Many patients still face risks from nosocomial transmissions from asymptomatic healthcare workers and patients
With covid-19 disrupting global healthcare services, people affected by life-threatening conditions such as cancer have faced substantial treatment delays or modifications. In the pandemic’s early days, with much unknown, this caution was understandable. For cancer, emerging data from small retrospective cohorts suggested a higher rate of serious complications and/or death following infection, particularly in late-stage metastatic disease. [1-4]
This has caused widespread anxiety, with many facing difficult conversations with their clinical teams, often via unfamiliar platforms, as new national treatment guidelines are interpreted into personal care plans to appropriately balance risks.
These delays to treatment, coupled with a large drop in diagnostic referrals from a population understandably reluctant to seek help for suspicious symptoms, have raised concerns of a “post-pandemic surge” in non-covid-associated mortality, as early-stage, curable cancers progress to inoperable disease, or spread beyond the primary site. 
To try to prevent this, there has been a rapid effort to reconfigure services, in order to safely treat patients with new or existing diagnoses of cancer. In the UK, this has led to the establishment of “covid-protected’ cancer hubs where, after centralised triage to prioritise patients based on clinical need, patients are screened up to 48hrs prior to admission for surgery at “clean” sites, including in the independent sector.  Institutes in other countries have taken similar approaches. As just one example, the Gustave Roussy in France has embedded routine RT-PCR triage into care pathways, with patients treated in appropriate settings as required. 
Such efforts are vital to reinstate safe care. Yet worries remain at the risks many patients still face from nosocomial transmissions from asymptomatic healthcare workers and patients. [8,9] Are our “protected” sites adequately protected?
Protecting the hubs
Emerging evidence suggests SARS-CoV-2 transmissions can occur in the pre-symptomatic or asymptomatic phase of infection.  Evidence suggests substantial asymptomatic covid-19 carriage and transmission with a significant proportion of healthcare workers carrying the virus pre- or asymptomatically. [11-17]
For truly “covid-protected” cancer treatment, it will therefore be essential to regularly screen asymptomatic staff in cancer hubs who interact with patients, and who may be carriers of covid-19.
Unfortunately, despite progress, many countries, including the US, are still not testing broadly, frequently or quickly enough—either in protected areas, or more broadly—to adequately prevent patients from infection during treatment. [18,19] The UK secretary of state for health’s announcement on 6th May that all medical staff are to be tested weekly is important in this regard, and will become more so as lockdown measures are relaxed further.  However, with so much focus simply on capacity, turnaround time has been neglected. Reliable UK data on this measure are lacking, and challenges to developing a rapid (reporting turnaround times <24hrs) and accessible testing pipeline have not been sufficiently addressed. Indeed, in April 2020, UK testing capacity exceeded the number of tests performed by two-fold or more, pointing to major unsolved hurdles in logistics.  Anecdotally, we’ve heard that turnaround times for healthcare worker testing can still be upward of three days, in some instances.
In the UK, overcoming current barriers to rapid, routine staff and patient testing in all protected cancer treatment areas will be essential for the restoration of safe cancer care.
Several opportunities present themselves. Self-swabbing and saliva approaches, rather than nurse-led nasopharyngeal (NP) swabbing could rapidly accelerate covid-19 testing, with emerging suggestions that the latter may be even more sensitive than NP swabs.  Turn-around times would be boosted further by rapid, high-throughput testing, or next-generation assays. [23-26]
Distinct IT systems, with limited interoperability, delay the ability of widespread testing to be implemented and results to be readily disseminated and acted upon, particularly for testing in the community. Local IT solutions are required to resolve such challenges, modelled to the needs of the community and healthcare system each laboratory serves.
Taken together, such developments could enable twice-weekly hospital testing of all staff and patients, cost-effectively, safely and rapidly.
Beyond the hubs
However, testing needs to expand beyond cancer hubs. A diagnosis of cancer is, like many serious conditions, accompanied by a need for access to a range of secondary care services. Simply protecting patients on wards prior to and during surgery, although necessary, is not sufficient to fully protect them from covid-19. We cannot just view them as “cancer” patients who need “cancer” services.
This means rigorous, frequent (arguably twice-weekly) testing of all healthcare workers working in proximity to patients, not just those working in “protected” areas—clearly an enormous task, requiring rapid organisational change. Naturally, as lockdown loosens, all patient admissions, both elective and emergency, will also need to be screened. To bring all this about, we must be flexible in the thresholds we set for evidence, particularly the need for stringent health economic evaluations, which seem almost absurd when the wider economic indicators are so catastrophic.
The benefits of getting this right would, of course, extend far beyond cancer care, greatly minimising risks for all patients, regardless of their condition. Effective covid-19 therapies are still lacking, and a vaccine may be years away. In their absence, the coronavirus’s main enemies are, currently, social distancing and protective equipment. They must also include widespread testing, with aggressive contact tracing and quarantining, and truly covid-protected hospital environments. Time is the virus’s greatest friend. We must not delay.
Charles Swanton, chief clinician, Cancer Research UK; UCL Cancer Institute; Francis Crick Institute.
Henry Scowcroft, patient editor, The BMJ and Communications Strategy Lead at Cancer Research UK.
Competing interests: HS a member of the National Cancer Research Institute’s Consumer Forum, as a patient advocate for research on cancer. He is a a patient advocate on an investigator-instigated, industry-supported cancer trial – DURANCE. CS has board membership with AstraZeneca, Medicxi, GRAIL, Achilles Therapeutics, and the American Association for Cancer Research. CS provides consultancy for Sarah Gannon Research Institute, Genentech and Achilles.
- Desai A, Sachdeva S, Parekh T, Desai R. COVID-19 and Cancer: Lessons From a Pooled Meta-Analysis. JCO Global Oncology. 2020;(6):557-559.
- Liang W, Guan W, Chen R, Wang W, Li J, Xu K et al. Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. The Lancet Oncology. 2020;21(3):335-337.
- Miyashita H, Mikami T, Chopra N, Yamada T, Chernyavsky S, Rizk D et al. Do Patients with Cancer Have a Poorer Prognosis of COVID-19? An Experience in New York City. Annals of Oncology. 2020
- Black J, Bailey C, Przewrocka J, Dijkstra K, Swanton C. COVID-19: the case for health-care worker screening to prevent hospital transmission. The Lancet. 2020;395(10234):1418-1420.
- Arons M, Hatfield K, Reddy S, Kimball A, James A, Jacobs J et al. Presymptomatic SARS-CoV-2 Infections and Transmission in a Skilled Nursing Facility. New England Journal of Medicine. 2020.
- Chau N, Lam V, Dung N, Yen L, Minh N, Hung L et al. The natural history and transmission potential of asymptomatic SARS-CoV-2 infection. 2020; medRxiv doi: 10.1101/2020.04.27.20082347.
- Day M. Covid-19: four fifths of cases are asymptomatic, China figures indicate. BMJ. 2020; 369:m1375.
- Mizumoto K, Kagaya K, Zarebski A, Chowell G. Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. Eurosurveillance. 2020;25(10).
- Bai Y, Yao L, Wei T, Tian F, Jin D, Chen L et al. Presumed Asymptomatic Carrier Transmission of COVID-19. JAMA. 2020;323(14):1406.
- Rothe C, Schunk M, Sothmann P, Bretzel G, Froeschl G, Wallrauch C et al. Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany. New England Journal of Medicine. 2020;382(10):970-971
- Tong Z, Tang A, Li K, Li P, Wang H, Yi J et al. Potential Presymptomatic Transmission of SARS-CoV-2, Zhejiang Province, China, 2020. Emerging Infectious Diseases. 2020;26(5):1052-1054.
- Ye F, Xu S, Rong Z, Xu R, Liu X, Deng P et al. Delivery of infection from asymptomatic carriers of COVID-19 in a familial cluster. International Journal of Infectious Diseases. 2020;94:133-138.
- Rivett L, Sridhar S, Sparkes D, Routledge M, Jones N, Forrest S et al. Screening of healthcare workers for SARS-CoV-2 highlights the role of asymptomatic carriage in COVID-19 transmission. eLife. 2020;9.
- Wyllie A, Fournier J, Casanovas-Massana A, Campbell M, Tokuyama M, Vijayakumar P et al. Saliva is more sensitive for SARS-CoV-2 detection in COVID-19 patients than nasopharyngeal swabs. 2020; medRxiv doi: 10.1101/2020.04.16.20067835.
- Yu L, Wu S, Hao X, Li X, Liu X, Ye S et al. Rapid colorimetric detection of COVID-19 coronavirus using a reverse tran-scriptional loop-mediated isothermal amplification (RT-LAMP) diagnostic plat-form: iLACO. 2020; medRxiv doi: 10.1101/2020.02.20.20025874.
- Ben-Assa N, Naddaf R, Gefen T, Capucha T, Hajjo H, Mandelbaum N et al. SARS-CoV-2 On-the-Spot Virus Detection Directly From Patients. 2020; medRxiv doi: 10.1101/2020.04.22.20072389.
- Butler D, Mozsary C, Meydan C, Danko D, Foox J, Rosiene J et al. Shotgun Transcriptome and Isothermal Profiling of SARS-CoV-2 Infection Reveals Unique Host Responses, Viral Diversification, and Drug Interactions. 2020; bioRxiv doi: 10.1101/2020.04.20.048066.
- Smyrlaki I, Ekman M, Vondracek M, Papanicoloau N, Lentini A, Aarum J et al. Massive and rapid COVID-19 testing is feasible by extraction-free SARS-CoV-2 RT-qPCR. 2020; medRxiv doi: 10.1101/2020.04.17.20067348.