Delta plus India: Does the new viral variant harm lungs tissues?

The Delta plus variant, which has been notified as a "variant of concern", has a greater affinity to lung tissues as compared to other strains. However, this doesn't mean that it will cause severe disease or is more transmissible, said Dr NK Arora, Chairman of COVID-19 working group under National Technical Advisory Group on Immunization (NTAGI).

"Delta plus is having greater affinity to mucosal lining in the lungs, higher compared to other variants, but if it causes damage or not is not clear yet. It also does not mean that this variant will cause more severe disease or it is more transmissible," Dr Arora told news agency PTI.

He said the impact of the Delta plus strain will become clear only as more cases are identified but it appears that the disease is generally mild in all those who have got either single or double dose of the vaccine.

"We need to keep a very close watch and look at its spread so that it will give us transmission efficiency," he said.

Arora said the number of cases identified of Delta plus variant may be more as there may be many asymptomatic individuals also -- those who do not have any Covid-19 symptoms but they are carrying the virus and spreading it.

"But the important point is that our genomic surveillance component has picked it up rightly and early enough. Now what will happen is that states have already been told that it is a variant of concern and it requires action which means that several states have already started making micro plans for the districts where the virus is identified so that their spread can be contained. Obviously vaccination will have to be increased in these districts," he said.

Whether the Delta plus variant can trigger the third wave of coronavirus, Arora said it is difficult to assess that as of now.

"Waves are linked to new variants or new mutations so there is a possibility as this is a new variant, but whether it will lead to a third wave it is difficult to answer as it will depend upon two or three things," he said.

"The first thing is we had a ferocious second wave in the last three months and it is still going on, we are seeing for the last 8-10 days the number of cases are stuck at 50,000, while at some places cases continue to come so that wave has not settled down," he said.

He said the second wave will influence the community's response to another variant and the third wave will depend upon what proportion of the population got infected in the second wave.

"If a large proportion is infected then in the next wave people can develop a common cold like illness but may not develop a serious or fatal illness," he said.

"Secondly, another thing that is important is vaccination -- the rapidity with which we vaccinate...even single dose is effective and the way we are planning, if we rapidly immunise then possibility of third wave becomes very less because vaccine plus infection plus Covid appropriate behaviour will save us from next wave, mitigate the next wave and the third wave will not be able to cause the damage as was caused in the first two waves," he added.

All about the Delta Plus variant of Covid-19

The new viral variant of Covid-19 -- Delta Plus -- was identified earlier this month. It was recently classified as a "variant of concern".

So far, 51 cases of the Delta Plus variant have been detected across 12 states, with Maharashtra reporting the maximum cases of this new strain.

The third wave of the Covid-19 may not be as severe as the second wave, and scaling up the vaccination drive may help mitigate it, said a study conducted by the Indian Council of Medical Research in collaboration with Imperial College of London.

The authors of the study include Balram Bhargava, Director General, ICMR, and Samiran Panda, Head, Infectious Disease Unit, ICMR.

The study, based on mathematical modelling analysis, showed that the new variant is unlikely to cause a new wave unless it leads to a complete loss of immune protection from the previous infection.

A more transmissible variant would have to cross the reproduction number threshold of 4.5 to cause a third wave, the study added.