A new study from the United Kingdom indicated that most people infected with COVID-19 remain contagious even after 5 days from the onset of symptoms.

A group of researchers at the London Institute carried out a study of daily symptom reports and tests, including polymerase chain reaction tests and lateral flow tests, more commonly known as rapid tests. Through this, the researchers found that lateral flow tests are not reliable for detecting the start of the infection, but they can be useful in determining when to shorten the quarantine period.

The study concluded that infection usually begins shortly after the onset of COVID-19 symptoms, where the lead researcher Ajit Lalvani said in a press statement: We recommend that anyone exposed to the virus and symptomatic should isolate for five days.

Similar to the UK, most COVID-19 guidelines in Canada recommend people self-isolate for five days after symptoms appear, and they can end quarantine after five days if symptoms do not persist. However, the authors of the new study emphasize the importance of following self-isolation guidelines, regardless of whether they are required or not.

On the other hand, co-author Siran Haqi said in the statement: "There is no longer a legal requirement for self-isolation if the COVID-19 test is positive [in the UK], but most people still want to isolate until they are no longer contagious," adding: "Our study is the first to assess how long the infection lasts, using real-world evidence from naturally acquired infection, and thus our results can provide guidance on how to safely end self-isolation."