Representative photo: mujitra/Flickr, CC BY 2.0
New Delhi: India has thus far sequenced close to 1.64 lakh samples of the novel coronavirus.
At a press conference in New Delhi on January 20, National COVID Task Force chairman Vinod K. Paul shared this figure and claimed it was a big achievement because India had sequenced the world’s second-highest number of samples containing this virus.
Is this true?
A look at GISAID, a global repository of SARS-CoV-2 genome data, indicates that with 1.64 lakh samples sequenced, India is actually at the 10th position. The US, the UK, Germany, Denmark, Canada, France, Japan, Sweden and Switzerland have sequenced more samples than India, in that order.
In addition, the fraction of positive samples that are being sequenced is more significant. And even on this front, India is at 144th position worldwide, having sequenced 0.26% of positive samples thus far.
So India is hardly second on either count.
Ever since the COVID-19 pandemic took off, India hasn’t been able to sequence even 1% of all positive samples at any point. The nine countries ahead of India in the absolute number of samples sequenced are also way ahead on the fraction of samples sequenced.
India changed its sampling strategy in April 2021, from the strategy it had adopted in December 2020. When the government formed the Indian SARS-CoV-2 Genetics Consortium (INSACOG) in December 2020, it said it would arrange to have 5% of all positive samples sequenced. But in April 2021, the government changed tack to say every sentinel site – a facility where a large number of people come to be tested – would have to send 30 samples every month for sequencing.
The number of sentinel sites in each of India’s states ranges from one to 21. This meant a maximum of 630 samples every month from each state.
Even despite this reduced target, The Wire Science found in November 2021 that many states had failed to meet it.
Further, a simple calculation based on official data suggests that the number of samples sequenced and analysed dropped during December-January from the November-December level. This is notable because December-January was when the omicron variant was leading to new outbreaks in different parts of India.
(Analysis after sequencing is important: it is the part where researchers assign the lineage to which the strain in question belongs.)
Specifically, compared to 3,700 samples sequenced and analysed from November 1, 2021, to December 1, 2021, only 1,403 were sequenced and analysed from December 1, 2021, to January 1, 2022 [footnote]Data accessed on January 20, 2022.[/footnote] This is an effective decline of 90%.
Paul claimed during the press conference that 16,000 samples had been sequenced in December – without clarifying whether the bulk of them had also been analysed, or if the data hadn’t been updated, or if there was another reason for the big discrepancy.
Meanwhile, the INSACOG weekly bulletins have continued their silence since December 4, 2021, on sequencing numbers.