Even as the first state-specific serosurvey in Odisha is under progress, all eyes are on the seroprevalence among the general population, when the second wave had a disastrous impact on many of the districts chosen for the study.
As per RMRC Bhubaneswar, a total of 6680 samples (1200 from health care workers and 5480 from the community) are to be collected from across the State, and of which, a total of 1,644 from the age-group of 6 to 17 years, 3,836 from adults and 1,200 from healthcare workers.
Meanwhile, the seroprevalence study has already been concluded in the State capital, where the impact of the second wave had been quite severe.
"The epidemic curves have a co-relation with seroprevalence," opined RMRC scientist Jayasingh Kshatri.
Sample the following.
- The first serosurvey in the Capital city was conducted in July when the seroprevalence in the City was a measly 1.5 per cent.
- The second study done in August 2020 had estimated the prevalence of Covid-19 antibody at a mere 5.24 per cent among the general population in the Smart City.
- The third seroprevalence survey conducted in mid-October, after the peak of the first wave, measured the presence of antibodies in 50 per cent of the population.
- An AIIMS - WHO sero survey between March 22 - May 7, 2021, had shown the prevalence of antibodies in 54 per cent adults and 45.4 per cent in children.
Experts, however, are of the view that as the infection rate in the second wave has been nearly 3-times more than the first wave, and also on account of faster vaccination (41 percent fully vaccinated), the seroprevalence this time in the Capital city could be detected in between 70-75 percent of the general population.
Odisha Has Any Safe Immunity Level?
A serosurvey done in Aug 2020 in Ganjam district had measured the seroprevalence among the general population at around 42.6 per cent. The peak in the district had come in September 2020.
When the second wave struck the State hard in April-May 2021, the seroprevalence, conducted as a part of the nationwide survey in June 2021, in the district had been measured at a whopping 70.9 per cent.
The big observation has been Ganjam saw only around 11k cases in the second wave - half of the first wave cases.
In Rayagada, the antibody presence is estimated in around 63 per cent general population. The second wave cases had been over 12k when the first wave cases were only 8.5k.
Another tribal district is Koraput, the seroprevalence is measured in around 63 per cent population in June 2021. The second wave cases have been over 10k; whereas the total cases in the first wave were around 7.9k.
Second Wave Hotspots
The last serosurvey in Bhubaneswar was conducted in October 2020, when the antibody prevalence in the general population had been estimated at over 50 per cent. And Bhubaneswar AIIMS study in Mar-May2021 estimated the prevalence at 54 per cent.
The outcome: The second wave cases in the Bhubaneswar had been 3-times that of the first wave.
A similar tendency has been observed in the case of the Sambalpur and Sundargarh districts.
Sambalpur: Total cases in the first wave was around 9.9k. But the second wave cases rose to around 12k. No serosurvey was done in the first wave. Because the infection rate had been very low.
Sundargarh: Data puts the total first wave count at over 15.6k. In the second wave, the total cases jumped sharply to cross 45k. Sero survey during the first wave conducted in Rourkela. The prevalence prior to the first wave peak was 24.6 per cent.
The Bottomline: A study of the above sero results shows a correlation between the high anti-body presence and a lesser impact of delta-variant led second wave.
"It seems a seroprevalence in the range of 80-84 per cent in the general population will prevent the possible third wave in Odisha. Ganjam results underline the fact, For which, epidemiologists believe that the third wave will not be a repeat of the second wave," said a senior RMRC scientist.