AstraZeneca’s intranasal FluMist vaccine should not be used during the forthcoming influenza season as it performs poorly compared to injectables, according to the US government.
FluMist is the only alternative to injectable vaccines on the market but according to the Centers for Disease Control and Prevention (CDC) should not be used during the 2016-2017 flu season “based on data showing poor or relatively lower effectiveness” compared to other vaccines over the last three years.
The ruling jeopardises a sizeable chunk of FluMist sales, which were $288m worldwide last year. The US accounted for $206m of that total, with $76m coming from Europe. AZ stressed that ex-US shipments are not affected by the decision and are proceeding as normal.
According to the CDC’s Advisory Committee on Immunization Practices (ACIP), preliminary data on the effectiveness of FluMist among children 2 years through 17 years during 2015-2016 season was just 3% (ranging from 49% to 37%) – meaning no protective benefit could be measured.
The figures also follow “two previous seasons … showing poor and/or lower than expected vaccine effectiveness” for AZ’s product, it adds.
The company takes issue with the CDC data, however, saying its figures for the 2015-2016 season “contrast with studies by AZ as well as preliminary independent findings by public health authorities in other countries … which demonstrate FluMist was 46-58% effective overall against the circulating influenza strains”.
The CDC estimates that overall efficacy for vaccines with a good match to the prevailing strains of influenza are typically in the 50-60% range, according to AZ, which added that it is ” working with the CDC to better understand its data to help ensure eligible patients continue to receive the vaccine in future seasons in the US”.
What is unclear at present is whether the removal of FluMist from the portfolio of vaccines that can be used in the US will lead to any shortages in the coming flu season.
The CDC suggests that AZ’s product accounted for 8% of the total projected supply and up to a third of vaccines given to children. It acknowledges that the ACIP’s decision could have implications for providers who have already placed orders for vaccine stocks, particularly paediatric practices.