With Odisha slipping into the unlock mode, and when around 20 districts in the State are going to witness lifting up of the night curfew in August, will the SARS-CoV2 rise over the third wave in the State?
Because, data from the second wave showed its lockdown only that has put the brakes on the transmission of the virus, despite epidemiological factors at play in the State. Therefore, the big question is which districts are going to be vulnerable to the third wave?
As per the Department of Science and Technology (DST) panel on Covid-19, the country may hit by the third wave of the coronavirus most probably in October-November. But the prediction is the third wave will only be a ripple effect of the second wave. It's unlikely to dwarf the heights of the second wave, the SUTRA model predicts.
"The third wave is contingent on and moderated by three factors: First, loss of immunity in recovered population; second, vaccination-induced immunity, third is the role of infectious variants or mutants and the behaviour of people post unlock," outlined Manindra Agarwal, member SUTRA Panel.
As per IIT Kanpur study, in the second wave, Odisha saw a soaring of cases in 15 districts. They are: Angul, Balasore, Balangir, Bargarh, Bhadrak, Cuttack, Jajpur, Jharsuguda, Kalahandi, Khordha, Nabarangpur, Nuapada, Puri, Sambalpur and Sundargarh. The second wave saw a total of over 5.8lakh confirmed cases between April to July 2. These 15 districts shared almost 95 per cent of the total caseload.
In the first wave, the worst-hit districts in the State were Ganjam, Gajapati, Puri, Nayagarh, Cuttack, Jagatsinghpur, Kendrapara, Khurda, Jajpur, Bhadrak, Bolangir, and Balasore. The first wave saw a total of over 2.74 lakh cases between March to October. And these districts had shared over 95 per cent of the burden.
The populous district serves the best epidemiological model, which spells out where the trouble of third-wave lies in Odisha.
As per a study published in Nature journal, serosurvey of 4,146 individuals (from 5,635 households) from three urban centres - Berhampur, Bhubaneswar and Rourkela- conducted after the first wave. The results showed around 31 per cent in Berhampur, 24 per cent in Rourkela and over 5 per cent in Bhubaneswar had developed IgG antibodies against Covid-19.
Moreover, ICMR's 2nd sero survey released in November reveals that on average nearly one-third of the population in the City (district) had antibodies. In high-risk areas like slums or congested areas, the antibody has been detected in over 50 per cent of people.
The RMRC Bhubaneswar serosurvey results indicated that on average nearly 50 per cent of the population in Bhubaneswar (28-63% range) had developed antibodies in the first wave, 46 per cent in Cuttack, 65% in Gajapati and 25 per cent in Rourkela.
DST Panel's Factor Number One: Loss of Immunity -
In the second wave, the worst-hit centres are Bhubaneswar, Sundargarh (includes Rourkela), Cuttack, and other western Odisha districts.
Except for Bhubaneswar, Cuttack, the second wave remain muted in districts having high seroprevalence during the first wave. The cases in second have been quite low in Ganjam and Gajapati.
Rourkela where only a quarter of the population had antibodies in the first wave, the Sundargarh district emerged as the top hotspot owing to a higher susceptible population. The case is the same with other hotspots in western Odisha.
"Since nearly 50 per cent population had no antibodies, they formed the susceptible group in the second wave. As the population of the Capital City is high, the second wave cases have increased by nearly 3-times," observed a senior scientist at RMRC Bhubaneswar and he further added that since the confirmed cases have been very high in the second wave, the seroprevalence would have been around 65-75 per cent this time. ( Antibodies in more than 60 per cent is believed to deliver herd immunity, says WHO)
The Factor Two: Vaccination Rate
As per the Harvard University vaccine index, a whopping 21 per cent of the population in the Khordha district has been fully vaccinated. Whereas the rate in the second wave hotspot districts is as follows:
- Sambalpur - 5.09%
- Cuttack - 4.79%
- Balasore - 4.69%
- Jharsuguda - 4.69%
- Bhadrak -3.99%
- Jajpur -3.16%
- Sundargarh -2.89%
- Kalahandi -3.11%
Vaccinate Rate In First Wave hotspots
- Ganjam - 4.04%
- Gajapati - 3.96%
The Vulnerable List
Post taking into account the factors detailed by the Govt Of India Covid-19 Panel, here is a list of districts (having large population) highly vulnerable to the third wave in Odisha
The Bottom Line: As per studies, since the IgG antibodies against SARS-CoV2 lasts till 8-11 months, high seroprevalence and minimal loss of immunity have prevented the second wave surge in Ganjam and Gajapati. But the timing of the third wave predicted by IIT Kanpur and DST Panel is October - November, unless significant vaccination done in districts, the unlock will make them prone to the third wave. However, the higher seroprevalence plus the high vaccination rate in Bhubaneswar will make it the least vulnerable to the third wave.