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Flu vaccine shot more effective than nasal sprays
by Camilla Abad - September 24, 2009 - comments
An injectable flu vaccine contains inactivated flu virus, while a nasal spray flu vaccine contains a live and weaker strain of the virus
Los Angeles, September 24 -- Getting flu vaccine injections is more effective than nasal spray vaccines in preventing seasonal flu in adults, a recent study finds.
In a study published in the New England Journal of Medicine this week, flu shots were found to offer twice as much protection than inhalable sprays in healthy adults.
Arnold Monto, an epidemiologist who conducted the research stated, "Based on our results, I would prefer getting a shot.”
Fluzone, FluMist and a placebo
Monto and his colleagues from the University of Michigan School of Public Health conducted the study in 1,952 healthy volunteers aged 18 to 49. They observed the effect of Fluzone, an injectable vaccine from Sanofi Pasteur SA, and FluMist, a nasal spray vaccine from MedImmune Inc., during the 2007 to 2008 flu season.
The volunteers were divided into three groups; one received Fluzone, another received FluMist and the third group received a placebo. They were all subjected to the same flu exposure.
Results showed that out of the 813 volunteers who received Fluzone, 28 or 3.4 percent developed influenza while out of the 814 volunteer who received FluMist, 56 or 6.9 percent developed influenza. From the group who received the placebo vaccine, 10.8 percent developed influenza.
Exact reason for the difference in vaccines' effect unclear
The results showed that an injectable flu vaccine provides double the protection of a nasal spray vaccine, however, the exact reason why this is so remains unclear. A possible reason may be the kind of virus the vaccines deliver into the body. An injectable flu vaccine contains inactivated flu virus while a nasal spray flu vaccine contains a live and weaker strain of the virus.
The nasal spray was primarily targeted to be used in children but it has been getting more and more popular in adults.
The study findings not relevant for swine flu
Regarding the vaccine against the H1N1 virus, Dr. Jay Butler from the Centers for Disease Control and Prevention revealed that this study may not necessarily hold true for it.
Health officials are also expecting that the first release of the H1N1 flu vaccine would be in the form of a nasal spray. It is, however, only approved for individuals aged 2 to 49.