Note: The above retraction by the CDC was posted mid-day today - 3 days after the new guidance (below) was posted - and now this `guidance' is apparently pending review.
Simply incredible . . .
#15,466
On Friday - with very little fanfare - the CDC updated their guidance on how COVID-19 spreads.
While many of the changes in the wording of this document are subtle and incremental in nature, they are nevertheless welcomed acknowledgements that COVID-19 spreads more easily - via aerosols and by asymptomatic cases - than previously stated.
All of this has been part of an ongoing debate among scientists for many months (see last April's COVID-19: The Airborne Division), but gained prominence in July when 200+ scientists from around the world signed an open letter to the WHO, urging them to reconsider their stance on the airborne spread of the virus.
It is Time to Address Airborne Transmission of COVID-19
Lidia Morawska, Donald K Milton
Clinical Infectious Diseases, ciaa939, https://doi.org/10.1093/cid/ciaa939
In fairness, the CDC has recommended - out of an abundance of caution - `airborne precautions' for health care workers since the beginning of this epidemic (see J. Infect. Dis.: Airborne or Droplet Precautions For COVID-19?).
But their guidance on how this virus spreads in the community has focused more on large droplet (short-range and short-lived) spread of the virus and contaminated fomites, rather than on aerosols, which may persist longer and travel farther.
You'll find the latest guidance below.
Updated Sept. 18, 2020COVID-19 is thought to spread mainly through close contact from person to person, including between people who are physically near each other (within about 6 feet). People who are infected but do not show symptoms can spread the virus to others. We are still learning about how the virus spreads and the severity of illness it causes.COVID-19 most commonly spreads
- Between people who are in close contact with one another (within about 6 feet).
- Through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks, or breathes.
- These particles can be inhaled into the nose, mouth, airways, and lungs and cause infection. This is thought to be the main way the virus spreads.
- Droplets can also land on surfaces and objects and be transferred by touch. A person may get COVID-19 by touching the surface or object that has the virus on it and then touching their own mouth, nose, or eyes. Spread from touching surfaces is not thought to be the main way the virus spreads.
- It is possible that COVID-19 may spread through the droplets and airborne particles that are formed when a person who has COVID-19 coughs, sneezes, sings, talks, or breathes. There is growing evidence that droplets and airborne particles can remain suspended in the air and be breathed in by others, and travel distances beyond 6 feet (for example, during choir practice, in restaurants, or in fitness classes). In general, indoor environments without good ventilation increase this risk.
COVID-19 spreads very easily from person to person
How easily a virus spreads from person to person can vary. Airborne viruses, including COVID-19, are among the most contagious and easily spread. Some viruses are highly contagious, like measles, while other viruses do not spread as easily. The virus that causes COVID-19 appears to spread more efficiently than influenza, but not as efficiently as measles, which is highly contagious. In general, the more closely a person with COVID-19 interacts with others and the longer that interaction, the higher the risk of COVID-19 spread.Spread between animals and people
- At this time, the risk of COVID-19 spreading from animals to people is considered to be low. Learn about COVID-19 and pets and other animals.
- It appears that the virus that causes COVID-19 can spread from people to animals in some situations. CDC is aware of a small number of pets worldwide, including cats and dogs, reported to be infected with the virus that causes COVID-19, mostly after close contact with people with COVID-19. Learn what you should do if you have pets.
Protect yourself and others
The best way to prevent illness is to avoid being exposed to this virus. You can take steps to slow the spread.
- Stay at least 6 feet away from others, whenever possible. This is very important in preventing the spread of COVID-19.
- Pandemics can be stressful. During times of increased physical distancing, it is still important to maintain social connections and care for your mental health.
- Cover your mouth and nose with a mask when around others. Masks should not replace other prevention measures.
- Wash your hands often with soap and water. If soap and water are not available, use a hand sanitizer that contains at least 60% alcohol.
- Stay home and isolate from others when sick.
- Use air purifiers to help reduce airborne germs in indoor spaces.
- Routinely clean and disinfect frequently touched surfaces.
- Learn more about what you can do to protect yourself and others.
While the science is far from settled, the preponderance of evidence suggests aerosol transmission is a contributing factor in community spread of the virus, and we should be looking more into indoor environmental controls, such as increased ventilation.
