Why Kerala man tested positive three weeks after returning from the Gulf

PCR test
The PCR test may be positive in 50% patients even two or three weeks after getting infected. (Representative image)

The news that a person was tested positive for COVID-19 three weeks after returning from the Gulf has confused many. Some people found it shocking and it has raised many questions about the incubation period and nature of the virus. Here are some of the most common queries about the corona virus and their answers.

The PCR test of a person has turned positive around 25 days after he returned from the Gulf. Is this an unexpected incubation period?

No, the incubation period is the time from the moment of exposure to an infectious agent until symptoms of the disease appear. The above mentioned patient was tested not because that patient had displayed symptoms. They in fact didn’t show any symptoms. The person was tested as part of the standard procedure to test those who have come into contact with a patient.

In the case of COVID-19, the incubation period is 5 days on an average. By observing the trend of the infection outside India, it is rare that the incubation period extends beyond two weeks. Such a case hasn’t been reported even here.

Then how did the PCR test come positive?

We use the PCR test to confirm the cases, right? This test may show positive even after the symptoms disappear. Many researches have revealed that the PCR test may show positive up to 15 to 30 days in 45% patients. It means, the PCR test may be positive in 50% patients even two or three weeks after getting infected.

Why is the quarantine period fixed at 28 days?

The duration of the quarantine was not decided based on the PCR test; instead it has been calculated on the basis of time taken for a patient to infect others. Many studies have shown that a patient would lose their infectivity within two weeks after getting infected. So, even if the PCR test comes positive, the chances of that patient infecting others are less. It would be lesser still after 28 days. These are the factors that determine the duration of the quarantine or the isolation period.

What does it mean when a few members of the same family shows positive in the PCR test?

The media has given importance to the fact that the PCR test came positive after so many days. However, what must really be noted is that more number of people has tested positive. If a person returns from a foreign country, he/she is asked to stay in isolation without contacting anyone. The number of persons testing positive in an area depends upon the effectiveness of this isolation method. The movements and contacts inside a house make another person infected which then would be spread to others as well. Most of them may not even show any symptoms. As the lockdown rules are stricter, it could be assumed that they do not have any contacts with the outside world. The virus may spread two or three times inside the same house. If the lockdown is lifted when the virus is still active in one of the family members and he or she chooses to go out and interact with others, it may create another wave of infections. So, it is important that everyone strictly stays inside the house during the home quarantine period.

However, the extent of the infection may be reduced if the infected person who roams around wears a mask. It is better that everyone wears a mask as the person may not realize whether they are carriers of the virus. (Many may be asymptomatic).

While standing in queues in a super market or any other public place, one should keep a distance of at least 1 meter from others as the person who is standing in front of us may be a carrier of virus.

The droplets that contain the virus may get stuck on many objects that we touch regularly. Try not to not touch your face, nose or eyes. Wash your hands at intervals using soap and water.

There is no point in claiming the preventive measures as ineffective just because a few persons tested positive way beyond the time expected. Cases like these remind us to be more vigilant and careful.

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