Temperature-dependent transmission of rotavirus in Great Britain and The Netherlands

Abstract

In Europe, rotavirus gastroenteritis peaks in late winter or early spring suggesting a role for weather factors in transmission of the virus. In this study, multivariate regression models adapted for time-series data were used to investigate effects of temperature, humidity and rainfall on reported rotavirus infections and the infection-rate parameter, a derived measure of infection transmission that takes into account population immunity, in England, Wales, Scotland and The Netherlands. Delayed effects of weather were investigated by introducing lagged weather terms into the model. Meta-regression was used to pool together country-specific estimates. There was a 13 per cent (95% confidence interval (CI), 11-15%) decrease in reported infections per 1 degrees C increase in temperature above a threshold of 5 degrees C and a 4 per cent (95% CI, 3-5%) decrease in the infection-rate parameter per 1 degrees C increase in temperature across the whole temperature range. The effect of temperature was immediate for the infection-rate parameter but delayed by up to four weeks for reported infections. There was no overall effect of humidity or rainfall. There is a direct and simple relationship between cold weather and rotavirus transmission in Great Britain and The Netherlands. The more complex and delayed temperature effect on disease incidence is likely to be mediated through the effects of weather on transmission.

Figure 1.

(a) Weekly reported rotavirus infections in children under 5 years of age. (b) Average weekly infection-rate parameter (black line) and reported rotavirus infections adjusted for under-ascertainment (grey bars) over the years 1993–2007. (i) England (aggregated across the nine regions), (ii) Wales, (iii) Scotland and (iv) The Netherlands, 1993–2007.

Figure 2.

Scatter plot of (a) reported rotavirus infections and average weekly temperatures over lags of 0–4 weeks and (b) the infection-rate parameter and average weekly temperature. The centre line is the estimated natural cubic spline (4 d.f), and the upper and lower lines represent the 95% CI. (i) England (aggregated across the nine regions), (ii) Wales, (iii) Scotland and (iv) The Netherlands, 1993–2007.

Figure 3.

(a) The effect of temperature for each lag week on reported rotavirus infections and (b) the infection-rate parameter. (i) England (aggregated across the nine regions), (ii) Wales, (iii) Scotland and (iv) The Netherlands, 1993–2007.

Figure 4.

Forrest plot with fixed effects summary estimate for (a) a 1°C increase in mean weekly temperature above a threshold of 5°C on reported rotavirus infections and (b) a 1°C increase in mean weekly temperature on the infection-rate parameter across the whole temperature range. England, Wales, Scotland and The Netherlands, 1993–2007.