This protective effect was even stronger in babies who were at higher genetic risk of worse lung function. We found that, while cat allergens showed no association, exposure to dog allergens was linked to improved lung function and a reduced risk of asthma. We don’t know why this happens; however, we do know that once a person becomes sensitive to dog allergens, they can make asthma symptoms worse. This suggests that early exposure to dog allergens could prevent sensitisation, perhaps by altering the nasal microbiome – the mixture of microbes living inside the nose – or by some effect on the immune system. Reference:Babies who grow up around dogs may have a lower risk of developing childhood asthma, European Respiratory Society, Meeting: European Respiratory Society Congress.