Tag Archives: Information

Using the Internet for More Than Just Cat Pictures

The Internet can be a highly useful tool – communicating with old or distant friends, finding out the latest news, purchasing the latest best-seller, looking at photos of cats, etc. People also go online when they, or someone they know, is ill, searching for information or posting on social media. Your Internet search provider tracks all of this, and this data can be used by researchers to track outbreaks and the spread of infectious diseases. A recent paper by Yang and colleagues [1] demonstrated such a feat with regards to dengue fever.

Dengue is quickly becoming one of the most endemic mosquito-borne disease worldwide, infecting around 390 million people each year in 128 countries,[2] and placing the local health services under immense pressure. The Aedes mosquito that transmits dengue thrives in slums / shanty towns.[3] One of the ways to reduce infection rates is to improve early case detection – identifying outbreaks early means that preventive measures, such as mosquito population control, providing mosquito screens or nets, etc., can be undertaken. However, there is no current surveillance system for dengue that is comprehensive, effective and reliable – governments tend to use reports from hospitals that are often delayed and/or inaccurate.

Yang, et al. combined dengue-related Internet searches with historical incidence data to track dengue activity in five areas, Mexico, Brazil, Thailand, Singapore and Taiwan. They were able to successfully estimate dengue activity one month prior to the publication of official local health records, with their method outperforming benchmark models across accuracy metrics in all areas, except Taiwan. The authors note that Taiwan had little previous dengue prevalence on which to base predictions, suggesting the methodology works best in areas where dengue is already endemic.

— Peter Chilton, Research Fellow


  1. Yang S, Kou SC, Lu F, Brownstein JS, Brooke N, Santillana M. Advances in using Internet searches to track dengue. PLoS Comput Biol. 2017; 13(7): e1005607.
  2. World Health Organization. Dengue and severe dengue. 2016.
  3. Ezeh A, Oyebode O, Satterthwaite D, et al. The history, geography, and sociology of slums and the health problems of people who live in slums. Lancet. 2017; 389: 547-58.

An Argument with Michael Marmot

About two decades ago I went head-to-head in an argument with the great Michael Marmot at the Medical Research Council. The topic of conversation was information that should be routinely collected in randomised trials. Marmot was arguing that social class and economic information should be collected. He made a valid point that these things are correlated with outcomes. I pointed out that although they may be correlated with outcomes, they were not necessarily correlated with treatment effects. Then came Marmot’s killer argument. Marmot asked whether I thought that sex and ethnic group should be collected. When I admitted that they should be, he rounded on me, saying that this proves his point. We met only recently and he remembered the argument and stood by his point. However, it turns out that it is not really important to collect information on the sex after all. Wallach and colleagues, writing in the BMJ,[1] cite evidence from meta-analyses of RCTs to show that sex makes no difference to treatment effects when averaged across all studies. So there we have it, a parsimonious data set is optimal for trial purposes, since it increases the likelihood of collecting essential information to measure the parameter of interest.

— Richard Lilford, CLAHRC WM Director


  1. Wallach JD, Sullivan PG, Trepanowski JF, Steyerberg EW, Ioannidis JPA. Sex based subgroup differences in randomized controlled trials: empirical evidence from Cochrane meta-analyses. BMJ. 2016; 355: i5826.