FluMist, the only non-injectable flu vaccine, was not recommended for use in the United States this winter. Studies showed it offered limited protection the last few years. MedImmune, the company that makes the vaccine, is attempting efforts to fix the vaccine which could be an important component in a future flu pandemic.
The vaccine is sprayed in the nose. It contains live, but weakened, viruses to initiate infection to trigger the immune system to respond. The weakened viruses do not make those who receive it sick. FluMist is a quadrivalent vaccine, protecting against four types of flu viruses.
Problems began for FluMist in 2013 when a different H1N1 strain of influenza A emerged. The virus in the vaccine did not appear to work very well in the nasal mist vaccine. MedImmune has tried two other versions of H1N1 viruses in the vaccine, which also have poor results. They need to find a strain that works rather than find out what was wrong with the old combination.
Last June, the Advisory Committee on Immunization Practices recommended that FluMist not be used this season, denying the product access to the market. MedImmune believes they may have located the problem, but there are still questions about why the vaccine has been lacking effectiveness.
H1N1 is not a player in this flu season, but H3N2 (another strain of influenza A) has dominated. Until there is another flu season when H1N1 plays a big role, there won’t be a good way to test whether the replacement virus in the vaccine works or not. It could be several years before H1N1 dominates flu activity. There is a concern for how long a vaccine company can remain in business when it cannot market its product.
Branswell, Helen. “Nasal flu vaccine may not be recommended for use in US for years.” Health. STAT, 23 Feb 2017. Web. 26 Feb 2017.