It still affects some two million Britons. Symptoms can last more than a year – ranging from fatigue to fever and tummy pain, say scientists.
The largest study of its kind underlines the importance of the jabs, say scientists.
It was based on 860,000 patients across the world. Overweight individuals, women, smokers and over 40s are most prone.
Illnesses, or “co morbities,” such as asthma, COPD (chronic obstructive pulmonary disorder), type 2 diabetes, coronary heart disease, immuno-suppression, anxiety and depression were also aggravating factors.
Lead author Professor Vassilios Vassiliou said: “Furthermore, severe illness during the acute phase, as reflected by the need for hospitalization or admission to an intensive care unit, is also associated with the development of long Covid.
“Conversely, it was reassuring to see people who had been vaccinated had significantly less risk – almost half – of developing long Covid compared to unvaccinated participants.
“These findings are important because they enable us to better understand who may develop long Covid and also advocate for the benefit of vaccination.”
Long Covid is an umbrella term for debilitation lasting more than 12 weeks.
They include breathlessness, raised heart rate, delusions, insomnia, loss of taste and smell, headaches and muscle weakness.
Effects linger in up to a fifth of survivors. An estimated 400,000 Britons have been hit for more than a year.
Prof. Vassiliou, of the University of East Anglia, said: “Long Covid is a complex condition that develops during or after having covid, and it is classified as such when symptoms continue for more than 12 weeks.
“Just over two million people in the UK are thought to suffer with long Covid and it affects people in different ways. Breathlessness, a cough, heart palpitations, headaches, and severe fatigue are among the most prevalent symptoms.
“Other symptoms may include chest pain or tightness, brain fog, insomnia, dizziness, joint pain, depression and anxiety, tinnitus, loss of appetite, headaches and changes to sense of smell or taste.
“We wanted to find out what factors might make people more or less susceptible to developing long Covid.”
The analysis in JAMA Internal Medicine pooled data from 41 studies to investigate risk factors in more detail than ever before.
Prof. Vassiliou said: “We found female sex, older age, increased BMI and smoking are associated with an increased risk of long Covid.
“In addition, co-morbidities such as asthma, COPD, Type 2 Diabetes, coronary heart disease, immunosuppression, anxiety and depression are also associated with increased risk.”
Most coronavirus patients will recover within a fortnight, suffering a fever, cough and losing their sense of smell or taste for several days.
However, tell-tale symptoms of the virus can persist for weeks on end in ‘long haulers’ – the term for patients plagued by lasting complications.
Co-author Dr. Eleana Ntatsaki, of University College London, added: “Our findings help define the full demographic characteristics and the risk factors for developing Long Covid.
“We can now better understand and serve this population with long-term care planning, support for Long Covid clinics and increase awareness of the prevalence and impact of the condition.
“Furthermore, we can have a better strategy for optimizing any modifiable risk factors, with public health promotion campaigns, encouraging smoking cessation, vaccination and healthy weight management in the target population.”
Produced in association with SWNS Talker