COVID-19 REINFECTION
Context
A team of scientists from the Indian Council of Medical Research (ICMR) examined the cases of 1,300 individuals who had tested positive for the corona virus twice.
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An understanding of the possibility of reinfection is crucial to the fight against the pandemic.
It will not only help decide the intervention strategies required to control the spread of the disease, but also help assess how long people would have to depend on masks and physical distancing.
It will have implications on the vaccination drive as well.
As of now, very few cases of reinfection have been confirmed. The first confirmed case was reported from Hong Kong in August last year. After that, a couple of cases from the United States and Belgium also emerged.
There have been several cases of people testing positive for the virus multiple times, even in India, but not all such cases are considered reinfections. That is because of what is called “persistent viral shedding”.
o Recovered patients can sometimes continue to carry low levels of virus within their system for up to three months. These levels are no longer enough to make the person sick or transmit the disease to others, but it can get detected in diagnostic tests.
Determination of reinfection – For a conclusive proof of reinfection, scientists rely only on genome analysis of the virus sample. Because the virus mutates continuously, the genome sequences of the two samples would have some differences.
o Therefore, when a person tests positive for a second time, and has to be checked for reinfection, there is usually no genome sequence from the previous infection to compare with.