Are Infections Good for Babies?

The challenge

There is a lot of scientific evidence that infections early in life may affect the risk of disease later in life. Over the last 20 to 30 years more and more children have been getting asthma, eczema and other allergic diseases both in the UK and in other developed countries. We do not know why but one possibility is because common infections early in life have become less frequent.

The Allergy and Infection Study was set up to find out if some common infections children catch when they are very young affect the way their body copes with diseases in the future. In particular we are interested to see if these infections play a part in the development of diseases such as asthma, hay fever and eczema.

What we are doing about it

Over 2,500 children have taken part in the Allergy and Infection Study. They were seen at home or in the clinic at age 1 and 2 years. A questionnaire was completed by the parents and a blood sample taken from the child. The blood samples have been tested in the lab to find out which children have had the common infections we are interested in and the age at which they were infected. We are currently looking at the infection data together with the information we collected from the questionnaires to find out which groups of children are more likely to have had the infections. For example, do children with older brothers and sisters get these infections earlier than first-born children? Does breastfeeding or attending childcare affect the chance of being infected? Are these infections more common in children of Pakistani or White British origin? The study team visited the children again at 4 years old to carry out allergy testing. This skin prick test is used routinely to identify children who are sensitive to common substances. Children who have a reaction on their skin to any of the common substances tested (such as cat hair or pollen) are more likely to have allergy symptoms like eczema, hay fever or asthma when they are older.

Our future plans

Next we will investigate whether having one of the common infections by age 1 or 2 years affects the chance of having a positive allergy test at age 4 years. We are also planning to use GP data to see if there is a link between the infections and having symptoms of eczema, hay fever or asthma during childhood. Our results will be important in helping us to understand why some children develop allergic diseases.

In the future, vaccines may be introduced against the infections that we are interested in. The results from this study will help find out what the benefits or risks of these vaccines might be and at what age children should be vaccinated if a vaccination programme is introduced.

To hear more about this research see Lucy’s talk at the 2015 BiB scientific conference here

Lucy Pembrey

Lucy Pembrey is a Lecturer in Epidemiology at the London School of Hygiene & Tropical Medicine. She has co ordinated the Born in Bradford Allergy and Infection Study since 2008.

Lucy has worked on epidemiological studies of infectious diseases for over 15 years and is particularly interested in how infections early in life affect the risk of disease throughout the life course.