Prolonged SARS-CoV-2 PCR positivity: a challenge for Australian clinicians

The NSW Department of Health has taken necessarily stringent steps to reduce the risk of workplace outbreaks as we progress along Australia’s flattened curve. Currently, two nasopharyngeal samples, polymerase chain reaction (PCR) negative for SARS-CoV2-2019 are required before asymptomatic individuals can return to “high-risk” workplaces such as hospitals, schools and prisons or close proximity living arrangements like residential aged care facilities, military barracks and group homes.²

In Newcastle, existent Hospital in the Home (HiTH) services have been redeployed as part of a tiered pandemic response under the banner COVID Care at Home (CCaH). CCaH offers daily telehealth monitoring and efficient “clearance” certification for patients in isolation or excluded from workplaces. In our experience with 45 COVID confirmed cases admitted to CCaH increased PCR surveillance also uncovered cases of prolonged RNA detection. One passenger from the vessel Ruby Princess returned PCR positive fifty-two days after her initial swab and more than sixty days after the first day of symptoms.

A review of international data showed that PCR positivity usually persists for between 20 to 30 days regardless of symptomology.⁴ Cases of SARS-CoV2-2019 RNA detection persisting for 60 or even 80 days have been recorded in the literature.^5,6 In the case of our patient the ongoing exclusion from the workplace created significant psychological and financial burden due to lack of leave entitlement. Similar policies in countries with even less worker-security, such as the United States, are likely to have even greater workforce impact. To tackle the issue of prolonged positivity we have convened a panel of clinicians in the disciplines of infectious diseases, population health and microbiology to make informed decisions about patients with prolonged viral RNA detection in regard to their ongoing need for isolation and exclusion from high-risk environments.

PCR positivity is not synonymous with infectivity.^7,8 Regardless, to maintain the good results Australia has enjoyed thus far we will need to persevere with a high level of vigilance. Making informed and safe decisions about clearance for high risk environments and supporting patients with prolonged exclusions from their workplace will be an ongoing challenge for Australian clinicians during the COVID pandemic.

References:

1. Eisen D. Employee presenteeism and occupational acquisition of COVID-19, Med J Aust 2020, Published online, 7 May 2020.
2. Communicable Diseases Network Australia, Coronavirus Disease 2019 (COVID-19) CDNA National Guidelines for Public Health Units. Version 2.7, 24 April 2020.
3. Greenhalgh T, Choon Huat Koh G, Car J. COVID-19: A remote assessment in primary care. BMJ 2020;368:m1182
4. Zhou F, Yu T, Du R, Fan G, et. al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan China: a retrospective cohort study. Lancet 2020; 395: 1054-62. Published online March 9, 2020.
5. Li J, Zhang L, Baihui  L, Song D. Case Report: Viral Shedding for 60 Days in Woman with Novel Coronavirus Disease, Am. J. Trop. Med. Hyg., 00(0) 2020 pp 1-4 doi:10.4269/ajtmh.20-0275, published online May 2020.
6. Liu W, Chang S-Y,Wang J, Tsai M, et. al. Prolonged virus shedding after seroconversion in patient with COVID-19. J. Infection. https://doi.org/10.1016/j.jinf.2020.03.063 0163-4453/© 2020 The British Infection Association. Published online April 2020.
7. Tang Y, Schmitz J, Persing D, Stratton C. The Laboratory Diagnosis of COVID-19 Infection: Current Issues and Challenges. JCM Accepted Manuscript Posted Online 3 April 2020. J. Clin Microbiol. Doi:10.1128/JCM.00512-20
8. Atkinson B, Petersen E. SARS-CoV-2 shedding and infectivity, letter to The Lancet, published online April 15 2020, doi.org/10.1016/S0140-6736(20)30869.