Considerations for Health Screening at Points of Entry
Updated August 26, 2022
Purpose
To assist ministries of health and their partners at points of entry (POE) in determining whether and how to conduct traveler health screening at POE to prevent importation or exportation of a communicable disease of public health concern.
Introduction
The objective of public health screening is to reduce the international spread of certain communicable diseases that may pose a threat to co-travelers and destination communities. If an outbreak is occurring within a country, exit screening may be performed for departing travelers to detect those who are sick or who have been exposed to the disease and prevent them from leaving the country. If an outbreak is occurring in another country, entry screening may detect sick or exposed travelers upon arrival so they can be directed to appropriate isolation and care, or follow-up such as monitoring, as needed.
Public health screening occurs in two stages:
(1) primary screening, includes observing travelers for obvious signs of illness, measuring their temperature, and collecting information on travel and exposure history; and
(2) secondary screening includes having a healthcare or public health professional (whenever possible) conduct an additional public health assessment of ill or potentially exposed travelers identified through the primary screening process. The purpose of secondary screening is to identify the subset of travelers detected in primary screening who may need additional public health interventions, such as laboratory testing, symptom monitoring, or restriction of movement (isolation if sick or quarantine if exposed).
In addition to detecting ill travelers, public health screening at POE provides an excellent opportunity for countries to educate travelers about the signs and symptoms of communicable diseases of public health concern, how to protect themselves and their families from infection, and what to do if they become sick.
Public health screening at POE is resource intensive but is a flexible intervention that can be scaled up or down according to the needs of the country and the status of an outbreak. It is important that countries continuously monitor the evolution of an outbreak globally, nationally, and locally and adjust screening processes according to current needs and priorities. Factors to consider when enhancing screening include the mode of transmission for a priority communicable disease, the level of community connectivity between travelers passing through a POE and a geographic area with increased epidemiologic burden during an outbreak of concern, and the availability of public health resources to dedicate to screening and follow up measures. For example, screening may be most important and effective early in an outbreak when it presents an opportunity to slow the geographic spread of a disease of public health concern, allowing further time for unaffected areas to prepare their health systems, citizens, and social institutions (e.g., schools, businesses) for possible disease importation. Further, the World Health Organization (WHO) may recommend enhanced screening measures when declaring a Public Health Emergency of International Concern.
When initiating POE screening, it is important to identify criteria for when screening may be stopped. Reasons could include a determination that the outbreak has been contained, limited public health resources are needed elsewhere (such as in communities), or screening is no longer beneficial to preventing the international spread of disease.
Countries may wish to adopt different screening strategies after a communicable disease has been introduced and there is sustained transmission in local communities. At that stage, entry screening may no longer be the best use of limited human and other resources; traveler education and community mitigation strategies (e.g., social distancing, closing schools, canceling or postponing mass gatherings) may be more beneficial in slowing the disease’s spread.
The sections below provide guidance on the following:
- Limitations of public health screening at POE
- Implementing public health screening at a POE
- Checklist for countries to understand if they have the capacity to implement public health screening at POE
- Additional considerations for implementing screening at ground crossings or ports
- Opportunities for health officials to communicate with the traveling public
Limitations of Public Health Screening at POE
Public health screening at POE is subject to important limitations and should be implemented concurrently with enhanced surveillance and other public health measures.1
The following limitations of public health screening at POE should be kept in mind:
- Screening is most effective for detecting overtly ill travelers with communicable diseases for which elevated temperature is a symptom or screeners could observe clear signs of illness; travelers who are infected but not exhibiting signs of illness (e.g., presymptomatic or asymptomatic) may be missed during screening at POE, especially if they do not self-report a possible exposure (see 3rd limitation below).
- Transmission from presymptomatic and asymptomatic infected persons can occur for certain diseases. This reduces the effectiveness of public health screening at POE, particularly exit screening, as asymptomatic travelers could infect co-travelers or others within the POE or at their destination.
- Obtaining reliable temperature readings is affected by multiple factors, including:
- The ambient environment in which the temperature is measured. If the environment is extremely hot or cold, body temperature readings may be affected, regardless of the device that is used to measure body temperature.
- Proper calibration of the thermometers per manufacturer standards. Improper calibration can lead to incorrect temperature readings.
- Proper use and reading of the thermometers.
- Non-contact infrared thermometers frequently used for health screening must be held at a certain distance from the temporal artery in the forehead to take the temperature correctly. Holding the device too far from or too close to the temporal artery or taking the temperature of a different part of the body may affect the reading.
- Thermal scanners require increased space, sustained power supply, trained personnel to monitor the screening process, and additional expertise and resources to meet manufacturers’ specifications. Additionally, a trained public health screener should confirm an elevated temperature reading from a thermal scanner by taking a second measurement on the individual using a non-contact infrared thermometer or oral thermometer.
- Effective screening depends on travelers behaving in a manner that may conflict with their immediate personal interests. To avoid disruptions to their travel, people might not reveal information about their symptoms or exposure history or try to disguise symptoms by taking medication.
Implementing Public Health Screening at a POE
Countries should evaluate their available resources and adopt a risk-based approach when determining which POE to select for public health screening activities.2 Some factors to consider are:
- The volume of travelers through the POE
- Demographic and travel information about travelers through the POE, including where they are coming from, going to, and stopping at, the purpose of travel, and how long they will stay 3
- The level of connectivity between travelers passing through the POE and geographic areas with known community transmission of the communicable disease of public health concern 3
- The level of cases occurring near the POE
- Screening feasibility at the POE (i.e., Is there a way to direct travelers through the screening process? Can screening staff easily access the designated location? Can ill travelers be isolated safely at the POE and transported safely to a referral healthcare facility?; refer to questions below for more detail)
- Ability to communicate in different languages spoken by travelers; accommodate family units if a member of the family is referred for screening, especially if the family includes children; screen individuals with disabilities; or engage with travelers who cannot or will not comply with the screening measures
Screening should only be implemented at POE where the safety and security of both travelers and screening personnel can be assured (e.g., screening should not be located in areas vulnerable to violence or outside areas lacking shade or protection from the elements).
These questions are meant to guide countries through considerations about the capacities needed to implement public health screening at POE. CDC recommends that countries do not implement screening until they can answer “Yes” to all “Yes/No” questions and have mechanisms in place to respond to suspected cases identified at POE, including isolation and referral for diagnostic testing or medical care as needed.
Does the COUNTRY have or has the COUNTRY identified:
The legal and regulatory authorities to detain, isolate, or quarantine travelers passing through a POE?
The legal and regulatory authorities to detain, isolate, or quarantine travelers passing through a POE?
Yes
Yes
No
No
Sufficient funding to support screening and follow-up actions including:
Is there funding to pay for:
- Screeners’ salaries
- Screening supplies and equipment
- Food, water, and other necessities for travelers who are being detained, for a limited amount of time, for evaluation at the POE.
- Every effort should be made to evaluate ill travelers quickly and either evacuate them for further diagnosis and care or allow them to continue their travel.
- A clear plan for follow-up of travelers who may have been exposed to disease1
Countries should consider overall funding needs and sources of funding both in the short and long terms.
Sufficient funding to support screening and follow-up actions including:
Is there funding to pay for:
- Screeners’ salaries
- Screening supplies and equipment
- Food, water, and other necessities for travelers who are being detained, for a limited amount of time, for evaluation at the POE.
- Every effort should be made to evaluate ill travelers quickly and either evacuate them for further diagnosis and care or allow them to continue their travel.
- A clear plan for follow-up of travelers who may have been exposed to disease1
Countries should consider overall funding needs and sources of funding both in the short and long terms.
Yes
Yes
No
No
Is there a referral healthcare facility for each priority POE where the staff will send ill travelers for diagnosis and care?
Is there a referral healthcare facility for each priority POE where the staff will send ill travelers for diagnosis and care?
Yes
Yes
No
No
Are there established methods to monitor exposed travelers, either remotely or in person, to identify those who develop symptoms so they can be isolated and referred to a healthcare facility for diagnosis and care, as needed?
Are there established methods to monitor exposed travelers, either remotely or in person, to identify those who develop symptoms so they can be isolated and referred to a healthcare facility for diagnosis and care, as needed?
Yes
Yes
No
No
If mandated quarantine or isolation of travelers are considered as strategies, has the COUNTRY identified:
Places to house travelers away from the POE for prolonged quarantine or isolation where their safety and physical and mental health can be assured?
Places to house travelers away from the POE for prolonged quarantine or isolation where their safety and physical and mental health can be assured?
Yes
Yes
No
No
A method to provide food, water, medications, and other necessities to quarantined or isolated individuals?
A method to provide food, water, medications, and other necessities to quarantined or isolated individuals?
Yes
Yes
No
No
A way to enable quarantined or isolated individuals to receive and send communications?
A way to enable quarantined or isolated individuals to receive and send communications?
Yes
Yes
No
No
Does the POE have:
Protocols for primary and secondary screening, including a clear definition for suspected cases, based on illness presentation and/or exposure history?
Effective screening requires having defined mechanisms to manage travelers meeting the primary screening definition of a suspected case, including those who are not ill but who have reported an exposure. Implementing primary screening without the ability to follow up when suspected cases are identified creates unnecessary confusion and delays during the screening process.
Protocols for primary and secondary screening, including a clear definition for suspected cases, based on illness presentation and/or exposure history?
Effective screening requires having defined mechanisms to manage travelers meeting the primary screening definition of a suspected case, including those who are not ill but who have reported an exposure. Implementing primary screening without the ability to follow up when suspected cases are identified creates unnecessary confusion and delays during the screening process.
Yes
Yes
No
No
An adequate number of trained primary and secondary screeners who demonstrate competency in carrying out assigned screening tasks?
Primary screeners do not need to have prior health or medical experience; they can be anyone who demonstrates competency in taking a temperature, observing for signs and symptoms of illness, asking screening questions or reviewing a health declaration form, and determining if a person needs to be sent to secondary screening based on established criteria.
Secondary screeners should ideally have medical training (nurse or physician).
The number of primary screeners needed may vary by POE and the resources available. Ideally, there should be two primary screeners for every 60 travelers per hour. Primary screeners should work in pairs, with one screener conducting visual observation and temperature checks and the other asking questions or reviewing health declaration forms to obtain information about travel history, possible exposures, and traveler-reported signs and symptoms of illness. Screening of each traveler should take less than approximately 1 minute/person, noting that most non-contact infrared thermometers require a rest period of 15 to 60 seconds between temperature readings, depending on the brand.
One onsite secondary screener per shift at each POE is usually sufficient.
The POE should have contingency staffing plans if secondary screeners are unable to perform their duties due to exposures or illness.
An adequate number of trained primary and secondary screeners who demonstrate competency in carrying out assigned screening tasks?
Primary screeners do not need to have prior health or medical experience; they can be anyone who demonstrates competency in taking a temperature, observing for signs and symptoms of illness, asking screening questions or reviewing a health declaration form, and determining if a person needs to be sent to secondary screening based on established criteria.
Secondary screeners should ideally have medical training (nurse or physician).
The number of primary screeners needed may vary by POE and the resources available. Ideally, there should be two primary screeners for every 60 travelers per hour. Primary screeners should work in pairs, with one screener conducting visual observation and temperature checks and the other asking questions or reviewing health declaration forms to obtain information about travel history, possible exposures, and traveler-reported signs and symptoms of illness. Screening of each traveler should take less than approximately 1 minute/person, noting that most non-contact infrared thermometers require a rest period of 15 to 60 seconds between temperature readings, depending on the brand.
One onsite secondary screener per shift at each POE is usually sufficient.
The POE should have contingency staffing plans if secondary screeners are unable to perform their duties due to exposures or illness.
Yes
Yes
No
No
Adequate personal protective equipment (PPE) 4 and screening tools (e.g., non-contact thermometers, batteries, health declaration forms)?
Adequate personal protective equipment (PPE) 4 and screening tools (e.g., non-contact thermometers, batteries, health declaration forms)?
Yes
Yes
No
No
A way to isolate symptomatic travelers safely and away from other travelers and POE personnel to await further evaluation or transfer to a healthcare facility?
CDC recommends that ill travelers not be held at the POE longer than necessary. As soon as possible, after identifying a suspect case, the traveler should be transported safely (with precautions to avoid exposing the driver or other transport personnel) to a pre-determined referral healthcare facility with known capacity and necessary infection prevention and control measures in place to handle cases of communicable disease.
A way to isolate symptomatic travelers safely and away from other travelers and POE personnel to await further evaluation or transfer to a healthcare facility?
CDC recommends that ill travelers not be held at the POE longer than necessary. As soon as possible, after identifying a suspect case, the traveler should be transported safely (with precautions to avoid exposing the driver or other transport personnel) to a pre-determined referral healthcare facility with known capacity and necessary infection prevention and control measures in place to handle cases of communicable disease.
Yes
Yes
No
No
An isolation area equipped with its own access to potable water, toilet, handwashing facilities, trash receptacles, and a place to sit or lie down?
An isolation area equipped with its own access to potable water, toilet, handwashing facilities, trash receptacles, and a place to sit or lie down?
Yes
Yes
No
No
Additional Considerations for Implementing Public Health Screening at Ground Crossings or Ports
Airports have established infrastructure, resources, and ability to funnel travelers through controlled pathways to enforce screening compliance. However, ground crossings and ports often lack the infrastructure and resources to carry out screening in a systematic way. Screening at ground crossings and ports slows travel and can be easy to bypass by taking a detour around the screening point, leading to travelers crossing at unstaffed sections of the border. Travelers who do not wish to be delayed or who are sick and do not want to be prevented from traveling may try to bypass POE screening.
Opportunities for Health Officials to Communicate with the Traveling Public
Points of entry provide opportunities for health officials to communicate with travelers about health risks in their countries and in other countries, how to protect themselves during travel, as well as what to expect after travel, especially if they have been in a country with active community transmission of a disease of public health concern.
The following are some recommended communication strategies for countries to consider developing in addition to, or apart from, other public health measures instituted at POE.
Key information to share with travelers includes:
- Before travel
- How to prepare for upcoming international travel, including:
- Measures to stay healthy and reduce the risk of infection during travel
- Public health measures in place at departure
- Recommendations to regularly check the information posted on official government websites of the destination country to find out about:
- Presence or level of ongoing community transmission of disease
- Screening in place at POE or regulatory measures (e.g., testing, monitoring, isolation, quarantine) for travelers
- Availability of healthcare services at their destination
- Screening or regulatory measures they should expect upon return to their country of origin
- How to prepare for upcoming international travel, including:
- During or after travel
- How to protect themselves and others from the disease of concern
- How to self-monitor for symptoms of the disease of concern and what to do if symptoms develop
Methods of communication for travel-related messaging include:
- Distributing Travel Health Alert Notices (T-HAN), electronically if possible, to arriving or departing travelers containing information about the disease and recommended public health actions
- Displaying health messages at POE in areas where they will be visible to most international travelers
- Creating audio or video messages about the disease and public health measures for use at POE or for airlines to broadcast during flights with information about what to expect onboard and upon arrival
- Disseminating relevant messages more broadly through other mechanisms, e.g., social media, television, radio, SMS
- Adapting the messages into multiple languages used by travelers through the POE or to convey the information using culturally appropriate materials
For examples of traveler health communications, visit Communication Resources for Travelers.
Footnotes
1 Measures may include contact tracing, community mitigation measures (e.g., school closures, canceling of large gatherings), maintaining physical distance, wearing a mask in public, and quarantine of exposed persons. Analyzing where travelers go after leaving the POE and how those locations are connected to other parts of the country can help to predict where the disease may spread if introduced via travel.
2 Tool to Prioritize Points of Entry and Points of Control (ToP POE/C)
3 CDC can provide the Population Connectivity Across Borders toolkit designed to support community engagement and analytic activities to characterize population movement and connectivity patterns (An approach to integrate population mobility patterns and sociocultural factors in communicable disease preparedness and response; Population Connectivity Across Borders (PopCAB) Toolkit)
4 Follow guidance on PPE use for healthcare workers conducting screening activities issued by your country.