SARS-CoV-2 Surveillance in Belgian Wastewaters

Wastewater-based surveillance was conducted by the national public health authority to monitor SARS-CoV-2 circulation in the Belgian population. Over 5 million inhabitants representing 45% of the Belgian population were monitored throughout 42 wastewater treatment plants for 15 months comprising three major virus waves. During the entire period, a high correlation was observed between the daily new COVID-19 cases and the SARS-CoV-2 concentration in wastewater corrected for rain impact and covered population size. Three alerting indicators were included in the weekly epidemiological assessment: High Circulation, Fast Increase, and Increasing Trend. These indicators were computed on normalized concentrations per individual treatment plant to allow for a comparison with a reference period as well as between analyses performed by distinct laboratories. When the indicators were not corrected for rain impact, rainy events caused an underestimation of the indicators. Despite this negative impact, the indicators permitted us to effectively monitor the evolution of the fourth virus wave and were considered complementary and valuable information to conventional epidemiological indicators in the weekly wastewater reports communicated to the National Risk Assessment&nbsp;Group.</p

Artériopathie oblitérante des membres inférieurs (audit de pratique, apport d'une coordination pluridisciplinaire dans la région Nord-Pas-de Calais)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Assessment of serological techniques for screening patients for COVID-19 (COVID-SER): a prospective, multicentric study

Introduction The COVID-19 pandemic caused by SARS-CoV-2 threatens global public health, and there is an urgent public health need to assess acquired immunity to SARS-CoV-2. Serological tests might provide results that can be complementary to or confirm suspected COVID-19 cases and reveal previous infection. The performance of serological assays (sensitivity and specificity) has to be evaluated before their use in the general population. The neutralisation capacity of the produced antibodies also has to be evaluated.Methods and analysis We set up a prospective, multicentric clinical study to evaluate the performance of serological kits among a population of healthcare workers presenting mild symptoms suggestive of SARS-CoV-2 infection. Four hundred symptomatic healthcare workers will be included in the COVID-SER study. The values obtained from a control cohort included during the prepandemic time will be used as reference. A workflow was set up to study serological response to SARS-CoV-2 infection and to evaluate antibody neutralisation capacity in patients with a confirmed SARS-CoV-2 infection. The sensitivity and specificity of the tests will be assessed using molecular detection of the virus as a reference. The measurement of IgM and IgG antibodies will be performed once per week for 6 consecutive weeks and then at 6, 12, 18, 24 and 36 months after the diagnosis. The kinetics of IgM and IgG will determine the optimal period to perform serological testing. The proportion of false negative PCR tests in symptomatic subjects will be determined on the basis of subsequent seroconversions.Ethics and dissemination Ethical approval has been obtained from the national review board for biomedical research in April 2020 (Comité de Protection des Personnes Sud Méditerranée I, Marseille, France) (ID RCB 2020-A00932-37). Results will be disseminated through presentations at scientific meetings and publications in peer-reviewed journals.Trial registration number NCT04341142

Clinical and laboratory characteristics of symptomatic healthcare workers with suspected COVID-19: a prospective cohort study

International audienceA comprehensive clinical and microbiological assessments of COVID-19 in front-line healthcare workers (HCWs) is needed. Between April 10th and May 28th, 2020, 319 HCWs with acute illness were reviewed. In addition to SARS-CoV-2 RT-PCR screening, a multiplex molecular panel was used for testing other respiratory pathogens. For SARS-CoV-2 positive HCWs, the normalized viral load, viral culture, and virus neutralization assays were performed weekly. For SARS-CoV-2 negative HCWs, SARS-CoV-2 serological testing was performed one month after inclusion. Among the 319 HCWs included, 67 (21.0%) were tested positive for SARS-CoV-2; 65/67 (97.0%) developed mild form of COVID-19. Other respiratory pathogens were found in 6/66 (9.1%) SARS-CoV-2 positive and 47/241 (19.5%) SARS-Cov-2 negative HCWs ( p = 0.07). The proportion of HCWs with a viral load > 5.0 log 10 cp/mL (Ct value  37). More than 90% of cultivable virus had a viral load > 4.5 log 10 cp/mL (Ct < 26) and were collected within 10 days after symptom onset. Among negative HCWs, 6/190 (3.2%) seroconverted. Our data suggest that the determination of viral load can be used for appreciating the infectiousness of infected HCWs. These data could be helpful for facilitating their return to work