14th May, 2020

What quarantine measures are required for health care workers travelling from higher prevalence areas to low prevalence areas? - Evidence April 14, 2020

Coronavirus/COVID-19

Context

  • Healthcare workers (HCWs) are a substantial vector of SARS-CoV-2 (COVID-19)
  • Travel from higher prevalence settings to low prevalence settings poses a risk of transmission of SARS-CoV-2 (COVID-19)
  • There may be state and territory, regional, local and/or community travel restrictions and requirements that need to be considered
  • Maintaining access to high quality primary health care is critical including during the period of restrictions due to social distancing requiremen

Recommendations

All alternatives to visiting the community should be explored including:

  • consultations by telehealth
  • remote support to local health staff
  • cancelling non-essential visits.

If there are any feasible alternatives to visiting a lower prevalence area, they should be pursued. All HCWs entering a lower prevalence area from a higher prevalence area are potentially symptomatic or asymptomatic carriers of COVID-19. It is therefore critical in these settings to be ambitious about prevention and minimise transmission risk, despite the additional burden this may place on services.

The median incubation period for COVID-19 is estimated at 5 to 6 days (1). Most studies report a maximum incubation period of 14 days. International quarantine policies are based on the 14-day incubation period. However, one case study indicates that the incubation period may be as long as 24 days (2). If the incubation period can be greater than 14 days, an extended quarantine duration may be required to minimise the spread of COVID-19 (2).

Based on current best available evidence (3):

  • less than 2.5% of infected persons will show symptoms within 2.2 days (Confidence Interval: 1.8 to 2.9 days) of exposure
  • around half of infected persons will show symptoms within 5 days – this means half will not show symptoms until after 5 days
  • 97.5% of infected persons will show symptoms within 11.5 days (Confidence Interval: 8.2 to 15.6 days)
  • among people who are infected and go on to develop symptoms, 101 in 10 000 will develop symptoms after 14 days (i.e. outside of the quarantine period), and this estimate may be conservative.

Given the risks associated with providing care while a symptomatic or asymptomatic carrier of COVID-19, HCWs should only travel from a higher prevalence area to a lower prevalence area if a visit is considered absolutely necessary. For example, this may include when a health service cannot meet the needs of the communityusing the combination of available staff providing in-person services and telehealth services by other HCWs, where relevant.

If a visit is considered absolutely necessary:

  • HCWs may travel from a higher prevalence area to a lower prevalence area if, in the last 14 days, they:
    • have not travelled overseas; and
    • have not had fever (≥38°C), chills, and/or night sweats; and
    • have not had acute respiratory infection, including sore throat, cough, or shortness of breath; and
    • have not had contact with a confirmed COVID-19 case without adequate use of PPE.
  • HCWs who have experienced fever or respiratory symptoms in the last 14 days may enter a lower prevalence area if
    • they no longer have fever or respiratory symptoms and
    • they have had a negative PCR test for COVID-19 since the onset of symptoms.

We recommend that to travel a higher prevalence area to a lower prevalence area for exemption, HCWs must not have experienced any of the signs or symptoms of COVID-19 (fever, chills, night sweats, or acute respiratory infection – including sore throat, cough, or shortness of breath) over the period of 14 days prior to entry. The rationale for including symptoms over the 14 day period prior to entry is that, under current guidelines, HCWs should be tested for COVID-19 if they have a fever (≥38°C, or history of fever) or acute respiratory infection (4).

HCWs should be aware of other symptoms of COVID-19 as they are identified. The Centre for Evidence-Based Medicine provides a ‘COVID-19 Signs and Symptoms Tracker’ that is updated as data emerges (5).

There are currently no guidelines specific to Aboriginal and Torres Strait Islander communities or to Australia on risk assessment on COVID-19 risk after exposure in the health care setting. Until local guidelines are developed, HCWs can assess their risk using the CDC (6) or WHO (7) risk assessment tools. 

If a visit is considered absolutely necessary:

As above, the Communicable Disease Network Australia (CDNA) COVID-19 guidelines (10) recommend that HCWs be tested for COVID-19 if they have experienced fever or respiratory symptoms. If HCWs have experienced symptoms in the last 14 days but return a negative PCR test for COVID-19 and are no longer symptomatic, they may enter a lower prevalence area, noting that: ‘A risk assessment should be undertaken for suspected cases who initially test negative for SARSCoV-2. If there is no alternative diagnosis and a high index of suspicion remains that such cases may have COVID-19, consideration should be given to continued isolation and use of the recommended infection control precautions, pending further testing’ (4).

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References

1.    Del Rio C, Malani PN. COVID-19—New Insights on a Rapidly Changing Epidemic. JAMA. 2020.

2.    Bai Y, Yao L, Wei T, Tian F, Jin D-Y, Chen L, et al. Presumed asymptomatic carrier transmission of COVID-19. JAMA. 2020.

3.    Lauer SA, Grantz KH, Bi Q, Jones FK, Zheng Q, Meredith HR, et al. The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: estimation and application. Annals of Internal Medicine. 2020.

4.    Communicable Diseases Network Australia. Coronavirus Disease 2019 (COVID-19): CDNA National Guidelines for Public Health Units v. 2.5. Available from: https://www1.health.gov.au/internet/main/publishing.nsf/Content/cdna-song-novel-coronavirus.htm. Communicable Diseases Network Australia. 2020. 26 March 2020.

5.    Centre for Evidence-Based Medicine. COVID-19 Signs and Symptoms Tracker. Available from: https://www.cebm.net/covid-19/covid-19-signs-and-symptoms-tracker/ Oxford, United Kingdom: Centre for Evidence-Based Medicine. 2020

6.    Centers for Disease Control and Prevention. Interim U.S. Guidance for Risk Assessment and Public Health Management of Healthcare Personnel with Potential Exposure in a Healthcare Setting to Patients with Coronavirus Disease (COVID-19) 2020 [updated 7 March 2020]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/guidance-risk-assesment-hcp.html.

7.    World Health Organization. Health workers exposure risk assessment and management in the context of COVID-19 virus. 2020. 19 March 2020.