A woman doctor in Assam has been infected with two different variants of COVID-19 at the same time. In probably the first reported case of its kind in India, the doctor tested positive for both Alpha and Delta variants of SARS-CoV-2. She was fully vaccinated.

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"We have detected double infection of #COVID19 by two different variants of concern-- Alpha and Delta. A lady doctor was found to be infected simultaneously with both the variants," Dr. BJ Borkakoti, Senior Scientist, Regional Medical Research Centre, Dibrugarh told ANI.

The doctor said that in terms of symptoms, the double-variant infection is similar to any other mono-infection. Dual infection does not necessarily cause the severe disease, he added. "We have followed the case for one month and she is quite all right. She was fully vaccinated," Dr. BJ Borkakoti added.

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The woman doctor contracted COVID-19 after her husband was infected by the Alpha variant. After a series of tests and re-tests, it was confirmed that she had been infected by both variants at the same time. While the Alpha variant of the virus originated from the UK, the Delta variant originated from India.

Assam has seen a spurt in COVID cases and on Monday five districts were declared as total containment zones following high positivity rate there. These districts include Jorhat, Golaghat, Sonitpur, Biswanath, and Lakhimpur. There will be a complete curfew in these districts on July 20 from 5am onwards and will continue till further orders.

Earlier double infections

Earlier, a 90-year-old woman in Belgium was reportedly infected by two variants - Alpha and Beta - simultaneously. She lived in a retirement home and had not been vaccinated. She died in March 2021.

Similar cases were reported from Brazil in January 2021. Scientists reported that two people had been simultaneously infected with two types of coronavirus, one of them a variant of concern called Gamma.

In Portugal, doctors treated a 17-year-old who appeared to have caught a second type of COVID while still recovering from a pre-existing infection.

The coronavirus has undergone several changes and mutations, managing to stay ahead of the researchers by increasing its ability to replicate or evade existing immunity from past infection or vaccination.