On surfaces under a range of temperatures and relative humidity

Relative humidity and temperature can be used to provide an estimated half-life for SARS-CoV-2 with this model with some degree of certainty. The predictive power is limited to temperature between 74°F-95°F and Relative Humidity between 20-60%. The formula below was developed in °C, but has been modified in the web calculator to use °F.

Background

  • Preventing person-to-person spread of SARS-CoV-2 is the only means to reduce the impact of COVID-19 in the absence of an effective therapeutic.
  • Transmission occurs primarily through respiratory droplets produced by talking, coughing and sneezing.
  • Contact with contaminated surfaces and objects may also contribute to spread.
  • SARS-CoV-2 will survive in saliva and respiratory fluids on surfaces for extended periods of time under certain conditions.
  • DHS S&T has studied the stability of SARS-CoV-2 in simulated saliva, using droplets of varying size deposited on a non-porous surface under a range of temperature and RH conditions.
  • Viral survival on surfaces is driven by temperature, relative humidity (RH), and matrix (e.g., bodily fluids).
  • These data have been used to develop a predictive model to estimate virus decay under a limited range of environmental conditions.
  • Testing performed on non-porous surfaces, specifically stainless steel, ABS plastic, and nitrile rubber.
  • There was no significant difference found in the decay of the virus found between stainless steel ABS plastic, and nitrile rubber.

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Under a range of temperatures, relative humidity, and UV index

 

Background

  • Minimizing person-to-person spread of SARS-CoV-2 is one of the main ways to reduce the impact of COVID-19.
  • Transmission is believed to occur through respiratory droplets produced by talking, coughing and sneezing. Contact with contaminated surfaces and objects may also contribute to spread.
  • Increased temperature and relative humidity cause a minimal increase in SARS-CoV-2 decay, but the addition of simulated sunlight causes rapid decay of the virus in aerosol.
  • These data have been used to develop a predictive model to estimate virus decay in aerosols under a limited range of environmental conditions.
  • The data that supports the decay of SARS-CoV-2 with simulated sunlight (UV) is published in the Journal of Infectious Diseases and can be found here.

Read the full article here