LONDON — The British government is backing four new studies to investigate why some people continue to have symptoms months after becoming sick with COVID-19.

The Department of Health on Thursday announced 18.5 million pounds ($26 million) in funding for research into the causes, symptoms and effects of the phenomenon known as “long COVID.”

While most people recover from the coronavirus in a few weeks, about one in 10 still have symptoms 12 weeks later. Researchers around the world are trying to understand the causes and dozens of symptoms that include breathlessness, headaches, fatigue and “brain fog.”

Britain’s All-Party Parliamentary Group on Coronavirus says the research is welcome but is not enough. The lawmakers are calling for long COVID-19 to be classed as an occupational disease of front-line workers so patients can receive compensation if they can’t work because of the illness.