ACIP Recommends Changes to Influenza Vaccine For Coming Season

At their June meeting, members of the Advisory Committee on Immunization Practices (ACIP) recommended changes to the influenza vaccine for the coming season. 

Lisa Grohskopf, MD, of the CDC Influenza Division led the panel through the proposed recommendations.

The panel recommended including A/Switzerland/9715293/2013 (H3N2)-like virus in place of A/Texas/50/2012 and B/Phuket/3073/2013-like (Yamagata lineage) virus in place of B/Massachusetts/2/2012 for the 2015-2016 seasonal influenza vaccine. The vaccine will also include an A/California/7/2009 (H1N1)pdm09-like virus. Quadrivalent vaccines will contain these three strains plus a B/Brisbane/60/2008-like virus (Victoria lineage).

The panel also revised their recommendations regarding LAIV for healthy children aged 2 to 8 years, stating instead that “no preference is expressed for LAIV or IIV for any person aged 2 through 49 years for whom either vaccine is appropriate.”

Tom Shimabukuro, MD, from the CDC’s Immunization Safety Office, provided an update on vaccine safety. Overall, there were no new concerns detected in VAERS surveillance. Children aged 6 to 23 months showed an increased relative risk for seizures following IIV3 and IIV4, a finding similar to previous seasons.

The panel delayed a vote on the H5N1 vaccine after a discussion led by Sonja Olsen, PhD, from the CDC. Olsen provided an overview of disease epidemiology and results of cross reactivity for the H5N1 vaccine.

From November 2003 through May 2015, the WHO has documented 850 cases of H5N1 in humans across 16 countries, with 413 deaths. 

In 2015, only three countries have reported cases of H5N1 in humans: China, Egypt, and Indonesia. In Egypt specifically, there has been a spike in cases, though this has been declining in recent weeks. Olsen said that this upsurge was likely due to an increase in the number of people exposed to infected poultry rather than any changes in the virus.

In the United States, experts have identified three different viruses in wild birds: H5N1 (a new reassortant), H5N8, and H5N2. 

The Q-Pan H5N1 vaccine was tested for cross reactivity against these strains. According to Olsen, the vaccine “offered some level of cross neutralization titers to a panel of H5N1 viruses from various clades, including newly emerging strains.” 

However, the vaccine did not have the same efficacy for other strains – it elicited no neutralizing antibodies for H5N8 and H5N2.

Olsen said she believes this lack of cross reactivity is due to the strains being evolutionarily distant.

The ACIP delayed a vote on the H5N1 influenza vaccine at this meeting, but officials said they will likely vote on recommendations for H5N1 vaccine use at a later date. In the meantime, officials with the CDC and WHO continue to monitor viral trends.