When reading an article that gives unqualified praise to “protective vaccinations” in the first sentence one cannot help but doubt the authors’ objectivity. The conclusion in the abstract—that no differences have been observed with regard to allergic disorders—also raises skepticism, since unvaccinated subjects in two of the three age groups under investigations tendentially showed fewer infections and atopic disorders than those who were vaccinated, and none of the unvaccinated children younger than 10 had developed asthma. The lack of statistical significance may be due to the low number of unvaccinated subjects included, which means that a credible statement about the risk of allergies is altogether impossible.

Another limitation of the article is the undifferentiated inclusion into the “vaccinated” group of all children who were vaccinated at some point in their lives. In order to determine adverse effects of vaccinations on the immune system it would seem that the timing of the vaccination is the crucial factor—which, in the past decades, has continually been brought forward. These days, entire conferences are dedicated to the negative effects of early vaccination on the immune system (1). A large-scale Canadian study found more than double the risk of asthma in 7-year-olds who were vaccinated in the 3^rd month of their lives compared with those who were vaccinated after the 5^th month (2).

A further limitation is the lack of differentiation by number and type of vaccinations. Measles and pertussis vaccinations affect the immune system in very different ways. The working group around Bernsen cited by Schmitz published a study in 2008 in which children vaccinated against pertussis were confirmed to have an increased risk of allergies when they finally did contract pertussis after all. Mascart described in details the long-term cytokine changes after pertussis vaccination in very young infants (3).