Abstract
Objective To assess the risk of hospital admission for coronavirus disease 2019 (covid-19) among patient facing and non-patient facing healthcare workers and their household members.
Design Nationwide linkage cohort study.
Setting Scotland, UK, 1 March to 6 June 2020.
Participants Healthcare workers aged 18-65 years, their households, and other members of the general population.
Main outcome measure Admission to hospital with covid-19.
Results The cohort comprised 158 445 healthcare workers, most of them (90 733; 57.3%) being patient facing, and 229 905 household members. Of all hospital admissions for covid-19 in the working age population (18-65 year olds), 17.2% (360/2097) were in healthcare workers or their households. After adjustment for age, sex, ethnicity, socioeconomic deprivation, and comorbidity, the risk of admission due to covid-19 in non-patient facing healthcare workers and their households was similar to the risk in the general population (hazard ratio 0.81 (95% confidence interval 0.52 to 1.26) and 0.86 (0.49 to 1.51), respectively). In models adjusting for the same covariates, however, patient facing healthcare workers, compared with non-patient facing healthcare workers, were at higher risk (hazard ratio 3.30, 2.13 to 5.13), as were household members of patient facing healthcare workers (1.79, 1.10 to 2.91). After sub-division of patient facing healthcare workers into those who worked in “front door,” intensive care, and non-intensive care aerosol generating settings and other, those in front door roles were at higher risk (hazard ratio 2.09, 1.49 to 2.94). For most patient facing healthcare workers and their households, the estimated absolute risk of hospital admission with covid-19 was less than 0.5%, but it was 1% and above in older men with comorbidity.
Conclusions Healthcare workers and their households contributed a sixth of covid-19 cases admitted to hospital. Although the absolute risk of admission was low overall, patient facing healthcare workers and their household members had threefold and twofold increased risks of admission with covid-19.
Comparison with other studies and policy implications We report the risk of covid-19 in nearly 250 000 household members of healthcare workers. Previous evidence on the risk of covid-19 to household members of healthcare workers is sparse,despite evidence that their safety is of major importance to healthcare workers. We show that the risk of hospital admission with covid-19 was nearly twofold higher in household members of patient facing compared with non-patient facing healthcare workers. Therefore, the susceptibility of household members, as well as healthcare workers themselves, needs to be considered when assessing occupational risk. Several studies have reported an increased risk of covid-19 infection and high prevalence of SARS-CoV-2 in healthcare workers, especially in front line workers.However, many of these reports were small, single centre, and cross sectional in nature and used methods highly susceptible to bias or restricted their populations to physicians and nurses.In a large healthcare worker population including a wide range of occupations with robust adjustment for confounding factors, we provide strong evidence that patient facing healthcare workers are at moderately increased risk of experiencing a sufficiently severe form of covid-19 to need hospital admission. We provide further evidence that within patient facing healthcare workers, those categorised as working in “front door” specialties are at the highest risk of admission with covid-19, probably reflecting the higher seroprevalence rates of SARS-CoV-2 in this population. In response to emerging evidence and international guidance, the NHS in Scotland introduced several changes to infection prevention and control guidance during the course of the pandemic.Despite this, the differential in risk between the general working age population (who had at this time minimal contacts outside their own households) and patient facing healthcare workers did not fall and may have increased. In contrast, the risk seemed to fall quickly in the “higher risk” intensive care settings. Consistent with international guidance, the NHS in Scotland recommends higher levels of personal protective equipment in higher risk settings, such as intensive care.In this context, it is notable that less than five healthcare workers based in intensive care were admitted to hospital, all of whom first tested positive for SARS-CoV-2 in early March. In view of the small numbers of staff in intensive care settings, considerable caution is needed in interpreting this finding, but it is consistent with a recent report from Wuhan that no healthcare workers in high risk clinical areas tested positive for SARS-CoV-2 in the context of robust infection control measures being in place.Together with the observations that the relative risk, compared with the general population, in patient facing healthcare workers continued to rise during the course of pandemic and that the overall risk was highest in front door healthcare workers, these findings raise particular concerns about moderate exposure settings, in terms of both the risk to staff and the risk of transmitting infection to the wider community. In moderate risk settings, where patients may have only suspected, or even unsuspected, covid-19, the use of more resource intensive and burdensome personal protective equipment of the kind deployed in high risk settings is very challenging.One proposed alternative, or additional, measure to improve safety is therefore to redeploy healthcare workers from patient facing to non-patient facing roles if they or their households are more susceptible to severe disease. Our findings suggest that this may be a feasible policy for two reasons. Firstly, non-patient facing healthcare workers and their households had similar risks of hospital admission to the general population. Secondly, the proportion of patient facing healthcare workers who themselves, or whose households, were at increased risk of admission (up to 1%) was low at around one in 20.
Limitations of study Several limitations need to be considered. Firstly, given the small number of deaths in the healthcare worker population, we were unable to estimate the risk of covid-19 related mortality compared with the general population. The Office for National Statistics (ONS) in England did not find increased covid-19 mortality among healthcare workers.Several reasons exist why hospital admission might be increased without an increase in deaths. Although we identified a cohort of healthcare workers, and sub-divided these by occupational roles, finding a risk only in patient facing healthcare workers, the ONS study relied on self-reporting for the population at risk, with information provided by the next of kin at registration. The ONS also reported mortality for healthcare workers regardless of their role.Furthermore, healthcare workers may present earlier, improving their survival for a given severity of covid-19, and/or they may have a lower threshold for admission. Secondly, we defined cases in our cohort on the basis of positive tests for SARS-CoV-2. The sensitivity of polymerase chain reaction tests for SARS-CoV-2 is 80-90% depending on the testing strategy,meaning that a proportion of true cases would have been misclassified. Thirdly, although we saw clear differences in risks across different exposure groups (patient facing and non-patient facing), and even within patient facing groups (for example, front door versus others), individuals within these groups will have differed in terms of the amount of time they spent in close contact with patients with covid-19. Our datasets were unable to define this degree of exposure. Therefore, in applying our findings, health service providers should consider how typical a healthcare worker is with respect to other healthcare workers in meeting our exposure definitions. Fourthly, given that the healthcare workers in our cohort were predominantly white, our analysis lacked power to comment on the risk of hospital admission in ethnic minority groups.Finally, we were unable to identify healthcare workers who would have been redeployed or advised to shield. Not accounting for this measure would have likely attenuated our risk estimates.
Conclusions As the northern hemisphere enters winter and non-pharmacological measures in populations are relaxed, governments, healthcare managers, and occupational health specialists need to consider how best to protect healthcare workers in the event of a resurgent pandemic. This is necessary to protect the healthcare workers and their families,in addition to reducing onward transmission into the community, and to maintain a functioning healthcare system. Our findings from the “first wave” in Scotland show that healthcare workers in patient facing roles—especially those in “front door” roles—are, along with their households, at particular risk. Crucially, those in non-patient facing roles had similar risks to the general population. These findings should inform decisions about the organisation of health services, the use of personal protective equipment, and redeployment.
Reference & Source Information: https://www.bmj.com/
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