Current understanding about how the virus that causes coronavirus disease 2019 (COVID-19) spreads islargely based on what is

known about similar coronaviruses.

Person-to-person Spread

The virus is thought to spread mainly from person-to-person.

• Between people who are in close contact with one
  another (within about 6 feet)h
• Via respiratory droplets produced when an
  infected person coughs or sneezes.
• These droplets can land in the mouths or noses
  of people who are nearby or possibly be inhaled into the lungs.

Spread from Contact with Infected Surfaces or Objects

It may be possible that a person can get COVID-19 by touching a surface
or object that has the virus on it and then touching their own mouth, nose, or
possibly their eyes, but this is not thought to be the main way the virus
spreads.

When Does Spread Happen?

• People are thought to be most contagious when
  they are most symptomatic (the sickest).
• Some spread might be possible before people show
  symptoms; there have been reports of this with this new coronavirus, but this is
  not thought to be the main way the virus spreads.

How efficiently does the virus spread?

How easily a virus spreads from person-to-person can vary. Some viruses
are highly contagious (like measles), while other viruses are less so. Another
factor is whether the spread continues over multiple generations of people (if
spread is sustained). The virus that causes COVID-19 seems to be spreading easily
and sustainably in Hubei province and other parts of China. In the United States,
spread from person-to-person has occurred only among a few close contacts and has
not spread any further to date.

There is Still More to be Learned

COVID-19 is an emerging disease and there is more to learn about its
transmissibility, severity, and other features and what will happen in the United
States. New information will further inform the risk assessment.

Read the latest Coronavirus Disease 2019 (COVID-19), Wuhan,
China situation summary.

CDC is responding to an outbreak of respiratory disease caused by a
novel (new) coronavirus that was first detected in Wuhan City, Hubei Province, China
and which has now been detected in 37 locations internationally, including cases in
the United States. The virus has been named “SARS-CoV-2” and the disease it causes
has been named “coronavirus disease 2019” (abbreviated “COVID-19”).

On January 30, 2020, the International Health Regulations Emergency
Committee of the World Health Organization declared the outbreak a “public
health
emergency of international concernexternal icon” (PHEIC). On January 31,
2020,
Health and Human Services Secretary Alex M. Azar II declared a public health
emergency (PHE) for the United States to aid the nation’s healthcare community in
responding to COVID-19.

Coronaviruses are a large family of viruses that are common in many
different species of animals, including camels, cattle, cats, and bats. Rarely,
animal coronaviruses can infect people and then spread between people such as with
MERS-CoV, SARS-CoV, and now with this new virus
(named SARS-CoV-2)

The SARS-CoV-2 virus is a betacoronavirus, like MERS-CoV and SARS-CoV.
All three of these viruses have their origins in bats. The sequences from U.S.
patients are similar to the one that China initially posted, suggesting a likely
single, recent emergence of this virus from an animal reservoir.

Early on, many of the patients in the COVID-19 outbreak in Wuhan, China
had some link to a large seafood and live animal market, suggesting animal-to-person
spread. Later, a growing number of patients reportedly did not have exposure to
animal markets, indicating person-to-person spread. Person-to-person spread has been
reported outside China, including in the United States and other locations. Chinese
officials report that sustained person-to-person spread in the community is
occurring in China. In addition, other destinations have apparent
community spread,
meaning some people have been infected who are not sure how or where they became
infected. Learn what is known about the spread of newly emerged
coronaviruses.

Imported cases of COVID-19 in travelers have been detected
in the U.S.
Person-to-person spread of COVID-19 also has been seen among close contacts of
returned travelers from Wuhan, but at this time, this virus is NOT currently
spreading in the community in the United States.

Both MERS-CoV and SARS-CoV have been known to cause severe illness in
people. The complete clinical picture with regard to COVID-19 is not fully
understood. Reported illnesses have ranged from mild to severe, including illness
resulting in death. Learn more about the symptoms associated with
COVID-19.

There are ongoing investigations to learn more. This is a rapidly
evolving situation and information will be updated as it becomes available.

Outbreaks of novel virus infections among people are always of public
health concern. The risk from these outbreaks depends on characteristics of the
virus, including how well it spreads between people, the severity of resulting
illness, and the medical or other measures available to control the impact of the
virus (for example, vaccine or treatment medications). The fact that this disease
has caused illness, including illness resulting in death, and sustained
person-to-person spread is concerning. These factors meet two of the criteria of a
pandemic. As community spread is detected in more and more countries, the world
moves closer toward meeting the third criteria, worldwide spread of the new
virus.

The potential public health threat posed by COVID-19 is high, both
globally and to the United States.

But individual risk is dependent on exposure.

• For the general American public, who are
  unlikely to be exposed to this virus at this time, the immediate health risk
  from COVID-19 is considered low.
• Under current circumstances, certain people will
  have an increased risk of infection, for example healthcare workers caring for
  patients with COVID-19 and other close contacts of persons with COVID-19. CDC
  has developed guidance to help in the risk assessment and
  management of people
  with potential exposures to COVID-19.

However, it’s important to note that current global circumstances
suggest it is likely that this virus will cause a pandemic. In that
case, the risk
assessment would be different.