Study shows advantage of adjuvanted split-virus H1N1 vaccine

A study published in The Lancet last week revealed that an adjuvanted split-virus pandemic influenza A H1N1 vaccine provided a stronger and more rapid immune response against the disease than a whole-virion vaccine.

Karl G. Nicholson of the University of Leicester in the United Kingdom and his colleagues conducted a parallel-ground, observer-blind, controlled trial, giving two doses of either whole-virion or split-virion vaccine to 347 health adults, HealthDay News reports.

They found that the adjuvanted vaccine had a much higher immune response and higher seroconversion rates that lasted up to six months after the vaccination. Also, the adjuvanted vaccine had more rapid seroconversion in comparison to the whole-virion vaccine.

While the vaccines were both well tolerated with no serious complications, the adjuvanted vaccine was associated with more general symptoms like chills, malaise, muscle pain and headaches and more injection-site reactions.

“Despite having half the antigen content of the whole-virion vaccine, the AS03A-adjuvanted split-virion vaccine was more immunogenic than the whole-virion vaccine in all-age groups,” the authors wrote, according to Health Day News. “The adjuvanted vaccine induced early seroprotection in three-quarters of people in the 18 to 44 years group and more than half of adults of all ages within one week of the first dose. This rapid protection could be crucially important in populations such as at-risk groups, or when giving the vaccine coincides with escalating disease activity.”