Published: 24th June 2021
Study suggests the need to monitor vaccine escaping variants
It also highlights the need to plan the next steps in the COVID-19 vaccine development by understanding the link between clinical protection and measured immunity against SARS-CoV-2 infection
The result of a preliminary study conducted by the Indian Council for Medical Research (ICMR) scientists on 274 samples of breakthrough infections in Odisha has highlighted the need to monitor the emergence of any vaccine-escaping variants.
It has also highlighted the need to plan the next steps in the COVID-19 vaccine development by understanding the link between clinical protection and measured immunity against SARS-CoV-2 infection. The study, a preprint that has not been peer-reviewed, states that the samples were collected from vaccinated individuals through passive and voluntary reporting to various healthcare facilities of Odisha to detect the SARS-CoV-2 infection, quantitative antibody titers and was correlated with demographic and clinical presentation and requirement of hospitalisation post-infection.
It said that 361 samples were referred to the laboratory for confirmation of breakthrough infection and quantitative antibody estimation. The RT-PCR reports of all these 361 individuals were found to be positive. However, 87 individuals were excluded as they were either not fully vaccinated or were found positive within 14 days of completing the second dose of their vaccination.
Out of the 274 samples with confirmed breakthrough infection, 35 (12.8 per cent) individuals received Covaxin and 239 (87.2 per cent) individuals received Covishield, the preliminary study said. It said seropositivity in individuals receiving Covishield was significantly higher than Covaxin. "More than 83.2 per cent of the individuals were found to be symptomatic with 9.9 per cent of those required hospitalisation. The seropositivity in individuals receiving Covishield (96.7 per cent) was significantly higher than in Covaxin (77.1 per cent)," the study said.
The study said hospitalised patients were having less median antibody titers than individual in home isolation. It also said the median age for breakthrough infection among the referred cases was 47.0 years (IQR: 28.0) with a significantly older age group among Covishield recipients. The median spike RBD IgG titre values for Covaxin and Covishield recipients were 213.5 AU/ml (IQR: 537.5) and 647.5 AU/ml (IQR: 1645.1) respectively. The study was approved by the institutional human ethical committee of ICMR - Regional Medical Research Centre, Bhubaneswar.