Severity of human metapneumovirus (hMPV) lower respiratory illness (LRTI) is considered similar to that observed for respiratory syncytial virus (RSV). However, differences in severity between both pathogens have been noted, suggesting degree of illness may vary in different populations. Moreover, a potential association between hMPV and asthma also suggests that hMPV may preferentially affect asthmatic subjects.
A population-based surveillance study in children <2 years admitted for severe LRTI in Argentina. Nasopharyngeal aspirates were tested by RT-PCR for hMPV, RSV, influenza A and human rhinovirus.
Of 3,947 children, 383 (10%) were infected with hMPV. The hospitalization rate for hMPV LRTI was 2.26 per 1,000 children (95% CI, 2.04-2.49). Thirty-nine (10.2%) patients infected with hMPV experienced life-threatening disease (LTD) [0.23 per 1,000 children (95% CI 0.16-0.31/1,000)], and two died [infant mortality rate 0.024 per 1,000 (95% CI 0.003-0.086)]. In hMPV infected children birth to an asthmatic mother there was an increased risk for LTD (OR=4,72 95% CI, 1.39-16.01). We observed a specific interaction between maternal asthma and hMPV infection affecting risk for LTD.
Maternal asthma increases the risk for LTD in children <2 years old hospitalized for severe hMPV LRTI.

© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America.