Most of the people in India who contracted Covid-19 after being fully vaccinated were infected by the Delta variant but less than 10% of them had to be hospitalised which shows that the inoculation is effective, according to the first nationwide study on breakthrough cases of coronavirus.
The new study, commissioned by the Indian Council of Medical Research, tracked 677 individuals from 17 states and Union Territories who got Covid even after being vaccinated. Sixty-seven of these cases required hospitalization; three of them died. In most of the breakthrough cases (87%), the patient was infected with the Delta variant of coronavirus.
“Only 9.8% cases required hospitalisation while fatality was observed in only 0.4% cases,” the study reported. “This clearly suggests that the vaccination does provide reduction in hospital admission and mortality,” it said. Some of those who died also had co-morbidities such as diabetes, cardiac disease and hypertension.
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The study also shows that none of those admitted to hospital required ventilator or oxygen support.
“This is highly significant, and underlines the crucial role of vaccines in reducing severity of the disease and mortality,” says Dr Samiran Panda, Head of ICMR’s Epidemiology and Communicable Diseases division.
The study, ‘Clinical characterization and Genomic analysis of COVID-19 breakthrough infections during second wave in different states of India’ was published on the preprint server medRxiv on Friday.
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Eighty-five patients contracted the infection after taking the first dose of the vaccine, while the remaining 592 were infected after receiving both doses.
A total 511 SARS-CoV-2 genomes were recovered, and an analysis determined that 443 (86.69 per cent) were of the Delta variant (B.1.617.2) that was first detected in India last year. Delta was predominant in samples from across India except the northern region, where Alpha (B.1.1.7, which was first detected in the United Kingdom) was predominant, the study says.
After smaller studies reported breakthrough infections in Kerala and Delhi, ICMR in April-May commissioned the nationwide study to understand the profile of patients and SARS-CoV-2 strains responsible for post-vaccination breakthrough infections.
Of the 677 patients in the study, 604 had been inoculated with Serum Institute of India’s Covishield vaccine while 71 had been administered Bharat biotech’s Covaxin shots.
The median age of patients in the study was 44. Co-morbidities were observed in 154 out of 677 cases (23 per cent), which included diabetes mellitus type-II, hypertension, as well as chronic cardiac, renal and pulmonary diseases, and obesity.
