New Study Pinpoints When COVID Symptoms Typically Begin After Exposure

A new study has found that COVID-19 symptoms typically begin within two days of being exposed to the virus. Researchers from the Imperial College of London purposely exposed 36 unvaccinated people to the virus, allowing them to track the entire course of the infection.

Half of the participants developed COVID-19, and 16 of them began showing symptoms within 42 hours of the infection. The symptoms peaked after about five days.

All of the positive cases were mild-to-moderate and produced symptoms, including a stuffy or runny nose, sneezing, a sore throat, fever, headaches, muscle/joint aches, and fatigue.

The researchers found that all the volunteers who tested positive had similar viral loads. The study also found that lateral flow tests using a nasal swab were the most effective at identifying the presence of the virus because there is a higher concentration of virus in the nose than in the throat.

"Our study reveals some very interesting clinical insights, particularly around the short incubation period of the virus, extremely high viral shedding from the nose, as well as the utility of lateral flow tests, with potential implications for public health," said Professor Christopher Chiu, from the Department of Infectious Disease and the Institute of Infection at Imperial College London and Chief Investigator on the trial.

The researchers are planning to do another study using the Delta variant.