People might start to exhibit symptoms of SARS-CoV-2 in five days finds new study

A new study has found that the incubation period for SARS-CoV-2 is around five days. To recap, SARS-CoV-2 is the coronavirus that causes the disease COVID-19. Coronaviruses are a large family of viruses that may cause illness in animals or humans.

The incubation period is the time from exposure to the virus until the first symptoms develop in a person, and is characteristic for each disease agent.

This scanning electron microscope image shows SARS-CoV-2 (orange)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S., emerging from the surface of cells (green) cultured in the lab. Image credit: AP

This scanning electron microscope image shows SARS-CoV-2 (orange) — also known as 2019-nCoV, the virus that causes COVID-19 — isolated from a patient in the U.S., emerging from the surface of cells (green) cultured in the lab. Image credit: AP

For this specific SARS-CoV-2, the median incubation period is 5.1 days, and the study suggests that about 97.5 percent of people who develop symptoms of this virus will start to exhibit symptoms within 11.5 days of exposure.

Hence the quarantine period of 14 days that is being followed worldwide is a good enough time period to observe a person who is suspected of being exposed to the virus.

However, the researchers said that for every 10,000 people who are quarantined for 14 days, an estimated 101 people would develop symptoms after being released from quarantine.

“Based on our analysis of publicly available data, the current recommendation of 14 days for active monitoring or quarantine is reasonable, although with that period some cases would be missed over the long-term,” said Justin Lessler, an associate professor in the Bloomberg School’s Department of Epidemiology in a statement.

The researches looked at 181 cases of people from China and other countries that were detected prior to 24 February and those that were reported in the media and included likely dates of exposure and symptom onset. They all have either a history of travel to Wuhan or Hubei in China.

The findings were published in the journal Annals of Internal Medicine.