While a surge in COVID-19 cases has forced several European and western countries to limit social gatherings, shut down bars, open field hospitals, such measures have become distant memories in much of Asia, especially India. For months now, life across Asia, where the virus first emerged, has mostly returned to normal.
Now, a team of Indian scientists has found the answer to the global divide of coronavirus behaviour.
According to scientists from the National Institute of Biomedical Genomics in Kalyani, West Bengal, the main reason behind the slow spread of mutant coronavirus in Asia compared to the West is because of deficiency of a particular human protein.
In a Times of India report, the scientists explained how higher levels of a human protein- neutrophil elastase-helps virus to enter human cells, multiply, and also spread faster from COVID-19 infected patients.
However, this protein is kept in check by the biological system, which produces another protein call alpha-1 antitrypsin (AAT). So, AAT deficiency leads to higher levels of neutrophil elastase in the cells, which helps the SARS-CoV-2 to spread more quickly.
The scientists noted the deficiency of AAT is much higher in Europe and America than among Asians. The study has been published in the journal, Infection, Genetics, and Evolution.
The team of scientists including Nidhan Biswas and Partha Majumder said that naturally occurring mutations in the AAT-producing gene result in the deficiency of the AAT protein.
According to Majumder and Biswas, AAT deficiency is the least in Asian countries--8 per 1,000 individuals in Malaysia, 5.4 per 1,000 individuals in South Korea, and 2.5 per 1,000 in Singapore.
Whereas, 67.3 per 1,000 individuals in Spain are AAT deficient. In France and the US, it is 51.9 per 1,000 and 29 individuals among 1,000 AAT deficient.
Earlier, the most popular speculation of different behaviour of COVID-19 in East and West was the higher temperature in Asia, Majumder said. He added, "We believed the cause had to be biological rather than physical or social".
However, the researchers emphasised that their findings along with other social factors might explain the differential geographical or ethnic spread of the coronavirus.