Surging Covid turns ‘endemic’: Sewage test to predict future waves

The Indian SARS-CoV-2 Genomics Consortium (INSACOG) is exploring options to study sewage samples for early prediction of future Covid waves, according to a senior scientist of the organisation.

INSACOG is the umbrella forum set up under the Union Ministry of Health & Family Welfare to carry out genomic sequencing of covid viruses in the country.

“INSACOG has started exploring the possibility to set up an early warning system for future Covid waves, may be one or two week before the surge, by monitoring sewage samples as being done in case of viral diseases like Polio to ensure better public health management” said Saumitra Das, former head and current senior advisor to INSACOG, to The Plurals on Friday.

“So far, we have not found that any new variant is triggering the current surge. The BA. 2.75 is just a reclassification and in reality, it is not much different from BA.2 though there may be few additional mutations. However, we are noticing another variant BA 2.38 is increasing gradually and may become more dominant with time” said Das, adding that lack of Covid appropriate behaviour and throwing the Covid caution into the wind seem to be responsible for the latest spike.

“Many thought that Covid has gone for good but the latest surge shows that it is turning out to be endemic”, added the scientist.

Public health experts agree with the ‘endemic’ assessment of the virus.

“The fourth wave of Covid 19 is raging in Kolkata and the rest of West Bengal though the virus is gradually turning into a less virulent endemic one” said Arup Haldar, a city based Covid physician and pulmonologist.

“Definitely the fourth wave is on and the actual number of affected must be at least 10 times more as most are not getting tested” said Ajoy Sarkar, a frontline Covid physician from city.

“However, we find that the current virus does not seem to be affecting lungs and other organs in most patients, and only comorbid patients are at risk; it seems that the Covid is fast turning into another influenza like endemic virus;” added Sarkar.

Haldar added that “even in case of comorbid patients turning critical, we do not know how much covid virus is responsible for the deterioration”, however reiterating that “the current wave underlines the fact that Covid is here to stay, turning endemic and will continue to cause surges from time to time; while not being much virulent”.

“The hospitalization figure clearly shows that the current virus is not that virulent; we currently have around 700 Covid hospitalisations in state though there have been around 19000 cases in last one week” pointed out a senior health department official; reminding that the number of deaths is also much less compared to earlier waves.

Despite the surge in positivity, many of the hospitals have kept only one dedicated section and intensive care unit (ICU) for Covid patients unlike in previous waves; when many of the health care units had turned only-Covid hospitals.

Incidentally in West Bengal’s first wave in Oct , 2020; the number of deaths per day was around 60 at its peak; while the figure more than doubled during the second peak in May, 2021, slashed down to less than 30 at the height of the third wave in January, 22. During the current wave, the highest death toll of 5 has been recorded two days recently including on July 14.

On July 14, the state registered 3029 cases, a close to 25 fold increase over last one month and currently standing second among the Indian states after Kerala in number of cases per day, with a positivity rate around 19 per cent.

While Kolkata Municipal Corporation and adjoining North 24 Parganas and other districts dominate the number of cases; the current wave seems to have already spread to all parts of West Bengal as indicated by a recent sentinel survey carried out by its health department.

The survey carried out in the second week of July shows that at least 9 districts and two health districts in the state are currently having a positivity rate of above 10 per cent including state capital Kolkata.

The survey, carried out randomly among the non-Covid hospital patients, found that while the ‘test positivity rate’ was 24.6 percent in Nandigram health district and 23.8 percent in North 24 Parganas; the figure was above 10 percent in Darjeeling, Uttar Dinajpur, health district of Basirhat, Howrah, Purba Bardhaman, Kolkata and Nadia.

Kolkata Municipal Corporation also has recorded a significant number of cases in the last 15 days. “The number is increasing; on July 4, we had 342 RT PCR positive cases; while on July 14, the figure jumped to 630 cases” pointed out Tapan Mukherjee, a health advisor of the civic body.

“The virus is currently spreading within a significant part of south Kolkata” added another KMC expert.

“Like in earlier spikes, south Kolkata boroughs like 7, 8, 9, 10, 12 are having most cases with wards like 108, 107, 93, 98 and 69 look most affected so far” added the expert.