"The nasal spray version of the flu vaccine did not protect young children against swine flu last year and might not this year"/AP

From the Associated Press:

The nasal spray version of the flu vaccine did not protect young children against swine flu last winter and might not work again this year, health officials said Thursday.

Preliminary results from three studies found that AstraZeneca's FluMist had little or no effect in children against swine flu. That was the most common bug making people sick last winter

Because this year's version of FluMist is the same, the Centers for Disease Control and Prevention said it's possible the spray vaccine won't work for swine flu this season, either. 

But officials say the spray is still OK to use... [OTOH] Vanderbilt University's Dr. William Schaffner, said pediatricians might want to opt for flu shots for their young patients "just to be on the safe side." 

What did I just hear from CDC and Dr. Schaffner?   CDC said it was okay to go ahead and give children a flu vaccine that is unlikely to provide them benefit against what was the most common flu virus last winter.  Dr. Schaffner implied parents might want to switch to a vaccine that would work better, but it wasn't a big deal.  

What this means is that neither CDC nor Dr. Schaffner think that whether kids receive a vaccine that works against last year's most common, and once-dreaded form of Influenza A, the "swine flu" variety, or get one that is ineffective, matters little.  They are admitting that, despite extensive warnings and advertising to the contrary, influenza is not that big a deal in children.  

More babies die from diarrhea (300/year in the US) than from influenza (about 100 children/year under 18). Gastroenteritis causes ten times as many hospitalizations in kids as influenza. but CDC does not have a large staff dedicated to it. OTOH, yearly flu shots (recommended for every American over 6 months old) are worth billions, each year.

Why the nasal spray didn't seem to work last year is a mystery: it has strong track record. The company said inadequate refrigeration of some doses shipped last summer could be an explanation... "Everyone was sitting around, scratching their heads" at the puzzling results, said Schaffner, who attended the meeting and helped review the research for the panel. 

The panel did not vote to change any of its guidance, but there was a consensus more investigation is needed quickly... 

The good news is that according to CDC, flu season has not started yet, despite some media hype:

Although the vaccine failed to protect children against last year's most common flu strain, there was no significant increase in child deaths from influenza. This begs the question: how well does the vaccine work in children when it works?

Most concerning is the fact there is no understanding of this vaccine failure. Presumably there was a manufacturing defect. But if so, why wasn't it remedied for this year? From CDC, there are no answers: 

CDC is in discussions with the manufacturer of LAIV [live, attenuated influenza vaccine], the Department of Defense, the Food and Drug Administration, and other partners to better understand the data from last season, and to determine causes and ways to address the low VE [vaccine efficacy] of LAIV against H1N1. For the current season, the U.S. Flu VE Network has expanded enrollment of children and will continue ongoing studies of serologic outcomes after vaccination in children getting IIV and LAIV. This additional data collected during 2014-2015 will help inform discussion about this matter further.