Pre-pandemic influenza vaccine (H5N1)

Pre-pandemic influenza vaccine (H5N1) (split virion, inactivated, adjuvanted) (A / VietNam / 1194/2004 NIBRG-14)

What is prepandemic influenza vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals?

Prepandemic Influenza Vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals is a vaccine that is given by injection. Contains fractions of influenza viruses that have been inactivated (killed). The vaccine contains a strain of the influenza virus called "A / VietNam / 1194/2004 NIBRG-14" (H5N1).

What is the vaccine used for?

Prepandemic Influenza Vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals is a vaccine intended for adults to protect against influenza caused by the H5N1 strain of influenza A virus. The vaccine is administered based on official recommendations.
The vaccine can only be obtained with a prescription.

How is the vaccine used?

The vaccine is given by injection into the shoulder muscle in two single doses, at least three weeks apart. Adults over the age of 80 may need a double dose of the vaccine (one 'injection into each shoulder) with a second double dose three weeks later.

How does the vaccine work?

The Prepandemic Influenza Vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals is a "prepandemic" vaccine. It is a special type of vaccine designed to protect against a strain of the flu that can cause a future pandemic.An influenza pandemic occurs when a new type of influenza virus is detected that is capable of spreading smoothly from person to person due to the lack of immunity (protection) among the population. A pandemic can affect most nations and regions of the world. Health experts express concern as to what a future flu pandemic could be
caused by the H5N1 strain of the virus. The vaccine was designed to provide protection against this strain so that it can be used before or during a flu pandemic.
Vaccines work by "teaching" the immune system (the body's natural defense system) to defend itself against a disease. This vaccine contains small amounts of hemagglutinins (surface proteins) of the H5N1 virus. The virus was first inactivated in order to do not cause any disease. When a person is vaccinated, the immune system recognizes the virus as "foreign" and produces antibodies against that virus. If exposed to the virus after vaccination, the immune system will be able to produce antibodies more quickly The body will then be able to protect itself from the diseases caused by this virus.
Before use, the vaccine must be prepared by mixing a suspension containing the virus particles with an emulsion. The resulting "emulsion", which will be injected, contains an "adjuvant" (an oil-based compound) to stimulate a better response.

What studies have been done on the vaccine?

The main vaccine study included 400 healthy adults between the ages of 18 and 60 and compared the ability of different doses of the vaccine, with or without adjuvants, to trigger the production of antibodies ("immunogenicity"). Participants were given two injections of the vaccine containing one of four different doses of hemagglutinin. The injections were performed at an interval of 21 days from each other. The main measures of effectiveness were the levels of antibodies to the influenza virus in the blood at three different times: before vaccination, on the day of the second injection (day 21) and 21 days after (day 42).
A further study examined the immugenicity of single or double doses of the vaccine in 437 people over the age of 60.

What benefit has the vaccine shown during the studies?

According to the criteria defined by the Committee for Medicinal Products for Human Use (CHMP), to be considered adequate, a prepandemic vaccine must induce protective levels of antibodies in at least 70% of people vaccinated.
The study revealed that the vaccine, containing 3.75 micrograms of hemagglutinin and adjuvant, produced an antibody response that meets these criteria. 21 days after the second injection, 84% of vaccinated people had antibody levels capable of protecting against the "H5N1.
Single doses of this vaccine also met these criteria in older people, except for the small number of patients over 80 years of age who had no protection against the virus at the start of the study. These patients required double doses of vaccine for protection.

What is the risk associated with the vaccine?

The most frequent side effects seen with prepandemic influenza vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals (occurring with more than one in 10 doses of the vaccine) are headache, arthralgia (joint pain), myalgia (pain muscles), injection site reactions (hardness, swelling, pain and redness), fever and fatigue. For the full list of side effects reported with the vaccine, see the package leaflet.
The vaccine should not be given to people who have had an anaphylactic reaction (severe allergic reaction) to any of the components of the vaccine or to any substance found in very low amounts in the vaccine such as eggs, chicken protein, ovalbumin (protein present in the vaccine). egg white), formaldehyde, gentamicin sulfate (an antibiotic) and sodium deoxycholate. Vaccination should be delayed in people who experience a sudden feverish attack.

Why has the vaccine been approved?

The CHMP decided that the benefits of the prepandemic influenza vaccine (H5N1) (split virion, inactivated, adjuvanted) GlaxoSmithKline Biologicals are greater than its risks for active immunization against the H5N1 subtype of influenza A virus. The committee recommended the granting of a marketing authorization for the vaccine.

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