The burden of seasonal respiratory infections on a national telehealth service in England

Abstract

Seasonal respiratory illnesses present a major burden on primary care services. We assessed the burden of respiratory illness on a national telehealth system in England and investigated the potential for providing early warning of respiratory infection. We compared weekly laboratory reports for respiratory pathogens with telehealth calls (NHS 111) between week 40 in 2013 and week 29 in 2015. Multiple linear regression was used to identify which pathogens had a significant association with respiratory calls. Children aged <5 and 5-14 years, and adults over 65 years were modelled separately as were time lags of up to 4 weeks between calls and laboratory specimen dates. Associations with respiratory pathogens explained over 83% of the variation in cold/flu, cough and difficulty breathing calls. Based on the first two seasons available, the greatest burden was associated with respiratory syncytial virus (RSV) and influenza, with associations found in all age bands. The most sensitive signal for influenza was calls for 'cold/flu', whilst for RSV it was calls for cough. The best-fitting models showed calls increasing a week before laboratory specimen dates. Daily surveillance of these calls can provide early warning of seasonal rises in influenza and RSV, contributing to the national respiratory surveillance programme.

Keywords: Early warning; public health; respiratory; syndromic surveillance; telehealth.

Fig. 1.

Seasonality of NHS 111 respiratory calls in England, week 40 in 2013–week 28 in 2015.

Fig. 2.

Small multiple charts showing seasonality of weekly counts of laboratory reports in England week 40 in 2013–week 20 in 2015. Each chart shows the same respiratory pathogens but with one of six selected pathogens highlighted. RSV, respiratory syncytial virus; HMPV, human metapneumovirus.

Fig. 3.

NHS 111 cold/flu calls in England with estimated pathogen burdens from regression model, week 40 in 2013–week 28 in 2015.

Fig. 4.

NHS 111 cough calls in England with estimated pathogen burdens from regression model, week 40 in 2013–week 28 in 2015.

Fig. 5.

Modelled burden of respiratory pathogens to NHS 111 in England during weeks 40–20, 2013/14 and 2014/15.