‘Identifying the virus in wastewater can act as early warning system’

Watching the rest of the world is useful, but not sufficient to make our own decisions. We need to continue to maintain surveillance, and increase the amount of genomic surveillance or sequencing being done. Based on the data available from India, there is no signal of an increase in cases. We are also aware that the bulk of cases in India were BA.2. This is the right time to relax restrictions, but maintain careful and complete watchfulness for an increase. 

The Deltacron is a recombinant, and recombinants will continue to arise. We need to monitor its spread, with clear directions on what level of spread will result in a change in approach to public health interventions.

It is important to remember that the risk of severe disease is in the elderly and not the young. India is very different from the US. We have also used different vaccines. Therefore, taking data directly from the US and applying it to India is inappropriate.

It is necessary to give boosters to those at highest risk of severe disease, the elderly uninfected as an example, as a precautionary measure. The focus now should be on developing an evidence informed strategy on which vaccines to be used as boosters, in whom and when. Different combinations of vaccines will result in different breadth and duration of protection, and different subsets of the population will have different needs depending on age, infection history and co-morbidities.

We need to decide the right strategies for their protection, understanding that while the next variant is not here yet, we need a better understanding of how different vaccines work to develop the best vaccine and the best strategy for the future.

The next variant capable of infecting the previously vaccinated and infected could arise tomorrow or next year. We do not yet have an understanding of the rate at which potentially dangerous variants can arise. Therefore, it is not possible to predict a wave with any degree of certainty at this time.

Based on clinical efficacy data, Paxlovid works better than Molnupiravir. When it is available, I am sure, it will be by used, particularly in India. However, it is important to remember that resistance to antivirals can arise very easily and therefore judicious use is critical. Paxlovid should be used in people who are at risk of severe disease, rather than indiscriminate use in the healthy infected population. Paxlovid is expected to work on all variants. 

Wastewater surveillance has tremendous value, even in India where sewerage systems are limited. Because the virus replicates well in the intestine and is shed in stool, identifying the virus in wastewater can act as an early warning system to indicate that more cases may be seen in the near future.

In India, we could think of wastewater surveillance in cities with international airports as well as the airports themselves to detect viruses being brought into the country. We could also map populations in cities and towns to their sewerage systems in order to detect potential clusters that may not be identified by surveillance conducted only at hospitals. Wastewater surveillance also has potential for the detection of other viruses and antimicrobial resistance genes, making it a good catch all technique for disease surveillance without needing to sample individuals.