ, points out that “the vaccine without adjuvant still contains only 50 µg of thimerosal, which provides less mercury than what can be consumed during a meal of fish”.

Side effects associated with an influenza vaccine are usually exceptional and are limited to mild pain where the needle entered the skin of the arm, mild fever, or mild pain throughout the day or so. two days after vaccination. Administration of acetaminophen (paracetamol) will help reduce these symptoms.

In rare cases, a person may have red or itchy eyes, cough, and slight swelling of the face within a few hours of getting the vaccine. Usually these effects go away after 48 hours.

For the pandemic A (H1N1) 2009 vaccine, clinical trials underway in Canada are not complete by the time the mass immunization campaign begins, but health authorities believe that the risk of adverse effects is minimal. According to the World Health Organization, only a few cases of minor side effects have so far been observed in countries where the vaccine has already been administered on a massive scale. In China, for example, 4 of the 39 people vaccinated would have experienced such effects.

People who already have a severe egg allergy (anaphylactic shock) should see an allergist or their family doctor before being vaccinated.

Penicillin allergy is not a contraindication. However, people who have had anaphylactic reactions to neomycin or polymyxin B sulfate (antibiotics) in the past should not receive the unadjuvanted vaccine (Panvax), since it may contain traces of it.

Thimerosal (vaccine preservative) is indeed a derivative of mercury. Unlike methylmercury – which is found in the environment and can cause severe brain and nerve damage, if ingested in large amounts – thimerosal is metabolized into a product called ethylmercury, which is quickly cleared by the body. . Experts believe that its use is safe and does not pose a danger to health. Claims that the mercury in vaccines may be associated with autism are contradicted by the results of several studies.

The pandemic vaccine was prepared using the same methods as all influenza vaccines approved and administered in recent years. The only difference is the presence of the adjuvant, which was necessary to produce such a quantity of doses at an acceptable price. This adjuvant is not new. It has been used for years to stimulate the immune response to vaccines, but its addition to influenza vaccines had not been previously approved in Canada. It has been done since October 21. Health Canada assures that it has in no way shortened the approval process.

If you have been a victim of the 2009 strain of the A (H1N1) virus, you have comparable immunity to that which the vaccine should provide. The only way to be sure that it is this strain of influenza virus that you have contracted is to get a medical diagnosis to that effect. However, since the confirmation that this flu was pandemic, the WHO recommended not to systematically detect the 2009 strain of A (H1N1). Because of this, the majority of people with influenza do not know whether they have been infected with the A (H1N1) virus or another influenza virus. Medical authorities believe that there is no danger in receiving the vaccine, even if one has already been infected with the pandemic virus.

Given the preponderance of influenza A (H1N1) in recent months, vaccination against seasonal influenza, scheduled for fall 2009, is postponed to January 2010, both in the private sector and in the public sector. This postponement aims to give priority to the vaccination campaign against influenza A (H1N1), and allows health authorities to adapt their strategy against seasonal influenza to future observations.

In Canada, between 4 and 000 people die of seasonal influenza each year. In Quebec, there are approximately 8 deaths per year. It is estimated that about 000% of people who contract the seasonal flu die from it.

Currently, experts estimate that the virulence of the A (H1N1) virus is comparable to that of the seasonal flu, that is to say that the death rate attributable to it is around 0,1%.

The swine flu vaccines used in the United States in 1976 were associated with a low (about 1 case per 100 vaccinations), but significant risk of developing Guillain-Barré syndrome (GBS – neurological disorder, probably of ‘autoimmune origin) within 000 weeks of administration. These vaccines did not have an adjuvant. The underlying causes of this association are still not known. Studies of other influenza vaccines given since 8 have shown no association with GBS or, in rare cases, a very low risk of about 1976 case per 1 million vaccinations. Quebec medical authorities believe that the risk is not higher for children who have never been vaccinated.

The Dr de Wals points out that this syndrome is very rare in children. “It mostly affects older people. To my knowledge, there is no reason to believe that children who have never been vaccinated are at greater risk than others. “

Pierre Lefrançois – PasseportSanté.net

Sources: the Quebec Ministry of Health and Social Services and the National Institute of Public Health of Quebec (INSPQ).