A commentary published this week in one of the world’s premier journals on vaccination raises concerns about the CDC’s recommendation against using the popular “FluMist” vaccine during the 2016 – 2017 flu season.
FluMist, a live attenuated influenza vaccine (LAIV), is a popular option for children because of how it is given: as a nasal spray administered by a health professional or trained volunteer, rather than as a “shot” or injection.
“When FluMist works, it stops infection,” said Parker A. Small, M.D., professor emeritus at the UF College of Medicine and a member of the Emerging Pathogens Institute. “By stopping infection,” he added, “it stops the spread of disease.”
Small is one of the authors of the commentary and a founder of the Alachua County School-Located Influenza Vaccination program, which purchased and administered FluMist. He has since retired from his administrative position and did not play a role in the program’s vaccination efforts in preparation for the 2016 – 2017 flu season.
In the article the authors suggests that FluMist has broad public appeal since it is not a shot and some studies have found inducing immunity through respiratory mucus secretions stops the virus from infecting the body. This is in contrast to flu shots, which, even if effective, do not stop infection – and subsequent transmission – despite significantly reducing the duration and severity of illness.
The article, titled “The Advisory Committee on Immunization Practices’ controversial recommendation against the use of live attenuated influenza vaccine is based on a biased study design that ignores secondary protection,” proposes that when FluMist is effective, it serves an epidemiological function, not only preventing infection but also the spread of disease within a community.
The article calls into question the CDC’s findings regarding FluMist’s effectiveness against the 2009 H1N1 strain of influenza. H1N1 is a type of influenza A, and these findings, which suggest that FluMist was ineffective against H1N1 during the 2015 – 2016 flu season, served as support for the decision to cease recommending its use, even though in many earlier seasons the vaccine was effective against H1N1 as well as other strains of the flu.
Additionally, two studies that did not use the CDC’s study design found that LAIV provided ample protection against influenza infection. The studies, conducted in Finland and the United Kingdom, found that LAIV provided protection against influenza A and influenza B strains of the virus.
Small advocates using an alternate study design in order to assess FluMist’s benefit to communities and its effect on the transmission of the virus. He suggested that FluMist would have provided additional protection against the flu this year.
“The decision to stop using FluMist was particularly unfortunate because it would have been effective against H3N2, which is causing disease this year,” he said. H3N2 is another influenza A strain, and it appears to be responsible for flu cases in the current 2016-2017 flu season.
While flu shots also provide protection against disease, their coverage rates are less than those gained with FluMist. Alachua County, Florida, has administered FluMist vaccine in schools as part of their Control Flu program, with the vaccine available to all students who do not have contraindications to vaccine. Because of the CDC recommendation, the school program in Alachua Country switched from FluMist to flu shots for the 2016-2017 flu season.
According to Kathleen Ryan, M.D., a clinical associate professor in the University of Florida College of Medicine’s department of pediatrics and the medical coordinator for Alachua County’s Control Flu program, there has been a 41 percent drop in vaccination rates at Alachua County public schools since switching from FluMist to flu shots. The drop was even more dramatic among elementary school children, who are among those most vulnerable to infection.
Small Jr. PA, Cronin BJ. The Advisory Committee on Immunization Practices’ controversial recommendation against the use of live attenuated influenza vaccine is based on a biased study design that ignores secondary protection. Vaccine (2017), http://dx.doi.org/10.1016/j.vaccine.2017.01.022