As the COVID-19 pandemic progresses, governments are urging high-risk individuals to strictly follow social distancing measures to reduce the risk of severe illness and death. Data from China show that 14% of cases are severe and 5% critical, with case fatality rates potentially as high as 1%, much higher than seasonal influenza. In the UK, up to 25% of the population is considered high risk, including those over 70 and individuals with chronic conditions. Strict restrictions are in place, which may lead to increased loneliness and loss of mental and physical function in vulnerable groups. A study of 799 patients in Wuhan found that those who died were older, more likely to be male, and had comorbidities such as hypertension, diabetes, and cardiovascular disease. Similar findings have been reported in other studies, with older age, cardiovascular disease, diabetes, and chronic respiratory disease all linked to increased mortality risk. Obesity and smoking are also associated with higher risks, and men are at higher risk in Italy than women, possibly due to higher smoking rates. However, the relative importance of different health conditions is unclear due to inadequate adjustment for confounding factors such as age, sex, and smoking. In China, health records are often incomplete, and chronic conditions are underdiagnosed. Smoking prevalence is also underestimated in some studies. These studies focus on high-risk patients admitted to hospitals, so findings may not apply to the general population. Current data suggest that younger adults have a lower case fatality rate compared to the elderly. Governments are using knowledge from other viruses to guide restrictions, as everyone must follow measures to protect those at higher risk. High-quality population-level data are needed to better understand risks and inform future policies.As the COVID-19 pandemic progresses, governments are urging high-risk individuals to strictly follow social distancing measures to reduce the risk of severe illness and death. Data from China show that 14% of cases are severe and 5% critical, with case fatality rates potentially as high as 1%, much higher than seasonal influenza. In the UK, up to 25% of the population is considered high risk, including those over 70 and individuals with chronic conditions. Strict restrictions are in place, which may lead to increased loneliness and loss of mental and physical function in vulnerable groups. A study of 799 patients in Wuhan found that those who died were older, more likely to be male, and had comorbidities such as hypertension, diabetes, and cardiovascular disease. Similar findings have been reported in other studies, with older age, cardiovascular disease, diabetes, and chronic respiratory disease all linked to increased mortality risk. Obesity and smoking are also associated with higher risks, and men are at higher risk in Italy than women, possibly due to higher smoking rates. However, the relative importance of different health conditions is unclear due to inadequate adjustment for confounding factors such as age, sex, and smoking. In China, health records are often incomplete, and chronic conditions are underdiagnosed. Smoking prevalence is also underestimated in some studies. These studies focus on high-risk patients admitted to hospitals, so findings may not apply to the general population. Current data suggest that younger adults have a lower case fatality rate compared to the elderly. Governments are using knowledge from other viruses to guide restrictions, as everyone must follow measures to protect those at higher risk. High-quality population-level data are needed to better understand risks and inform future policies.