Long lasting anti-IgG chikungunya seropositivity in the Mayotte population will not be enough to prevent future outbreaks: A seroprevalence study, 2019.

Chikungunya is an arboviral disease causing arthralgia which may develop into a debilitating chronic arthritis. In Mayotte, a French overseas department in the Indian Ocean, a chikungunya outbreak was reported in 2006, affecting a third of the population. We aimed at assessing the chikungunya seroprevalence in this population, after over a decade from that epidemic. A multi-stage cross sectional household-based study exploring socio-demographic factors, and knowledge and attitude towards mosquito-borne disease prevention was carried out in 2019. Blood samples from participants aged 15-69 years were taken for chikungunya IgG serological testing. We analyzed associations between chikungunya serological status and selected factors using Poisson regression models, and estimated weighted and adjusted prevalence ratios (w/a PR). The weighted seroprevalence of chikungunya was 34.75% (n = 2853). Seropositivity for IgG anti-chikungunya virus was found associated with living in Mamoudzou (w/a PR = 1.49, 95%CI: 1.21-1.83) and North (w/a PR = 1.41, 95%CI: 1.08-1.84) sectors, being born in the Comoros islands (w/a PR = 1.30, 95%CI: 1.03-1.61), being a student or unpaid trainee (w/a PR = 1.35, 95%CI: 1.01-1.81), living in precarious housing (w/a PR = 1.30, 95%CI: 1.02-1.67), accessing water streams for bathing (w/a PR = 1.72, 95%CI: 1.1-2.7) and knowing that malaria is a mosquito-borne disease (w/a PR = 1.42, 95%CI: 1.21-1.83). Seropositivity was found inversely associated with high education level (w/a PR = 0.50, 95%CI: 0.29-0.86) and living in households with access to running water and toilets (w/a PR = 0.64, 95%CI: 0.51-0.80) (n = 1438). Our results indicate a long-lasting immunity from chikungunya exposure. However, the current population seroprevalence is not enough to protect from future outbreaks. Individuals naïve to chikungunya and living in precarious socio-economic conditions are likely to be at high risk of infection in future outbreaks. To prevent and prepare for future chikungunya epidemics, it is essential to address socio-economic inequalities as a priority, and to strengthen chikungunya surveillance in Mayotte.

Positive SARS-CoV-2 RT-qPCR of a nasal swab spot after 30 days of conservation on filter paper at room temperature.

We tested the use of nasal swabs spotted onto filter paper (Whatman 3M) for the molecular diagnosis of SARS-CoV-2 infection. Spots of a positive nasal swab in conservation medium (B.1.177 strain, 21Ct) were still positive (duo E-gene/IP4) after 10, 20, and 30 days of conservation at room temperature, with Ct values of 28, 27, and 26, respectively. Direct spotting of the swab at bedside (omicron strain) still gave a positive result after 10 days in two RT-qPCR systems: 33.7 Ct using duo E-gene/IP4, and 34.8 using a specific Omicron system. Spotting of a dilution range of media spiked with the Delta (strain 2021/FR/0610, lineage B 1.617.2) and Omicron strains (strain UVE/SARS-CoV-2/2021/FR/1514) showed a threshold of 0.04 TCID50 after 10 days of conservation. We show, for the first time, that this simple and low-cost conservation method can be used to store samples for RT-qPCR against SARS-CoV-2 for up to at least 1 month.

Management and Outcome of COVID-19 Positive and Negative Patients in French Emergency Departments During the First COVID-19 Outbreak: A Prospective Controlled Cohort Study.

INTRODUCTION: Few studies have investigated the management of COVID-19 cases from the operational perspective of the emergency department (ED), We sought to compare the management and outcome of COVID-19 positive and negative patients who presented to French EDs. METHODS: We conducted a prospective, multicenter, observational study in four EDs. Included in the study were adult patients (≥18 years) between March 6-May 10, 2020, were hospitalized, and whose presenting symptoms were evocative of COVID-19. We compared the clinical features, management, and prognosis of patients according to their confirmed COVID-19 status. RESULTS: Of the 2,686 patients included in this study, 760 (28.3%) were COVID-19 positive. Among them, 364 (48.0%) had hypertension, 228 (30.0%) had chronic cardiac disease, 186 (24.5%) had diabetes, 126 (16.6%) were obese, and 114 (15.0%) had chronic respiratory disease. The proportion of patients admitted to intensive care units (ICU) was higher among COVID-19 positive patients (185/760, 24.3%) compared to COVID-19 negative patients (206/1,926, 10.7%; P <0.001), and they required mechanical ventilation (89, 11.9% vs 37, 1.9%; P <0.001) and high-flow nasal cannula oxygen therapy (135, 18.1% vs 41, 2.2%; P < 0.001) more frequently. The in-hospital mortality was significantly higher among COVID-19 positive patients (139, 18.3% vs 149, 7.7%; P <0.001). CONCLUSION: Emergency departments were on the frontline during the COVID-19 pandemic and had to manage potential COVID-19 patients. Understanding what happened in the ED during this first outbreak is crucial to underline the importance of flexible organizations that can quickly adapt the bed capacities to the incoming flow of COVID-19 positive patients.

Changes over time in anxiety, depression, and stress symptoms among healthcare workers in French emergency departments during the first COVID-19 outbreak.

STUDY OBJECTIVE: Assess the changes in anxiety, depression, and stress levels over time and identify risk factors among healthcare workers in French emergency departments (EDs) during the first COVID-19 outbreak. METHOD: A prospective, multicenter study was conducted in 4 EDs and an emergency medical service (SAMU). During 3 months, participants completed fortnightly questionnaires to assess anxiety, depression, and stress using the Hospital Anxiety and Depression and the Chamoux-Simard scale. The changes in anxiety, depression, and stress levels over time were modelled by a linear mixed model including a period effect and a continuous time effect within periods. RESULTS: A total of 211 respondents (43.5 %) completed the survey at inclusion. There was a decrease in mean anxiety (from 7.33 to 5.05, p < 0.001), mean depression (from 4.16 to 3.05, p = 0.009), mean stress at work (from 41.2 to 30.2, p = 0.008), and mean stress at home (from 33.0 to 26.0, p = 0.031) at the beginning of each period. The mean anxiety level was higher for administrative staff (+0.53) and lower for paramedics (-0.61, p = 0.047) compared to physicians. The anxiety level increased with the number of day and night shifts (0.13/day, p < 0.001, 0.12/night, p = 0.025) as did stress at work (1.6/day, p < 0.001, 1.1/night, p = 0.007). Reassigned healthcare workers were at higher risk of stress particularly compared to SAMU workers (stress at work: p = 0.015, at home: p = 0.021, in life in general: p = 0.018). CONCLUSION: Although anxiety, depression, and stress decreased over time, anxiety was higher among physicians and administrative staff. Reassignment and working hours were identified as potential risk factors for mental health distress in EDs.

Development and Evaluation of a duo SARS-CoV-2 RT-qPCR Assay Combining Two Assays Approved by the World Health Organization Targeting the Envelope and the RNA-Dependant RNA Polymerase (RdRp) Coding Regions.

The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide has highlighted the importance of reliable and rapid diagnostic testing to prevent and control virus circulation. Dozens of monoplex in-house RT-qPCR assays are already available; however, the development of dual-target assays is suited to avoid false-negative results caused by polymorphisms or point mutations, that can compromise the accuracy of diagnostic and screening tests. In this study, two mono-target assays recommended by WHO (E-Sarbeco (enveloppe gene, Charite University, Berlin, Germany) and RdRp-IP4 (RdRp, Institut Pasteur, Paris, France)) were selected and combined in a unique robust test; the resulting duo SARS-CoV-2 RT-qPCR assay was compared to the two parental monoplex tests. The duo SARS-CoV-2 assay performed equally, or better, in terms of sensitivity, specificity, linearity and signal intensity. We demonstrated that combining two single systems into a dual-target assay (with or without an MS2-based internal control) did not impair performances, providing a potent tool adapted for routine molecular diagnosis in clinical microbiology laboratories.

COVID-19 outbreak among French firefighters, Marseille, France, 2020.

We investigated a COVID-19 outbreak at a fire station in Marseille, France. Confirmed cases were defined as individuals with positive SARS-CoV-2 reverse transcription (RT)-PCR and/or neutralising antibodies. All 85 firefighters at work during the outbreak period were included after questioning and sampled for RT-PCR and viral neutralisation assay. Twenty-three firefighters were confirmed positive, 19 of them were symptomatic, and four asymptomatic cases were confirmed by virus neutralisation. A total of 22 firefighters had specific neutralising antibodies against SARS-CoV-2. Neutralising antibodies were found in four asymptomatic and 18 symptomatic cases. Eleven symptomatic cases had high titres (≥ 1:80). The earliest detection of neutralising antibodies was 7 days after symptom onset, and 80% had neutralising antibodies 15 days after onset. One viral culture was positive 13 days after onset. The attack rate was 27%. We identified two introductions of the virus in this outbreak, through a presymptomatic and a paucisymptomatic case. Asymptomatic cases were not the source of a third generation of cases, although they worked without wearing a mask, indicating that asymptomatic cases did not play a significant role in this outbreak. Management and strategy based on early research of clinical signs associated with self-quarantine was effective.

COVID-19 Repeated Convalescent Plasma Collection: Analysis of 149 Donations from 88 French Military Health Workers.

BACKGROUND: Passive therapy with convalescent plasma (CP) could be an effective and safe treatment option in COVID-19 patients. Neutralizing antibodies present in CP generated in response to SARS-CoV-2 infection and directed against the receptor-binding domain of the spike protein are considered to play a major role in the viral clearance. CP infusion may also contribute to the modulation of the immune response through its immunomodulatory effect. We describe for the first time the effectiveness of a CP collection protocol from repeated donations in young patients. MATERIALS AND METHODS: We enrolled health service workers who experienced mild to moderate COVID-19 and from whom several donations have been collected. No minimal severity threshold and no biological cure criteria were required. Donors could return to a second plasma donation 14 days after the first donation. A minimal neutralizing antibody titer of 1:40 was considered for clinical use. RESULTS: Eighty-eight donors were included (median age 35 [28-48] years, 41 women), and 149 plasma products were collected. COVID-19 were mainly WHO stage 2 infections (96%). Among the 88 first donations, 76% had neutralizing antibody titers higher than or equal to 1:40. Eighty-eight percent of donors who came for a second donation had a neutralizing antibody titer of 1:40. Median durations were 15 (15-19) and 38 (33-46) days from the first to the second donation and from recovery to the second donation, respectively. Sixty-nine percent of donors who came for a third donation had a neutralizing antibody titer of 1:40. Median durations were 16 (13-37) and 54 (49-61) days from the second to the third donation and from recovery to the third donation, respectively. No significant difference was observed between the IgG ratio and the age of the donors or the time between recovery and donation. The average IgG ratio did not significantly vary between donations. When focused on repeated blood donors, no significant differences were observed either. CONCLUSION: The recruitment of young patients with a mild to moderate CO-VID-19 course is an efficient possibility to collect CP with a satisfactory level of neutralizing antibodies. Repeated donations are a well-tolerated and effective way of CP collection.