Optaflu - flu vaccine

What is Optaflu?

Optaflu is a vaccine available in suspension for injection in pre-filled syringes. The vaccine contains, as active ingredients, the inactivated surface antigen of three different strains (types) of influenza virus (ie A / Salomon Islands / 3/2006, A / Wisconsin / 67/2005 and B / Malaysia / 2605/2004 ).

What is Optaflu used for?

Optaflu is used for vaccination against adult flu, particularly those with a greater risk of developing complications of the disease. The vaccine should be used according to official recommendations.

The vaccine can only be obtained with a prescription.

How is Optaflu used?

Optaflu is given as a single 0.5 ml injection into the muscle that covers the shoulder joint.

How does Optaflu work?

Optaflu is a vaccine. Vaccines act by "teaching" the immune system (the body's natural defense system) to defend itself against a disease. Optaflu contains fragments of the surface of three different strains of the influenza virus. When a person is vaccinated, the immune system recognizes the fragments of the virus as "foreign" and produces antibodies against that virus. In the event of exposure to any of these virus strains in the future, the immune system will be able to produce antibodies more quickly. Antibodies will help the body protect itself against diseases caused by these influenza virus strains.

Each year, the World Health Organization (WHO) provides recommendations on which flu strains to include in the upcoming flu season vaccines, and these viral strains must be inserted into Optaflu before the vaccine can be used. Optaflu currently contains fragments of the viral strains that are expected to cause influenza in the 2007/2008 season, in accordance with WHO recommendations for the northern hemisphere and the European Union (EU). The viral strains contained in Optaflu will have to be replaced again, before the vaccine can be used in subsequent seasons.

The viruses used in Optaflu are grown in mammalian cells, unlike those found in other flu vaccines, which are grown in chicken eggs.

How has Optaflu been studied?

The effects of Optaflu were first tested in experimental models before being studied in humans.

The efficacy of Optaflu was initially assessed using a vaccine composition that included the viral strains that were expected to cause influenza in the 2004/2005 season. The efficacy of the vaccine was evaluated in a main study involving 2, 654 adult patients, half of whom were elderly (people over 60 years of age). The effects of Optaflu were compared with those of a similar influenza vaccine produced in eggs. The study compared the ability of the two vaccines to trigger the production of antibodies (immunogenicity), comparing antibody levels before injection and after three weeks. The immunogenicity of the current vaccine formulation has been confirmed in 135 adults, about half of whom are elderly.

What benefit has Optaflu shown during the studies?

In the main initial study, both Optaflu and the comparator vaccine reported adequate antibody levels for protection against all three influenza strains, as set out in the criteria set by the Committee for Medicinal Products for Human Use (CHMP) for influenza vaccines produced from cell cultures. The two vaccines showed similar results in stimulating the production of antibodies in adult patients both below and above 60 years of age.

The current composition of Optaflu, for the 2007/2008 season, has registered antibody responses against the three influenza strains included in the vaccine similar to those observed in the main study.

What is the risk associated with Optaflu?

The most common side effects with Optaflu (seen in more than 1 patient in 10) are headache, erythema (redness of the skin), pain, malaise and fatigue. These reactions normally disappear within one to two days without treatment. For the full list of all side effects reported with Optaflu, see the Package Leaflet.

Optaflu should not be used in people who may be hypersensitive (allergic) to the active substances or to any of the other substances. People with fever or an acute infection (of short duration) cannot receive the vaccine until complete recovery.

Why has Optaflu been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Optaflu's benefits are greater than its risks for prophylaxis of influenza in adults, particularly in those at greater risk of developing associated complications. The Committee therefore recommended that Optaflu be given marketing authorization.