A study of 1,718 healthcare workers from 503 hospitals in 17 countries shows that overall, 1 in 10 healthcare workers involved in intubating seriously ill patients with novel coronavirus disease 2019 (COVID-19) later reports symptoms or lab-confirmed COVID-19 themselves. The study was led by consultant anaesthetist Dr Kariem El-Boghdadly and his colleagues at Guy’s and St Thomas’ NHS Foundation Trust, London, UK, with colleagues across the 17 countries*. The research is published in Anaesthesia (a journal of the Association of Anaesthetists).
A likely route of transmission of the novel coronavirus SARS-CoV-2 is via aerosols, which are small droplets containing the virus breathed out by someone infected. Healthcare workers involved in aerosol-generating procedures, such as tracheal intubation of ill patients, may be at elevated risk of acquiring COVID-19; however, the magnitude of this risk was previously unknown. As cases of COVID-19 continue to rise globally, there are increasing concerns about the risks of SARS-CoV-2 transmission to healthcare workers involved in direct patient care. During the SARS-CoV-1 outbreak (in 2002-2003), healthcare workers were disproportionately affected, with those at greatest risk involved in aerosol-generating procedures.
To understand these risks further, the intubateCOVID registry was launched by the authors on 23 March 2020. Information about the registry was disseminated via national and international professional organisations and social media. Data collection for the registry is ongoing, but this study of data reported up to 2 June 2020 was undertaken to ensure timely dissemination of results that would potentially guide clinical practice during the COVID-19 pandemic.
Information on tracheal intubation episodes, personal protective equipment (PPE) use and subsequent health status was collected. The primary endpoint was the incidence of laboratory-confirmed COVID-19 diagnosis or new symptoms requiring self-isolation or hospitalisation after an intubation episode. Emails were sent each week to participants prompting them to report their COVID-19 infection status as one of the following four options: (1) laboratory-confirmed COVID-19; (2) admission to hospital with COVID-19-related symptoms; (3) self-isolation due to COVID-19 related symptoms; or (4) no COVID-19 symptoms or diagnosis.
The authors analysed 5,148 intubations by 1,718 participants who recorded at least one intubation and one follow-up. A total of 184 participants (10.7%) met the primary endpoint (reporting a COVID-19 outcome) over a median follow-up period of 32 days, of whom 144 (8.4%) reported symptomatic self-isolation, 53 (3.1%) reported laboratory-confirmed COVID-19 infection, and 2 (0.1%) reported hospital admission with COVID-19 symptoms (some participants fell into more than one of these categories, for example initially self-isolating then later reporting laboratory-confirmed diagnosis).
The cumulative incidence within 7, 14 and 21 days of the first tracheal intubation episode was 3.6%, 6.1%, and 8.5% respectively, possibly indicating the time delay in developing symptoms that have been seen with this new disease or allowing for repeated exposure to the virus.
Analysis of the data identified that being female was associated with an increased risk of reporting a COVID-19 outcome, though the reasons for this are unclear. The authors also found that the proportion of participants that reported a COVID-19 outcome varied by country. The UK, which provided almost half (49%) of the study participants, had 13% of participants reporting a COVID-19 outcome. For the USA, this proportion was 8%, Australia 9%, Sweden 16% and Ireland 18%.**
Regarding PPE, the authors say: “We did not detect an association with the use of PPE in accordance with WHO standards, though perhaps the wide range of combinations of PPE reported may have hampered our ability to identify any relationship. Regardless, a significant concern highlighted by the data is the insufficient utilisation of PPE in more than 12% of cases. Although the reasons for deficiencies in PPE utilisation are beyond the scope of these data, this finding might reflect global concerns around lack of PPE.”
The authors make clear that it is impossible to determine for certain whether those infected in the study were infected during intubation procedures, or during other events in the hospital or the community. However, their interpretation is that it is more likely that the reported incidence of infection was primarily related to workplace exposures rather than transmission in the community.
They add: “Regardless of the exposure source, our results have significant implications for individual healthcare workers, the workforce, and wider society. Self-isolation due to symptoms or laboratory-confirmed COVID-19 of potentially a tenth of the workforce involved in tracheal intubation means that institutions should consider building capacity and resilience in workforce planning during this pandemic and thereafter. Diminishing the availability of vital, highly-trained health providers means that institutions could be left with a shortfall in their capacity to deliver essential healthcare services to both COVID-19 and non-COVID-19 patients. At a public health level, household members of these clinicians will also face the requirement for self-quarantine and are at risk of subsequently contracting the disease, thus amplifying the potential implications of healthcare worker infection.”
They also say that their study could be underestimating the infection rate in clinicians involved in tracheal intubation, as a proportion of those without reported COVID-19 outcomes in the study may be asymptomatic carriers. They say: “Therefore, policies for regular testing of those at greatest risk to personal and public health may be valuable. This could identify both asymptomatic carriers, as well as healthcare workers whose symptoms may be consistent with COVID-19 but are due to alternative causes.”
The authors draw attention to strengths and weaknesses of their study, with strengths including that it used data from the largest international prospective database of high-risk aerosol-generating procedures globally that continues to collect surveillance data that can help inform practice; the follow-up rate of participants after reporting tracheal intubation episodes in the cohort was high; and the study reports data that has not yet been included in any pandemic literature to date. Weaknesses include the previously mentioned inability to confirm the source of infection, and underestimation of infections due to the presence of asymptomatic infection; that self-reported data has known pitfalls; and the study lacked a control group. The authors therefore suggest a cautious interpretation of the findings.
They conclude: “Approximately 10% of healthcare workers in our sample were either diagnosed with new COVID-19 infection or required self-isolation or hospitalisation with new symptoms following involvement in tracheal intubation of patients with suspected or confirmed COVID-19. This information should inform decision-making and planning of safe and sustainable delivery of health care services globally. Future work should focus on screening and identifying interventions to reduce risks to healthcare workers providing care for COVID-19 patients.”