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The study confirms previous estimates of the incubation period

A new study confirms previous estimates suggesting that the median incubation period for the new coronavirus, SARS-CoV-2, is approximately 5 days.

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A new study indicates that SARS-CoV-2 (above) has a median incubation period of approximately 5 days before it begins to trigger symptoms in humans.

For real-time updates on the latest developments regarding the novel coronavirus and COVID-19, click here.

One of the most frequent questions asked by the public since the beginning of the new coronavirus outbreak was: what is the incubation period of the virus?

This refers to the period between the virus contracting and the appearance of physical symptoms.

According to information from the World Health Organization (WHO), current estimates indicate that SARS-CoV-2 could take 1 to 14 days to incubate. However, they suggest that the most common incubation period is around 5 days.

Now, a new study from the Johns Hopkins Bloomberg School of Public Health in Baltimore, MD, confirms that the median incubation period for the new virus is around 5 days, which means that about half of people who contract SARS-CoV-2 will begin to show symptoms at that time.

The researchers based their results – presented in Annals of internal medicine – on the data of 181 subjects with confirmed COVID-19. Most of these people had been stationed or traveled to and from Wuhan in China, the epicenter of the epidemic.

Confirming existing estimates, the current study also estimated that the median incubation period for SARS-CoV-2 is 5.1 days.

While this means that half of the people with the virus will show symptoms within 5 days, for many others, it will take longer. Overall, 97.5% of people will show symptoms within the first 11.5 days.

“This work provides further evidence for a median incubation period for COVID-19 of approximately 5 days, similar to SARS,” investigators write in their study.

“Under conservative assumptions,” researchers say, only about 101 in 10,000 people who contract SARS-CoV-2 can develop symptoms after 14 days. This is the period that public health agencies, such as the Centers for Disease Control and Prevention (CDC), currently recommend for self-quarantine.

“Based on our analysis of publicly available data, the current 14-day recommendation for active monitoring or quarantine is reasonable, although some cases would be lacking in the long run by that time.”

– Senior author Justin Lessler, Ph.D.

In commenting on the current findings, virologists point out that the study appears to confirm that current public health strategies – such as the 14-day quarantine – are correct.

However, they also warn that some of the hypotheses made by the original researchers when they conducted their study may be incorrect.

For example, Prof. Jonathan Ball, of the University of Nottingham in the United Kingdom, notes that “we must recognize that the models [the study authors] using it to estimate the incubation period makes key assumptions, and perhaps the assumption that it is most likely to impact their data is that a person was infected as soon as he came into contact with the virus. “

“This,” he points out, “may not be true – the true time point of the infection may be much later, but assuming that the infection occurred at an earlier date, the incubation period will appear longer.”

You can read the full comments of Prof. Ball and other experts here.

For real-time updates on the latest developments regarding the novel coronavirus and COVID-19, click here.

For information on how to prevent the spread of coronavirus, this page of the Centers for Disease Control and Prevention (CDC) provides advice.

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