Rather than a new wave, Covid pandemic will continue to smoulder, says immunologist

The Covid does not spread uniformly in countries, states or even cities; it spreads in neighbourhoods. So the patterns of the outbreaks have always been local and much more complicated than any idea of a uniform ‘wave’ said Satyajit Rath, immunologist and visiting professor at Indian Institute of Science Education and Research

Hindustan Times talks to Satyajit Rath, immunologist and visiting professor at Indian Institute of Science Education and Research (IISER), Pune, to know more.

The patterns of the Covid outbreaks have always been local and much more complicated than any idea of a uniform wave, said Satyajit Rath, immunologist and visiting professor at Indian Institute of Science Education and Research (Satish Bate/HT PHOTO)

The Delta variant is predominating the pandemic across the globe. Genome sequencing shows that the situation is similar in Maharashtra too. So, what role will the Delta variant and Delta plus variants play in the anticipated third wave outbreak in the state?

I do not think that any of this is easily predictable. The trend with Sars-CoV-2 has so far been that more transmissible variants tend to survive and spread. However, none of them has been more drastically ‘lethal’. I see no reason to think that this trend will change, so it is unlikely that a more ‘lethal’ variant will emerge. The lineage of delta variants is already quite strongly transmissible, but it remains possible that an even more transmissible new variant might emerge. Since large-scale vaccination campaigns are going on the world over, it also becomes possible that new variants that can establish infection even in vaccinated individuals might emerge and spread in vaccinated groups. However, again, there is no reason to expect that such new variants will be much more ‘lethal’.

On this background, I guess that, rather than a new ‘wave’, the epidemic will continue to smoulder, with ups and downs, with local outbreaks waxing and waning in different places.

It has never been particularly useful to think about the idea of a ‘wave’ for the epidemic. The disease does not spread uniformly in countries, states or even cities; it spreads in neighbourhoods. So the patterns of the outbreaks have always been local and much more complicated than any idea of a uniform ‘wave’.

Data on the Genome Surveillance portal shows there has been a gradual rise of AY.4 sub-lineage in Maharashtra. Your comments on epidemiological characteristics of the variant or its transmissibility.

So far, the AY.4 sub-lineage is a type of delta variant; one of many. While it has indeed been growing in proportion in some places such as in Karnataka, it has not done so in other places. So its significance is unclear as yet, and needs more studies. It is not dramatically more ‘lethal’, as far as current evidence shows. It is not growing in proportion in Kerala, for example, though Kerala’s vaccination rate is quite high, so it may not correlate with so-called ‘breakthrough’ infections. We will have to await more studies.

What should be the main cause of concern for the public health department in Maharashtra?

The main causes for concern for public health departments remain the same as they have been for a year and a half; - we need much more durable, systematic and large-scale Covid-19 surveillance, we need community partnerships in covid-appropriate behaviour with special emphasis on mask usage, we need expansion of an equitable vaccination campaign, we need durable, long-term expansions of decentralised public health care facilities including community outreach for both Covid-19 and for other currently neglected illnesses, and beyond this, we need support for marginalised livelihoods.