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Govt tags Delta+ as a ‘variant of concern’
The Delta Plus appears to be a further evolution of the Delta variant (or B.1.617.2, which was first seen in India) with a particular mutation known as K417N, which has separately demonstrated properties that could make it more resistant to vaccines as well as immunity from a past infection.
The “Delta Plus” is a variant of concern (VOC) in India, the Union health ministry said on Tuesday, citing an analysis by a consortium of genomic sequencing labs that has purportedly found the mutated virus to spread more readily, affect the lungs more strongly, and possibly reduce the ability of some antibodies to neutralise it.
The Delta Plus, scientifically known as the AY.1 variant , appears to be a further evolution of the Delta variant (or B.1.617.2, which was first seen in India) with a particular mutation known as K417N, which has separately demonstrated properties that could make it more resistant to vaccines as well as immunity from a past infection.
The government has now alerted the states where the VOC has been found. “The Union health ministry has advised Maharashtra, Kerala and Madhya Pradesh that the public health response measures, while broadly remaining the same, have to become more focused and effective. Chief secretaries have been advised to take up immediate containment measures in the districts and clusters (as identified by Insacog) including preventing crowds and intermingling of people, widespread testing, prompt tracing as well as vaccine coverage on a priority basis,” the health ministry said in a statement.
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The statement came within hours of Union health secretary Rajesh Bhushan saying at press briefing that AY.1 was a variant of interest -- a classification used when a variant is being studied. Bhushan said Delta Plus was found in nine countries and that in India, there were 22 cases.
“In India, 16 samples have been found in Ranagiri and Jalgaon in Maharashtra. Some cases have been seen in Madhya Pradesh and Kerala. Today, Union health ministry has sent them an advisory to advise them on how to address this,” he said.
At present, there are four VOCs recognised by the World Health Organization (WHO): Alpha, Beta, Gamma and Delta. Each of these has a unique constellation of mutations that separately or collectively make the virus more transmissible, virulent or resistant. The Delta variant is the first that is believed to do all three.
Delta Plus is the addition of a mutation identified as K417N, which has also been found in the Beta variant. Beta, or B.1.351 seen first in South Africa, is regarded as one of the most resistant variants of the coronavirus till now.
The health ministry statement said an analysis by Insacog showed Delta Plus “has the following characteristics: increased transmissibility; stronger binding to receptors of lung cells; potential reduction in monoclonal antibody response”.
The statement did not give more details about the analysis but suggests the authorities may now be moving with abundant caution, especially since India’s government drew criticism for not spotting the Delta variant on time.
Of the six districts identified by the government on Tuesday, Ratnagiri and Jalgaon in Maharashtra, Palakkad and Pathanamthitta in Kerala, and Bhopal and Shivpuri in Madhya Pradesh , the trajectory of cases in Ratnagiri has been more or less flat, with new cases reducing by 5% over the last two weeks. In case of the others, this reduction is in the high double digits.
Over the course of the coming weeks, a number of indicators will help determine the nature of the threat Delta Plus poses. These are indicators India has missed in the past, most recently with the Delta variant.
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CASE NUMBERS
The Delta variant began driving up case numbers in Maharashtra in late February, which the trajectory becoming particularly sharp in the second week of March. By March 17, cases in the rest of the country began tracking a similar path as Maharashtra.
HOSPITALISATION RATES
Typically, only a small proportion of positive cases require hospitalisation. An analysis by Public Health England of infection and hospital admission rates in the UK, particularly in areas where the Delta variant took hold, showed the risk of hospitalisation doubled as compared to the Alpha variant.
Authorities across India in general, and those in districts identified as Delta Plus-affected by the government in particular, will need to keep a close watch on hospitalisation rates, which is one of the first proxies for virulence.
BREAKTHROUGH INFECTIONS
States will need to leverage the Indian Council of Medical Research (ICMR) test reporting mechanism to track new infections and whether these include people who have already been infected or vaccinated previously . The PHE study cited above has, for instance, shown that a VOC like the Delta could lead to a sharp drop in protection among people who have just one dose of vaccine.
“The interpretation should be based on sequence data and biological data both. Clinical correlation is important, and backed by lab data to show why we see what we see in people,” said Dr Gagandeep Kang, physician-scientist, Christian Medical College, Vellore, Tamil Nadu.
Most crucially, India will need to improve its genome surveillance infrastructure -- a stand also taken by Anurag Agrawal, the head of CSIR Institute of Genomics & Integrative Biology (IGIB) and one of the key officials of Insacog.
In a column for medical journal Nature published on June 1, Agrawal said: “India urgently needs to intensify sequencing of unusual outbreaks, reinfections and cases in which vaccinated people become infected, while maintaining ‘sentry sequencing’ of a constant number of representative samples nation-wide.”
The country did not do this in the case of the Delta variant.
