The Advisory Committee on Immunization Practices (ACIP) has voted to restore the recommendation it withdrew two years ago for the use of an intranasal flu vaccine. The recommendation reflects positive results from a U.S. study in children between their second and fourth birthdays.
AstraZeneca announced that ACIP, an advisory panel of the Centers for Disease Control and Prevention (CDC), has voted in favor of a renewed recommendation for the use of the company’s FluMist Quadrivalent (influenza vaccine live, intranasal) for the 2018–2019 season. Limited quantities of FluMist (which remained licensed but not ACIP-recommended) continue to be available in the U.S. for the current flu season.
For the 2016–2017 and 2017–2018 flu seasons, the ACIP had recommended that FluMist not be used due to concerns about its effectiveness against influenza A(H1N1)pdm09 viruses during the 2013–2014 and 2015–2016 influenza seasons. The ACIP reviewed data in June 2016 that showed no significant vaccine effectiveness among children 2 through 17 years of age for the vaccine for all influenza A and B viruses combined.
But AstraZeneca said a new study evaluating the shedding and antibody responses of the H1N1 strain in the live attenuated influenza vaccine (LAIV) demonstrated that the new 2017–2018 H1N1 LAIV post-pandemic strain (A/Slovenia) performed significantly better than the 2015–2016 H1N1 LAIV post-pandemic strain (A/Bolivia) that was previously associated with reduced effectiveness. The antibody response induced with the new H1N1 LAIV strain was comparable to earlier data seen with the highly effective H1N1 LAIV strain included in the vaccine before the 2009 influenza pandemic.
The study involved 200 U.S. children older than 2 but younger than 4 years of age. After the first dose of FluMist Quadrivalent, 23% of children vaccinated with the 2017–2018 H1N1 LAIV strain developed a fourfold antibody rise, compared to 5% with the 2015–2016 H1N1 LAIV strain. After the second dose, those results increased to 45% and 12%, respectively. The data also demonstrate that the new 2017–2018 H1N1 LAIV strain resulted in increased vaccine virus replication in vaccinated children.
“This study validates the improvements we’ve made to our strain selection process and confirms an improved H1N1 LAIV strain was included in the 2017–2018 formulation,” said Gregory Keenan, Vice President of U.S. Medical Affairs for AstraZeneca. The full results of the study will be presented at a forthcoming medical meeting.
FluMist will be available in the U.S. for the 2018–2019 influenza season, pending annual strain approval from the FDA. The vaccine has remained recommended for use and available in Canada and the European Union. It can be used in children, adolescents, and adults ages 2 through 49 years.