Community Spread

Community Spread

Coronavirus Home

Home

Your Health

Vaccines

Cases & Data

Work & School

Healthcare Workers

Health Depts

Science

More

Important update: Healthcare facilities

CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination.
Learn more

Find the latest information:
Aquatics FAQs
Recommendations for Fully Vaccinated People
COVID-19 Homepage

What You Need to Know
COVID-19 Community Levels help individuals and communities decide which prevention actions to take based on the latest information.
Each level helps convey how much COVID-19 is impacting your community using data on hospitalizations and cases.
Using these data, communities are classified as low, medium, or high.
For each level, CDC recommends actions you can take to help you protect yourself and others from severe impacts of COVID-19.

Scientific evidence and studies behind specific COVID-19 guidance and recommendations

Facebook
Twitter
LinkedIn
Syndicate

CDC INFORMATION

About CDC
Jobs
Funding
Policies
File Viewers & Players
Other Languages

Español
繁體中文
Tiếng Việt
한국어
Tagalog
Русский
العربية
Kreyòl Ayisyen
Français
Polski
Português
Italiano
Deutsch
日本語
فارسی
English

CDC Website Exit Disclaimer external icon

Exit Notification / Disclaimer Policy

Close

Links with this icon indicate that you are leaving the CDC website.

The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link.
CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.

For more information on CDC's web notification policies, see Website Disclaimers .

Many people in the United States have some protection, or immunity, against COVID-19 due to vaccination, previous infection, or both. This immunity, combined with the availability of tests and treatments, has greatly reduced the risk of severe illness, hospitalization, and death from COVID-19 for many people.
At the same time, some people—such as those who are older, are immunocompromised , have certain disabilities, or have certain underlying health conditions—continue to be at higher risk for serious illness. Learn more about the factors that can affect your risk of getting very sick from COVID-19 to better understand how COVID-19 could affect you and others around you.
For Healthcare Facilities: Prevention actions in healthcare facilities , such as hospitals, rehabilitation centers, and nursing homes, are not linked to COVID-19 Community Levels.
Take action to protect yourself and others from COVID-19 based on the COVID-19 Community Level in your area.
People may choose to wear a mask at any time. Masks are recommended in indoor public transportation settings and may be required in other places by local or state authorities.
To receive email updates about COVID-19, enter your email address:

Official Site of the State Of New Jersey
Information on testing, vaccines, and help finding appointments near you.
Medical Information from healthcare professionals on symptoms, when to seek medical attention, and proper steps to take if exposed to COVID-19.
Call (COVID-19 Vaccination and Testing) :
1-800-962-1253 (10a-6p, M-F; 10a-4p, Sa)
Information on testing, vaccines, and help finding appointments near you.
Call (Medical COVID-19 Questions) :
Medical Information from healthcare professionals on symptoms, when to seek medical attention, and proper steps to take if exposed to COVID-19.
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.

For a full list of topics: A-Z Index

Facebook
Twitter
LinkedIn
Syndicate

CDC Confirms Possible Instance of Community Spread of COVID-19 in U.S.

CDC INFORMATION

About CDC
Jobs
Funding
Policies
File Viewers & Players
Other Languages

CONNECT WITH CDC

Facebook
Twitter
Instagram
LinkedIn
Snapchat

Youtube
Syndicate
CDC TV
RSS
Email

Español
繁體中文
Tiếng Việt
한국어
Tagalog
Русский
العربية
Kreyòl Ayisyen
Français
Polski
Português
Italiano
Deutsch
日本語
فارسی
English

Facebook

Twitter

Instagram

LinkedIn

Snapchat

Youtube
Syndicate
CDC TV
RSS
Email

CDC Website Exit Disclaimer external icon

Exit Notification / Disclaimer Policy

Close

Links with this icon indicate that you are leaving the CDC website.

The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link.
CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.

For more information on CDC's web notification policies, see Website Disclaimers .

For Immediate Release: Wednesday, February 26, 2020
Contact: Media Relations
(404) 639-3286
The Centers for Disease Control and Prevention (CDC) has confirmed an infection with the virus that causes COVID-19 in California in a person who reportedly did not have relevant travel history or exposure to another known patient with COVID-19.
At this time, the patient’s exposure is unknown. It’s possible this could be an instance of community spread of COVID-19, which would be the first time this has happened in the United States. Community spread means spread of an illness for which the source of infection is unknown. It’s also possible, however, that the patient may have been exposed to a returned traveler who was infected.
This case was detected through the U.S. public health system — picked up by astute clinicians. This brings the total number of COVID-19 cases in the United States to 15.
The federal government has been working closely with state, local, tribal, and territorial partners, as well as public health partners, to respond to this public health threat. Unprecedented, aggressive efforts have been taken to contain the spread and mitigate the impact of this virus.
This is a rapidly evolving situation. CDC will continue to update the public as circumstances warrant. For more information about COVID-19 visit www.cdc.gov/covid19 .
CDC works 24/7 protecting America’s health, safety and security. Whether disease start at home or abroad, are curable or preventable, chronic or acute, or from human activity or deliberate attack, CDC responds to America’s most pressing health threats. CDC is headquartered in Atlanta and has experts located throughout the United States and the world.
To receive email updates about this page, enter your email address:

By Alison Pearce Stevens September 1, 2022

By Rina Diane Callabar August 31, 2022

By Carolyn Gramling August 24, 2022

What ‘community’ spread of coronavirus means

As COVID-19 spreads, the best advice for preventing the disease is to wash your hands

About Tina Hesman Saey

E-mail

Twitter

About Aimee Cunningham

E-mail

Twitter

About Erin Garcia de Jesús

E-mail

Twitter

Classroom Resources for This Article

By Science News Staff January 30, 2020

By Erin Garcia de Jesús January 28, 2020

By Tina Hesman Saey February 28, 2020

By Rina Diane Callabar August 31, 2022

By Carolyn Gramling August 24, 2022

By Bethany Brookshire August 11, 2022

More Information

Using Science News Explores in the Classroom

Rights & Permissions

Newsletters

Follow Science News on Facebook

Follow Science News on Twitter

Follow Science News via RSS

Follow Science News on Instagram

Society for Science

About the Society

Donate

Careers

With “community spread” of the new coronavirus, public-health experts warn people in some areas may need to avoid crowds as much as they can, such as subway stations (pictured here), concerts and airports.
U.S. public health officials reported on February 26 that a 50-year-old California woman had become infected with the novel coronavirus that has been spreading around the world since late December. This case marks a troubling new phase of the outbreak in the United States, experts say. The reason: No one knows yet where or how she picked up the virus.
Until now, all U.S. cases were due to people who had been in China, where the viral infection first emerged, or who had been in contact with others known to be infected.
The woman had not traveled to China or had not been exposed to someone known to be carrying the virus. As such, she appears to be the first case in the United States of what’s known as community spread. That means she picked up her illness from some unknown infected person with whom she had come into contact.
Since the start of the outbreak, there have been more than 83,000 cases of the COVID-19, as the viral disease is now known. The sickness has shown up in at least 57 countries. A few regions — including Italy, Iran, South Korea and Japan — have reported sustained community spread. That means the virus is moving from person to person in places outside China’s borders.
The World Health Organization, or WHO, announced on February 28 that it had upgraded the risk of global spread by the COVID-19 virus to “very high.” It did not yet call the disease a pandemic. “We don’t see evidence yet that the virus is spreading freely in communities. As long as that is the case, we still have a chance of containing this virus,” said Tedros Adhanom Ghebreyesus in a news briefing. He is the director-general of WHO, which is based in Geneva, Switzerland.
Weekly updates to help you use Science News Explores in the learning environment
There was a problem signing you up.
Here’s what that California case means. We also explain what to expect in the coming days and months and what to do if you think you are infected.
The California woman came to a local hospital with severe symptoms. Public health officials aren’t sure how she became infected with SARS-CoV-2. That’s the virus causing COVID-19. Without a clear idea of her infection’s source, she probably wasn’t the first person to get infected in that area, says Aubree Gordon. Gordon is an epidemiologist at the University of Michigan in Ann Arbor.
“It [probably] means there’s an unknown number of other cases” in Northern California, Gordon says. “It’s probably not a super large number,” she adds. There is the worry, however, that “there may be a large number of people who are infected but haven’t started to show symptoms.”
One reason some infections may go unnoticed is that it currently is the season for respiratory diseases. Influenza and the common cold have symptoms similar to COVID-19. Indeed, flu and colds remain the likely culprit for most current cases of respiratory disease in the United States. So, against the backdrop of so many cold and flu cases, the new coronavirus will be hard to detect.
If health officials conducted more tests, they’d probably find more cases, says Michael Osterholm. He’s an epidemiologist at the University of Minnesota in Minneapolis. “Absence of evidence is not evidence of absence [of disease],” he notes.
That’s hard to say right now. Experts have been expecting community spread. That’s based on the findings of computer models that track where and when the virus might spread from China. Those models had indicated that COVID-19 probably had already been introduced in the United States. The California case now hints that there may be undetected infections across the country.
People need to “prepare themselves for the possibility that there will be multiple outbreaks,” Gordon says. Throughout the United States, this virus may spread widely “in the coming months to a year,” she says. Or, she warns, “It could be days. It’s really hard to say.”
Katelyn Gostic agrees. She works in Illinois at the University of Chicago. There she studies the spread of infectious diseases. “We should definitely be prepared for the possibility that the outbreak is going to grow in the United States,” she says. That doesn’t mean people should panic, she adds. From what is already known about the virus, most people “are going to be just fine even if they get sick.” But people should be prepared to change their behaviors. That may mean avoiding crowds and staying home when symptoms of infection emerge.
No one knows for sure how many people have been infected with SARS-CoV-2. That’s partly because there aren’t enough kits to test everyone. It’s also partly because people may be infected with the virus but have no symptoms or very mild ones. Such people may still be able to infect others.
For instance, a woman from China passed the virus to colleagues in Germany before she knew she was ill. That case was controversial. Researchers have found other evidence of people with very mild or no symptoms transmitting the virus. One was a woman in Wuhan, China. She gave the virus to five relatives in Anyang, China. The woman never had symptoms. Tests would later show she had the virus, according to a February 21 report in JAMA . Two of her relatives developed severe disease.
Health officials in Nanjing, China, tracked down other people who had been in contact with COVID-19 patients. They report finding that among those contacts were 24 people who had no symptoms when they were tested for the virus. Five of them would go on to become sick. Twelve also had chest X-rays that suggested they were infected. But especially troubling, seven of these infected contacts never showed signs of disease.
People with symptoms were infectious for up to 21 days. People with no symptoms tended to be younger. They also tended to have detectable virus for a median of four days. But one man with no symptoms passed on the virus to his wife, son and daughter-in-law. He may have been infectious for up to 29 days, researchers now note in a report that has not yet been peer reviewed by other scientists.
What’s more, people may still give off virus after they are no longer sick. Four health-care workers from Wuhan still had positive test results five to 13 days after their symptoms cleared. Researchers shared this observation February 27 in JAMA . Researchers don’t yet know whether viruses that are present after symptoms disappear are infectious.
“There’s really no doubt that there are many undetected cases,” says Erik Volz. He’s a mathematical epidemiologist. He works in England at Imperial College London.
Undetected cases matter because they may seed outbreaks when travelers carry them to other countries, says Gostic. And even the best efforts to screen airline passengers for COVID-19 will miss about half of cases , Gostic and her colleagues reported February 25 in eLife .
Those missed cases at airports “are not due to correctable mistakes,” Gostic says. It’s not that sick travelers are trying to avoid detection. And it’s not that screeners are bad at their jobs. “It’s just a biological reality,” she says, that most infected travelers won’t realize they’ve been exposed and won’t show symptoms.
That is true for most infectious diseases. But the share of COVID-19 cases with mild or undetectable disease poses a big challenge. So does the ability of this virus to spread through the air. People may catch the virus without ever knowing they came into contact with it. These people could unknowingly start epidemics in new places. “We just see this as inevitable,” Gostic says.
As of February 28, the virus has infected more than 83,000 people in 57 countries.
Because this coronavirus hadn’t infected people before the outbreak in China, no one has prior immunity to it. So this coronavirus spread might be similar to pandemic flu, Volz says. Although seasonal flu circulates around the world each year, pandemic flu is caused by new viruses that haven’t previously infected humans.
Examples include the 1918 “Spanish flu”, the “Asian flu” of 1957 and 1958, and the H1N1 flu in 2009. Depending on the country, that 2009 flu infected 5 percent to 60 percent of people . The 1918 pandemic infected an estimated third to half of everyone alive at the time, Volz says.
There has been a great deal of misinformation surrounding the new coronavirus disease, called COVID-19. Scientists are still working to understand the virus and its spread. We wanted to fill readers in on the latest scientific evidence and expert advice on what to expect when
Nylon Lingerie
Private Fetish
Private School Education

Community Spread

Report Page