CHENNAI: As the country slowly recovers from the aftermath of Covid second wave, the concern has now shifted to the Delta Plus Variant that has now surfaced in many parts of the country. TNIE catches up with Dr Chandrakant Lahariya, epidemiologist, public health expert and co-author of the book, 'Till We Win: India's Fight Against The Covid-19 Pandemic.'
Coronavirus has mutated and studies revealed that the Delta variant was the cause of the massive second wave in the country. It is said to be a variant of concern. What are the characteristics of this variant and how is it different?
Essentially, the Delta Plus variant is very similar to the Delta variant. The plus variant has an additional mutation called the K417N. Early evidence indicates that the mutation shows some resistance to monoclonal antibody therapy. Otherwise, its features are similar to that of the Delta variant. Studies are still being done on whether this variant has higher transmissibility and immune escape rates, in comparison to the Delta variant. This is a variant of concern as it is similar to the previous variant. Delta and Delta plus are more transmissible when compared to the Alpha variant. Both have the capacity or ability of immune escape which means individuals infected in the past can still develop an infection. Both carry the quality of breakthrough infections which means people vaccinated also can get infected. However, immune escape is only found in less per cent of the population while vaccines have an 80-90 per cent efficacy rate.
Do the present vaccines work against this variant? ICMR has also said that they were studying the efficacy of vaccines against this variant.
The studies so far have found that available vaccines work against Alpha, Beta, Gamma, and Delta variants. The only difference is that the number of neutralizing antibodies required to neutralize the newer variant is relatively higher. But, Covishield and Covaxin would work against the currently circulating variants. In a recently published paper on Covishield, additional booster shots have shown to produce a higher amount of antibodies sustainable over a period of time. Antibodies are also only one of the markers of immunity, while there is also cell-mediated immunity. This immunity is not measured in the routine process.
Presently, in India, the time gap between the first dose and second dose of Covishield is longer; up to two months. Would the first dose alone provide adequate protection against this variant?
Covishield vaccine during initial trials was to be a single-shot vaccine. But, the researchers during subsequent trials found that additional shots would give higher antibody levels, and finally, it was released as a two-shot vaccine. Researchers found, longer the gap, the protection is better. Recently, studies have also shown single shots of vaccines provide 70 per cent protection against moderate to severe infection. The purpose of vaccines is to reduce hospitalisation. Vaccination is one of the tools to prevent severe illness and a single shot too will be very beneficial.
As of June 25, about 50 cases of this variant were detected from the 45,000 samples sequenced. Do you think we should improve our sequencing capacity? Given that there is also a delay in getting the results, as it took one month for TN to get back the results and by that time, most contacts of the positive patients may have recovered from the Delta plus variant infection.
Genomic sequencing is a time-consuming and expensive process. The surveillance capacity is currently low but the country is adding more labs for sequencing. Presently, the government has set a target of sequencing five per cent of active cases which can be a hard task for a country like India. The approach of sequencing must not be a proportionate method but a smart way. We have to identify the pockets of Delta Plus cases and more samples must be collected from such places. Similarly, there's also a method of genotyping through which you identify a particular section of a variant. This is low cost and a fast process. In several States, the number of labs is restricted. Setting up of new labs will smoothen the process.
Reports have said that Delta Plus has a greater affinity to the lungs. How much do we know about this and should there be more studies on the effects of it?
There is not much difference between Delta and Delta Plus in terms of how it infects people. Once there are more studies, we will know for sure.
Does this variant have the potential to cause the third wave?
India faced a second wave due to the Delta variant and the majority of people were infected by it. They must have developed immunity against it and since these variants are similar, they are likely to be protected against the Delta plus variant. So, it is unlikely for the variant to cause a third wave. But, the third wave could happen due to other factors such as waning immunity over a period of time. Also, we do not know if another new variant will form in any part of the world, and if it could cause the third wave. If we scale up the vaccination drive, that will delay the third wave. The third wave could be less effective than the second wave and it could be localised.
With the lockdown relaxations, how can we keep the surveillance in check?
The second wave caught us unprepared and unaware. Awareness of Covid appropriate behaviour must be stepped up. The State must look at localised data on transmission. Genomic sequencing is also essential and we need to prepare the health system. Primary health centres must be equipped with enough oxygen cylinders. We also have to plan beyond the third wave on how society will move on.
How can people protect themselves from the newer variant?
Masks and physical distancing is the key. We must avoid social gatherings, marriages and functions for now. The basic precautions remain the same. Also, people must get inoculated at the earliest.
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