Influenza Vaccine 2019 Update – the Return of a Reformulated Live-Attenuated Vaccine

Frank Bell, MD, FAAP
Swedish Pediatric Infectious Disease, Seattle
Swedish Pediatrics Representative, Washington Chapter of the American Academy of Pediatrics

‘Tis the season! – the influenza vaccine season that is. Now well into November, it’s time for some urgency in reminding our yet-to-be-vaccinated patients that influenza season is around the corner, and for those who were waiting until the last minute (perhaps thinking to maximize vaccine efficacy) it is now time to get the vaccine.  Our 2019 record year for measles in Washington State reminds us that the vaccine needs to get out of the vial and into the patient in order to be effective.

There is much about the influenza season that is unpredictable, but two things we know are that influenza will arrive before the winter is out and that it will be unpleasant for many, hospitalizing for some and deadly for others.  The last two winter seasons have been long (with 2018-2019 the longest of the last decade) and severe (high rates of pediatric admissions & deaths in 2017-2018). In fact, there were 302 pediatric deaths over the two seasons, including deaths within our state.  Last year, as is typically the case, close to one-half of pediatric deaths were in children felt to be previously healthy.

For the 2019-2020 season we have several pediatric influenza vaccines at our disposal.  All are Quadrivalent.

  • Four “traditional” inactivated influenza vaccines (IIV), produced using conventional techniques from embryonated chicken eggs
  • A cell-culture-based inactivated influenza vaccine (also an IIV), licensed for children ≥ age 4 yrs
  • A reformulated live-attenuated vaccine (LAIV), i.e. a return of the cold-adapted strain, capable of replicating in the nose but incapable of producing influenza-like illness

The much-anticipated return of the intranasal vaccine is welcome news for our pediatric patients following three consecutive seasons when the live attenuated vaccine was not recommended (or available) in the US given uncertainty about efficacy against previously-circulating H1N1 strains.  The return of confidence and decision to again recommend use of a live attenuated (LAIV) vaccine likely reflects a pragmatic decision by the AAP, CDC & Advisory Committee on Immunization Practices (ACIP) to learn more about the reformulated nasal vaccine and to obtain contemporary data on efficacy.  Unfortunately manufacturing constraints have meant that availability has been limited for many this season.  Such limitations notwithstanding, I am glad to have LAIV back in our armamentarium again.

AAP Resources for Influenza for the 2019-2020 Season

Recommendations for Prevention and Control of Influenza in Children, 2019-‘20

AAP news ‘Updated AAP flu policy offers more options this year’