This article is more than 5 years old. Information may no longer be current.
Immune responses from adjuvanted pandemic flu vaccine persist into following season
Click Here to Manage Email Alerts
Either one full dose or two half doses of the trivalent inactivated 2009 H1N1 influenza vaccine, that included the AS03 adjuvant, elicited robust immune response levels that persisted above those considered to be protective for at least 6 to 18 months among otherwise healthy children aged 6 months and older, according to study findings.
“In this report, we present the results of two, phase IV studies conducted to assess the immunogenicity, reactogenicity and safety of [trivalent inactivated vaccine] containing the A(H1N1)pdm09 strain in children 6 months to 9 years of age and 10 to 17 years of age who had previously received two half doses or one full dose of [the vaccine],” Timo Vesikari, MD, PhD, of the University of Tampere Medical School in Finland, and colleagues wrote.
The researchers noted that they did not reach their recruitment target.
“As the target recruitment was not met, the post-vaccination GMT values are descriptive, and the immunogenicity data should be interpreted accordingly,” the researchers wrote.
For the study, Vesikari and colleagues aimed to assess the persistence and boostability of trivalent inactivated vaccine in 231 children previously vaccinated with AS03-adjuvanted A(H1N1)pdm09 vaccine. Children were randomly assigned in a 1:1 fashion to receive TIV or a control vaccine.
Hemagglutination-inhibition and neutralizing antibody responses against the strain were assessed before day zero, at day 28 and again at 6 months after study vaccination. Safety measures were assessed for 6 months and reactogenicity was assessed during the 7-day post-vaccination period.
The overall number of children with hemagglutination-inhibition titers ≥ 1:40 for the A(H1N1)pdm09 strain at day zero was more than 93.9%. This increased to 100% by day 28 and month 6 in the TIV group.
Further, the researchers found that hemagglutination-inhibition titers against A(H1N1)pdm09 were increased 9-fold in children aged between 6 months and 9 years and by 4-fold among children aged between 10 and 17 years.
The immunogenicity against other seasonal strains was not negatively affected by the AS03 adjuvant nor was safety compromised, according to the researchers.
“These findings support a prime-boost schedule using an adjuvanted influenza vaccine followed by non-adjuvanted influenza vaccine administered across two influenza seasons in children 6 months to 17 years of age,” the researchers wrote.
Disclosure: Vesikari reports receiving payment and travel expenses for advisory board memberships from GSK, Merck, Sanofi Pasteur MSD, and Pfizer. Please see the full study for a list of all other authors’ relevant financial disclosures.
Click Here to Manage Email Alerts