India is currently in the midst of a deadly surge of COVID-19 cases, which has severely overwhelmed the healthcare infrastructure. More than 250,000 daily cases have been reported since 17th April 2021 and more than 300,000 cases since 21st April 2021. Experts suggest that the spike may be due to a new mutant, termed the ‘triple mutant,’ another variant of the ‘double mutant,’ which was the first lineage identified in India.
Genome sequences of the SARS-CoV-2 virus analyzed from cases in India showed that the viral strain predominant in cases from the state of Maharashtra since early this year contained two mutations—L452R and E484K. This variant was named B.1.617 and was classified as a ‘variant of concern.’ The E484 mutation is linked to higher infection rates and is also found in COVID-19 variants from Brazil and South Africa.
Triple Mutant
While mutations are common as the virus navigates its way through multiple infections, some mutations can result in higher infectivity and lethality. Latest reports show a new variant in cases from West Bengal, a state in the eastern region of India.
This ‘triple mutant’- B.1.618 is suspected of having evolved from the double mutant and could be highly transmissible and likely to evade the immune response. It is characterized by the deletion of two amino acids in the spike protein and also contains the E484K and D618G mutations. This triple mutant has been detected in other states such as Maharashtra, Delhi, and Chattisgarh too.
“There are many unknowns for this lineage at this moment, including its capability to cause reinfections as well as vaccine breakthrough infections. Additional experimental data is also required to assess the efficacy of vaccines against this variant,” Dr. Vinod Scaria, a scientist at the CSIR-Institute of Genomics and Integrative Biology, New Delhi, wrote on Twitter.
As of April 23, 2021, the triple mutant was detected in 8% of the samples sequenced by INSACOG (Indian SARS-CoV-2 Genomic Consortia), as compared to 29% of samples that contain the double mutant. To make matters complicated, the percentage of viral strains sequenced from infected people is neither consistent nor adequate to estimate the prevalence of mutations accurately. This is due to the rapid increase in the number of cases and inadequate healthcare infrastructure to sequence each sample.
Currently, the variants are being investigated for their infection rates and susceptibility to approved COVID-19 vaccines. Preliminary results suggest that vaccines can protect against the double mutant. Scientists believe that most vaccines should reduce the severity of infection, irrespective of the variant.
Speaking to Business Insider, Dr. Paul Tambyah, a Professor of Medicine at the National University of Singapore, said, “there is good data suggesting that the immune system, not just antibodies, can respond to multiple different mutants”.
Related Article: Novel COVID-19 “Double Mutant” Poses New Challenge to India’s Vaccine Rollout
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