Suchergebnisse

Convenience Samples by Internet and the Press - Gay and Lesbian Press Survey 2011. Since 1985, the Gay Press Survey, based on a convenience sample, has collected data through an anonymous self-administered questionnaire on lifestyles and preventive sexual behavior among Men having Sex with Men or MSM (Bochow et al., 2003). First broadcast in the gay press, the questionnaire, since 2004, has also been available online via information or gay dating sites. From 15 May to 15 July 2011, the survey Gay News was renewed and collected a total of 10,587 questionnaires MSM residing in France, 1,084 via the press and 9,503 via the Internet. This article describes the methodology developed and the main results by comparing the two collection methods. The advantages and limitations of Internet use over paper in convenience sample surveys are discussed.

Following the emergence of a novel strain of influenza A(H1N1) in Mexico and the United States in April 2009, its epidemiology in Europe during the summer was limited to sporadic and localised outbreaks. Only the United Kingdom experienced widespread transmission declining with school holidays in late July. Using statistical modelling where applicable we explored the following causes that could explain this surprising difference in transmission dynamics: extinction by chance, differences in the susceptibility profile, age distribution of the imported cases, differences in contact patterns, mitigation strategies, school holidays and weather patterns. No single factor was able to explain the differences sufficiently. Hence an additive mixed model was used to model the country-specific weekly estimates of the effective reproductive number using the extinction probability, school holidays and weather patterns as explanatory variables. The average extinction probability, its trend and the trend in absolute humidity were found to be significantly negatively correlated with the effective reproduction number - although they could only explain about 3% of the variability in the model. By comparing the initial epidemiology of influenza A (H1N1) across different European countries, our analysis was able to uncover a possible role for the timing of importations (extinction probability), mixing patterns and the absolute humidity as underlying factors. However, much uncertainty remains. With better information on the role of these epidemiological factors, the control of influenza could be improved.