Injected flu shots or nasal flu spray?  The short answer, like so many things in life: it depends.

Data out this week summarizing the effectiveness of influenza vaccination for children over the past few seasons. The study published online was a meta-analysis –meaning it was a study of previously published studies — looking for the aggregate effect. Researchers wanted to evaluate the effectiveness of the flu shot compared to the nasal flu mist in protecting children. This year, the American Academy of Pediatrics (AAP) has recommended injected flu shots over nasal flu mist (the CDC recommended both without preference) and this study sought to evaluate the data used in that recommendation and evaluate the track record for influenza vaccinations in recent years.

There’s bad news, so-so news, and I think good (great) news here.

Background: There are multiple kinds of flu (called strains). The flu vaccine typically has 3 or 4 of the strains thought to be the ones that will likely come to the US. The nasal flu mist always has all four. This year the flu vaccination was changed to include two new strains compared to the vaccine last year (one new Influenza A and one new Influenza B). And as below, the nasal flu mist vaccine was redesigned to provoke better protection in the lining of your nose and throat based on data that efficacy had been poor, specifically for children, in recent years.

The bad news: The data included in the analysis (covering over 17,000 children) found likely what you’ve heard…that in the past years (specifically 2013 until 2016) the nasal flu mist wasn’t very effective protecting children against infections for Influenza A. The data also found that the nasal flu mist was mildly superior in protecting children from Influenza B.

The so-so news: We don’t know yet about this year’s influenza vaccination efficacy so there’s nothing conclusive today in the news despite what you’re reading…but we have a hunch. Especially because England has been widely giving children nasal spray flu vaccine since 2012.

The good news: The flu vaccine protects against influenza infections which can be gnarly and even deadly. Also, researchers note in the discussion of the study (and in an accompanying commentary) that the nasal flu spray vaccine has been redesigned (laboratory data demonstrated “improved replicative fitness in the lab and increased shedding and antibody responses).” In addition, preliminary estimates from the flu season in the United Kingdom suggest good effectiveness. The new 2018-2019 nasal flu vaccine may show great promise for improved efficacy protecting against Influenza A. In addition, in the United Kingdom during the 2017-2018 flu season, they found the redesigned nasal vaccine proved much better against strains of Influenza A (90% vaccine effectiveness against H1N1 strain last season)!

Below is an annotation I made summarizing figure 2 in the study and summarizing my opinion (feel good about either flu vaccination this year!)

BOTTOM LINE: Influenza infections are currently spreading all over the US. The influenza vaccine is an effective way (ahem: the best way, in fact) to protect your child from getting influenza. New data out of Europe where children were immunized with 2017-2018 redesigned nasal flu spray look very promising for great effectiveness for both Influenza A subtypes and Influenza B. England Public Health reports that last year, where they used updated nasal spray vaccine, the nasal spray was 90% effective against Influenza A (H1N1). This is very encouraging that the new nasal spray will work very well with children. But the data summarized in this week’s report (poor efficacy for Flu A with nasal) reflects why The AAP recommends shots over nasal this year. GET FLU SHOTS for everyone in your family. If you get a nasal flu spray (for those over age 2 who are healthy and without underlying medical problems) the hope is it will likely work very well protecting you and your child, as well, because of the redesign.


Annotation of data published online January 7, 2019