ROCKVILLE, MD. (FRONTLINE MEDICAL NEWS) – A committee of Food and Drug Administration advisers backed the World Health Organization’s influenza vaccine recommendations for the 2017-2018 season at a meeting March 9.

In a unanimous vote, members of the Vaccines and Related Biological Products Advisory Committee recommended that trivalent vaccines for the 2017-2018 season should contain the following vaccine strains: A/Michigan/45/2015(H1N1)pdm09-like, A/Hong Kong/4801/2014(H3N2)-like, and B/Brisbane/60/2008-like.

Quadrivalent vaccine should add the B/Yamagata lineage B/Phuket/3073/2013-like virus, the committee recommended.

These recommendations echo those from the 2016-2017 season, with the exception of a slight update to the H1N1 strain, which had previously been A/California/7/2009(H1N1)pdm09-like virus.

Regarding vaccine efficacy, the cell propagated A/Hong Kong strain was the strongest candidate, covering 93% of A(H3N2) viruses seen in the 2016-2017 season, according to Jacqueline Katz, PhD, director of the WHO Collaborating Center for Surveillance, Epidemiology and Control of Influenza at the Centers for Disease Control and Prevention. In comparison, the egg propagated version of the A/Hong Kong virus covered 59%.

For the influenza B virus, the Yamagata lineage and Victoria lineage strain cycled monthly as the predominant strain in the 2016-2017 season, with a split of “around 50/50,” leaning toward Yamagata in North America, Europe, and Oceana, Dr. Katz explained. The Victoria lineage, in some cases, accounted for nearly 75% of B viruses in Africa and South America.

Committee members expressed concern over the difference between strain prevalence in the United States and abroad and considered recommending a strain that did not coincide with the WHO recommendation, something that has not happened in the history of the advisory committee.

“I’m very aware of influenza vaccinations being a global enterprise, and companies manufacture vaccines for use in multiple countries,” said Committee Chair Kathryn Edwards, MD, professor of pediatrics at Vanderbilt University, Nashville, Tenn. “If we to select a B strain that differed from the WHO recommendation, would that adversely impact vaccine production for the U.S. market?”

Despite these questions, the committee continued to back the WHO recommendations.

Historically, the advisory committee has recommended flu vaccine strains earlier in the year, according to Beverly Taylor, PhD, head of influenza scientific affairs and pandemic readiness at Seqirus Vaccines. Dr. Taylor presented the vaccine manufacturers’ perspective. The delay has put added pressure on manufacturers.

“We haven’t seen impacts yet on start of vaccination dates,” said Dr. Taylor. “But the very clear message from manufacturers is if you keep squashing that manufacturing window, then there will reach a point where we are concerned we will see an impact on vaccine supply time.”

None of the committee members presented waivers of conflict of interest. While the FDA is not obligated to follow the recommendations of the advisory committee, it generally does.

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