Concerning COVID: Why Is Quarantine 14 Days?

November 2, 2020 |

Concerning COVID

November 2, 2020

Today’s Concerning COVID is one students have asked a lot, especially those who have found themselves in quarantine this semester:

Why does quarantine have to be 14 days, while isolation (when you’re sick) is only 10? If you’re in quarantine, why not just get tested and be released if you’re negative for COVID?

The 14-day quarantine is the maximum time it takes for COVID-19 to manifest itself. Close contacts may feel frustrated that they must be confined for longer than those who are actually sick. However, the 14-day incubation period, or the amount of time before symptoms appear, is actually longer than the time an infected person is contagious, 10 days.

Another common frustration is having to be quarantined in spite of a negative test result. The answer is that though you may receive a negative test result and are symptom-free, unfortunately, you may still be an agent of transmission.

Research shows it may take up to 14 days from exposure of COVID-19 to testing positive. The virus has to replicate (grow in number) enough in a person’s body for that person to show signs and symptoms. Therefore, someone may contract and transmit COVID-19 before they even show signs. This necessitates a quarantine for that amount of time in order to monitor for symptoms and detect cases early. 97% of people will show symptoms by day 11 or 12; however, by day 14, 99% of people will have shown symptoms. By quarantining the extra two or three days, we put a safety measure in place to decrease the likelihood of further spread of a person who is not experiencing symptoms.

Further research conducted on isolation shows that if a person no longer is showing symptoms 10 days after their onset, the virus no longer has the replication component (ability to grow) and this lessens viral load (amount of virus in the body) which drastically decreases the risk of transmission.

Two reasons people often think they should be released from quarantine early, is they may have received a negative test and they have no symptoms. The issue with the first point is there is a possibility of a false negative test especially in the first 5 days after exposure. The first day after contact exposure to a person who has COVID-19 one will not have enough virus developed in their body to create a positive test. By day 4 it is still possible, one study reports up to 67%, to have a false negative test. As we might not be certain when exact the exposure occurred, quarantine is recommended even for those who test negative.

Should a person receive a false negative and have no symptoms it is possible they could be asymptomatic. The CDC reports research shows, “half of all infections are the result of transmission of asymptomatic hosts.” While it might be frustrating to be quarantined when you feel healthy, you can have a positive impact in stopping the spread of COVID on our campus.

Considerations for Quarantine of Contacts of COVID-19 Cases. (2020). Retrieved October 21, 2020, from file:///Users/lydiaq/Downloads/WHO-2019-nCoV-IHR_Quarantine-2020.3-eng.pdf

COVID-19 Pandemic Planning Scenarios. (2020, September 10). Retrieved October 21, 2020, from

Lauer, S. A., Grantz, K. H., Bi, Q., Jones, F. K., Zheng, Q., Meredith, H. R., Azman, A. S., Reich, N. G., & Lessler, J. (2020). The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of internal medicine, 172(9), 577–582.

Kucirka, L., Lauer, S., Laeyendecker, O., Boon, D., & Lessler, J. (2020, August 18). Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure. Retrieved October 21, 2020, from

Redford, G. (2020, October 05). Your COVID-19 testing questions – answered. Retrieved October 21, 2020, from

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  • Jane Nicholas, MD says:

    I would like to see your reference that indicates the contagious period for a known positive and symptomatic patient is only 10 days total.
    CDC, WHO, Harvard and other sources indicate that a patient still sheds virus and is contagious until 10 to 14 days AFTER symptoms have resolved.