Munoz also notes that all pediatric influenza vaccines recommended this year are quadrivalent. This has been an ongoing transition from trivalent formulations, she notes. As far as which strains the vaccine will cover, this year’s composition of the flu vaccines this year has been updated to include the influenza A (H1N1) pdm09 and A (H3N2) components. Coverage for B strains is unchanged from previous seasons, according to AAP.
According to ACIP, the 2019-20 quadrivalent flu vaccine will include protection against the A/Brisbane/02/2018 (H1N1) pdm09-like virus, an A/Kansas/14/2017 (H3N2)-like virus, a B/Colorado/06/2017–like virus (Victoria lineage), and a B/Phuket/3073/2013-like virus (Yamagata lineage). Additionally, the US Food and Drug Administration (FDA) expanded the age indication for the Afluria Quadrivalent vaccine this year. The vaccine was previously approved for use in children aged 5 and up, and now can be used in children aged 6 to 35 months. Children aged 6 to 25 months should receive the 0.25 mL dose, and children who are over 36 months of age should receive the 0.5 mL dose, according to ACIP. Pediatricians will have to watch which vaccine they are using, as there are several variations now for children aged 6 to 35 months, Munoz notes.
“Make sure to look at the vaccine brand and formulation,” Munoz advises. “There are different options for babies aged 6 to 35 months.”
There are now 4 egg-based quadrivalent flu vaccines licensed for children aged 6 months and older, 1 inactivated cell-based quadrivalent vaccine for children aged 4 years and older, and 1 quadrivalent live attenuated vaccine for children aged 2 years and older. New formulas of vaccines with a volume of 0.5 mL have been approved for children aged 6 to 36 months depending on the vaccine formula used. Children aged 36 months and older should receive the 0.5 mL dose, according to the recommendations. The ACIP recommends that a 0.25 mL dose is indicated for Afluria Quadrivalent, 0.5 mL doses are indicated for Fluarix and FluLaval quadrivalents, and either a 0.25 mL or 0.5 mL dose can be used of Fluzone Quadrivalent. The dose for the intranasal vaccine, FluMist, is 0.2 mL, or 0.1 mL in each nostril.
Which vaccine is chosen may also depend on supplies, with some manufacturer’s anticipating shipping delays due to the timing of the World Health Organization’s decision on which flu strains to include in this year’s vaccine.
As for timing, AAP recommends that children aged 6 months to 8 years who are receiving the flu vaccine for the first time, or who received only 1 dose prior to July 2019, be vaccinated with 2 doses of the vaccine by the end of October. Children who need only 1 dose, regardless of age, should also be vaccinated by the end of October, AAP states, reflecting the recommendation from ACIP.
There is also a new antiviral treatment available to pediatric patients, according to AAP. Baloxavir marboxil was licensed in 2018 for early treatment of influenza in patients aged older than 12 years who have been sick for less than 2 days. The new medication requires only a single dose, notes AAP, adding that clinical trials of the drug are still ongoing in hospitalized patients. The AAP recommends that any children hospitalized with suspected or confirmed influenza be treated with some form of antiviral medication approved for their age group, regardless of the duration of symptoms.