No link between acellular pertussis vaccine and food allergy

By Rob Goodier

NEW YORK (Reuters Health) - A study of nearly 700 UK children found no difference in the rate of children's food allergies whether they were injected with whole-cell or acellular pertussis vaccines.

The study follows observations of an uptick in food allergies at the time that Europe, the U.S. and Australia switched from whole cell to acellular versions of the vaccine.

"The question is whether different vaccines interact with the immune system to cause a slight tendency towards atopic disease/allergy. We did not find any data to suggest this, although it is important to note our study was small and therefore not well-powered to detect anything other than a very big effect," Dr. Paul Turner, a pediatrician and clinical lecturer at the Imperial College London, who led the study, told Reuters Health by email.

Dr. Turner and his team presented findings from their research March 5 at the annual meeting of the American Academy of Allergy, Asthma and Immunology in Los Angeles, California.

The researchers looked at 696 children who received their pertussis vaccinations in 2001 and 2002 at the time that the UK was making the switch to the acellular vaccine.

The children received their first vaccination before the age of 18 weeks, and, if administered, their second and third doses before 12 months of age.

Of the 356 children who received only whole-cell vaccines, 2.2% developed food allergies by age 10. By comparison, 340 children received at least one dose of the acellular vaccine and 2.9% developed food allergies (p=0.64).

"The study did not find a link between type of vaccine and food allergy, so that is not a concern," said Dr. Jay Portnoy, Director of the Division of Allergy, Asthma and Immunology at Children's Mercy Hospitals and Clinics in Kansas City, Missouri, who was not involved in the research.

Dr. Turner's post-hoc analysis examined the third of three birth cohorts, the one that happened to occur at the time of the vaccine switch. Peanut allergy increased from the first cohort to the second, but the increase did not coincide with the switch to the acellular vaccine, Dr. Turner said.

So, what might have caused the increase in food allergies?

"There are so many influences on the immune system - the most significant of which are environmental exposures to stimuli which interact with the immune system (such as other 'bugs' which influence our 'microbiome') as well as, for food allergy, the timing of dietary introduction of food allergens. It is very likely that no single factor is 'to blame,'" Dr. Turner said.

SOURCE: http://bit.ly/1LRZjUC

J Allergy Clin Immunol 2016.

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