Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department

Robledo-Aceves, Mireya; Moreno-Peregrina, María de Jesús; Velarde-Rivera, Fernando; Ascencio-Esparza, Elba; Preciado-Figueroa, Francisco M.; Caniza, Miguela A.; Escobedo-Melendez, Griselda

Finally, we found that having a complete schedule of vaccinations was a protective factor to prevent severe viral bronchiolitis in infants and young children. This could be a surrogate factor linked to better socioeconomic status and better life habits, as less tobacco smoke, less crowding, or better medical assistance. However, socioeconomic status or parent's level of education was not possible to compare between patients and controls because this information was missing in the majority of the cases, being a limiting of our study. In Mexico, the Ministry of Health provides the seasonal flu vaccines to all children older than 1 year, but vaccination against RSV is not available to date. Although this protective association does not explain the decreased incidence of severe bronchiolitis among vaccinated children, it is important to note that these data reflect that the healthy control group had better health care, including vaccinations against preventable infections. Pregnancy history factors, such as adequate prenatal care and taking calcium during pregnancy, were protective factors for severe viral bronchiolitis in this study. Although a previous report did not find these factors protective, [24] studies in low-income populations should be done to more thoroughly investigate these protective associations.