A study in Great Britain has revealed that children given the H1N1 vaccine containing an adjuvant (booster) had stronger immune responses than those who received unadjuvanted shots.

The adjuvanted vaccine used most often was GlaxoSmithKline’s Pandemrix; Baxter’s Celvapan was reserved for those allergic to eggs.

The United States did not give H1N1shots with a booster to children; Dr. Matthew Snape of the Oxford Vaccine Group believes this current study will encourage the United States regarding the efficacy of the adjuvant.

An adjuvant is added to a vaccine in an effort to increase the body’s immune response to the vaccine itself.

The results of the efficacy of the vaccine was especially encouraging in children under 3, who, according to Dr. Snape, have traditionally not responded as well to flu vaccines, even though they are among the most vulnerable to influenza. 

For those three and under, the immune response to Pandemrix was 98.2%, while the response to Celvapan was 80.1% (Reuters).  Although reactions to the Pandemrix were more prevalent ,, they were relatively minor and consisted of site irritation and fevers.

Typically, unadjuvanted flu shots last for one year, according to WebMd.  Those given with a booster will probably last longer, and will “adjust” to variations of the H1N1.  This is especially encouraging since researchers believe that the H1N1 virus will be the most dominant during the next flu season, although it may shift somewhat (Reuters).