Responses to live attenuated flu vaccine in children who received Pandemrix

  • Höschler K & al.
  • Vaccine
  • 18 Apr 2018

  • from Dawn O'Shea
  • Vaccination News
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Early influenza vaccination with a powerful adjuvant maintains functional immunity for several years, preventing natural infection, according to research carried out by Public Health England (PHE).

Published in Vaccine, the phase III/IV open-label study examined the effect of a single dose of live attenuated influenza vaccine (LAIV) (Fluenz) in children naïve to or in previous receipt of AS03B-adjuvanted A/H1N1pdm09 influenza vaccine (Pandemrix), to investigate whether early exposure to an adjuvanted subunit influenza vaccine impacts on subsequent response to quadrivalent LAIV (qLAIV). A total of 256 participants aged 5-10  years were recruited to the study from October 2014 to February 2015.

On analysis, four-fold titre increases by Haemagglutination Inhibition (HAI) were observed for 39 per cent and 43 per cent of subjects for the two influenza B vaccine strains and 8 per cent for the A/H3N2 strain. There were no significant differences in antibody titres pre- or post-vaccination or in seroconversion rates between the Pandemrix-naïve and previously vaccinated groups. In both groups, the response to the qLAIV A/H1N1pdm09 component was barely detectable.

Previous receipt of Pandemrix was associated with significantly higher levels of A/H1N1pdm09 neutralising antibody, but decreased neuraminidase antibody inhibition pre-vaccination. The differences were maintained post-vaccination.

The authors concluded that previous receipt of Pandemrix has a significant impact on the influenza immune status of children several years later. This suggests that early vaccination with a powerful adjuvant maintains functional immunity for several years, which prevents natural infection, they say.