GlaxoSmithKline's ($GSK) Pandemrix swine flu vaccine produced a swifter, stronger immune response and was likely to offer better protection than one produced by rival Baxter ($BAX), according to a British study. The scientists were assessing the safety and immunogenicity of the vaccines, which were purchased by the U.K. government in 2009.
The randomized, observer-blind, parallel-group, controlled trial included healthy adults aged 18-44 years, 45-64 years and 65 years and older who received two doses of vaccine given 21 days apart. Pandemrix contains an adjuvant called AS03 and could protect most adults and young people with a single dose, but two doses might be required for older people, as Reuters notes .
Adjuvants are designed to boost the body's response to a vaccine and were widely used in Europe last year to deal with the H1N1 swine flu pandemic. But U.S. health officials stuck with the standard unadjuvanted formulation used in seasonal flu vaccines. Study leader Karl Nicholson said the H1N1 flu pandemic was a relatively mild strain, so the U.S. decision to avoid adjuvanted vaccines had not proved too risky. However, that may not be the case in future if more dangerous flu strains were involved, he cautioned.
Pandemrix is produced using chicken eggs and was selected as the standard H1N1 vaccine in Britain during the swine flu pandemic. Baxter's cell culture vaccine, Celvapan, was also used in Britain but was largely reserved for people with egg allergies, as Reuters notes.