The first study to explore global variations in COVID-19 symptoms has found significant variations around the world – alongside differences in presence of underlying health conditions.
The research, undertaken by the Global COVID Observatory at Imperial College London and published in *eClinicalMedicine*, analysed data from 78,299 individuals in 190 countries between April and September 2020. Of these, 64,699 were symptomatic and untested, 7,980 tested positive, and 5,620 tested negative.
Partnering with *healthily*, an online symptom mapper, the researchers say the study creates a framework for further research to use global self-reported data in identifying parallels between health conditions, world region, and symptom profile of infectious diseases.
Joint senior author Professor Aldo Faisal, of Imperial’s Departments of Computing and Bioengineering, said: “Understanding symptom variation by location and health is crucial for clinical practice. It could help speed up diagnosis, predict outcomes more precisely, and target treatment – particularly with the emergence of new variants."
The data represents a snapshot of symptoms from the early stage of the pandemic, relating to the Sars-CoV-2 strains circulating between April and September 2020.
The team used clustering to identify similarities between the symptom profile of different countries and underlying health conditions. Most responses were from India (22.5%), Mexico (16.8%), Pakistan (9.5%), Philippines (9%), United Kingdom (5.7%), and Brazil (5.5%).
They found that responders who tested positive were more likely to report joint pain, loss of appetite, and loss of smell and taste than those who had tested negative or had symptoms but had not been tested.
Fewer COVID-19 positive responders reported sore throat and nasal congestion than those who had tested negative or had symptoms but were untested.
Of the responders with COVID-19, 60.3% had no underlying chronic disease, 30.7% had one underlying chronic disease, 7.1% reported two underlying chronic diseases, and 1.9% reported three or more.
These rates mirrored those responders who tested negative or had symptoms but were untested.
Individuals with underlying lung conditions and/or type 2 diabetes were more likely to report several symptoms than respondents with no underlying conditions.
Individuals with COVID-19 who had asthma were more likely to report fatigue than those who had no underlying conditions at 62.3% compared with 49.8%). They were also more likely to report headache (56.2% vs 45.8%), shortness of breath (25.3% vs 13.7%), sputum production (17.4% vs 10.7%), chest pain (12.4% vs 6.8%), chills (26.8% vs 17.1%), or diarrhoea (31.3% vs 22.7%).
Those who tested positive and had an underlying lung condition, such as COPD, were more likely to report chest pain compared with those who had no underlying disease at 15.2% compared to 6.8%.
They were also more likely to report sputum production at 22.2% compared to 10.7%, but less likely to report loss of smell and taste (29.3% vs 46.0%).
COVID-19 positive responders with Type 2 diabetes were more likely to report a raised temperature.
Loss of smell and taste was more likely to be reported as a symptom among positive individuals with no underlying disease compared with responders who had a lung condition, type 1 diabetes, type 2 diabetes or high blood pressure.
Respondents in Brazil were five times more likely to report chest pain and joint pain than other countries, while those in Pakistan were four times more likely to report chest pain and five times more likely to report joint pain.
Respondents in the UK were five times more likely to report shortness of breath and sputum, and three times more likely to report chills, fatigue, and headache.
Joint senior author Professor Céire Costelloe, of Imperial’s School of Public Health, said: “Global snapshots like these can help to inform our treatment of patients, whose age and underlying health conditions like asthma or diabetes will likely affect their COVID-19 symptoms and outcome. The approach could also help to inform public health messaging and practice by monitoring in real-time the effects of new outbreaks or variants on a population.”
Kadirvelu B, Burcea Gm Quint JK et al. Variation in global COVID-19 symptoms by geography and by chronic disease: a global survey using the COVID-19 Symptom Mapper. *eClinicalMedicine* 15 March 2022
Leave a Reply