oa Seasonal Variation in Respiratory Syncytial Virus Infection in a Desert Climate: A Report from Qatar

Background

Respiratory viruses have a predictable seasonality, which varies regionally. The reason for such seasonality is not well known yet, but atmospheric factors such as high humidity and temperature may assist virus survival in small particle droplets or aerosols, and on infected surfaces.

Objective

The goal of the study was to determine the seasonal variation in respiratory syncytial virus (RSV) infection in a desert climate.

Methods

A retrospective and cross sectional study was performed at Hamad Medical Corporation (HMC), the only tertiary and academic medical center in the State of Qatar. The study included infants and young children ages 0 to 24 months that were admitted to our pediatric ward with diagnosis of acute bronchiolitis from the period of January 2010 to December 2012. The following information were collected: gestational age, gender, respiratory virus real time polymerase chain reaction (RVRT-PCR) conducted on nasopharyngeal secretions, and hospital length of stay (LOS).

Results

835 infants and young children met the study criteria with mean age at diagnosis of 3.61 ± 3.56 months ranging from 0.33 to 24 months. RVRT-PCR was performed on 769 (92.0%) of the participants. RSV was positive in 352 (45.7%) children admitted with clinical bronchiolitis. In addition, no viruses were identified in 142 (18.4%), and respiratory viruses other RSV were found in 275 (35.7F%) of children. Our investigation shows that there has been a steady and periodic seasonal variation in the RSV rate over the study period. A seasonal trend for the RSV (detected by RVRT-PCR) rate was evident (Fig. 1), showing annual peaks in the months of October, November, December, and January, with a significant test for seasonality (test statistics [T] =  3.15, P = 0.009).

Conclusions

In countries with desert hot weather, bronchiolitis might affect infants and children throughout the year. Our results suggest that the combination of uninterrupted RSV seasonality can provide factual guidance for healthcare planning and application of RSV prevention scheme, such as extending the palivizumab vaccine series.

Figure 1: Sequence chart for RSV rate of infection during various months in children admitted with acute clinical bronchiolitis