A dramatic rise in food allergies over the past 20 years had Australian medical professionals scratching their heads, with three in every ten babies born each year developing food-related allergy or eczema.
The reason had long remained a mystery, but Telethon Kids Institute researchers have now found a possible link between the increase in food allergies and the phasing out of older style versions of the whooping cough vaccine given to babies.
Professor Tom Snelling, vaccine researcher at the Wesfarmers Centre of Vaccines and Infectious Diseases, based at Telethon Kids, said Australian babies previously received the ‘whole-cell’ whooping cough vaccine, but this was replaced by the updated ‘acellular’ vaccine in the late 1990s.
“We noticed an increase in both the number of cases of food allergies and their severity after the whole-cell version was replaced – leading us to believe that the older style vaccine may have helped to protect kids against food allergies.”
“Allergies occur when the immune system reacts to everyday substances such as different types of food. By harmlessly mimicking infection, some vaccines such as the whole-cell whooping cough vaccine have the potential to help to train the immune system, and steer it away from developing allergic reactions.”
To explore this theory, he and colleagues reviewed the cases of 500 children diagnosed with food allergy by specialist allergists over the past 20 years.
“The results showed us that children who had received one or more doses of whole-cell vaccine were 23 per cent less likely to be diagnosed with a food allergy than those who didn’t,” Professor Snelling said.
A pilot study involving 150 babies – now expanded to a national trial – was conducted in Perth in 2019, with half the participants receiving a dose of the whole cell version as their first whooping cough vaccine followed by two acellular versions, and half receiving the usual schedule of three doses of acellular whooping cough vaccines only.
“These studies aim to provide further evidence that a single initial dose of the whole cell vaccine might help to protect young babies against developing life-threatening allergies,” Professor Snelling said.