Virus, allergic sensitisation and cortisol in infant bronchiolitis and risk of early asthma.

Background: Acute bronchiolitis during infancy and human rhinovirus (HRV) lower respiratory tract infections increases the risk of asthma in atopic children. We aimed to explore whether specific viruses, allergic sensitisation or cortisol levels during acute bronchiolitis in infancy increase the risk of early asthma, using recurrent wheeze as a proxy.
Methods: In 294 children with a mean (range) age of 4.2 (0-12) months enrolled during hospitalisation for acute infant bronchiolitis, we analysed virus in nasopharyngeal aspirates, serum specific immunoglobulin E against food and inhalant allergens, and salivary morning cortisol. These factors were assessed by regression analyses, adjusted for age, sex and parental atopy, for risk of recurrent wheeze, defined as a minimum of three parentally reported episodes of wheeze at the 2-year follow-up investigation.
Results: At 2 years, children with, compared to without, recurrent wheeze had similar rates of respiratory syncytial virus (RSV) (82.9% versus 81.8%) and HRV (34.9% versus 35.0%) at the acute bronchiolitis, respectively. During infancy, 6.9% of children with and 9.2% of children without recurrent wheeze at 2 years were sensitised to at least one allergen (p=0.5). Neither recurrent wheeze nor incidence rate ratios for the number of wheeze episodes at 2 years were significantly associated with specific viruses, high viral load of RSV or HRV, allergic sensitisation, or morning salivary cortisol level during acute bronchiolitis in infancy.
Conclusion: In children hospitalised with acute infant bronchiolitis, specific viruses, viral load, allergic sensitisation and salivary morning cortisol did not increase the risk of early asthma by 2 years of age.
Competing Interests: Conflict of interest: J.O.G. Hunderi has nothing to disclose. Conflict of interest: L.B. Rolfsjord has nothing to disclose. Conflict of interest: K.C.L. Carlsen received payment for a presentation during EAACI 2018 from Thermo Fisher Scientific. Conflict of interest: R. Holst has nothing to disclose. Conflict of interest: E. Bakkeheim has nothing to disclose. Conflict of interest: T.L. Berents reports service on an advisory board for Sanofi and a lecture for Perrigo, outside the submitted work. Conflict of interest: K-H. Carlsen has nothing to disclose. Conflict of interest: H.O. Skjerven has nothing to disclose.
(Copyright ©ERS 2020.)