Seasonality of Infections Caused by Respiratory Viruses in Newborns and Their Relation to Meteorological Factors

Objectives − Most viral respiratory tract infections (VRTI) are seasonal diseases and frequently severely affect public health by causing seasonal epidemics and pandemics, also in newborns. The objective of this study was to analyse the relation of meteorological factors to the occurrence of neonatal VRTI and to estimate their predictive role for VRTI seasonality.Patients and methods − The retrospective observational cohort study enrolled 228 newborns (56% male and 29% preterm) aged up to 44 postmenstrual weeks, hospitalized due to acute VRTI between January 2015 and December 2020 in the central Slovenian region. The meteorological data for the same geographical region and time period were assessed, and correlation, multiple regression and cut-off values were analysed. Results − A typical seasonal distribution of VRTI from December to March was observed and the large majority of cases were due to respiratory syncytial virus (RSV) infection. Low air temperature, high relative humidity, shorter daily solar radiation and increased cloud cover were associated with an increased risk of neonatal, either RSV or non-RSV VRTI.Conclusions − Meteorological factors, particularly air temperature and relative humidity, were associated with neonatal VRTI occurrence in the temperate climate of central Slovenia. The average daily air temperature below 4.9 and 3.8 °C could predict the onset of the VRTI and RSV VRTI season, respectively. These factors could be used as real-time predictive warning, especially for RSV season onset and the need to begin RSV immunoprophylaxis in vulnerable newborns.