COVID-19: The Novel CoronavirusPage 6 of 10

4. Response to the Pandemic

Until scientists can discover effective treatments and vaccines for COVID-19, public health measures are the only means available to limit the spread of the virus and to buy time for the development of treatments and vaccines.

What We Learned from SARS

The SARS outbreak was contained in human populations in 2003 largely by aggressive use of traditional public health interventions. The same public health interventions must be used today to stop the spread of COVID-19. The public health measures used during the SARS outbreak were:

  • Finding and isolating patients
  • Quarantining contacts
  • Measures to “increase social distance,” such as canceling mass gatherings and closing schools
  • Recommending that the public augment personal hygiene and wear masks
  • Limiting the spread of infection by domestic and international travelers, by issuing travel advisories and screening travelers at borders
  • Enhanced infection control measures in settings where care was provided to persons with SARS, especially in healthcare facilities and homes (Bell, 2004)

These measures also contained a smaller SARS outbreak in 2004 that originated from a laboratory-acquired infection. Measures to decrease the interval between onset of symptoms and isolation were effective in containing community transmission.

Some measures were implemented because of recommendations by WHO, while others were implemented by governments on their own initiative. A novel technology, infrared scanning, was used extensively in some countries to try to identify persons with fever at international borders and in public places (Bell, 2004).

Identifying and isolating patients, combined with rapid identification and management of contacts, were highly effective in interrupting transmission in several countries. For example, a study in Singapore demonstrated a correlation between rapidly isolating patients after onset of symptoms and a decreased number of secondary cases among their contacts (Bell, 2004).

Contacts in these countries were placed in various forms of quarantine or, less commonly, monitored for symptoms without confinement but isolated if and when symptoms emerged. The location of quarantine was usually at home but was sometimes at a designated residential facility (e.g., for travelers, persons who did not wish to remain at home for fear of exposing their families, homeless persons, and noncompliant persons). In some cases, quarantined persons were allowed to leave the quarantine site with the permission of local health authorities if they wore masks and did not use public transportation or visit crowded public places. In at least one area, these restrictions were applied to essential workers and termed work quarantine (Bell, 2004).

Ten Weeks into the COVID-19 Epidemic

On January 23, 2020, when the death count from the novel coronavirus reached 15, a quarantine was declared in Wuhan, China. Air travel was cancelled and trains and buses were stopped. Schools were closed and workers were given additional time off to try to prevent people from congregating and spreading the virus. People were encouraged to stay at home and to use a mask if they had to leave their homes (The Atlantic, 2020).

Travel was banned in the Chinese cities of Huanggang and Ezhou as infections were confirmed there. By January 24, an area with a population of 35 million people was quarantined. In the following days, up to 50 million people in China were quarantined, though that may have been too late to stop the spread of the virus (The Atlantic, 2020).

Wuhan is a city of 11 million people that is a major travel hub. Around 3,500 people daily take direct flights from Wuhan to cities outside of China. The virus began spreading during Lunar New Year celebrations when people travel to be with their families all over China and in other Asian countries. Although the Chinese government shut down travel to and from Wuhan, it is estimated that around 5 million people had already traveled from the city after the outbreak began and before travel restrictions were put into place by the Chinese government (NY Times, 2020b).

On January 30, WHO declared a global health emergency, and January 31 most airlines suspended flights to and from China.

Also, on January 31, the CDC issued mandatory 14-day quarantine orders for 195 U.S. citizens evacuated on a flight from Wuhan, China to a military base in Riverside, California. “CDC, under statutory authority of the HHS secretary, has issued federal quarantine orders for all 195 passengers,” according to CDC’s Messonnier. “While we recognize this is an unprecedented action, we are facing an unprecedented public health threat,” she said (NY Times, 2020c).

The Secretary of Health and Human Services (HHS), Alex M. Azar II, announced that further U.S. citizens returning from Hubei Province would also be quarantined for up to 2 weeks and foreign nationals who had been to China during the last 14 days would not be allowed to enter the United States (NY Times, 2020c).

Travelers who had been in Hubei Province in the previous 14 days were redirected to one of eleven U.S. airports to undergo screening. Screening at the eleven airports included:

  • If a traveler has fever, cough, or trouble breathing, CDC staff at the airport will evaluate for illness and the person will be taken to a medical facility for further evaluation and care. The patient will not be able to complete their travel itinerary.
  • If a traveler does not have symptoms (fever, cough, trouble breathing), he or she will be placed under a federal, state, or local quarantine order for a 14-day period from the time of departure from China. The traveler may not be able to complete their travel itinerary until the 14-day period has elapsed.

For travelers from other parts of China (outside Hubei Province) in the last 14 days:

  • If a traveler has fever, cough, or trouble breathing, CDC staff at the airport will evaluate the person for illness. He or she will then be taken to a medical facility for further evaluation and care. The person may not be able to complete their travel itinerary.
  • If a traveler does not have symptoms, he or she will be allowed to reach their final destination. After arrival at their final destination, the traveler will be asked to monitor their health for a period of 14 days from the time they left China. A health information card will be given that tells the person what symptoms to look for and what to do if symptoms develop. During that time, the person should stay home and limit interactions with others as much as possible. State or local health departments will make contact for further follow up (CDC, 2020h).

On January 27, 2020, CDC issued updated travel guidance for China, recommending that travelers avoid all nonessential travel to the entire country.

Effective February 2, 2020, the U.S. government suspended entry of foreign nationals who had been in China within the past 14 days.

U.S. citizens, residents, and their immediate family members who have been in Hubei province and other parts of mainland China are allowed to enter the United States, but they are subject to health monitoring and possible quarantine for up to 14 days (CDC, 2020h).

Traveler’s Card in English

Health Alert Card for Tavelers from China

Source: CDC, 2020.

Testing for COVID-19

CDC Test Kit for COVID-19

Image of Sample CDC Test Kit for COVID-19

Source: CDC, 2020.

CDC’s policy is to test people with a history of exposure who are showing symptoms. Testing people too early can potentially miss infections because the virus hasn’t established itself sufficiently in the system to be detected, the test may give a false negative result, and people may later become sick (CDC, 2020c).

According to a CDC press briefing on February 14, 2020:

CDC tested all of the initial 195 people who returned from Wuhan on January 29. But since that time we have learned more about how the virus behaves in people and when is the optimal time to test them [so as] to best inform our public health response. CDC may do testing of all people again if the risk warrants it, but right now, CDC staff (at each base where people are quarantined) are checking temperatures twice daily and monitoring people for any new symptoms. If someone has symptoms compatible with this new virus they’re medically evaluated and they’re tested (CDC, 2020c).

CDC has since expanded its testing policy for COVID-19 because of a new case in Solano County, California. A woman who was transferred from a local hospital to UC Davis Medical Center in Sacramento may be the first case of community spread of the disease in the United States. Even though the patient was showing symptoms of Covid-19, she did not meet the criteria of recent travel to China or contact with an infected person and therefore was not tested for several days.

“As soon as that case was recognized, we . . . revised our definition,” said CDC director Robert Redfield on February 27 at a congressional hearing. “If a public official suspects coronavirus, then we should get a test for coronavirus. That updated guidance went out today.”

Public Health Measures Recommended by CDC

Public health measures are used to slow down the spread and limit the size of an epidemic. These measures save lives and also buy time for treatments and vaccines to be developed.

CDC has established the following exposure risk categories to help guide optimal public health management of people following potential COVID-19 exposure (CDC, 2020i).

*In general, geographic exposure categories do not apply to travelers who only transit through an airport.
Source: CDC, March 7, 2020.

Risk Categories for Exposures Associated with International Travel or Identified during Contact Investigations of Laboratory-confirmed Cases

Risk Level

Geographic (Travel-associated) Exposures*

Exposures Identified through Contact Investigation

High

Travel from Hubei Province, China

Living in the same household as, being an intimate partner of, or providing care in a nonhealthcare setting (such as a home) for a person with symptomatic laboratory-confirmed COVID-19 infection without using recommended precautions for home care and home isolation

Medium (assumes no exposures in the high-risk category)

  • Travel from mainland China outside Hubei Province or Iran
  • Travel from a country with widespread sustained transmission, other than China or Iran
  • Travel from a country with sustained community transmission
  • Close contact with a person with symptomatic laboratory-confirmed COVID-19
  • On an aircraft, being seated within 6 feet (two meters) of a traveler with symptomatic laboratory-confirmed COVID-19 infection; this distance correlates approximately with 2 seats in each direction
  • Living in the same household as, an intimate partner of, or caring for a person in a nonhealthcare setting (such as a home) to a person with symptomatic laboratory-confirmed COVID-19 infection while consistently using recommended precautions for home care and home isolation

Low (assumes no exposures in the high-risk category)

Travel from any other country

Being in the same indoor environment (e.g., a classroom, a hospital waiting room) as a person with symptomatic laboratory-confirmed COVID-19 for a prolonged period of time but not meeting the definition of close contact

No identifiable risk

Not applicable

Interactions with a person with symptomatic laboratory-confirmed COVID-19 infection that do not meet any of the high-, medium- or low-risk conditions above, such as walking by the person or being briefly in the same room.

* * *

CDC recommends the following guidelines after determining risk categories for people exposed to the coronavirus (CDC, 2020h).

The public health actions recommended in the table below apply to people who have been determined to have at least some risk for COVID-19. People who are being managed as asymptomatic in a particular risk level who develop signs or symptoms compatible with COVID-19 should be moved immediately into the symptomatic category in the same risk level and be managed accordingly. The risk level does not change if symptoms develop.

EMS = emergency medical services; HCF = healthcare facility; PUI = Person Under Investigation for COVID-19
1For the purpose of this document: subjective or measured fever, cough, or difficulty breathing.
Source: CDC, March 7, 2020.

Summary of CDC Recommendations for Management of Exposed Persons with by Risk Level and Presence of Symptoms

Risk Level

Management if Asymptomatic

Management if Symptomatic1

High Risk

  • Quarantine (voluntary or under public health orders) in a location to be determined by public health authorities
  • No public activities
  • Daily active monitoring, if possible based on local priorities
  • Controlled travel
  • Immediate isolation with consideration of public health orders
  • Public health assessment to determine the need for medical evaluation; if medical evaluation warranted, diagnostic testing should be guided by CDC’s PUI definition
  • If medical evaluation is needed, it should occur with pre-notification to the receiving HCF and EMS, if EMS transport indicated, and with all recommended infection control precautions in place
  • Controlled travel: Air travel only via air medical transport. Local travel is only allowed by medical transport (e.g., ambulance) or private vehicle while symptomatic person is wearing a face mask

Medium Risk

Close contacts in this category:

  • Recommendation to remain at home or in a comparable setting
  • Practice social distancing
  • Active monitoring as determined by local priorities
  • Recommendation to postpone long-distance travel on commercial conveyances
  • Self-isolation
  • Public health assessment to determine the need for medical evaluation; if medical evaluation warranted, diagnostic testing should be guided by CDC’s PUI definition
  • If medical evaluation is needed, it should ideally occur with pre-notification to the receiving HCF and EMS, if EMS transport indicated, and with all recommended infection control precautions in place
  • Controlled travel: Air travel only via air medical transport. Local travel is only allowed by medical transport (e.g., ambulance) or private vehicle while symptomatic person is wearing a face mask

Travelers from mainland China (outside Hubei Province) or Iran

  • Recommendation to remain at home or in a comparable setting
  • Practice social distancing
  • Self-monitoring with public health supervision as determined by local priorities
  • Recommendation to postpone additional long-distance travel on commercial conveyances after they reach their final destination

Travelers from other country with widespread transmission

  • Recommendation to remain at home or in a comparable setting
  • Practice social distancing
  • Self-monitoring
  • Recommendation to postpone additional long-distance travel on commercial conveyances after they reach their final destination

Travelers from other country with sustained community transmission

  • Practice social distancing
  • Self-observation

Low Risk

  • No restriction on movement
  • Self-observation
  • Self-isolation, social distancing
  • Person should seek health advice to determine if medical evaluation is needed
  • If sought, medical evaluation and care should be guided by clinical presentation; diagnostic testing for COVID-19 should be guided by CDC’s PUI definition
  • Travel on commercial conveyances should be postponed until no longer symptomatic

No Identifiable Risk

None

  • Self-isolation, social distancing
  • Person should seek health advice to determine if medical evaluation is needed
  • If sought, medical evaluation and care should be guided by clinical presentation; diagnostic testing for COVID-19 should be guided by CDC’s PUI definition
  • Travel on commercial conveyances should be postponed until no longer symptomatic

Note: The public health management recommendations made above are primarily intended for jurisdictions not experiencing sustained community transmission. In jurisdictions not experiencing sustained community transmission, CDC recommends that post-exposure public health management for asymptomatic exposed individuals continue until 14 days after the last potential exposure; however, these decisions should be made based on the local situation, available resources, and competing priorities. These factors should also guide decisions about managing symptomatic exposed individuals.

International travelers and other potentially exposed individuals in jurisdictions experiencing sustained community transmission should follow local guidance.

Prevention

There is currently no vaccine to prevent a COVID-19 infection. The best way to prevent infection is to avoid being exposed to the virus. Everyday actions to help prevent the spread of respiratory viruses include (CDC, 2020i):

  • Wash your hands often with soap and water for at least 20 seconds, especially after going to the bathroom; before eating; and after blowing your nose, coughing, or sneezing.
  • If soap and water are not readily available, use an alcohol-based hand sanitizer with at least 60% alcohol. Always wash hands with soap and water if hands are visibly dirty.
  • Avoid touching your eyes, nose, and mouth with unwashed hands.
  • Avoid close contact with people who are sick.
  • Stay home when you are sick.
  • Cover your cough or sneeze with a tissue, then throw the tissue in the trash.
  • Clean and disinfect frequently touched objects and surfaces using a regular household cleaning spray or wipe. (CDC, 2020j)