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Covid_RG1 : Environmental drivers of SARS-cov2 emergence and spread

1.1 Drivers of the SARS-CoV-2 emergence.

Understanding the SARS-CoV-2 life cycle (where, when and why it circulates) is a question that requires additional research. While this will also appear in the medium/long term research needs, it seems important to better understand the contribution of animal/human proximity urgently to take appropriate action for example on land use, food system, including agriculture, intensive farming and live animal markets, on contacts between human and both wild, domestic animals and pets, etc. Understanding how human activities, environmental change/disturbances and animal behavior facilitate SARS-CoV-2 infection requires a joint effort between health, ecological and social sciences.

1.2 Drivers of the SARS-CoV-2 spread.

The impact of climate and seasonality on the coronavirus is not definitely known. The initial spread of the virus was primarily in countries of the northern temperate climates, but it appears that it can also effectively spread more globally, including in warm and humid climates. So this important question still needs to be addressed. Furthermore, the role of different media in viral spread should be better assessed: transmission through aerosols and air particles; behaviour and virulence of SARS-CoV-2 in water (freshwater, marine water, wastewater), soils and wastes. These media could be reservoirs of virus particularly in cities. Short term research is needed to mitigate transmission of the virus through these media.

1.3 Improved modelling of virus spread including impact of mitigation and exit strategies.

Robust open models are needed by the public authorities, and reducing uncertainties is an important objective. It is important to explore how environmental conditions (temperature, relative humidity, wind, UV light, etc.) affect the virus and its survival, which may affect the spread significantly. Models should now take into account the new tools that are foreseen for mitigation such as contact tracing (including technologies such as apps for mobile phones, artificial intelligence and immunological tests). A modelling effort is required on the one hand to take control measures that limit transmission and to evaluate/validate their effectiveness, and on the other hand to prevent a possible evolution of SARS-CoV-2 towards better transmitted or more virulent genetic variants. Evaluation of spread, severity, immunity and persistence of immunity is most likely modified by environmental conditions. Therefore, models need to be optimized for taking such conditions into account.