Impact of Lockdown on the Epidemic Dynamics of COVID-19 in France

Roques, Lionel; Klein, Etienne K.; Papaïx, Julien; Sar, Antoine; Soubeyrand, Samuel

doi:10.3389/fmed.2020.00274

Cited by 61 publications

(72 citation statements)

References 31 publications

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“…In [42], the authors find that the basic reproduction ratio, which was R 0 ≈ 3.41 before lockdown, has been reduced to 0.52, which corresponds to q ≈ 6.6. This is consistent with the factor q = 7 found in [40]. Of course important factors like risk status or age (see for instance [16,18]) have been put in evidence, but they are not easy to study from the point of view of transmission rates.…”

Section: Choice Of a Set Of Parameterssupporting

confidence: 78%

Heterogeneous social interactions and the COVID-19 lockdown outcome in a multi-group SEIR model

Dolbeault

Turinici

2020

Math. Model. Nat. Phenom.

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We study variants of the SEIR model for interpreting some qualitative features of the statistics of the Covid-19 epidemic in France. Standard SEIR models distinguish essentially two regimes: either the disease is controlled and the number of infected people rapidly decreases, or the disease spreads and contaminates a significant fraction of the population until herd immunity is achieved. After lockdown, at first sight it seems that social distancing is not enough to control the outbreak. We discuss here a possible explanation, namely that the lockdown is creating social heterogeneity: even if a large majority of the population complies with the lockdown rules, a small fraction of the population still has to maintain a normal or high level of social interactions, such as health workers, providers of essential services, etc. This results in an apparent high level of epidemic propagation as measured through re-estimations of the basic reproduction ratio. However, these measures are limited to averages, while variance inside the population plays an essential role on the peak and the size of the epidemic outbreak and tends to lower these two indicators. We provide theoretical and numerical results to sustain such a view.

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Section: Choice Of a Set Of Parameterssupporting

confidence: 78%

Heterogeneous social interactions and the COVID-19 lockdown outcome in a multi-group SEIR model

Dolbeault

Turinici

2020

Math. Model. Nat. Phenom.

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“…Limiting movement vs limiting the probability of transmission per contact. Before the lockdown, the basic reproduction number R 0 in France was about 3 [7,3], and was then reduced by a factor 5 to 7, leading to values around 0.5 (see [10,7] and Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

“…Model M 0 : SIR model for the whole country. The first model is the standard mean field SIRD model that was used in [3,10]:…”

Section: Mechanistic Modelsmentioning

confidence: 99%

A parsimonious model for spatial transmission and heterogeneity in the COVID-19 propagation

Roques

Bonnefon

Baudrot

et al. 2020

Preprint

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Raw data on the cumulative number of deaths at a country level generally indicate a spatially variable distribution of the incidence of COVID-19 disease. An important issue is to determine whether this spatial pattern is a consequence of environmental heterogeneities, such as the climatic conditions, during the course of the outbreak. Another fundamental issue is to understand the spatial spreading of COVID-19. To address these questions, we consider four candidate epidemiological models with varying complexity in terms of initial conditions, contact rates and non-local transmissions, and we fit them to French mortality data with a mixed probabilistic-ODE approach. Using standard statistical criteria, we select the model with non-local transmission corresponding to a diffusion on the graph of counties that depends on the geographic proximity, with time-dependent contact rate and spatially constant parameters. This original spatially parsimonious model suggests that in a geographically middle size centralized country such as France, once the epidemic is established, the effect of global processes such as restriction policies, sanitary measures and social distancing overwhelms the effect of local factors. Additionally, this modeling approach reveals the latent epidemiological dynamics including the local level of immunity, and allows us to evaluate the role of non-local interactions on the future spread of the disease. In view of its theoretical and numerical simplicity and its ability to accurately track the COVID-19 epidemic curves, the framework we develop here, in particular the non-local model and the associated estimation procedure, is of general interest in studying spatial dynamics of epidemics.

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“…National lockdown proved to be effective in decreasing the contact rate and therefore the number of infectious cases, resulting in a drastic drop of the basic reproductive number (R0, i.e., the expected number of new cases generated by a single infectious case) from 3.3 at the beginning of the epidemic to 0.47. 12 As expected from this value of <1, the epidemic died out, and the restriction policies were progressively eased from May 11 onward, allowing resumption of renal transplantation activity.…”

mentioning

confidence: 77%

IMPact of the COVID-19 epidemic on the moRTAlity of kidney transplant recipients and candidates in a French Nationwide registry sTudy (IMPORTANT)

Legeai

Anglicheau

Pastural

et al. 2020

Kidney International

109

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End stage kidney disease increases the risk of COVID-19 related death but how the kidney replacement strategy should be adapted during the pandemic is unknown. Chronic hemodialysis makes social distancing difficult to achieve. Alternatively, kidney transplantation could increase the severity of COVID-19 due to therapeutic immunosuppression and contribute to saturation of intensive care units. For these reasons, kidney transplantation was suspended in France during the first epidemic wave. Here, we retrospectively evaluated this strategy by comparing the overall and COVID-19 related mortality in kidney transplant recipients and candidates over the last three years. Cross-interrogation of two national registries for the period 1 March and 1 June 2020, identified 275 deaths among the 42812 kidney transplant recipients and 144 deaths among the 16210 candidates. This represents an excess of deaths for both populations, as compared with the same period the two previous years. This difference was integrally explained by COVID-19, which caused the death of 44% of recipients and 42% of candidates. Taking into account the size of the two populations and the geographical heterogeneity of virus circulation, we found that the excess of risk of death due to COVID-19 was similar for recipients and candidates in high viral risk area but four-fold higher for candidates in the low viral risk area. Thus, in case of a second epidemic wave, kidney transplantation should be suspended in high viral risk areas but maintained outside those areas, both to reduce the excess of deaths of candidates and avoid wasting precious resources.

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Impact of Lockdown on the Epidemic Dynamics of COVID-19 in France

Cited by 61 publications

References 31 publications

Heterogeneous social interactions and the COVID-19 lockdown outcome in a multi-group SEIR model

Heterogeneous social interactions and the COVID-19 lockdown outcome in a multi-group SEIR model

A parsimonious model for spatial transmission and heterogeneity in the COVID-19 propagation

IMPact of the COVID-19 epidemic on the moRTAlity of kidney transplant recipients and candidates in a French Nationwide registry sTudy (IMPORTANT)

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