Screening

Management of contacts

Definition

  • The World Health Organization defines a contact as a person who has experienced any one of the following exposures during the 2 days before and the 14 days after the onset of symptoms of a probable or confirmed case:[779]

    • Face-to-face contact with a probable or confirmed case within 3 feet (1 meter) and for more than 15 minutes

    • Direct physical contact with a probable or confirmed case

    • Direct care for a patient with probable or confirmed COVID-19 without using recommended personal protective equipment

    • Other situations as indicated by local risk assessments.

  • The Centers for Disease Control and Prevention (CDC) defines a close contact as someone who has been within 6 feet (2 meters) of an infected person for at least 15 minutes over a 24-hour period, beginning 2 days before symptom onset (or 2 days before testing in asymptomatic patients).[125]

  • Consult local guidance as definitions of a contact may vary depending on local public health advice.

Quarantine periods

  • The World Health Organization recommends that asymptomatic contacts of confirmed or probable cases, including healthcare workers, be quarantined in a designated facility or in a separate room in the household for 14 days from the last contact with the case. Any person in quarantine who develops symptoms should be treated and managed as a suspected case and tested according to national testing strategies and guidelines. Laboratory testing is not a requirement for leaving quarantine after 14 days for contacts who do not develop symptoms.[779] Testing can be used as a measure to shorten quarantine (e.g., to 7 days) if the contact shows no symptoms and presents a negative test, in the context of the Omicron variant. Where testing to shorten quarantine is not possible, quarantine may be ended after 10 days without testing if the contact presents no symptoms.[780]

  • In the UK, contacts are no longer required to self-isolate.[781]

  • In the US, the CDC recommends that contacts who are up-to-date with vaccinations do not need to quarantine unless they develop symptoms. However, they should get tested at least 5 days after their exposure even if they don’t develop symptoms (except people with confirmed COVID-19 within the past 90 days), and take precautions until day 10 (e.g., wear a mask around others, take precautions if traveling, avoid being around people who are at high risk). Contacts who are not up-to-date with their vaccinations are required to quarantine for at least 5 days, get tested at least 5 days after their exposure even if they don’t develop symptoms, and take the same precautions until day 10.[782] CDC: quarantine and isolation calculator Opens in new window

  • Consult local guidance for recommended quarantine locations and timeframes as recommendations vary depending on local public health advice.

Screening of asymptomatic populations

The World Health Organization does not currently recommend widespread screening of asymptomatic individuals due to the significant costs associated with it and the lack of data on its operational effectiveness. Testing of asymptomatic individuals is currently recommended only for specific groups including contacts of confirmed or probable cases and frequently exposed groups such as healthcare workers and long-term care facility workers.[581]

Drive-through screening centers

Drive-through screening centers have been set up in some countries for safer and more efficient screening. The testee does not leave their car throughout the entire process, which includes registration and questionnaire, exam, specimen collection, and instructions on what to do after. This method has the advantage of increased testing capacity and prevention of cross-infection between testees in the waiting space.[783]

Temperature screening

There is little scientific evidence to support temperature screening with thermal cameras or temperature screening products (e.g., noncontact infrared thermometers) as a reliable method for the detection of COVID-19 or any other febrile illness, especially if used as the main method of testing.[784][785][786]

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