Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add filters

Database
Language
Document Type
Year range
1.
medrxiv; 2021.
Preprint in English | medRxiv | ID: ppzbmed-10.1101.2021.05.13.21257088

ABSTRACT

After one year of stop-and-go COVID-19 mitigation, some European countries still experience sustained viral circulation due to the B.1.1.7 variant. As the prospect of phasing out this stage through vaccination draws closer, it is critical to balance the efficacy of long-lasting interventions and their impact on the quality of life. Focusing on the current situation in France, we show that moderate interventions require a much longer time to achieve the same result as high intensity lockdowns, with the additional risk of deteriorating control as adherence wanes. Integrating intensity and duration of social distancing in a data-driven "distress" index, we show that shorter strict lockdowns are largely more performant than longer moderate lockdowns, for similar intermediate distress and infringement on individual freedom. Our study shows that favoring milder interventions over more stringent short approaches on the basis of perceived acceptability could be detrimental in the long term, especially with waning adherence.


Subject(s)
COVID-19
2.
medrxiv; 2020.
Preprint in English | medRxiv | ID: ppzbmed-10.1101.2020.08.10.20171744

ABSTRACT

A novel testing policy was implemented in May in France to systematically screen potential COVID-19 infections and suppress local outbreaks while lifting lockdown restrictions. 20,736 virologically-confirmed cases were reported in mainland France from May 13, 2020 (week 20, end of lockdown) to June 28 (week 26). Accounting for missing data and the delay from symptom onset to confirmation test, this corresponds to 7,258 [95% CI 7,160-7,336] cases with symptom onset during this period, a likely underestimation of the real number. Using age-stratified transmission models parameterized to behavioral data and calibrated to regional hospital admissions, we estimated that 69,115 [58,072-77,449] COVID-19 symptomatic cases occurred, suggesting that 9 out of 10 cases with symptoms were not ascertained. Median detection rate increased from 7% [6-9]% to 31% [28-35]% over time, with regional estimates varying from 11% (Grand Est) to 78% (Normandy) by the end of June. Healthcare-seeking behavior in COVID-19 suspect cases remained low (31%) throughout the period. Model projections for the incidence of symptomatic cases (4.5 [3.9-5.0] per 100,000) were compatible with estimates integrating participatory and virological surveillance data, assuming all suspect cases consulted. Encouraging healthcare-seeking behavior and awareness in suspect cases is critical to improve detection. Substantially more aggressive and efficient testing with easier access is required to act as a pandemic-fighting tool. These elements should be considered in light of the currently observed resurgence of cases in France and other European countries.


Subject(s)
COVID-19
3.
medrxiv; 2020.
Preprint in English | medRxiv | ID: ppzbmed-10.1101.2020.05.08.20095521

ABSTRACT

As several countries around the world are planning exit strategies to progressively lift the rigid social restrictions implemented with lockdown, different options are being chosen regarding the closure or reopening of schools. We evaluate the expected impact of reopening schools in lIe-de-France region after the withdrawal of lockdown currently scheduled for May 11, 2020. We explore several scenarios of partial, progressive, or full school reopening, coupled with moderate social distancing interventions and large-scale tracing, testing, and isolation. Accounting for current uncertainty on the role of children in COVID-19 epidemic, we test different hypotheses on children's transmissibility distinguishing between younger children (pre-school and primary school age) and adolescents (middle and high school age). Reopening schools after lifting lockdown will likely lead to an increase in the number of COVID-19 cases in the following 2 months, even with lower transmissibility of children, yet protocols exist that would allow maintaining the epidemic under control without saturating the healthcare system. With pre-schools and primary schools in session starting May 11, ICU occupation would reach at most 72% [55,83]% (95% probability ranges) of a 1,500-bed capacity (here foreseen as the routine capacity restored in the region post-first wave) if no other school level reopens before summer or if middle and high schools reopen one month later through a progressive protocol (increasing attendance week by week). Full attendance of adolescents at school starting in June would overwhelm the ICU system (138% [118,159]% occupation). Reopening all schools on May 11 would likely lead to a second wave similar to the one recently experienced, except if maximum attendance is limited to 50% for both younger children and adolescents. Based on the estimated situation on May 11, no substantial difference in the epidemic risk is predicted between progressive and prompt reopening of pre-schools and primary schools, thus allowing full attendance of younger children mostly in need of resuming learning and development. Reopening would require however large-scale trace and testing to promptly isolate cases, in addition to moderate social distancing interventions. Full attendance in middle and high schools is instead not recommended. Findings are consistent across different assumptions on the relative transmissibility of younger children and for small increase of the reproductive number possibly due to decreasing compliance to lockdown.


Subject(s)
Occupational Diseases , COVID-19 , Phobic Disorders
4.
medrxiv; 2020.
Preprint in English | medRxiv | ID: ppzbmed-10.1101.2020.04.13.20063933

ABSTRACT

BackgroundMore than half of the global population is under strict forms of social distancing. Estimating the expected impact of lockdown and exit strategies is critical to inform decision makers on the management of the COVID-19 health crisis. MethodsWe use a stochastic age-structured transmission model integrating data on age profile and social contacts in Ile-de-France to (i) assess the epidemic in the region, (ii) evaluate the impact of lockdown, and (iii) propose possible exit strategies and estimate their effectiveness. The model is calibrated to hospital admission data before lockdown. Interventions are modeled by reconstructing the associated changes in the contact matrices and informed by mobility reductions during lockdown evaluated from mobile phone data. Different types and durations of social distancing are simulated, including progressive and targeted strategies, with large-scale testing. ResultsWe estimate the reproductive number at 3.18 [3.09, 3.24] (95% confidence interval) prior to lockdown and at 0.68 [0.66, 0.69] during lockdown, thanks to an 81% reduction of the average number of contacts. Model predictions capture the disease dynamics during lockdown, showing the epidemic curve reaching ICU system capacity, largely strengthened during the emergency, and slowly decreasing. Results suggest that physical contacts outside households were largely avoided during lockdown. Lifting the lockdown with no exit strategy would lead to a second wave overwhelming the healthcare system, if conditions return to normal. Extensive case-finding and isolation are required for social distancing strategies to gradually relax lockdown constraints. ConclusionsAs France experiences the first wave of COVID-19 pandemic in lockdown, intensive forms of social distancing are required in the upcoming months due to the currently low population immunity. Extensive case-finding and isolation would allow the partial release of the socio-economic pressure caused by extreme measures, while avoiding healthcare demand exceeding capacity. Response planning needs to urgently prioritize the logistics and capacity for these interventions.


Subject(s)
COVID-19
SELECTION OF CITATIONS
SEARCH DETAIL