Assessing the Extent of Covid-19 Transmission in French Guiana

Intro: The emergence of SARS-CoV-2 was accompanied by great uncertainty regarding the main epidemiological characteristics of the transmission. In a context where epidemiological surveillance was mainly targeted on symptomatic patients, we assessed the extent of SARS-CoV-2 transmission in French Guiana conducting an intra-household transmission study and population-based seroprevalence surveys repeated over time. Method(s): Household monitoring included virological and clinical follow-up for all household members for the first 28 days after the date of confirmation of the index case and serological follow-up over a 12-month period. Three seroprevalence surveys were conducted in July and September 2020 and in September 2021. Finding(s): A total of 57 dwellings including 245 individuals were included in the intra-household study. The average time between the date of onset of symptoms and the date of confirmation of diagnosis and inclusion in the study was 4.2 days and 7.2 days respectively. Secondary transmission was found in three quarters of households with a secondary infection rate of 35%. The highest transmission rate were observed in the most disadvantaged populations, within couples and from adults to children. Population-based seroprevalence studies have made it possible to monitor seroprevalence rates, which have varied from 15% at the time of the epidemic peak of the first epidemic wave to 65% of the population at the beginning of the fourth wave, despite the low impact of vaccination in French Guiana. Conclusion(s): The results obtained highlighted a high transmission of the virus in French Guiana associated with a low severity rate linked to the structure of the particularly young population. The project has provided health authorities with useful data to support prevention and control strategies and has allowed to evaluate the impact of interventions implemented during the pandemic.Copyright © 2023

Sleep Apnea Diagnosed by Full Polysomnography Is a Factor of Acute Hypoxic Respiratory Failure in Covid-19: A Prospective Clinical-Based Cohort Study

Introduction: COVID-19 is a respiratory disease with clinical manifestation, severity, and outcomes heterogeneity, from asymptomatic presentation to an acute hypoxemic respiratory failure. Clinical characteristics and comorbidities may affect susceptibility to a more severe COVID-19. We hypothesize that obstructive sleep apnea (OSA) may be a significant factor that mitigates COVID-19 severity. Methods: A prospective multicentric cohort "Co-survivors" with a sample size of 400 patients was set and started recruiting in June 2020. Patients with a respiratory presentation of COVID-19 were selected. All severities of COVID-19 were allowed from outpatients to patients requiring prolonged invasive mechanical ventilation. At 3-months follow-up, patients underwent a cardio-respiratory clinical investigation. Initial and actual clinical manifestations and comorbidities were collected. All patients underwent a full polysomnography (PSG) or respiratory polygraphy (PG). Results: At the time of the analysis, 121 patients were included in the cohort. OSA was diagnosed before COVID-19 and already treated in 10 patients, and 23 were waiting for investigation. Full PSG was performed in 88 patients (80 PSG and 8 PG). OSA was absent in 15 (17%) patients, while mild, moderate, and severe OSA was present in 30 (34.1%), 21 (23.9%) and 22 (25%), respectively. Outpatient COVID-19 was reported in 30 (34.1%), hospitalization was needed without and with acute respiratory failure in 13 (14%) and 45 (51%) patients, respectivelly. These later were predominantly male and older, did not exhibit more comorbidity but metabolic characteristics with significant higher body mass index and waist circumference. Sleep recordings revealed an AHI of 7.4 [1.7;15.4], 15.7 [8.3;48.9] and 21.9 [14;35.1] p<0.01 in these three classes of COVID-19 severity, respectively. Finally, undiagnosed OSA was a factor of COVID-19 severity. Conclusions: Patients with OSA are highly represented in a population of COVID-19 survivors. About 10% of the patients were diagnosed prior to infection, undiagnosed moderate or severe OSA was diagnosed in 48.9% of the remaining patents. Moreover, OSA is likely to be a factor of acute respiratory failure in patients infected with SARS-CoV-2.