Allergic asthma is one of the most common major non-communicable diseases worldwide, with a substantial impact on quality of life. The prevalence is still rising, especially in low to middle income countries. However, there is still no definitive cure available. Epidemiologic studies implicate an association between severe lower respiratory tract infection during the first months of life and the development of allergic asthma later on. Besides, since maternal rather than paternal allergy is strongly associated with allergy development in progeny, we hypothesize that severe RSV infection lowers the threshold for allergic sensitization in susceptible individuals, especially those born from allergic mothers. Next to genetic influence, a circulating factor (e.g. maternal antibodies) might be responsible for this effect. Over the last years, the host lab has developed novel models that are very relevant to study the link between viral infections and allergic asthma in murine models. An infection model with PVM, the murine analogue of RSV, has been established in both neonatal and adult mice. By gaining more insights in the foundations of asthma, we aim to find novel and better targets for treating and/or preventing allergic asthma.