Identifying risk factors for infection with the new coronavirus (COVID-19)

Date of ISAC Approval: 
25/03/2020
Lay Summary: 
In 2019 a new infection emerged (COVID-19) which is caused by a new coronavirus. Because it is a new disease, we do not know how underlying health conditions affect the risk of catching COVID-19. Public Health England has collected information about the first few hundred COVID-19 cases in England using questionnaires, including pre-existing health conditions such as diabetes. This study will compare the presence of these health conditions among patients with COVID-19 to the general population, adjusting for differences in age, sex, ethnicity, deprivation and region. This will help us to understand better which health conditions may increase the risk of infection among the general population. Patients with COVID-19 who were admitted to intensive care with pneumonia will also be compared to people admitted to intensive case with pneumonia at the same time last year. This will help understand whether the risk factors for severe COVID-19 pneumonia are different from those for severe pneumonia from other causes. Finally, we will describe how common each risk factor is in the general population, according to age, sex and region, so that our results can be used to predict health service use. This work is part of the Health Protection Research Unit in Immunisation, a partnership between the London School of Hygiene & Tropical Medicine and Public Health England. The findings will inform Public Health England’s policy advice to the government, advice for people with underlying health conditions, and planning for the demand on health services during the COVID-19 pandemic.
Technical Summary: 
This study will describe associations between underlying health conditions and early COVID-19 infections in England, compare the profile of underlying health conditions among COVID-19 pneumonia requiring ITU admission to those for severe pneumonia of other causes, and describe the prevalence of these conditions among the general population in England. For the first two aims, a case-control study design will be used, with two control groups. Cases will comprise the ‘first few hundred’ COVID-19 cases in England, January-March 2020, using a depersonalised dataset from Public Health England. For the main analysis, controls will be the general population active in CPRD, January-March 2019. Potential risk factors will be chronic heart, respiratory, kidney, neurological and liver diseases, immunosuppression, asthma requiring medication, malignancy, organ transplant recipients, pregnancy and smoking status. A secondary analysis we will compare COVID-19 cases admitted to ITU with pneumonia to controls admitted to ITU with pneumonia in January - March 2019. Both analyses will use multivariable logistic regression to calculate odds ratios adjusted for age, sex, ethnicity, region and deprivation. Among individuals eligible to be selected as general population controls, summary data of the prevalence of the underlying health conditions stratified by age, sex and region will be described to enable findings to be used in modelling to inform policy responses to COVID-19. The results will inform planning for the demand on health services during the COVID-19 pandemic, and Public Health England’s advice to the public and government about the risk of COVID-19 for people with underlying health conditions.
Health Outcomes to be Measured: 
Primary: Laboratory-confirmed infection with novel coronavirus (SARS-CoV-2) - indicated by inclusion in Public Health England COVID-19 'first few hundred' case dataset. Secondary outcomes: - Severe pneumonia (requiring admission to intensive care) due to laboratory-confirmed infection with novel coronavirus (SARS-CoV-2). - Prevalence among the general population of underlying health conditions which are being considered as possible risk factors for COVID-19.
Collaborators: 

Helen McDonald - Chief Investigator - London School of Hygiene & Tropical Medicine (LSHTM)
Daniel Grint - Collaborator - London School of Hygiene & Tropical Medicine (LSHTM)
Helen McDonald - Corresponding Applicant - London School of Hygiene & Tropical Medicine (LSHTM)
Helen Strongman - Collaborator - London School of Hygiene & Tropical Medicine (LSHTM)
Jemma Walker - Collaborator - London School of Hygiene & Tropical Medicine (LSHTM)
Julia Stowe - Collaborator - Public Health England
Liam Smeeth - Collaborator - London School of Hygiene & Tropical Medicine (LSHTM)
Nick Andrews - Collaborator - Public Health England

Linkages: 
HES Admitted;Patient IMD; Practice IMD (Standard);Pregnancy Register