MRC-University of Glasgow Centre for Virus Research

• New study in reveals the key Long Covid characteristics affecting populations worldwide, including fatigue, shortness of breath and having trouble thinking clearly.
• 6-12 months after hospital discharge, 70% of study participants were affected by Long Covid in high-income countries, and 42% in low and middle-income countries.
• Study is set in 25 sites across 17 countries, including the UK, Brazil, Colombia, France, The Gambia, Gibraltar, India, Israel, Italy, Malaysia, Norway, Portugal, Russian Federation, South Africa, Spain, Sudan and Ukraine. 

A study by an international COVID-19 research group, led by international researchers part of the ISARIC (the International Severe Acute Respiratory and emerging Infection Consortium - a network of global clinical research networks), hosted at the University of Oxford’s Pandemic Sciences Institute, is one of the largest international studies to provide evidence for the longer-term impact of COVID-19 illness in populations worldwide.

This observational study uses data collected from sites in High-, Middle- and Low-Income Countries, whereas most previous studies on Long Covid have focused on patients in high-income (HICs) countries and have thus provided a limited understanding of the wider individual and socioeconomic impact of Long Covid.

The World Health Organization (WHO) has defined Long Covid as the continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with these symptoms lasting for two months or longer with no other explanation.

The study aimed to characterise Long Covid, explore risk factors for developing the condition, and better understand the impact on daily activities and quality of life in different regions. The results highlight the potential long-term impact of Long Covid on population health globally, which may disproportionately impact economically disadvantaged populations. Researchers discovered that six to 12 months after discharge from hospital, 70% of participants from high-income countries and 45% in lower- and middle-income countries were affected by Long Covid, with fatigue, breathlessness and “brain fog” the most common symptoms.

The study enrolled 11,860 people from 25 research sites across four continents, specifically adults admitted to hospital due to COVID-19 or diagnosed with COVID-19 during their hospital stay.

Dr Louise Sigfrid, Senior Clinical Research Fellow at the Pandemic Sciences Institute, said: "Our findings show the strength of working together with specialist, patients and community groups co-developing and harmonising our methods when studying Long Covid. Long Covid presents problems not just for individuals, but also for health systems and the wider economy. As we prepare for future epidemics and pandemics, it's crucial we plan how to understand, prevent and manage long-term health problems to improve outcomes for everyone."

These findings highlight the burden of Long Covid on the population, and although the proportion was found to be lower in LMICs, the burden on individuals and health systems may be larger in lower resourced settings.

The range of countries across four continents, using a standardised assessment tool, allowed researchers to compare Long Covid experiences in different economic and healthcare settings. The study found:

• Long Covid presents with similar symptoms in different regions globally, impacting on functioning and quality of life. The data collected reflects participants’ responses for up to 12 months after being discharged.
• The most common symptoms reported included fatigue, headaches, shortness of breath, and muscle and joint pain.
• Brain-related symptoms, like trouble concentrating, were also commonly reported
• People in high income countries were more likely to not feel fully recovered, compared to those in resource-limited settings.
• Approximately 1 in 10 participants was affected by moderate-to- severe breathlessness
• Male patients had a lower risk of developing symptoms such as reduced functioning and lower quality of life than females, across HICs and LMICs.

The research was carried out by scientists from University of Oxford and the University of Glasgow, UK; Universidad de La Sabana in Colombia, the National Institute for Communicable Diseases in South Africa, Oswaldo Cruz Foundation (Fiocruz) in Brazil, University Hospital of North Norway, Sechenov University, Russian Federation, University Hospital of Parma, Italy; Lugansk State Medical University, Ukraine; Ziauddin University, Pakistan; Sunway Medical Centre, Malaysia; Terna Specialty Hospital & Research Centre, India and other collaborating institutions. Patient groups around the world were also involved in the design of the study including,  Long Covid Support UK.

Dr Luis Felipe Reyes from Universidad de La Sabana, Colombia, emphasised the importance of this research: "This study gives us crucial insights into how Long Covid affects people in different parts of the world, including resource limited countries. It shows that we need to pay attention to long-term health effects everywhere, not just in rich countries. This information will help us better prepare our healthcare systems and support patients in places like Colombia and other parts of South America."

Dr Daniel Munblit from King's College London and Sechenov University, Moscow, added: "This study worked well because researchers in many countries agreed to do things the same way. This let us pool and compare results from different places, which is really important for understanding big health problems like Long Covid."

Dr Janet Scott from the MRC-University of Glasgow Centre for Virus Research (CVR) and NHS Highland suggested why Long Covid may be more common in richer countries: "There are several possible reasons: perhaps there are differences in the immune responses of people who have grown up in different places, or possibly the timing of COVID-19 waves and different virus types in each country played a part. It may even be that people in richer countries are more aware of Long Covid and have better documented access to healthcare to report their concerns, although this study did actively follow up with participants to make this possibility less likely”.  

Dr Scott adds, "People with Long Covid need ongoing support for their long-lasting health problems. This study shows we need to include research on long-term health effects in our plans for future pandemics. Long Covid isn't just a health issue – it affects jobs, families, the economy, and needs urgent attention from governments.”

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First published: 22 October 2024