Vaccination is still key to preventing flu

The American Academy of Pediatrics (AAP) Committee on Infectious Diseases has released a policy statement of updated recommendations for influenza prevention, reiterating once again the importance of vaccination.

“First and foremost we always emphasize that vaccination is the best preventive measure we have against influenza,” says Henry H. Bernstein, DO, MHCM, FAAP, one of the contributors to this year’s recommendation report.

There aren’t any drastic changes to this year’s recommendation overall, but Bernstein says pediatricians should note that the intranasal formulation of the vaccine still is not available to practitioners. The live attenuated influenza vaccine (LAIV) was administered intranasally and was a popular choice in the pediatric population, but it was shelved last year because of concerns about its efficacy.

Bernstein says he doesn’t see the intranasal vaccine making a comeback for this flu season. The vaccine manufacturer is currently researching why the LAIV was not as effective against H1N1 strains, he says, and hopefully they will find a solution.

The AAP’s recommendation also addresses administration to individuals with egg allergies. “The AAP suggests that we don’t even need to ask about egg allergies because we don’t need to invoke special precautions should they be egg allergic. That’s because the rate of anaphylaxis is no different or greater in an egg allergic child than in one without those allergies,” Bernstein says. “It doesn’t matter whether or not you’re allergic to eggs. Standard vaccination procedures should be in place.”

The Centers for Disease Control and Prevention (CDC) recommends that flu vaccination be done in a location where allergic reactions can be treated, but pediatricians are always equipped to handle these situations, Bernstein says. The exception for increased precautions is among patients who have had an allergic reaction specifically to the flu vaccine in the past. In those cases, special precautions are warranted, he notes.

This year’s formulations

Beyond these recommendations, the AAP policy statement details this year’s vaccine formulation, which is slightly different than last year. The 2016-2017 flu season was moderate with influenza A (H3N2) viruses being the predominant viruses circulating. Children and the elderly, as well as those with decreased immune systems, were most at risk of severe illness, and flu activity last year increased in mid-December with a peak in late February. The report points out that last year’s vaccine matched the circulating strains well.

For this year, both trivalent and quadrivalent inactivated influenza vaccines (IIVs) are available for use, and both formulations contain an A/Michigan/45/2015 (H1N1)pdm09-like virus, an A/HongKong/4801/2014 (H3N2)-like virus, and a B/ Brisbane/60/2008-like virus (B/ Victoria lineage). Quadrivalent vaccines also include the B/Phuket/3073/2013-like virus (B/Yamagata lineage). The influenza A (H1N1) virus is in both vaccine formulations, but is different than the strain featured in last year’s vaccine, according to the report.

The AAP also stresses that all children aged older than 6 months, caregivers, pregnant women, and healthcare providers should be vaccinated. The bulk of pediatric flu deaths-more than 80%-occur in unvaccinated children aged 6 months and older, according to the committee, and even in cases in which vaccinated children do get the flu, their illness is shorter and less severe. Pediatricians should offer and encourage the vaccine as soon as it’s available, with a goal of vaccination by late October, the report notes.

In terms of dosage, that depends on the child’s age at the time of the first dose and the child’s vaccine history. Children aged 6 months through 8 years need 2 doses if they have received fewer than 2 doses of any trivalent or quadrivalent vaccine before July 2017, but need only 1 dose if they have had 2 or more flu vaccines in the past. Children aged 9 years and older need only 1 dose of the vaccine, the committee says.

Other recommendations

Bernstein says the AAP also wants to emphasize the importance of using oral antiviral medications in treating cases of influenza, with the caveat that antiviral treatments for the flu are not a substitute for prevention through vaccination.

As far as contraindications for vaccination, the AAP notes that vaccination should not be withheld for minor illness with or without fever, especially for children with mild upper respiratory symptoms or allergic rhinitis. For children who are diagnosed with moderate to severe illness with fever, vaccination with IIV may be withheld until after resolution of the illness based on the judgment of the physician, the committee says.

Bernstein also addressed a recent study published in Vaccine that compares rates of miscarriage in women who did and did not receive flu vaccines. Some concern has been raised about spontaneous abortion in pregnant women receiving the flu shot as a result of the study, which used a small sample, but the CDC and its Advisory Committee on Immunization Practices (ACIP) have not recommended any changes to vaccination protocols as a result of the limited study. More study is under way, and Bernstein says the ACIP will address the study at its next meeting.