Single vaccine sufficient to treat all strains of SARS-CoV-2: Study

WASHINGTON: Scientists in the United States of America (USA) have assessed the genome sequences of the novel coronavirus from more than 27,000 COVID-19 positive individuals. The findings of the assessment revealed that the virus has mutated minimally since the beginning of the outbreak in China in December 2019, suggesting that the successful development of just one vaccine would be sufficient to combat the pandemic.

The study has been published in the journal PNAS and has characterised the diversification of the novel coronavirus SARS-CoV-2 since the beginning of the pandemic by aligning 18,514 independent virus genome sequences sampled from individuals in 84 countries, and scanned them for variations.

According to the scientists, including those from the Walter Reed Army Institute of Research (WRAIR) in the USA, the analyses reveal low estimates of genetic differentiation of the virus following the initial outbreak in Wuhan, China. They added that the SARS-CoV-2 genome has evolved through a mostly random process rather than through adaptation to the human hosts it encounters. Earlier studies had pointed to the domination of a mutant form of the virus in several parts of the world in which a molecule aspartic acid — denoted as D — in the viral spike protein, which it uses to enter host cells, is replaced by another molecule glycine (G). However, the scientists behind the current study said this ‘D614G’ mutation cannot be seen as evidence of the virus adapting to humans.

“Like other reports, we noticed that the D614G mutation in the Spike has rapidly increased in frequency since the beginning of the epidemic, but we could not link this mutation to specific adaptive forces,” said Morgane Rolland, a co-author of the study from WRAIR.

Scientists said that linking genotypes of different strains to specific traits is a complicated process and requires further detailed studies. Keeping in mind the low level of genetic mutation of the novel coronavirus, a single vaccine would be sufficient to treat people with different strains of the virus. “Viral diversity has challenged vaccine development efforts for other viruses such as HIV, influenza and dengue, but global samples show SARS-CoV-2 to be less diverse than these viruses,” Rolland said.