Background On 7 February 2020, French Health authorities were informed of a confirmed case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in an Englishman infected in Singapore who had recently stayed in a chalet in the French Alps. We conducted an investigation to identify secondary cases and interrupt transmission. Methods We defined as a confirmed case a person linked to the chalet with a positive reverse-transcription polymerase chain reaction sample for SARS-CoV-2. Results The index case stayed 4 days in the chalet with 10 English tourists and a family of 5 French residents; SARS-CoV-2 was detected in 5 individuals in France, 6 in England (including the index case), and 1 in Spain (overall attack rate in the chalet: 75%). One pediatric case, with picornavirus and influenza A coinfection, visited 3 different schools while symptomatic. One case was asymptomatic, with similar viral load as that of a symptomatic case. Seven days after the first cases were diagnosed, 1 tertiary case was detected in a symptomatic patient with from the chalet a positive endotracheal aspirate; all previous and concurrent nasopharyngeal specimens were negative. Additionally, 172 contacts were monitored; all contacts tested for SARS-CoV-2 (N = 73) were negative. Conclusions The occurrence in this cluster of 1 asymptomatic case with similar viral load as a symptomatic patient suggests transmission potential of asymptomatic individuals. The fact that an infected child did not transmit the disease despite close interactions within schools suggests potential different transmission dynamics in children. Finally, the dissociation between upper and lower respiratory tract results underscores the need for close monitoring of the clinical evolution of suspected cases of coronavirus disease 2019.

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To monitor the prevalence of hepatitis B and hepatitis C a cross-sectional survey was conducted in 2004 among French metropolitan residents. A complex sampling design was used to enroll 14,416 adult participants aged 18-80 years. Data collected included demographic and social characteristics and risk factors. Sera were tested for anti-HCV, HCV-RNA, anti-HBc and HBsAg. Data were analyzed with SUDAAN software to provide weighted estimates for the French metropolitan resident population. The overall anti-HCV prevalence was 0.84% (95% CI: 0.65-1.10). Among anti-HCV positive individuals, 57.4% (95% CI: 43.2-70.5) knew their status. Factors associated independently with positive anti-HCV were drug use (intravenous and nasal), blood transfusion before 1992, a history of tattoos, low socioeconomic status, being born in a country where anti-HCV prevalence >2.5%, and age >29 years. The overall anti-HBc prevalence was 7.3% (95%: 6.5-8.2). Independent risk factors for anti-HBc were intravenous drug use, being a man who has sex with men, low socioeconomic status, a stay in a psychiatric facility or facility for the mentally disabled, <12 years of education, being born in a country where HBsAg prevalence >2%, age >29 and male sex. The HCV RNA and HBsAg prevalence were 0.53% (95% CI: 0.40-0.70) and 0.65% (95% CI: 0.45-0.93), respectively. Among HBsAg positive individuals, 44.8% (95% CI: 22.8-69.1) knew their status. Anti-HCV prevalence was close to the 1990s estimates whereas HBsAg prevalence estimate was greater than expected. Screening of hepatitis B and C should be strengthened and should account for social vulnerability.

During this large outbreak, the estimated risk of viremic blood donation was high, but low compared to the risk of mosquito-borne CHIKV transmission. The estimated risk was corroborated by the concordant results with the observed risk.

AND THE COLLABORATIVE STUDY GROUP 4 drug abuse (21 cases, 14 men all õ 40-years-old), previous The aims of this study were the following: 1) to estitransfusion (22 cases, 18 women), and not having paid mate the prevalence of hepatitis C virus (HCV) antibody employment. Although routes of transmission other (anti-HCV) in a population-based survey of French resithan IV drug abuse and transfusion may not be formally dents not selected for risk factors; 2) to investigate the excluded they were not found to be statistically signifiassociation between anti-HCV seropositivity, viremia, cant. Hepatitis C appears to be a major public health the infecting HCV genotype, and the alanine transamiconcern in France. A more active screening policy may nase ( 1 The most serious conseprevalence of 1.15%. Fifty percent of these positive vol-quences of HCV result from chronic infection. However, the unteers also had an abnormal ALT level and 81% were development of an HCV carrier state without major liver HCV-RNA positive by polymerase chain reaction (PCR). anomalies as assessed by liver function tests is not uncomThe prevalence weighted for age, sex, and place of resi-mon and some patients with histological evidence of chronic dence was 1.05% (95% CI: 0.75-1.34). The weighted preva-active hepatitis or cirrhosis present minimal clinical evidence lence was lower among men ú 40-years-old (0.5%; 95% of liver disease.2,3 HCV infection is most commonly identified CI: 0.1-1.0) and was close to 1% in all other age and sex following diagnosis of chronic liver disease of 10 to 30 years groups. Prevalence was inversely correlated with socio-duration. 4 Surveys of overt clinical infections thus give a poor professional status with the highest rate being found estimate of the overall prevalence of HCV infection in the among those with no paid employment (2.2%; 95% CI: general population. Only seroprevalence studies using large 1.3-3.0). The HCV prevalence (1.7%; 95% CI: 1.0-2.3) was numbers of subjects not selected for risk factors can yield highest in southeastern France. Seventy-eight percent accurate information on the health burden associated with of positive intervenous (IV) drug abusers were infected HCV in the general population. Although long-term mortality with HCV genotypes 1a or 3, whereas 80% of the transfu-associated with chronic hepatitis C remains to be detersion-associated cases were infected by HCV genotypes mined, 5 prevalence data from representative surveys would 1b or 2a. Only three variables were significantly associ-help plan clinical and prevention activities. ated with HCV seropositivity in multivariate analysis: IV Most available information about HCV antibody (anti-HCV) seroprevalence in the French population are from studies of high risk groups, 6-8 blood donors (anti-HCV prevalence from 0.6% to 0.8% in 1991, 9,10 and 0.3% in 1994 11 ), and pregAbbreviations: HCV, hepatitis C virus; anti-HCV, HCV antibody; ELISA, enzyme-linked nant women (prevalence from 1% to 2%).12 immunosorbent assay; SIA, strip immunoblot assa...

Although pertussis vaccination coverage is very high in France, the organism is still circulating, affecting, within the pediatric population, mostly non- or incompletely vaccinated infants. These results strongly support the importance of adhering to the immunization schedule and suggest introducing booster dose(s) to prolong vaccine immunity and reduce the exposure to Bordetella pertussis of infants too young to be immunized.

The objective was to develop and to validate an immunossay to identify recent human immunodeficiency virus type 1 (HIV-1) infections that can be used on dried serum spots (DSS). A single, indirect enzyme-linked immunosorbent assay was developed to quantify antibodies toward four HIV-1 antigens: consensus peptides of the immunodominant epitope of gp41 (IDE), consensus V3 peptides, recombinant integrase, and recombinant p24. The parameters of the logistic regression used to classify the samples were estimated on a training sample (210 serum samples) using resampling techniques to get stable estimates and then applied to a validation sample (761 serum samples). The IDE and V3 peptides were the best able to discriminate between the antibodies present in serum from recently (<6 months) infected individuals and those with long-lasting infection. Combined quantification of antibody binding to these two synthetic antigens allowed us to identify recent infections with an area under the receiver operating characteristic curve of 0.949 and a sensitivity of 88.3%, with a specificity of 97.6% in patients with long-term infection (but not AIDS) and 86.0% in patients suffering from AIDS with a threshold of 0.50 in the validation sample. This simple immunoassay can be used to identify recently HIV-1-infected patients. Its performance is compatible with its use in population-based studies including DSS.The human immunodeficiency virus (HIV) epidemic is generally assessed by monitoring seroprevalence i.e., the proportion of persons with HIV antibodies (including recently infected people and people who were infected several years previously). To understand recent changes in the HIV epidemic, it is necessary to estimate the incidence, i.e., the number of newly infected subjects in a defined period. A strategy based on a sensitive/less sensitive testing algorithm was recently used to identify serum samples from recently infected individuals (16). This strategy that uses both a sensitive and a less-sensitive enzyme immunoassay (S/LS EIA), also called a detuned assay, was applied to various situations, providing estimates of HIV incidence (12,14,16,18,24,33,35). One of the major drawbacks of this strategy is that the test is an adaptation of a commercial EIA, which poses problems for long-term availability. It is therefore necessary to develop and to validate simple immunoassays that can continuously be used independent of any commercial source. The knowledge of the anti-HIV type 1 (anti-HIV-1) antibody response (5,8,20,38) and recent studies aimed at identifying antigens to distinguish recent infections (27, 30) allowed us to design a candidate assay to assess persons with recent infection. We report the development and the validation of this assay for the identification of recent HIV-1 infections (EIA-RI) and its application to dried blood spots.

We assessed the quantitative contribution of pig farming to antimicrobial resistance in the commensal flora of pig farmers by comparing 113 healthy pig farmers from the major French porcine production areas to 113 nonfarmers, each matched for sex, age, and county of residence. All reported that they had not taken antiimicrobial agents within the previous month. Throat, nasal, and fecal swabs were screened for resistant microorganisms on agar containing selected antimicrobial agents. Nasopharyngeal carriage of Staphylococcus aureus was significantly more frequent in pig farmers, as was macrolide resistance of S. aureus from carriers. Nongroupable streptococci from the throat were more resistant to the penicillins in pig farmers. The intestinal isolation of enterococci resistant to erythromycin or vancomycin was not significantly higher in pig farmers in contrast to that of enterobacteria resistant to nalidixic acid, chloramphenicol, tetracycline, and streptomycin. Prevalence of resistance in predominant fecal enterobacteria was also significantly higher in pig farmers for cotrimoxazole, tetracycline, streptomycin, and nalidixic acid. We determined a significant association between pig farming and isolation of resistant commensal bacteria.