The virus that causes COVID-19 is thought to spread mainly from person to person, mainly through 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 is more likely when people are in close contact with one another (within about 6 feet).
COVID-19 seems to be spreading easily and sustainably in the community (“community spread”) in many affected geographic areas. Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.
Learn what is known about the spread of newly emerged coronaviruses.
Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.
COVID-19 is caused by a coronavirus called SARS-CoV-2. Coronaviruses are a large family of viruses that are common in people and may different species of animals, including camels, cattle, cats, and bats. Rarely, animal coronaviruses can infect people and then spread between people. This occurred with MERS-CoV and SARS-CoV, and now with the virus that causes COVID-19. More information about the source and spread of COVID-19 is available on the Situation Summary: Source and Spread of the Virus.
It is not yet known whether weather and temperature impact the spread of COVID-19. Some other viruses, like the common cold and flu, spread more during cold weather months but that does not mean it is impossible to become sick with these viruses during other months. At this time, it is not known whether the spread of COVID-19 will decrease when weather becomes warmer. There is much more to learn about the transmissibility, severity, and other features associated with COVID-19 and investigations are ongoing.
Quarantine means separating a person or group of people who have been exposed to a contagious disease but have not developed illness (symptoms) from others who have not been exposed, in order to prevent the possible spread of that disease. Quarantine is usually established for the incubation period of the communicable disease, which is the span of time during which people have developed illness after exposure. For COVID-19, the period of quarantine is 14 days from the last date of exposure, because 14 days is the longest incubation period seen for similar coronaviruses. Someone who has been released from COVID-19 quarantine is not considered a risk for spreading the virus to others because they have not developed illness during the incubation period.
The virus that causes COVID-19 is spreading from person-to-person. Someone who is actively sick with COVID-19 can spread the illness to others. That is why CDC recommends that these patients be isolated either in the hospital or at home (depending on how sick they are) until they are better and no longer pose a risk of infecting others.
How long someone is actively sick can vary so the decision on when to release someone from isolation is made on a case-by-case basis in consultation with doctors, infection prevention and control experts, and public health officials and involves considering specifics of each situation including disease severity, illness signs and symptoms, and results of laboratory testing for that patient.
Current CDC guidance for when it is OK to release someone from isolation is made on a case by case basis and includes meeting all of the following requirements:
- The patient is free from fever without the use of fever-reducing medications.
- The patient is no longer showing symptoms, including cough.
- The patient has tested negative on at least two consecutive respiratory specimens collected at least 24 hours apart.
Someone who has been released from isolation is not considered to pose a risk of infection to others.
Coronaviruses are generally thought to be spread from person-to-person through respiratory droplets. Currently there is no evidence to support transmission of COVID-19 associated with food. Before preparing or eating food it is important to always wash your hands with soap and water for 20 seconds for general food safety. Throughout the day wash your hands after blowing your nose, coughing or sneezing, or going to the bathroom.
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.
In general, because of poor survivability of these coronaviruses on surfaces, there is likely very low risk of spread from food products or packaging that are shipped over a period of days or weeks at ambient, refrigerated, or frozen temperatures.
Learn what is known about the spread of COVID-19
Generally coronaviruses survive for shorter periods of time at higher temperatures and higher humidity than in cooler or dryer environments. However, we don’t have direct data for this virus, nor do we have direct data for a temperature-based cutoff for inactivation at this point. The necessary temperature would also be based on the materials of the surface, the environment, etc. Regardless of temperature please follow CDC’s guidance for cleaning and disinfection.
At this time, CDC has no data to suggest that this new coronavirus or other similar coronaviruses are spread by mosquitoes or ticks. The main way that COVID-19 spreads is from person to person. See how coronavirus spreads for more information.
The number of cases of COVID-19 being reported in the United States is rising due to increased laboratory testing and reporting across the country. The growing number of cases in part reflects the rapid spread of COVID-19 as many U.S. states and territories experience community spread. More detailed and accurate data will allow us to better understand and track the size and scope of the outbreak and strengthen prevention and response efforts.