Coronavirus Disease 2019 Open Cohort Study
Study acronym
COCS
Background
COVID-19 created an urgent need for reliable information about its clinical presentation, transmission, risk factors and outcomes across different populations. Early case definitions were largely based on travel history, contact with confirmed cases and respiratory symptoms. However, community transmission, asymptomatic infection, emerging variants, vaccination and geographical differences made it necessary to continually review these definitions.
There was also limited information about COVID-19 in African populations and its interaction with prevalent diseases such as malaria, pneumonia, tuberculosis, HIV, sickle cell disease and diarrhoeal illnesses.
Study purpose
The study aimed to refine COVID-19 case definitions and improve understanding of the disease’s incidence, clinical spectrum, risk factors, distribution and outcomes across different populations.
It also sought to produce evidence for public-health education, clinical research, disease surveillance and future epidemic-response planning.
Study design
COCS comprised several related observational components:
- A voluntary global online cross-sectional survey.
- An online open cohort with repeated follow-up.
- Retrospective review of hospital admissions before and during the COVID-19 pandemic.
- Prospective surveillance of patients admitted with COVID-19 and other coexisting illnesses.
- Additional social, healthcare-provider, economic and systematic-review studies related to COVID-19.
No investigational medicines or therapeutic interventions were administered.
Online study population
The online component targeted consenting adults aged 18 years and above. Participants were recruited through online platforms, email, social media and the study website.
The first phase planned to enrol approximately 5,000 respondents globally. About 500 participants were expected to enter the longer-term cohort component.
Hospital-based study population
The hospital component included retrospective records and prospective enrolment of patients admitted to medical and paediatric wards at Mbale and Soroti Regional Referral Hospitals.
The study examined patients with COVID-19 and conditions including:
- Malaria
- Blackwater fever
- Pneumonia
- Tuberculosis
- HIV
- Diarrhoeal diseases
- Neonatal sepsis
- Meningitis
- Measles
- Sickle cell disease
- Pregnancy and pregnancy-related outcomes
Study sites
The hospital surveillance component was conducted at:
- Mbale Regional Referral Hospital
- Soroti Regional Referral Hospital
The initial online component was designed for global participation.
Principal investigator
The Principal Investigator was Professor Peter Olupot-Olupot.
The multidisciplinary study team included investigators from Mbale, Soroti and Lira, together with personnel responsible for project coordination, data management, administration, statistical analysis and quality assurance.
Project management
Dr Charles Benard Okalebo served as the Project Manager and Quality Assurance Officer.
Main objectives
The study sought to:
- Characterise the clinical spectrum of COVID-19.
- Refine COVID-19 case definitions using information from different populations.
- Describe the epidemiology, risk factors and geographical distribution of COVID-19.
- Document clinical outcomes across different age groups and underlying health conditions.
- Examine COVID-19 co-infections and their outcomes.
- Compare hospital admissions and outcomes before and during the pandemic.
- Assess the effect of COVID-19 control measures on other infectious diseases.
- Generate evidence for public-health education, policy and further clinical research.
Study outcomes
The hospital surveillance component assessed outcomes including prolonged hospitalisation and death during admission. It also examined disease patterns, patient characteristics, treatment received, coexisting illnesses and changes in hospital admissions before and during the COVID-19 pandemic.
The online component assessed reported exposures, symptoms, risk factors and outcomes and provided automated guidance on actions such as self-isolation, contacting a health service or seeking medical attention.
Study period
The original online study proposed a baseline survey followed by cohort follow-up for 12 months. The amended protocol added longer-term hospital surveillance
Ethics and participant protection
Online participation was voluntary and limited to consenting adults. The survey was designed to be anonymous and not to collect names, telephone numbers or email addresses.
Hospital participants in the prospective component were to provide informed consent before enrolment. The protocol also described secure electronic data collection, restricted database access and encryption of information during transmission.
The Mbale Regional Referral Hospital Research and Ethics Committee and Uganda National Council for Science and Technology was obtained.
Protocol information
The final Protocol Version 2.0 was amended on dated 11 March 2021.
Study status
The amended protocol planned prospective surveillance until March 2026. The responsible study team should confirm whether data collection has formally ended and provide the current analysis, reporting, publication and close-out status.
Publications: