SARS-CoV-2: how the history of human populations influences their immune response
During the COVID-19 pandemic, the clinical spectrum observed among people infected with SARS-CoV-2 ranged from asymptomatic carriage to death. Researchers at the Institut Pasteur, the CNRS and the Collège de France, in collaboration with researchers around the world1, have investigated the extent and drivers of differences in immune responses to SARS-CoV-2 across populations from Central Africa, Western Europe and East Asia. They show that latent cytomegalovirus infection and human genetic factors, driven by natural selection, contribute to population differences in immune response to SARS-CoV-2 and the severity of COVID-19. Understanding the factors underlying such population disparities could help to improve patient management in future epidemics. These results were published on August 9, 2023 in Nature.
The Institut Pasteur’s Human Evolutionary Genetics Unit2 , led by Lluis Quintana-Murci, investigates how human populations differ in their immune responses to infection. These differences may result from different environmental exposures or from past population history, including natural selection, shaping the patterns of genetic diversity of human groups. In this study, published in Nature, the scientists investigated the extent and causes of disparities in the responses to the SARS-CoV-2 virus, focusing on populations from different geographic and ethnic backgrounds.
During the COVID-19 pandemic, the SARS-CoV-2 virus caused a wide range of clinical manifestation, from asymptomatic infection to fatal disease. Although advanced age remains a primary risk factor, male gender, comorbidities and various human genetic and immunological factors also contribute to disease severity. To study variations in immune responses to SARS-CoV-2 across human populations, scientists exposed immune blood cells from 222 healthy donors from Central Africa, Western Europe, and East Asia to the virus.
Single-cell RNA sequencing was used to analyze the SARS-CoV-2 responses of 22 blood cell types. These data were then combined with serological and genetic information collected from the same individuals, making it possible to assess the degree of disparity between populations in terms of their immune responses to SARS-CoV-2, and to identify contributing factors.
Scientists have identified around 900 genes that that respond differently to SARS-CoV-2 between populations. Using statistical genetic analyses, they show that these disparities are mainly due to variation in blood cellular composition: the proportion of each cell type differs from one population to another. We know that blood cell composition can be influenced by environmental factors such as exposure to cytomegalovirus (a human infection of the herpes family, which is usually harmless) and cytomegalovirus prevalence varies widely among populations: Central Africans present 99% seropositivity, in contrast to only 50% in East Asians and 32% in Europeans. The team found that an individual’s environment, specifically latent cytomegalovirus infection, will thus influence the immune cell response to SARS-CoV-2.
Furthermore, the scientists have identified around 1,200 human genes whose expression in response to SARS-CoV-2 is under the control of human genetic factors and the frequency of the alleles3 that regulate these genes can vary between the populations studied. Using population genetics approaches, they have identified recurrent selection events targeting genes involved in anti-viral functions. "We know that infectious agents have had a strong impact on human survival and exerted massive selective pressures that have shaped population genetic variation. We show that past natural selection has impacted present immune responses to SARS-CoV-2, particularly in people of East Asian ancestry, in whom coronaviruses generated strong selective pressures around 25,000 years ago," explains Maxime Rotival, a researcher in the Institut Pasteur's Human Evolutionary Genetics Unit and co-last author of the study.
Between 1.5% and 2% of the genomes of Europeans and Asians is of Neanderthal origin. There is growing evidence of links between Neanderthal ancestry and present-day immunity to infection. By comparing the 1,200 genes identified with the Neanderthal genome, the scientists have discovered dozens of genes that both alter antiviral mechanisms and result from ancient introgression between Neanderthals and modern humans (Homo sapiens). "Previous studies have shown the link between some of the genes identified in our study and the severity of COVID-19. Our comprehensive population-based study highlights the direct impact of genetic variants governing immune responses to SARS-CoV-2 on the severity of COVID-19. It also establishes links between past evolutionary events, such as natural selection or Neanderthal admixture, and current population disparities in immune responses and disease risk," explains Lluis Quintana-Murci, Head of the Human Evolutionary Genetics Unit at the Institut Pasteur, Professor at the Collège de France and co-last author of the study.
"By identifying the precise cellular and molecular pathways of the genetic variants associated with COVID-19 severity, this study paves the way for precision medicine strategies that could either identify high-risk individuals or facilitate the development of new treatments," adds Darragh Duffy, Head of the Institut Pasteur's Translational Immunology Unit.
This research was funded by the institutes mentioned above, and the French National Research Agency (ANR) (COVID-19-POPCELL, POPCELL-REG, COVIFERON), the European Horizon Health 2021 program (UNDINE), the French Foundation for Medical Research (FRM), the Allianz/Institut de France Foundation and the Fondation de France.
[1] Institut Imagine (France), Ghent University (Belgium), University of Rome (Italy), University of Detroit (USA), The Rockefeller University (USA), C2I Hong Kong (China), University of Melbourne (Australia).
[2] At the CNRS, this unit is known as the "Evolutionary Genomics, Modeling and Health Unit" (CNRS/Institut Pasteur).
[3] An allele is a version of a gene that is caused by a mutation. A gene has several alleles that perform the same function as the original gene, but in their own specific ways.
Source
Dissecting human population variation in single-cell responses to SARSCoV-2, Nature, 9 August 2023
Yann Aquino1,2,27, Aurelie Bisiaux1,27, Zhi Li1,27, Mary O'Neill1,27, Javier Mendoza-Revilla1, Sarah Helene Merkling3, Gaspard Kerner1, Milena Hasan4, Valentina Libri4, Vincent Bondet5,Nikaia Smith5, Camille de Cevins6,7, Mickael Menager6,7, Francesca Luca8,9,10, Roger Pique-Regi8,9, Giovanna Barba-Spaeth11, Stefano Pietropaoli11, Olivier Schwartz12, Geert Leroux-Roels13, Cheuk-Kwong Lee14, Kathy Leung15,16, Joseph T.K. Wu15,16, Malik Peiris17,18,19,Roberto Bruzzone18,19, Laurent Abel20,21,22, Jean-Laurent Casanova20,21,22,23,24, Sophie A.Valkenburg18,25, Darragh Duffy5,19, Etienne Patin1, Maxime Rotival1,28* & Lluis Quintana-Murci1,26,28*
1. Institut Pasteur, Universite Paris Cite, CNRS UMR2000, Human Evolutionary Genetics Unit, Paris, France.
2. Sorbonne Universite, College Doctoral, Paris, France.
3. Institut Pasteur, Universite Paris Cite, CNRS UMR2000, Insect-Virus Interactions Unit, Paris, France.
4. Institut Pasteur, Universite Paris Cite, Cytometry and Biomarkers UTechS, Paris, France.
5. Institut Pasteur, Universite Paris Cite, Translational Immunology Unit, Paris, France.
6. Universite Paris Cite, Imagine Institute, Laboratory of Inflammatory Responses and Transcriptomic Networks in Diseases, Atip-Avenir Team, INSERM UMR1163, Paris, France
7. Labtech Single-Cell@Imagine, Imagine Institute, INSERM UMR1163, Paris, France
8. Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA.
9. Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, USA.
10. Department of Biology, University of Rome Tor Vergata, Rome, Italy
11. Institut Pasteur, Universite Paris Cite, CNRS UMR3569, Structural Virology Unit, Paris, France.
12. Institut Pasteur, Universite Paris Cite, CNRS UMR3569, Virus and Immunity Unit, Paris, France.
13. Ghent University and University Hospital, Ghent, Belgium.
14. Hong Kong Red Cross Blood Transfusion Service, Hospital Authority, Hong Kong SAR, China.
15. WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
16. Laboratory of Data Discovery for Health (D24H), Hong Kong Science Park, Hong Kong SAR, China
17. Division of Public Health Laboratory Sciences, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
18. HKU-Pasteur Research Pole, School of Public Health, The University of Hong Kong, Hong Kong SAR, China.
19. Centre for Immunology and Infection, Hong Kong Science Park, Hong Kong SAR, China
20. St. Giles Laboratory of Human Genetics of Infectious Diseases, The Rockefeller University, New York, NY, USA.
21. Laboratory of Human Genetics of Infectious Diseases, INSERM UMR1163, Necker Hospital for Sick Children, Paris, France.
22. Imagine Institute, Paris Cite University, Paris, France.
23. Department of Pediatrics, Necker Hospital for Sick Children, Paris, France.
24. Howard Hughes Medical Institute, New York, NY, USA.
25. Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Australia
26. Chair Human Genomics and Evolution, College de France, Paris, France.
27. These authors contributed equally.
28. These authors jointly supervised this work.
https://doi.org/10.1038/s41586-023-06422-9
JOURNAL
Nature
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Dissecting human population variation in single-cell responses to SARSCoV-2
Patient experiences with hospitals worsened during first two years of pandemic
Hospitals with higher staffing levels holding on to better scores longer
Peer-Reviewed PublicationThe experiences of patients hospitalized during the COVID-19 pandemic was significantly worse than in the years before the crisis, with hospitals with higher staffing levels holding on to better scores longer, according to a new RAND Corporation study.
Patients particularly reported worse staff responsiveness and hospital cleanliness, possibly reflecting staffing shortages in the hospital workforce and the effects of protocols needed to limit the spread of COVID-19, according to researchers.
Deficits were largest for hospitals that in the pre-pandemic period were lower-performing and had lower staffing levels. The findings are published in the journal JAMA Health Forum.
“This unprecedented decline in patient experience was seen in every region of the U.S., with relatively little regional variation,” said Marc Elliott, the study’s lead author and a senior principal researcher at RAND, a nonprofit research organization. “Hospitals with higher staffing levels and better overall pre-pandemic quality were more resilient and slower to see their decline. But eventually even their patients also reported worse experiences.”
The onset of the COVID-19 pandemic created unprecedented challenges for the nation’s acute-care hospitals, including having health care professionals fear being exposed to COVID at work and infecting family members.
To comply with Centers for Disease Control guidelines related to COVID infection control, hospitals adopted new protocols involving social distancing, masks and face shields, and restricted visitor access.
To examine how the pandemic-era changes affected patient experiences, the RAND study analyzed responses to the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey, which is routinely administered to patients treated at the nation’s short-term acute care hospitals following their discharge.
The survey is sponsored by the federal Centers for Medicare & Medicaid Services and is a widely used tool to report hospital quality to consumers.
Researchers analyzed survey results from more than 9 million patients who were treated at 3,381 hospitals, compiling results from 2018 through 2021.
The analysis found that by the fourth quarter of 2021, a summary measure of patient experiences was 3.6 percentage points lower across all hospitals than would have been expected without the pandemic – considered a medium effect size for patient experience measures.
Scores decreased by large amounts for questions about staff responsiveness and hospital cleanliness. Moderate declines were seen for overall hospital rating and recommendation, communication about medicines, communication with nurses, communication with doctors and care transitions.
The decline of the overall rating and hospital recommendation lagged the decline in more specific patient experience measures, possibly reflecting lower expectations in patients’ overall assessments at the onset of the pandemic, according to the study.
However, as the pandemic continued, the global ratings also declined to a similar extent as the more specific measures of patient experience.
Support for the study was provided by the federal Centers for Medicare & Medicaid Services.
Other authors of the study are Megan K. Beckett of RAND; Christopher W. Cohea, Laura A. Giordano and Chelsea Russ of the Health Services Advisory Group; William G. Lehrman,
Elizabeth H. Goldstein and Lee A. Fleisher of the Centers for Medicare & Medicaid Services; and Paul D. Cleary of the Yale School of Public Health.
RAND Health Care promotes healthier societies by improving health care systems in the United States and other countries.
JOURNAL
JAMA Health Forum
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Changes in Patient Experiences of Hospital Care During the COVID-19 Pandemic
ARTICLE PUBLICATION DATE
25-Aug-2023
Changes in patient experiences of hospital care during the pandemic
JAMA Health Forum
Peer-Reviewed PublicationAbout The Study: The results of this study suggest that higher-staffed and higher-performing hospitals were more resilient to the conditions of the COVID-19 pandemic, but by late 2021, patients’ experience of care had declined in all hospitals.
Authors: Marc N. Elliott, Ph.D., of the RAND Corporation in Santa Monica, California, is the corresponding author.
To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/
(doi:10.1001/jamahealthforum.2023.2766)
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
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Embed this link to provide your readers free access to the full-text article
About JAMA Health Forum: JAMA Health Forum is an international, peer-reviewed, online, open access journal that addresses health policy and strategies affecting medicine, health and health care. The journal publishes original research, evidence-based reports and opinion about national and global health policy; innovative approaches to health care delivery; and health care economics, access, quality, safety, equity and reform. Its distribution will be solely digital and all content will be freely available for anyone to read.
JOURNAL
JAMA Health Forum
Families with a team mindset strengthened their bonds during COVID-19 pandemic
Despite reports of families disintegrating under the hardships and constraints of the COVID-19 pandemic, a new study suggests that many families may have formed stronger bonds instead.
One key difference between families that emerged from the pandemic stronger and unified compared with those that struggled was having a cohesive, family-oriented mindset. Families in which individuals perceived themselves as members of a team who were working for their collective benefit and found personal fulfillment in meeting the wants and needs of the other members were more likely to improve their family’s well-being during the pandemic, the researchers found.
Published in the Journal of Marriage and Family, the findings come from a nationwide survey of more than 590 people conducted in September 2022 that explored changes in family relationships during the pandemic and identified the factors associated with resilient families.
“Although many studies have examined resilience in individuals in the aftermath of the pandemic, our study is one of the first to investigate resilience at the family level,” said first author Allen W. Barton, a professor of human development and family studies and an Extension specialist at the University of Illinois Urbana-Champaign. “Prior scholars have theorized about the importance of a cohesive family mindset for promoting resiliency when families face adversity, but empirical research investigating this idea has been almost nonexistent.”
Barton’s co-authors were Scott M. Stanley, a research professor and co-director of the Center for Marital and Family Studies at the University of Denver; and U. of I. graduate students Noah B. Larsen and Qiujie Gong.
In the study, individuals were asked how aspects of their family life had changed during the pandemic – specifically, their marriage or current romantic relationship, their relationships with their children and other immediate family members they lived with, as well as those with members of their extended family.
Respondents provided information about various individual and family-level factors that could characterize pandemic-related changes in well-being, such as destructive communication patterns, how much they felt their spouse or partner appreciated them, and levels of perceived stress, loneliness and financial hardship.
The participants, who were recruited through the research survey firm Prolific, were over age 18, parenting at least one child between the ages of 4 and 17, currently in a romantic relationship and U.S. residents.
A slight majority (53%) of the participants were women, who ranged in age from 24 to 75, were white (88%), married (82%) and with a median household income between $75,000 and $85,000, according to the study.
Using the analytic technique of latent profile analysis, which grouped participants based on similarities in their responses to four COVID-19-related questions, the researchers identified three groups of families – those whose functioning worsened across multiple family relationships, who composed about 10% of the sample; those whose family well-being improved (42%); and those whose family dynamics remained stable (48%).
The researchers looked at several variables as potential predictors that differentiated individuals in these three family groups, including individual and demographic factors such as income, education level and financial hardship, along with family-level factors such as couples’ communication, their levels of social integration, their perceptions of their partners’ gratitude toward them and a cohesive family mindset.
The study results showed significant differences among the groups for several couple and family factors but few differences in the individual and demographic factors. However, only one variable significantly differentiated individuals across the three family groups – a cohesive family mindset.
Those in the improved family functioning group reported the highest levels of this mindset, while those in the worsened family functioning group reported the lowest levels of it, the researchers found.
“During times of adversity and hardship, orientations to family life that emphasize teamwork and personal fulfillment through meeting the needs and wants of the broader family unit, versus meeting the needs and wants of oneself, may provide a unique strength-based asset for families,” Barton said.
As individuals adopt this type of mindset, their personal desires may align with familial investments, the researchers hypothesized in the study.
“A cohesive family mindset creates a home in which the sacrifices necessary for the good of the family are not a barrier to one’s happiness, but another means by which happiness can be realized,” Barton said.
Individuals in the worsened functioning group indicated their family members engaged in more destructive communication during conflicts, such as heated arguments and incivility; and the adults had lower levels of perceived gratitude from their partners than those in the other two groups, who scored similarly on both factors, according to the study.
Likewise, the researchers found that individuals in the worsened family functioning group had higher levels of both perceived stress and loneliness compared with their peers in the improved family functioning group.
JOURNAL
Journal of Marriage and Family
METHOD OF RESEARCH
Survey
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Family resiliency in the aftermath of the COVID-19 pandemic: A latent profile analysis
Spending on mental health services has risen by more than 50% since beginning of pandemic
Study finds rise among privately insured; surge continued even as use of telehealth plateaued
Peer-Reviewed PublicationSpending on mental health services among Americans with private health insurance has surged since the beginning of the COVID-19 pandemic, continuing to rise even as the use of telehealth has plateaued, according to a new study.
Spending on mental health services rose by 53% from March 2020 to August 2022 among a large group of people with employer-provided insurance, according to researchers from the RAND Corporation and Castlight Health. During the same period, use of mental health services increased by 39%.
The researchers say it is uncertain if the trend will continue since some rules that expanded payment for telehealth services expired when the nation’s public health emergency ended in May. The findings are published by the journal JAMA Health Forum.
“If greater utilization of health services drives higher health care spending, insurers may begin pushing back on the new status quo,” said Jonathan Cantor, lead author of the study and a policy researcher at RAND, a nonprofit research organization. “Insurers may look for ways to curb costs and that could mean less flexibility about using telehealth for mental health services.”
To examine trends in mental health services after the start of the pandemic, researchers examined claims from about 7 million commercially insured adults from January 2019 through August 2022.
The conditions examined were anxiety disorders, major depressive disorder, bipolar disorder, schizophrenia and PTSD. The claims information was from Castlight Health, a health benefit manager for employer-sponsored health insurance plans for about 200 employers in all 50 states.
Researchers found that during the acute phase of the pandemic (March 2020 to December 2020), in-person mental health services declined by 40% while tele-mental health services increased roughly 10-fold as compared to the year prior. Overall, there was a 22% increase in use of mental health services during the period.
During the post-acute period (December 2020 to August 2022), tele-mental health service utilization stabilized at roughly 10 times pre-pandemic levels. By contrast, in-person mental health services increased 2.2% each month over the period.
By August 2022, in-person mental services had returned to 80% of pre-pandemic levels. Overall, mental health service use in August 2022 was nearly 39% higher than before the pandemic. The trends were generally consistent across mental health conditions.
During the post-acute period, there was a gradual increase in spending rates as tele-mental health service spending remained stable while spending on in-person care gradually increased. The average spending rate in the post-acute period was more than $3.5 million per 10,000 beneficiaries per month, compared to about $2.3 million per month during the pre-pandemic period.
“The changes that occurred during the COVID-19 pandemic have triggered a significant expansion in the use of mental health services among adults with employer-based health insurance,” Cantor said. “It’s remains uncertain whether this trend will continue or return to levels similar to those seen before the pandemic.”
“The demand for mental health services further underscores the critical need to integrate behavioral health services into primary care,” said Dena Bravata, study co-author and senior scientific advisor, apree health. “Through this integration we can address the growing issues around lack of access, affordability and stigma, while providing a more comprehensive, person-centered approach to overall health.”
Support for the study was provided by the National Institute of Mental Health and the National Institute on Aging.
Other authors of the study are Ryan K. McBain and Christopher Whaley of RAND, and Pen-Che Ho of Castlight Health, a part of apree health.
RAND Health Care promotes healthier societies by improving health care systems in the United States and other countries.
JOURNAL
JAMA Health Forum
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Telehealth and In-Person Mental Health Service Utilization and Spending, 2019 to 2022
ARTICLE PUBLICATION DATE
25-Aug-2023
Excess all-cause mortality in China after ending the zero COVID policy
JAMA Network Open
Peer-Reviewed PublicationAbout The Study: In this study across all regions in mainland China, an estimated 1.87 million excess deaths occurred among individuals 30 years and older during the first two months after the end of China’s zero COVID policy, a proactive strategy that deploys mass testing and strict quarantine measures to stamp out any outbreak before it can spread.
Authors: Hong Xiao, Ph.D., and Joseph M. Unger, Ph.D., M.S., of the Fred Hutchinson Cancer Research Center in Seattle, are the corresponding authors.
To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/
(doi:10.1001/jamanetworkopen.2023.30877)
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
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Embed this link to provide your readers free access to the full-text article
About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.
JOURNAL
JAMA Network Open
Severe COVID-19 twice as common among bus drivers
Bus drivers were at double the risk of being hospitalized for severe COVID-19 in the later stages of the pandemic, and several occupations in education and healthcare were also at risk of serious illness. This has been shown by a study at the University of Gothenburg.
The study is based on large amounts of data from several different registers, in total 552,562 cases of confirmed COVID-19 infection and 5,985 cases of severe COVID-19 infection. These cases, based on hospitalizations from October 2020 to December 2021, were then cross-referenced with the person’s occupation in November of the previous year. The study compared occupations that involved working closely with other people and occupations that had little or no close contact with colleagues or the public.
While the risk of hospitalization for severe COVID-19 was found to be particularly elevated among bus and tram drivers (98% increased risk), the study also highlights staff at after-school clubs (72% increased risk), registered nurses (68% increased risk), compulsory school teachers (60% increased risk) and preschool child minders (60% increased risk).
Low risk for the individual
The researchers stress that the individual risk of workers in a given profession being hospitalized for COVID-19 has remained very low, as the number of affected people in the occupational groups is small.
The results also indicate certain differences between men and women in several occupations. For example, there was a 53% increased risk of hospitalization with COVID-19 among specialist doctors of both genders, but narrowing the focus solely to female specialists, the increase in risk was significantly higher, at 105%.
“When looking at specific occupations, interesting gender differences emerge. Among women, there are increased risks for specialist doctors, nurses, midwives and preschool staff. Male occupations that carry higher risk include bus and tram drivers and security guards. This also reflects the fact that we have a gender-segregated labor market,” says Maria Åberg, Professor of General Medicine at Sahlgrenska Academy, the Faculty of Medicine at the University of Gothenburg.
Focus on the workplace
Above all, the researchers hope that the results of the study will be an eye-opener for employers. The results clearly show a work-related contagion in several different types of contact professions, not only in health care. It highlights the need for improved risk assessment and preventive measures in these sectors.
Kjell Torén, Senior Professor of Occupational and Environmental Medicine at Sahlgrenska Academy at the University of Gothenburg:
“The workplace is also an important arena for informing about and carrying out vaccination. Over the course of our research, we have come to the strong conclusion that workplaces or employers need to be involved in getting these high-risk occupations access to vaccination, for example by allowing them to be vaccinated during working hours or by organizing vaccination sessions at their place of work. And occupational healthcare has an important role to play in making this happen,” he says.
Maria Åberg again:
“We know that vaccination protects against severe COVID-19 and we believe that vaccination in high-risk workplaces during working hours would further reduce the risks. This applies in particular to bus and tram drivers and preschool staff. Healthcare workers were usually offered vaccination during working hours, but perhaps additional measures could have increased vaccination uptake,” she says.
Published in the Scandinavian Journal of Work, Environment & Health, the study was conducted in collaboration with Karolinska Institutet.
The study does not take into account vaccination levels among the cases included in the data set, which the researchers plan to pursue in a later study.
METHOD OF RESEARCH
Case study
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Occupational risks associated with severe COVID-19 disease and SARS-CoV-2 infection – a Swedish national case-control study conducted from October 2020 to December 2021
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