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Coronavirus Update: Transmission – What Do We Know?

Coronavirus Update: Transmission – What Do We Know?

On January 30, 2020, the first confirmed case of person-to-person 2019 novel coronavirus (2019-nCoV) transmission was reported in the United States. Also on January 30, 2020, the International Health Regulations Emergency Committee of the World Health Organization declared the outbreak a public health emergency of international concern; the US Health and Human Services Secretary declared a public health emergency for the United States as well, in an effort to assist the US healthcare community in responding to 2019-nCoV. On January 31, President Trump signed a presidential "Proclamation on Suspension of Entry as Immigrants and Nonimmigrants of Persons who Pose a Risk of Transmitting 2019 Novel Coronavirus."

According to the CDC website, persons under investigation for 2019-nCoV are tracked and updated every Monday, Wednesday, and Friday. As of Wednesday, February 12, 2020, there are 14 confirmed cases in the US, with 66 pending cases and 347 cases which tested negative.

Microbes are transmitted in a variety of ways, including the following:

  • Direct contact (eg, MRSA, VRE)
  • Bloodborne transmission (eg, hepatitis B, C, HIV) through sexual activity, sharps injuries, and/or needles
  • Droplet transmission (eg, influenza, pertussis) when microbes are carried through the air (about 6 feet) when an infected person talks, coughs, or sneezes, and droplets land on a susceptible host’s eyes, nose, or mouth
  • Airborne transmission (eg, measles, tuberculosis) when a microbe becomes aerosolized and exits an infected source via talking, coughing, and sneezing, and is strong enough to survive travel on air currents over distance and time, infecting a susceptible host

Much is unknown about how 2019-nCoV is transmitted. The current knowledge is largely based on what is known about other coronaviruses. Person-to-person transmission occurs most frequently among close contacts (about 6 feet). In the United States, the one confirmed case of person-to-person transmission occurred between spouses in Chicago. Person-to-person spread is thought to occur through droplet transmission, similar to the way influenza and other respiratory pathogens spread. These droplets can land in the eyes, mouths, or noses of nearby people, and the virus may be transmitted in the air when it is inhaled into the lungs of someone in close proximity. It is currently unclear if a person can get 2019-nCoV by touching a surface or object contaminated with the virus and then touching their own mouth, nose, or eyes.

With most respiratory viruses, people are most contagious when they are symptomatic. However, with the 2019-nCoV, there have been reported cases of transmission from infected patients who were asymptomatic to close contacts. The current state of knowledge about the 2019-nCoV transmission is ongoing, and as information is revealed, this will inform our risk assessment and prevention strategies.

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Filed under: Health Policy and Trends, Infectious Diseases, Public Health

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