Public Health Guidance for Potential COVID-19 Exposure Associated with Travel

Public Health Guidance for Potential COVID-19 Exposure Associated with Travel
Updated Jan. 15, 2021

To reduce introduction and spread of new variants of SARS-CoV-2, CDC issued an Order pdf icon[101 KB, 9 pages] effective January 26, 2021. It requires all air passengers arriving to the US from a foreign country to get tested for COVID-19 infection no more than 3 days before their flight departs and to provide proof of the negative result or documentation of having recovered from COVID-19 to the airline before boarding the flight. For more information on this testing requirement, see the Frequently Asked Questions.

CDC has separate guidance for exposures in healthcare personnel and critical infrastructure workers, and for quarantine of contacts of persons with COVID-19.

Cruise ships in U.S. waters or intending to return to U.S. waters must continue to follow CDC’s Framework for Conditional Sailing Order (CSO) and the Technical Instructions for Mitigation of COVID-19 Among Cruise Ship Crew.

Summary of Recent Changes

As of December 2, 2020

  • Added recommendations for predeparture and post-arrival testing and new considerations for post-arrival management of international travelers

View Previous Updates

Background

The COVID-19 pandemic has spread throughout the world. Individuals who travel may be at risk for exposure to SARS-CoV-2, the virus that causes COVID-19, before, during, or after travel. This could result in travelers’ spreading the virus to others at their destinations or upon returning home.

As part of a broader strategy aimed to limit continued new introduction of SARS-CoV-2  into U.S. communities, all travelers should remain vigilant for signs and symptoms of COVID-19, and take recommended precautions to limit community spread after traveling from one location to another. Travelers with greater potential risk of exposure because of the circumstances of their travel (e.g., travel from a country with a level 2, 3 or 4 travel health notice), or activities during travel are recommended to take additional precautions during the 14 days after travel.

Audience and Purpose

This page provides U.S. public health officials with an overview of CDC’s recommendations and considerations for management of domestic and international travelers with potential SARS-CoV-2 exposure.

Recommendations and Considerations

CDC’s recommendations and considerations for public health management of international and domestic travelers are provided below. Health departments have the authority to exceed CDC recommendations in their jurisdictions. Travelers should follow guidance and requirements of destination countries for international travel, or state, territorial, tribal, and local authorities for U.S. domestic travel.

International Travelers: Predeparture Testing Recommendations

Predeparture testing may detect travelers infected with SARS-CoV-2 before they initiate their travel. CDC recommends testing with a nucleic acid amplification test (NAAT) or antigen test and receipt of results 1-3 days before departure for international travelers, particularly those traveling long-distance on public transportation conveyances, such as airplanes, buses or trains, or passing through transportation hubs such as airports where social distancing may be challenging, as a means to reduce the risk of SARS-CoV-2 transmission during travel. Testing does not eliminate all risk, but when predeparture testing is combined with self-monitoring for symptoms of COVID-19, wearing masks, social distancing, and hand hygiene, it can make travel safer by reducing spread on conveyances and in transportation hubs.

CDC modeling indicates that predeparture testing is most effective when combined with self-monitoring (Johansson et al). Travel should be delayed (i.e., individuals should self-isolate) if symptoms develop or a pre-departure test result is positive. Testing before departure results in the greatest reduction of transmission risk during travel when the specimen is collected close to the time of departure. Earlier testing, i.e., more than 3 days before travel, provides little benefit beyond what self-monitoring alone can provide. Furthermore, a lower sensitivity test (e.g., antigen test) closer to the time of travel (i.e., with rapid availability of results) can be as effective as, or more effective than, a higher sensitivity NAAT (e.g., reverse transcription polymerase chain reaction test [RT-PCR]) performed several days before travel. Predeparture testing should be completed and results provided to the traveler before travel is initiated. Travelers who test positive should remain in isolation and delay travel until they meet criteria for discontinuing isolation. Travelers whose test results are not available before departure should delay their travel until results are available.

CDC modeling indicates that testing on the day of travel provides the greatest reduction in transmission risk while traveling (Johansson et al). However, for logistical reasons (e.g., rebooking of travel and avoiding potential exposures in airport terminals where social distancing may be challenging), CDC recommends departing air travelers get tested before they initiate travel, rather than at the airport immediately prior to their flight. Testing is being offered at a number of airports, both domestically and internationally, and many air travelers are choosing to get tested in airports because of convenience and ease of access. If testing is offered in airport settings, all results (positive or negative) must be reported in real time to the health department of jurisdiction, and positive results in departing air travelers should be reported immediately to both the local health department and the CDC quarantine station of jurisdiction. Ideally, travelers’ consent should also be obtained before testing to notify the airline of a positive result. Plans should also be in place to prevent travel of persons who test positive and their travel companions, who in most cases would be considered close contacts, including request by the health department to CDC for use of federal public health travel restrictions and denial of boarding by the airline (see section below). Testing sites should also have plans to manage individuals who test positive and their travel companions, including temporary isolation or quarantine and safe private transportation home that does not involve public transportation.

International Travelers: Recommendations and Considerations for Post-arrival Testing and Management

Travel poses a risk of introducing additional cases of COVID-19 to destination communities. All travelers should be advised to take precautions to protect others until 14 days after arrival, including social distancing, wearing masks (including in shared spaces within households, by both travelers and nontravelers, when only some people traveled), hand hygiene, and monitoring themselves for symptoms of COVID-19.

CDC recommends the following for international air travelers and others with higher risk of exposure (see CDC’s After You Travel Internationally webpage for examples of higher-risk exposures associated with travel):

  • A post-arrival test 3-5 days after arrival at destination, combined with self-monitoring and a 7-day period of staying home (or in a comparable location such as a hotel room)
    • The 7-day period should be completed even if the test is negative.
    • In the absence of testing, this period should be extended to 10 days.
  • Avoiding contact with people at higher risk for severe illness for 14 days, regardless of testing.

Below we provide technical considerations for U.S. health departments in developing their strategies for post-arrival management of travelers, including the timing of testing and using testing in combination with other measures.

Note: These considerations are specifically intended for management of asymptomatic travelers with no known exposures to a person with COVID-19. They are not intended to be used in developing policies for management of individuals with probable or confirmed COVID-19 or those who have had close contact to a person with COVID-19.

Technical Considerations on Testing and Post-arrival Management (based on CDC modeling)

Mathematical models have provided some insights to potential impacts of testing and various quarantine periods. CDC modeling suggests that, when combined with post-arrival testing and self-monitoring for symptoms of COVID-19 (with subsequent isolation for those who test positive or develop symptoms), the period of staying home or in a comparable location such as a hotel (referred to as stay-at-home period in the remainder of this section) can be shortened without substantially increasing the risk of introducing additional cases of COVID-19 to the destination community (Johansson et al).

The optimal post-arrival test timing and reduction in risk of introducing additional cases of COVID-19 at destination (referred to as transmission risk in the remainder of this section) vary depending on what other measures are taken. The scenarios below assume all travelers self-monitor for symptoms of COVID-19 and self-isolate if symptoms develop.

Stay-at-home Period with or without Post-arrival Testing

  • With a stay-at-home period for 14 days after travel (i.e., with or without testing), the transmission risk can be almost eliminated. Although a 14-day stay-at-home period provides the greatest reduction in transmission risk, it may be perceived as burdensome and incompatible with critical work or essential errands, and compliance may be poor.
  • Combined with a 7-day stay-at-home period, testing at 3-4 days post-arrival is optimal and provides a comparable reduction in transmission risk to a 14-day stay-at-home period. To achieve this level of risk reduction, the 7-day period should be completed even if the test is negative. For practical purposes, the post-arrival testing period may be extended to 3-5 days after arrival at destination.
  • A stay-at-home period of 7-10 days without testing provides a greater reduction in risk than post-arrival testing alone, regardless of when the testing occurs.
  • Regardless of the stay-at-home period, travelers should also take precautions to prevent transmission within their households, including mask wearing including in shared spaces within households, by both travelers and nontravelers, when only some people traveled.

Predeparture Testing and Post-arrival Testing with No Stay-at-home Period

  • The combination of predeparture and post-arrival testing provides additional risk reduction over either predeparture or post-arrival testing alone, with a moderate reduction in transmission risk at destination.

Post-arrival Testing Alone with No Stay-at-home Period

  • A single test at 1-3 days post-arrival provides a greater reduction in transmission risk at destination than testing only prior to travel, although the reduction in risk is still relatively small.

Predeparture Testing with No Post-arrival Management (other than symptom monitoring)

  • Predeparture testing is important to prevent transmission during travel but is less likely to detect infections in travelers who might have been exposed after their predeparture test or who were infected close to the time of testing.
  • Such travelers are likely to experience their entire infectious period in the destination location and, therefore, pose the highest transmission risk at destination.

References

Johansson MA, Wolford H, Paul P, et al. Reducing travel-related SARS-CoV-2 transmission with layered mitigation measures: Symptom monitoring, quarantine, and testing. Available at: https://www.medrxiv.org/content/10.1101/2020.11.23.20237412v1external icon

Clifford S, Quilty BJ, Russell TW, Liu Y, Chan Y-WD, Pearson CAB, et al. Strategies to reduce the risk of SARS-CoV-2 re-introduction from international travellers. medRxiv. 2020; 2020.07.24.20161281. doi:10.1101/2020.07.24.20161281

Ashcroft P, Lehtinen S, Angst DC, Low N, Bonhoeffer S. Quantifying the impact of quarantine duration on COVID-19 transmission. medRxiv. 2020; 2020.09.24.20201061. doi:10.1101/2020.09.24.20201061

Quilty BJ, Clifford S, Group2 C nCoV working, Flasche S, Eggo RM. Effectiveness of airport screening at detecting travellers infected with novel coronavirus (2019-nCoV). Eurosurveillance. 2020;25: 2000080. doi:10.2807/1560-7917.ES.2020.25.5.2000080

Wells CR, Townsend JP, Pandey A, Krieger G, Singer B, McDonald RH, et al. Optimal COVID-19 quarantine and testing strategies. medRxiv. 2020; 2020.10.27.20211631. doi:10.1101/2020.10.27.20211631

Individuals with Confirmed or Probable COVID-19 or Known Exposure to Someone with COVID-19

Individuals with confirmed or probable COVID-19 should remain in isolation and delay travel until they meet criteria for discontinuing isolation. Individuals who have been exposed (i.e., close contacts) to a person with confirmed COVID-19 should remain in quarantine and delay travel until they meet criteria for release from quarantine. Health departments may request use of federal public health travel restrictions for individuals with confirmed COVID-19 or with known exposure, if they intend to travel before being cleared to do so by public health authorities, by contacting the CDC quarantine station with jurisdiction for the area where the person is located.

If travel is necessary (e.g., for repatriation or to obtain medical care that is not available locally), transportation should be conducted in a manner that does not expose conveyance operators (e.g., air crews, bus drivers) or other travelers. The mode of transportation should be guided by distance (e.g., ground vs. air transportation) to final destination as well as the clinical condition of the traveler (i.e., whether medical care may be needed en route).

  • Options for travelers with confirmed or probable COVID-19 are private vehicle or approved medical transport (i.e., ground or air medical transport with infection control precautions in place to protect vehicle operators and medical personnel).
  • Options for travelers with known exposure to someone with COVID-19 are private vehicle or private air charter with precautions in place to protect air crews.

Travel should also be coordinated with public health authorities at traveler’s intended destination. For international transport with a destination within the United States, per CDC regulations (42 Code of Federal Regulations, Part 71: Foreign Quarantineexternal icon), the conveyance operator must notify CDC in advance through the CDC quarantine station with jurisdiction for the port of entry or the CDC Emergency Operations Center (770-488-7100 or eocreport@cdc.gov).

International Air Passenger Contact Information

CDC supports domestic COVID-19 control efforts by making contact information for international air passengers available to state and local health departments for the purpose of public health follow-up or contact tracing. At present, collection of traveler contact information is occurring for passengers from countries subject to entry restrictions under Presidential Proclamation.

Follow-up with travelers may include contacting travelers, providing instructions for what travelers should do if they develop illness compatible with COVID-19, follow-up of test results, and intermittent check-ins during the post-arrival period. Mobile applications or automated text messaging may be useful to provide information to travelers or conduct monitoring of travelers. Follow-up with travelers is at the discretion of health departments and may be considered by jurisdictions that are implementing containment measures. Decisions about whether to conduct follow-up and what it would involve could be based on the status of the COVID-19 outbreak in the jurisdiction, status of the COVID-19 outbreak in travelers’ countries or states of origin, the volume of travelers, available resources, competing priorities of public health officials, and other factors, as applicable.

Crews on Passenger or Cargo Flights

CDC and the Federal Aviation Administration have jointly provided Updated Interim Occupational Health and Safety Guidance for Air Carriers and Crews pdf icon[PDF – 7 pages]external icon. This FAA-CDC guidance includes recommendations for aircrews to self-monitor under the supervision of their employer’s occupational health program and to remain in their hotel rooms to the extent possible and practice social distancing while on overnight layovers. As long as crew members re­­­­­main asymptomatic and have no known exposures to a person with COVID-19, they may continue to work on flights into, within, or departing from the United States. Crew members who follow their carrier’s occupational health plan as well as the FAA-CDC guidance are not subject to CDC’s recommendation to stay at home after international air travel. If they develop fever, cough, shortness of breath, or other symptoms of COVID-19, crew members should self-isolate and be excluded from work on commercial flights until cleared to work by their employer’s occupational health program following CDC’s criteria for Discontinuation of Isolation for Persons with COVID-19 Not in Healthcare Settings.

Crew members who have known exposure (i.e., close contacts) to a person with COVID-19 should be excluded from work until they meet criteria for release from quarantine. While air travel is a vital economic activity, CDC does not recommend allowing crew members with known exposures to continue to work, even if asymptomatic, because of the inability of crew members to remove themselves from the workplace if they develop symptoms during a flight and the challenges involved in effectively isolating a symptomatic person on board an aircraft.

Previous Updates