key: cord-0687899-84kzr28f
authors: Andersen, Mikkel Porsborg; Østergaard, Lauge; Phelps, Matthew; Butt, Jawad Haider; Køber, Lars; Gislason, Gunnar; Christensen, Helle Collatz; Torp-Pedersen, Christian; Schou, Morten; Fosbøl, Emil L.; Kragholm, Kristian
title: Risk of coronavirus disease 2019 (Covid-19) contraction and severe infection in home- or healthcare professionals
date: 2021-06-16
journal: J Infect
DOI: 10.1016/j.jinf.2021.06.012
sha: 2952c8b47b98f6f29b1f387d0ae9a26345ec1d4a
doc_id: 687899
cord_uid: 84kzr28f

nan

The Corona virus disease (Covid-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has to date led to more than 3.5 million deaths and over 170 million confirmed cases worldwide. 1 Therefore, vaccine development has been of highest priority. Late 2020, the first Covid-19 vaccines were approved and used in the US, but on a worldwide level, there is ongoing shortage of vaccines and knowledge regarding vaccine prioritization for high-risk groups are warranted. Studies have indicated high numbers of Covid-19 positive tests among healthcare professionals. [2] [3] [4] [5] [6] A recent Journal of Infection publication showed that home-or healthcare personnel from six UK-based hospitals were more likely to be tested positive for Covid-19 compared to the general population. 6 Home-and healthcare workers are an essential part of the healthcare system and reducing potential infection transmission in this setting would be beneficial to maintain a sufficient and effective healthcare system, alongside reducing transmission risk to citizens, patients and family members. With ongoing shortage of vaccines, prioritization is needed to reduce transmission risk to vulnerable patients and citizens to lower Covid-19 related morbidity and mortality. However, knowledge on the risk of Covid-19 in home-or healthcare personnel compared to the background population is lacking but essential.

This nationwide register-based study of risk of Covid-19 contraction and severe infection in relation to home-or healthcare professional status identified all residents in Denmark between aged 25-65 and alive on February 1st, 2020. Home-or healthcare professional status was available from education and employment registries until January 31st, 2020. The civil personal registration number (CPR) was used to link registry data. Data on patient age, sex, migration, Danish native versus non-native (immigrant or descendant) residency and cohabitation status were derived from the Danish Civil Registration System. Comorbidities were assessed from International Classification of Disease version 10 (ICD-10) diagnoses registered in the Danish National Patient Register including hypertension, diabetes, obesity, sleep apnea, chronic obstructive pulmonary disease (COPD), previous myocardial infarction (MI), ischemic heart disease (IHD), heart failure, stroke, peripheral vascular disease, rheumatic disease, chronic kidney disease, and malignant disease. From the Danish Prescription Registry, we defined hypertension when at least two antihypertensive drug prescriptions were filled in two consecutive 100-day periods prior to Covid-19 diagnosis. Diabetes and COPD were defined as a prescription fill for a relevant antidiabetic drug or relevant inhalation medication (anticholinergic alone or in combination with long-acting beta-2 agonist) no later than one year before Covid-19, or a relevant diagnosis code in the Danish National Patient Register any time be-fore Covid-19. As a measure of socioeconomic position, information on equivalized income based on a modified scale from the Organization for Economic Cooperation and Development (OECD) to ensure comparability between different household sizes, were assessed from Statistics Denmark and aggregated from quartiles of equivalized household income levels within the following age groups; 25-34, 35-44, 45-54, and 55-65.

Outcomes were 1) Covid-19 contraction defined as positive PCR test, 2) Covid-19 severe infection defined as composite of severe diagnosis (specific ICD-10 code B972A), intensive care unit (ICU) admission or death within 30 days after positive Covid-19 test, and 3) individual endpoints of ICU admission and death. Individuals were followed until outcome of interest, non-Covid-19 death or October 28, 2020, whichever came first. Multivariable Cox regression was performed to assess absolute risks and risk ratios for outcomes, standardized to the age, sex, equivalized income, native versus non-native residency status and comorbidity distribution of all patients.

Of approximately 5.8 million Danes, we identified ( N = 3063,127) aged 25-65 and excluded 37,626 due to missing education or employment status, leaving 3024,501 as the study population; 512,145 (16.9%) were home-or healthcare professionals. Between February 1st, 2020, and October 28th, 2020, 24,757 were tested positive for Covid-19; 6793 (27.4%) were homeor healthcare professionals. Baseline characteristics are displayed in Table 1 .

Results are displayed in Fig 1 . Standardized Several studies have addressed the occupational hazard of Covid-19 disease in home-or healthcare professionals but only few had the possibility to compare the risk to the general population. [2] [3] [4] [5] [6] One study documented a significantly higher hospitalization rate for Covid-19 infected healthcare workers relative to Covid-19 positive population controls. 5 Another study based on point-prevalence of PCR-positive Covid-19 tests indicated significantly higher Covid-19 risk among healthcare workers from six UK-based hospitals in comparison to the general population. 6 We found a significantly higher Covid-19 contraction risk of approximately two-fold that of the general population among home-or healthcare professionals. Adding to current literature, we showed that the elevated risk of Covid-19 contraction did not translate into a higher risk of severe Covid-19 disease trajectory. However, we are not able to report long-term functional impairment related to Covid-19. As such, our study cannot be used to conclude that healthcare professionals suffer no severe Covid-19 related sequalae, as more studies examining both short-and long-term outcomes of function following Covid-19 are warranted. The increased risk of Covid-19 contraction supports that Covid-19 can be viewed as an occupational hazard for home-and healthcare workers and stresses the importance of adequate protection and vaccination.

Our study findings support that the working age population of home-and healthcare workers should have a high priority for vaccine distribution.

In conclusion, home-or healthcare professionals had significantly higher Covid-19 contraction risk but not severe infection risk. Since our study indicates a significantly elevated risk of Covid-19 contraction among home-and healthcare professionals and issues with vaccine shortage remains, it is important to prioritize Covid-19 vaccination of home-and healthcare professionals.

Lars Køber reports personal fees from Speakers honorarium from Novo, Novartis, AstraZeneca and Boehringer outside the submitted work. Christian Torp-Pedersen reports grants from Bayer, grants from Novo Nordisk outside the submitted work. All other authors have nothing to declare. 

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

The dataset generated during the current study is not publicly available. All data were accessed in the research environment of Statistics Denmark where multiple registries can be combined with the limitation that individual data cannot be exported from the research environment. Further, individual information is encrypted. Thus, datasets cannot be made available. Other researchers that wish to access the data and codes can contact the authors of this study for collaboration on further studies.

World Health Organization. WHO coronavirus disease (COVID-19) dashboard

COVID-19 in healthcare workers: a living systematic review and meta-analysis of prevalence, risk factors, clinical characteristics, and outcomes

Risk of COVID-19 in health-care workers in Denmark: an observational cohort study

Risk of COVID-19 among front-line health-care workers and the general community: a prospective cohort study

Risk of hospital admission with coronavirus disease 2019 in healthcare workers and their households: nationwide linkage cohort study

Snapshot PCR surveillance for SARS-CoV-2 in hospital staff in England

The authors would like to extend their gratitude towards Jørn Korsbø Pedersen and his colleagues at Statistics Denmark for their