Quadrivalent Influenza Vaccine Reported 51% Effective for Children

Sanofi Vaxigrip Tetra safely protected children aged 6–35 months against various influenza illness

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A new flu vaccine study reported 2 doses of an inactivated quadrivalent influenza vaccine (IIV4) was effective in young children, even against mismatched strains. 

According to this study of 4,980 healthy children between the ages 6 to 35 months, in both hemispheres, over 4 years, who had not previously been vaccinated against flu, received 2 full doses of Vaxigrip Tetra 28 days apart, a placebo, or an investigational trivalent inactivated vaccine. 

This study reported the flu vaccine’s efficacy analysis against any influenza A or B strain was 50.98 percent and was 68.4 percent against vaccine-similar strains.

This efficacy rate is superior to the last 4 years of flu vaccine data reported by the Centers for Disease Control and Prevention. 

The level of efficacy observed here is similar to that reported for another full-dose inactivated quadrivalent influenza vaccine in this same age group.   

Together, this study’s results provide ‘convincing evidence that inactivated quadrivalent influenza vaccines are effective at preventing influenza in children aged 6–35 months.’ said these researchers. 

And, ‘as IIV4 gradually replaces IIV3 globally, it may help further reduce influenza-associated morbidity and mortality in young children.’ 

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The study was, however, limited by the vaccine strains that circulated during the 4 flu seasons, which included, influenza A(H3N2) and B/Yamagata strains dominated. 

Thus, efficacy could be demonstrated against the A/H1N1, A/H3N2, and B/Yamagata strains but not against the B/Victoria strain. 

The efficacy of IIV4 against the B/Victoria strain will have to be established in further studies. 

The study was funded by Sanofi Pasteur, which produces Vaxigrip Tetra.

Various business relationships were disclosed by these researchers.

Medical writing was provided by Dr. Phillip Leventhal and paid for by Sanofi Pasteur. Employees of Sanofi Pasteur participated in conceiving and designing the study, drafting and editing the article, deciding to submit the article for publication, and approving the final, submitted version.