New AY.12 sub-lineage of Delta Variant

Indian states have reported new cases of sub-lineage AY.12 of SARS-CoV-2 Delta variant, in recent months. According to experts, this new sub-lineage could be a reason behind the recent surge in COVID cases in Israel.


  • According to India Sars Cov2 Genome Consortium (INSACOG’s) update, even though 60 percent of the population are fully vaccinated in Israel, Delta variant cases have increased.
  • The number of Delta Family have expanded from four to 13 variants.
  • In India, most widely prevalent variant of concern is being dubbed as sub-lineage AY.12.

What is AY.12 mutation?

Delta variant (B.1.617.2) has given rise to several sub-lineages and are dubbed as ‘Delta Plus’ variants. Delta plus variant bear most of its characteristic mutations but in different ways. Out of all, sub-lineages AY.12 has all the characteristic Delta mutations.  However, according to INSACOG, it is not yet clinically tested whether AY.12 is different from Delta or B.1.617.2. AY.12 has lost some of the mutations as it happens in Delta lineage.

First case of AY.12

In India, first case of AY.12 lineage was reported on September 7, 2020. Till August 26, 2021, 44,083 sequences of the same lineage have been reported worldwide. In India, out of total 78865 samples; 67699 samples have been sequenced and 50869 of them have been analysed.  Although, in India, only 0.002 of the samples available have been sequenced

AY.12 in Israel

AY.12 is a dominant strain in Israel, currently. Around 51 percent of the samples were tested with this variant.

About Delta Variant

Delta variant is also known as lineage B.1.617.2 and Indian variant. This was first detected in 2020 in India. The variant was named as its current form by World Health Organization (WHO) on May 31, 2021.




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