Match List-I with List-II and select the correct answer using the code given below the Lists: List-I (Variant of COVID-19): A. Alpha, B. Beta, C. Gamma, D. Delta List-II (First identified in): 1. India, 2. Brazil, 3. Britain, 4. South Africa

Correct — A, A-3, B-4, C-2, D-1. The World Health Organization began labelling variants with Greek letters in May 2021, taking them in the order the variants were designated. Alpha was first identified in Britain, in Kent in late 2020, so A goes to 3. Beta was first reported from South Africa, which puts B at 4. Gamma came from Brazil, detected in travellers from the Amazonas region, so C is 2. Delta was first identified in India and drove the second wave there in the spring of 2021, so D is 1. Only one code carries all four.

• (b)A-1, B-2, C-4, D-3 — Reverses the two ends, sending Alpha to India and Delta to Britain, and also swaps Beta and Gamma between Brazil and South Africa.
• (c)A-1, B-4, C-2, D-3 — Gets Beta and Gamma right but exchanges Alpha and Delta, which is the single most widely reported pair of the four.
• (d)A-3, B-2, C-4, D-1 — Correct on Alpha and Delta, but it swaps Beta and Gamma, sending Beta to Brazil and Gamma to South Africa.

The Greek-letter scheme was adopted precisely so that variants would not be named after the places they were found. The technical lineage labels stayed in use alongside it — Alpha is B.1.1.7, Beta is B.1.351, Gamma is P.1 and Delta is B.1.617.2 — and a variant is designated only when there is evidence that it changes transmissibility, severity or the effectiveness of countermeasures.

Two anchors settle the whole code. Delta was first identified in India, which is the fact every candidate sitting this paper had lived through, and Alpha came from Britain. Fixing those two removes three of the four options at once. The remaining discrimination is Beta against Gamma, and the letters run in the order the variants were designated, which puts South Africa's before Brazil's. Omicron, from southern Africa, was designated in November 2021, months after this exam.

• The WHO introduced Greek-letter labels for variants on 31 May 2021.
• Alpha is B.1.1.7, first identified in Britain; Beta is B.1.351, from South Africa.
• Gamma is P.1, from Brazil; Delta is B.1.617.2, first identified in India.
• Delta drove India's second wave in the spring of 2021, the months immediately before this exam.
• Omicron was designated in late November 2021, after this paper was set.

• Assuming the Greek letters run in the order the countries appear in the second list.
• Swapping Beta and Gamma, the pair that most candidates have the least direct memory of.

A four-pair matching item on a subject the candidates had lived through, with two pairs almost free and two requiring recall.

No directly related past PYQ was found.

• practice — not a real PYQ

  The Delta variant of SARS-CoV-2 carries which technical lineage designation?

  • (a)B.1.1.7
  • (b)B.1.351
  • (c)P.1
  • (d)B.1.617.2

  Answer(d) B.1.617.2 — the lineage first identified in India and labelled Delta by the WHO.

• practice — not a real PYQ

  Why did the WHO adopt Greek letters for naming variants?

  • (a)To avoid naming variants after places
  • (b)To indicate severity in order
  • (c)To match vaccine brand names
  • (d)To record the order of vaccine approval

  Answer(a) To avoid naming variants after places — the labels replaced references to the country of first detection.