Delta variant behind 86% of India's 'breakthrough' cases during COVID-19 second wave: ICMR study

The Delta variant of SARS-COV-2 was the major reason for breakthrough infections during the second wave of COVID-19 pandemic in the country, but only 9.8 percent cases required hospitalisation and fatality was observed in only 0.4 percent cases, a new study conducted by the Indian Council of Medical Research has shown. The study, “Clinical characterization and Genomic analysis of COVID-19 breakthrough infections during second wave in different states of India”, is the first such analysis on breakthrough infections post-vaccination. It was published on the preprint server medRxiv on Friday, and is yet to be peer-reviewed, reported the Indian Express. Breakthrough infections are those cases where a person gets infected even after getting vaccinated. The study indicated that majority of the clinical cases in the breakthrough were infected with the Delta variant in India. However, the death rate among vaccinated individuals was found to be low. The researchers tracked 677 individuals from 17 states and Union Territories who contracted the disease even after being vaccinated. Sixty-seven of these cases (9.8 percent) required hospitalization while, three of them died. “Only 9.8% cases required hospitalization while fatality was observed in only 0.4% cases,” the study reported, adding “This clearly suggests that the vaccination does provide reduction in hospital admission and mortality.” The ICMR study is a clinical characterisation and genomic analysis of COVID-19 positive cases who had taken one or two doses of the vaccine before they caught the infection What are the important findings of the ICMR study

• The overall majority (86.09 percent) of the breakthrough infections were caused by the Delta variant (B.1.617.2)
• The study found that southern, western, eastern, and north-western regions of India predominantly reported breakthrough infections from mainly Delta and then Kappa variant of SARS-CoV-2
• Of the 677 patients analysed, 85 caught the infection after taking the first dose of the vaccine, while 592 were infected after receiving both the doses
• A total of 482 cases (71%) were symptomatic with one or more symptoms, while 29% had asymptomatic SARS-CoV-2 infection
• Fever was the most consistent presentation (69 percent), followed by body ache including headache and nausea (56 percent), cough (45 percent), sore throat (37 percent) loss of smell and taste (22 percent), diarrhoea (6 percent), breathlessness (6 percent) and 1 percent had ocular irritation and redness
• A total of 604 patients had received Covishield vaccine, 71 had received Covaxin and two were vaccinated with Sinopharm
• A total 511 SARS-CoV-2 genomes were recovered, and an analysis determined that 443 (86.69 percent) 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
• The present study revealed the infection among breakthrough cases predominantly occurred through Delta variants indicating its high community transmission during March-June followed by Alpha and Kappa variants
• The 17 states and Union Territories from where the samples were collected are Maharashtra, Kerala, Gujarat, Uttarakhand, Karnataka, Manipur, Assam, Jammu and Kashmir, Chandigarh, Rajasthan, Madhya Pradesh, Punjab, Puducherry, New Delhi, West Bengal, Tamil Nadu and Jharkhand
• The study found that southern, western, eastern and north-western regions of India predominantly reported breakthrough infections from mainly Delta and then Kappa variant of SARS-CoV-2