Effectiveness of influenza vaccine for the prevention of asthma exacerbations. Christy C, Aligne CA, Auinger P, Pulcino T, and Weitzman M. Archives of Disease in Childhood 2004; 89:734-735.
Do asthmatic children vaccinated against influenza experience fewer asthma exacerbations?
This retrospective study selected—from a total population of 1400 asthmatic children—400 children between 1 and 19 years of age who received the influenza vaccine, and 400 who did not.
The researchers compared the two groups with respect to clinic visits, emergency department (ED) visits, and hospitalizations for asthma or pneumonia during the next year.
Compared to children who received influenza vaccine, children who did not receive the vaccine were more likely to be black and less likely to be Hispanic and also to have not received the vaccine previously.
Those that received the vaccine were more likely to have clinic visits for asthma or pneumonia than those who did not receive it. These children were also more likely to have had asthma related ED visits and hospitalizations.
The outcomes of this study found no evidence that influenza vaccination reduced the total number of asthma exacerbations or pneumonia in the following year.
This study is difficult to interpret because of biases in case and control selection. A carefully controlled prospective study with well-defined endpoints would be more helpful.