Bhubaneswar: The fourth-round serosurvey of the Indian Council of Medical Research (ICMR) in three southern Odisha districts revealed that 65.12 per cent in the community and 85.53 per cent of healthcare workers have developed antibodies, Director, Health Services, Bijay Mohapatra informed on Saturday.
The serosurvey was conducted by the Regional Medical Research Centre (RMRC), a permanent research centre of the ICMR, in Ganjam, Rayagada and Koraput districts with logistic support from the Odisha government. A total of 120 samples from the community and 311 from health workers were collected between June 16 and 20.
“The survey showed 70.9 per cent seroprevalence in Ganjam district and 63 per cent and 61.3 per cent in Rayagada and Koraput districts respectively,” Mohapatra added.
Stating that the serosurvey report is satisfactory compared to the national average of 67.6 per cent, he said people developed antibodies due to direct exposure to COVID-19 in both first and second waves and after getting vaccinated against the virus. “Senior citizens and healthcare workers have mostly developed antibodies as they were vaccinated in the first phase,” he added.
Till June 20, Odisha administered 93.73 lakh doses. Among them, only 17.97 lakh citizens had received two doses.
The latest national serosurvey also included children between six and 17 years of age.
Speaking to Odisha Bytes, RMRC director Sanghmitra Pati said 50-60 per cent of the children surveyed have developed antibodies. “These children must have got the infection from their parents or other family members. The seroprevalence shows they are tolerant to the infection,” she added.
On how long antibodies last in infected persons, she said studies show a waning of antibodies against nucleocapsid antigen protein but not a complete disappearance by the end of 16 weeks. “We collected serum samples from 76 individuals for 16 weeks with weekly and fortnightly frequency during each follow-up and tested them in two CLIA-based platforms for testing SARS-CoV-2 antibodies both qualitatively and quantitatively,” she said.
Pati further said 30 cases (39.47 per cent) became seronegative in the qualitative assay, although all the sera samples (100 per cent) remained positive when tested in the quantitative assay.
“The lower persistence of anti-nucleocapsid SARS-CoV-2 antibody may not be the exact phenomenon as those cases were still seropositive against spike protein and helped in neutralising the virus,” she added.
