Pro-CCV Dovetail reports: As the world enters the second year of the Chinese Communist virus (New Coronavirus) epidemic, the various types of variant viruses that have mutated from the original strain have become a major challenge for governments.
What are the noteworthy variant viruses that are currently circulating around the globe? What is their transmission strength and pathogenicity? Are existing vaccines effective in preventing them?
Coronaviruses mutate naturally during transmission, resulting from random, small errors that occur during virus replication. Researchers have found that a new coronavirus makes roughly one or two replication errors every month – these errors are known as mutations (or mutations). To date, tens of thousands of mutations have occurred in neo-coronaviruses, but the number of mutations that actually change viral fitness is small. When a virus accumulates enough mutations to change its fitness, a unique variant is formed.
In this paper, we identify the six most notable variant viruses and their respective characteristics.
B.1.617 (Indian “double variant”)
The new variant that has recently caused the outbreak in India to spiral out of control, with the number of confirmed cases soaring by hundreds of thousands in a single day within a month, is B.1.617 – also known as the “double mutant strain”. The variant has a total of 13 mutations, but two of them – E484Q and L452R – make it particularly problematic. The former is located on the spike protein, which binds to the human cell surface receptor and has shown greater transmission and antibody avoidance in some other variants, while the latter, L452R, is thought to be more infectious than the others, but the reason for this is not yet known. Notably, the same mutation is present in a more transmissible variant (CAL.20C) in California (USA).
The Indian variant of the virus spread rapidly between January 1 and April 4 this year, with the percentage of new variants in red in the graph. (Hindustan Times)
The strain was first identified in India in October last year (2020), but has only started to grow gradually since January this year. According to the Hindustan Times, the strain accounted for only 24% of all variants in India in February and March of this year, but it reached 80% on April 1.
Last week, the Indian Council of Medical Research (ICMR) said that the new Covaxin crown vaccine developed by Bharat Biotech India was effective in neutralizing this double mutant strain.
Currently, according to the GISAID (Global Initiative for Sharing Avian Influenza Data) platform, this variant has been detected in 21 countries.
B.1.351 (South African variant)
Variant B.1.351, first detected in South Africa last December, has now spread to at least 20 countries and has formed local transmission chains in North America, the UK, France, Germany and other European countries.
The AstraZeneca vaccine is popular in low- and middle-income countries because of its low price, but it may be difficult to protect against the South African variant. (AP)
South African researchers extrapolated the variant’s infectivity based on computer modeling to be 50% higher than other variants previously transmitted in South Africa (the study has not been peer-reviewed).
The companies developing the Moderna (Moderna) and Pfizer (Pfizer) vaccines have both said that initial trials have shown reduced effectiveness of their vaccines against the variant. Data from Johnson & Johnson’s U.S. biotechnology company Novavax Pharmaceuticals also showed reduced protection, but still a 60% effectiveness rate for mild and moderate infections.
In addition, laboratory data showed that B.1.351 evaded antibody responses 20% higher than the other variants in terms of infectivity in people with a history of new crown infections.
P.1 (Brazilian variant)
A close relative of the South African variant, the Brazilian variant P.1 shares several mutations with it, including the spine protein mutation N501Y, which helps the virus target human cells better, and E484K, which weakens antibody immunity.
Variant P.1 was discovered by Japanese health authorities in four travelers returning to Japan from Brazil, and after arriving in Manaus, the capital of the Brazilian Amazon state, with the variant, the variant spread rapidly to major cities in South America. As of press time, the variant has spread to at least 37 countries, with widespread local transmission occurring in Sweden in addition to Latin American countries.
Newcastle pneumonia outbreak in Brazil: People in a cemetery in Brasilia, Brazil, hold funerals for loved ones who died from complications of Newcastle pneumonia. (AP)
A study released last month by scientists at the University of Oxford (not yet peer-reviewed) showed that although this variant shares the same mutation as the South African variant, its ability to break through the immune response (including vaccines and natural antibodies) is much weaker than the latter.
B.1.1.7 (UK variant)
The B.1.1.17 variant was first identified in southern England last September, and its share quickly grew to two-thirds of the total number of confirmed cases in London in just three months, leading to a third wave of the outbreak in Europe.
Patrick Vallance, chief scientific advisor, confirmed at a press conference that the new variant of coronavirus in the UK is 70% more efficient than the original virus. Several follow-up studies have shown that this variant is also significantly more lethal than the previous variant. In a study published in the British Medical Journal (BMJ) in March, patients infected with this variant had a 68% higher risk of death than other patients (actual risk range 32% to 104%).
The variant has now spread to at least 94 countries, with larger spreads occurring in the United States, Canada, and South American countries in addition to European countries.
B1.526 (New York variant)
In addition to B.1.1.7 from the U.K., another new strain that has spread rapidly in New York in recent months is B1.526, first identified by researchers last November and reported by the New York City Health Department on April 12 to have reached 45% of all genetically sequenced samples in the city, surpassing the U.K. variant (30%).
The strain contains the mutation E484K, which bypasses antibody immunity, while another form of the B1.526 strain contains the S477N mutation, which helps reinforce the binding of the virus to human cells. However, the pathogenicity and drug resistance of this strain is still unknown, but researchers at Columbia University found that patients carrying the E484K mutation were about six years older than the average patient and were more likely to be hospitalized.
CAL.20C (California variant)
A more transmissible variant of CAL.20C (also known as B.1.427/B.1.429) has also recently been identified in California on the west coast of the United States. This strain, which was undetected last September, has become a major source of infection in California in late January. According to a study jointly published this month by the University of California, San Francisco (UCSF), the University of California, Berkeley (UC Berkeley) and others in the academic journal Cell, CAL.20C is 20% more infectious than the original virus strain.
Further research is needed to determine the drug resistance and lethality of this variant.
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