Addendum. National Advisory Committee on Immunization (NACI) Statement on influenza vaccination for the 2007-2008 season.

The recommended dosage schedule and type of influenza vaccine are presented in Table 2. Influenza vaccines available in Canada are available as split-virus or inactivated subunit preparations. Two products (Vaxigrip, Fluviral S/F) are split-virus vaccines that are treated with an organic solvent to remove surface glycoproteins, producing a split virus resulting in reduced vaccine reactogenicity. Influvac is a surface antigen, trivalent, inactivated subunit vaccine, which is currently approved for use among persons ≥ 18 years of age. Each 0.5 mL dose of vaccine contains 15 μg of hemagglutinin of each antigen. Children < 9 years of age require two doses of influenza vaccine given 4 weeks apart if they have received one or no doses in the previous influenza season. Eligible children who are entering their third or more year of being vaccinated and who received only 1 dose in each of their first 2 years of being vaccinated, can receive a single annual dose. In other words, if a child has had a single dose of vaccine in any previous 2 or more years, whether consecutive or not, then only one dose is necessary subsequently.