Context: Emerging variants, with evidence of higher transmissibility and immune escape, demand re­strategised responses.

• Genome sequencing refers to figuring out the order of DNA nucleotides, or bases, in a genome, that is the order of adenine (A), guanine (G), thymine (T) and cytosine (C), that make up an organism's DNA.
• The human genome is made up of over 3 billion of these genetic letters.

About Delta strain behind second wave of pandemic:

• Delta variant B.1.617.2, was first reported from Maharashtra in October 2020.
• By April 2021, the Delta variant became the most circulating variant in Delhi and was found in nearly 60% of the samples analysed.
• It is 50% more transmissible than the Alpha variant (which already had 70% higher transmissibility over the ancestral virus).
• Associated with high viral load and resulted in higher proportion of breakthrough infection (people already vaccinated getting infected).

Importance of genome sequencing in pandemic fight

• Essential to keep track of variants: Total of 10 variants of COVID-19 reported till now.
• Understanding changing nature of disease: Conducting further studies necessary to understand variant’s transmissibility, immune escape and potential to cause severe disease.
• Underlying factor in successful pandemic fights: The United States and the United Kingdom had scaled up genomic sequencing, tracked the emerging variants and used that evidence for timely actions.

Policy gaps in India’s pandemic fight

• Not enough focus on genomic sequencing: While the government has faltered on vaccination coverage, the sequencing has remained at a very low level of a few thousand cases only.
• Slow pace at which data is being shared: Reportedly, the Indian government took two weeks, from early March — when research scientists submitted information on new variants — to issue a public announcement on the variants on March 24, 2021.

Way forward

• Scale-up genomic sequencing: Collect sufficient and representative samples, track district-level trends, national level analysis, ensure timely public sharing etc.
• Invest and support more scientific and operational research on vaccine effectiveness: Data should be analysed on a regular basis and should include stratifiers like age, gender and comorbid conditions, etc.
• Optimise vaccine policy: Decisions on vaccine priority list, optimising gap between two doses based on risk and immunity etc.
• Evidence-based policies: The only assured way to fight pandemic is to use scientific evidence to decide policies, modify strategies and take corrective actions.
  • As Indian States plan to open up after COVID­19 restrictions, districts with higher cases of Delta variant in circulation should aim for far stricter adherence to COVID appropriate behaviour.