Eric Hickman: 4th-Wave Of COVID-19 Will Push Rates To Zero

The process happens at a glacial pace in the life-forms we are most familiar with (say mammals) because reproduction takes years. Viruses replicate in a matter of hours to days, and more specifically, single-strand RNA viruses (of which the coronavirus, SARS-CoV-2, is one) replicate faster than other viruses.

Viruses that encode their genome in RNA, such as SARS-CoV-2, HIV and influenza, tend to pick up mutations quickly as they get copied inside their hosts, because enzymes that copy RNA are prone to making errors.

Nature.com, 09/08/2020, “The coronavirus is mutating – does it matter?”

The concerning new Sars-CoV-2 variants emerging from the U.K., South Africa, and Brazil have yet to become dominant in the U.S. On February 7, a study reported that the more transmissible U.K. variant is now “spreading rapidly in the U.S.” It could become the dominant strain by late March. Italy’s health ministry said on February 12 that the U.K. variant makes up 17.8% of cases and will likely become prevalent in the coming months. The vaccine-weakening South African and Brazilian variants got detected in the U.S. in January. There are now several cases dotted around the U.S. They will presumably gain traction as they did in their original countries. This process takes months.

New Variants

The variants detected recently in the U.K. and South Africa have several novel changes in their spike-protein genes.

Scientists think one mutation these variants share could help the virus attach to and enter cells. The recently detected variant from Brazil shares a key spike-protein mutation with the one from South Africa.

“What we’re seeing is exactly what we expect to see. The surface proteins of the virus are under tremendous pressure to change.” – Sean Whelan, a virologist at Washington University in St. Louis.

“All the virus really cares about is multiplying. If it can get into the cells of the [host] and avoid the immune system of that host, it will multiply. Whether it causes the disease is a different question.”

Some scientists worry that South Africa’s variant could be better at evading antibodies produced in response to natural infection and vaccination. Preliminary estimates suggest the variant from the U.K. is 50%–70% more transmissible than earlier versions of the virus. And U.K. scientists said recently that early data suggested it could also be deadlier.

The variants found in the U.K. and South Africa have become the dominant types in countries where they were first detected.

COVID-19 Wave Rates, Eric Hickman: 4th-Wave Of COVID-19 Will Push Rates To Zero

Chart Source: Wall Street Journal

 

Parallel Evolution

The variant from the U.K. has spread widely abroad. As of late January, it had been reported in 70 countries and territories. The variant from South Africa has been reported in more than 30, while the U.K. variant was detected in more than two dozen U.S. states through late January. The Centers for Disease Control and Prevention projected it could become the dominant domestic strain by mid- to late March unless steps are taken to slow it. Variants first found in South Africa and Brazil have also been detected in the U.S.

WSJ, 01/30/2021, “How Coronavirus Mutations Are Taking Over”

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