Protein Deficiency May Explain Faster COVID-19 Spread In Europe, US Compared To Asia

Why does COVID-19 mutation 614G spread faster in Western regions than in Asia? According to a new study from researchers in India, there might be a biological reason behind the trend.

SARS-CoV-2 variant 614G was first detected around January 2020, and it quickly took over the original strain detected in China. Soon, it spread widely and rapidly across the globe. However, a team of researchers from the National Institute of Biomedical Genomics in the Indian state of West Bengal, observed that the strain's spread had not exactly been uniform. In their study published in the journal "Infection, Genetics and Evolution," they noted that Western regions are particularly hard hit compared to Asia.

The researchers found that it took 5.5 months for 614G to spread in East Asia, which is longer than the 2.83 months in North America and 2.15 months in Europe.

"Such rapid increase was not observed in East Asia after the arrival of 614G in that region," the researchers wrote.

The researchers determined what might be the reason behind the discrepancy -- a protein deficiency that's more prevalent in Europe and North America.

They explained that higher levels of the human protein called neutrophil elastase allows the 614G virus to enter the cells and multiply. This particular protein is usually inhibited by the production of another protein called alpha-1-antitrypsin (AAT), which protects the lungs from inflammation and tissue damage. This means that a deficiency in AAT would then allow the virus to spread faster.

According to the researchers, AAT deficiency is actually more prevalent in Europe (9.36%) and North America (16.31%) compared to East Asia (less than 2%).

"AAT deficiency is highly prevalent in European and North-American populations, but much less so in East Asia," the researchers wrote. "Therefore, the 614G subtype is able to infect and spread more easily in populations of the former regions than in the latter region."

"Many were speculating why coronavirus spreads differentially across geographies," study co-lead Partha Majumder told Times of India. "The most popular speculation was the higher temperature in Asia was not congenial to the virus. We believed the cause had to be biological, rather than physical or social."

The researchers noted that other factors could influence the differences in the way the virus has been spreading. But their work, they said, provides a biological explanation for the discrepancy.

"We emphasize that this finding along with other social factors may explain the differential geographical/ethnic spread of 614G," the researchers wrote.

"Our work opens up the possibility for considerations of AAT supplements in the prevention of SARS-CoV-2 Spike 614G subtype virus," they added.

This is not the first time that researchers have explored the role of AAT in COVID-19.

In January, a study also explored AAT's promise as a possible candidate for the treatment of COVID-19. Another group of researchers also published in The Lancet "an urgent call to action" for the care of patients with AAT deficiency (AATD), regardless of whether they have COVID-19 or not.

"As AATD represents a large population in countries that have a high incidence of COVID-19 and high mortality associated with the disease, these actions for patients with AATD could help to reduce COVID-19-related morbidity and mortality," the researchers wrote. "As the COVID-19 pandemic continues, strategies are needed to address the risks for patients with AATD as a matter of urgency."