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Covid-19 mutants: How dangerous are different strains?

Analysis so far by the Consortium on Genomics (INSACOG), a grouping of 10 National Laboratories under the Ministry of Health and Family Welfare, revealed 771 variants of concerns (VOCs) have been detected in a total of 10,787 positive samples

twitter-logoPB Jayakumar | March 25, 2021 | Updated 18:46 IST
Covid-19 mutants: How dangerous are different strains?
The N440K variant that is associated with immune escape has been found in 123 samples from 11 districts of Kerala

Concerns related to fast spreading of Covid-19 virus and possibility of vaccines becoming ineffective cannot be ruled out with genomic sequencing and analysis of circulating viruses in India revealing a total of 771 variants, including presence of a 'double mutant', say experts.

Analysis so far by the Consortium on Genomics (INSACOG), a grouping of 10 National Laboratories under the Ministry of Health and Family Welfare, revealed 771 variants of concerns (VOCs) have been detected in a total of 10,787 positive samples, including 736 samples positive for viruses of the UK (B.1.1.7) lineage, 34 samples of the South African (B.1.351) lineage and one sample of the Brazilian (P.1) lineage. The N440K variant that is associated with immune escape has been found in 123 samples from 11 districts of Kerala.

Generally, all viruses, including SARS-CoV-2, change over time resulting in the emergence of new variants, most without a direct benefit either to the virus or other public health impacts, note experts.

UK (B.1.1.7) variant

According to World Health Organization (WHO) data, this variant appeared in the United Kingdom since 20 September 2020 and has so far been reported in 125 countries, including seven new countries in the last one week. Generally, it is found to have increased transmissibility by 36%-75% and secondary attack rate by 10% to 13%. However, no significant impact on post vaccine neutralisation was seen on vaccines of Moderna, Pfizer-BioNTech, Oxford-AstraZeneca, Novavax and Bharat Biotech. The assessment is it may possibly increases risk of hospitalisation, severity and mortality.

South Africa (B.1.351)  variant

Detected since August 2020, this has spread to 75 countries, including 11 countries in the last one week. The virus variant was seen to be many times more transmissible than previously circulating variants. It possibly increases risk of in-hospital mortality by 20% and potentially increases risk of reinfection. Post-vaccine neutralisation reductions range from minimal to moderate for Moderna and Pfizer, however there is also some evidence of more substantial reductions have been found for the Oxford-AstraZeneca vaccine. In a small study, AstraZeneca did not demonstrate vaccine efficacy against mild-moderate COVID-19 disease, while efficacy against severe disease was not assessed. Results for Novavax and Janssen vaccines are pending.

Japan/Brazil (B.1.1.28.1) variant

This was detected in December 2020 and was found to be more transmissible than previous circulating variants. Severity is still being investigated, but has been found to cause reinfections.Limited to modest reduction in post vaccine neutralisation was seen in vaccines of OxfordAstraZeneca, Moderna and Pfizer. The neutralisation activity was reduced by 2.6 to 10-fold depending on the vaccine and individuals. In particular, among people vaccinated with the Sinovac product (CoronaVac vaccine), the plasma failed to efficiently neutralise variant P.1 suggesting possibility of reinfection.Now this variant is seen in 41 countries, including three new countries in the last one week.

The WHO also suggests countries to monitor and assess some new variants of interest (VOIs). These are B.1.525 (UK and Nigeria), B.1.427/B.1.429 (US) and B.1.1.28.2, alias P.2 (Brazil).

The WHO says these VOCs have commonly demonstrated an increase in transmissibility compared to wild-type (non-VOC) variants, and a veracity to rapidly replace other circulating strains. The potential for virus mutation increases with the frequency of human and animal infections. Therefore, reducing transmission of SARS-CoV-2 by using established disease control methods as well as avoiding introductions to animal populations, are critical aspects to the global strategy to reduce the occurrence of mutations that have negative public health implications.

Also Read: What is 'double mutant' Covid-19 and how harmful is it?

Also Read: India reports new 'double mutant' strain, multiple Covid-19 variants

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