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Thursday, August 13, 2015

Flu shots: Who needs them and which type is best?

Flu vaccines are recommended every season for just about everyone over the age of 6 months. There are specifics to age group and risk factors that help determine if they need an injectable vaccine or if they can get the nasal vaccine.

For as common as the flu vaccine is, there is often confusion about who needs what for many reasons:

  • it changes yearly 
  • recommendations vary by age and history of flu vaccine or not
  • there are options for nose sprays and shots. The nose spray (FluMist) and the injectable vaccine (many brands available for different age groups and our office uses Fluzone quadrivalent) both have the same strains as the other each year but they differ in that the spray is a live virus that has been changed so it doesn't cause all the symptoms as the natural virus but still gives the body memory fighter cells (antibodies). The injectable vaccine is an inactivated virus (not live virus) vaccine. It is safer for people with decreased immune function, such as infants and young children or those with compromised immune systems from disease or chemotherapy.
  • there is concern that it might be of little value (this is a whole blog in itself and won't be discussed here) 



If you really want to get to the details, this year's trivalent (3 strain) influenza vaccines will contain: 
  • hemagglutinin (HA) derived from an A/California/7/2009 (H1N1)-like virus

  • A/Switzerland/9715293/2013 (H3N2)-like virus

  • B/Phuket/3073/2013-like (Yamagata lineage) virus

Quadrivalent (4 strain) influenza vaccines will contain these vaccine viruses, and a B/Brisbane/60/2008-like (Victoria lineage) virus, which is the same Victoria lineage virus recommended for quadrivalent formulations in 2013–14 and 2014–15
All FluMist last year and this year are quadrivalent. Injectable vaccines vary by manufacturer and the one we will offer is a quadrivalent type.


Last year there was concern that the FluMist didn't work as well as the injectable. In previous years the mist was considered to work better than the shot. We do not have data on the efficacy of the vaccines this year, so I encourage you to pick the one that best suits the needs of your child because any vaccine is better than no vaccine at all, even if the effectiveness isn't 100% (which it will never be).

Here's a breakdown of what is needed by age group to help decide what your child will need. For people with egg allergies, see the bottom of this page. (Quick note: this year there is a delay of shipment of the FluMist again. The flu shot will be available sooner than the mist, and any child over 6 months can do the shot. It is never wrong to give the shot to ensure protection especially if you're in an area that the flu season is starting. The flu season is generally October to May, with peak activity December to February.)


Six months - 2 years


This age group should get the injectable flu vaccine and cannot get the nasal FluMist.

For children under 9 years of age who have not had two flu vaccines, they will need two doses of the same strain. Think of it as the first dose is a primer dose, getting the body primed to make continued antibodies. The second dose boosts that primer. Each season we need a booster to get the antibodies for the strain of virus that is anticipated that year. Talk to your doctor to see if your child will need one or two doses. Each dose must be at least 28 days apart, but can be separated by many months and count as long as they are the same strains of virus. In recent years the same virus strains were in two different seasons, so it even counted if one was given one season and the other the following year. That doesn't often happen and usually two vaccines in the same season must be given. The strains are different this year from last, so if your baby got only one dose last season, he will need two this season.


2 - 4 years


This group can get the FluMist if they have not had wheezing. The reason for this is the nasal vaccine is a live virus and could trigger wheezing in a susceptible child. The injectable vaccine does not carry this risk. If they have had wheezing or if they just have an aversion to things in their nose they can do the injectable vaccine.

These children are still in the age group that might require two doses, see the 6 months - 2 years section for more information on that.

5 - 9 years

This age group is eligible for either the injectable or nasal vaccine. If they have wheezing in the past 12 months you will need to discuss with your doctor or nurse if they should get the nasal FluMist. Since the FluMist is a live virus, it is possible that it can trigger wheezing. My personal recommendation is if the child prefers the nasal spray over the shot and the parent is able to handle any wheezing that might happen, the nasal vaccine is okay. If the child tends to have severe wheezing that is difficult to control or needs oral steroids often, it is not recommended to risk the mist. Most children do not report wheezing after the FluMist, but it is always a possibility.  

Children under 9 years of age who have not had two flu vaccines of the same strain (generally in the same season) will need two doses for full protection. See the 6 months - 2 years section for more information.

10+ years

This age group is also eligible for either the injectable or nasal vaccine. If they have asthma or recent wheezing, you will need to discuss with your doctor or nurse if they should get the nasal FluMist. Since the FluMist is a live virus, it is possible that it can trigger wheezing. My recommendation is usually if the child or teen prefers the nasal spray over the shot and the parent (or older child) is able to handle any wheezing that might happen, the nasal vaccine is okay. If there is a history of severe wheezing I do not recommend the mist. Most people do not report wheezing after the FluMist, but it is always a possibility.  

Only one dose of vaccine is required at this age, regardless of immunization history.

If you're more of a visual person, the following is from the CDC:


For those with egg allergies,  this is helpful guidance from the CDC. People with egg allergy may tolerate egg in baked products but that does not eliminate the risk of vaccine reaction. If children have never eaten egg but previously performed allergy testing shows probable egg allergy talk to your doctor before vaccination.