When my baby drops her dummy on the floor, I pick it up and suck it before I give it back to her. Could me sucking the dummy make her ill, or is it an acceptable thing for a parent to do?

Dr Eliane Abou-Jaoude, an allergy and immunology fellow at Henry Ford Health System in Detroit, USA, has just led a study into how different cleaning methods for dummies or pacifiers affect allergy-linked antibodies in a baby’s blood.

She says: “Our study looked at infants and the method in which their pacifier was cleaned: Sterilisation (boiling, placing in a dishwasher), washing with hands and soap, or by the parent sucking on the pacifier and giving it to their children. Our idea was behind the fact that the bacteria a child is exposed to in infancy can affect the development of the immune system.

“We looked at IgE levels – IgE is an antibody in the blood that all people have, and the level is usually higher in people who have allergies, asthma or eczema. We wanted to see if this level was different in children whose parents used various cleaning methods to clean their pacifiers.

“We found that beginning around 10 months of age and until 18 months, the children whose pacifiers were cleaned by the parent sucking on them had lower IgE trajectory. We only have results until 18 months, but we plan on looking at this group of children around age five years again.

“This wasn’t a cause and effect study, so we can’t state that if you clean your child’s pacifier by sucking on it that the child will have low IgE levels and not develop allergies. We aren’t telling parents to change pacifier cleaning methods because both good and bad bacteria can transfer to the child.

“These results support the concept that transfer of parental microbiota to children may suppress IgE production, a biomarker linked to the development of childhood allergic disorders.”