Empirical social contact patterns are essential to understand the spread of infectious diseases. To date, no such data existed for France. Although infectious diseases are frequently seasonal, the temporal variation of contact patterns has not been documented hitherto. COMES-F is the first French large-scale population survey, carried out over 3 different periods (February-March, April, April-May) with some participants common to the first and the last period. Participants described their contacts for 2 consecutive days, and reported separately on professional contacts when typically over 20 per day. 2033 participants reported 38 881 contacts (weighted median [first quartile-third quartile]: 8[5–14] per day), and 54 378 contacts with supplementary professional contacts (9[5–17]). Contrary to age, gender, household size, holidays, weekend and occupation, period of the year had little influence on the number of contacts or the mixing patterns. Contact patterns were highly assortative with age, irrespective of the location of the contact, and gender, with women having 8% more contacts than men. Although most contacts occurred at home and at school, the inclusion of professional contacts modified the structure of the mixing patterns. Holidays and weekends reduced dramatically the number of contacts, and as proxies for school closure, reduced R₀ by 33% and 28%, respectively. Thus, school closures could have an important impact on the spread of close contact infections in France. Despite no clear evidence for temporal variation, trends suggest that more studies are needed. Age and gender were found important determinants of the mixing patterns. Gender differences in mixing patterns might help explain gender differences in the epidemiology of infectious diseases.

Cotrimoxazole (trimethoprim/sulfamethoxazole [TMP-SMX]) is an alternative treatment for toxoplasmic encephalitis because it is inexpensive, well-tolerated, and as effective as pyrimethamine-sulfadiazine, which is the first-line drug regimen). We report results of a large cohort study of patients with acquired immunodeficiency syndrome who were treated for toxoplasmic encephalitis with cotrimoxazole. The mean follow-up period was more than three years. Our results confirm that cotrimoxazole is effective (85.5%), with a relatively low incidence of side effects (22%; 7.4% requiring treatment interruption). Relapse occurred in 30.1% of the patients at a mean ± SD of 7.8 ± 16.2 months after the first episode. The only risk factor for relapse was poor treatment and/or prophylaxis adherence. Mortality was significantly higher (P < 0.05) before 1996 than after 1996 (the era of highly active antiretroviral therapy). There was a non-significant trend towards a higher rate of relapse among patients treated before 1996 (P = 0.06). Consequently, cotrimoxazole could be a first-line drug regimen for curative treatment and prophylaxis of toxoplasmic encephalitis.