There are over 40 cases in the country of the new Delta Plus strain, which has been tagged as a "Variant of Concern" by the government.
Yesterday, the government sent a warning to Maharashtra, Kerala and Madhya Pradesh on Delta Plus cases found there and urged "immediate containment measures". According to the letter, Delta Plus cases have been found in Maharashtra's Ratnagiri and Jalgaon; in Palakkad and Pathanamthitta in Kerala; and in Bhopal and Shivpuri in Madhya Pradesh.
A four-year-old is among those infected in Kerala.
"As of now among the samples sequenced (45,000+) in India, Delta plus variant -- AY.1 --has been observed sporadically in Maharashtra, Kerala and Madhya Pradesh, with around 40 cases identified so far and no significant increase in prevalence," the ministry said in its statement.
Sources say that cases of the new strain, a mutation of the Delta strain or B.1.617.2 variant first detected in India, are not confined to these states.
There are 21 cases in Maharashtra, six in Madhya Pradesh, three in Kerala, three in Tamil Nadu, two in Karnataka and one each in Punjab, Andhra Pradesh and Jammu, according to sources.
Delta Plus cases, still low in numbers, are emerging as large parts of India are ending severe lockdowns and restrictions with Covid cases on the decline after a fierce second wave ambushed the nation's health infrastructure in April-May.
INSACOG (Indian SARS-CoV-2 Genomic Consortia), a consortium of 28 labs tasked with genome sequencing of the virus causing Covid, says properties of the Delta Plus are still being investigated. It is characterized by a mutation in the spike protein, which helps the virus gain entry into human cells.
"Currently the number of such Delta plus variants in India are only few but the distribution/detection in various states during past two months indicate that it is already present in some states and states may need to enhance their public health response by focusing on surveillance, enhanced testing, quick contact-tracing and priority vaccination," it says.
Maharashtra says it is collecting data like travel history and vaccination status of those who have reported this version of the virus.
"The Centre has sent an advisory to these states about their public health response. The measures, while broadly remaining the same as have been implemented by them earlier, have to become more focused and effective. We don't want this small number to take a bigger form," VK Paul, the head of the National Expert Group on Vaccine Administration, told reporters.
Very little is known about this strain, which is now in nine countries - US, UK, Portugal, Switzerland, Japan, Poland, Russia and China besides India.
"After the report of AY.1 by the Public Health England (PHE) on June 11, retrospective analysis of samples revealed the first occurrence of this lineage from a sample collected from Maharashtra. The sample was collected on April 5. As of June 18, 205 sequences of AY.1 lineage was detected worldwide, with the US and the UK having over half of the known cases," the government said.
The Delta Plus, much like the Delta strain that has spread to 80 countries, is highly infectious and fast-spreading, the government says.
According to INSACOG, the Delta Plus shows "increased transmissibility, stronger binding to receptors of lung cells and potentially reduced monoclonal antibody response".
It may also show resistance to existing treatment protocol for Covid, experts worry. There are concerns over whether current vaccines will be effective against the Delta Plus.
The government said while the two vaccines being used in India, Serum Institute of India's Covishield and Bharat Biotech's Covaxin, are effective against the Delta variant, data on how they work on the Delta Plus would be shared later.