UK records 250% rise in daily COVID-19 cases. Read details

With more than half a billion coronavirus cases recorded worldwide since the start of the pandemic, there has been rising concern about the lasting symptoms seen in people with long Covid.

However almost none of the existing research has compared long Covid sufferers with people who have never been infected, making it possible that some of the health problems were not caused by the virus.

A new study published in The Lancet journal asked more than 76,400 adults in the Netherlands to fill out an online questionnaire on 23 common long Covid symptoms. Between March 2020 and August 2021, each participant filled out the questionnaire 24 times. During that period, more than 4,200 of them -- 5.5 percent -- reported catching Covid. Of those with Covid, over 21 percent had at least one new or severely increased symptom three to five months after becoming infected.

The research also recorded symptoms before and after Covid infection, allowing the researchers to further pinpoint exactly what was related to the virus. It found that common long Covid symptoms include chest pain, breathing difficulties, muscle pain, loss of taste and smell, and general fatigue.

The authors of the study said its limitations included that it did not cover later variants, such as Delta or Omicron, and did not collect information about some symptoms such as brain fog, which have since been considered a common sign of long Covid.