A majority — over 86% — of the breakthrough infection after COVID-19 vaccination have been caused by the Delta variant, with hospitalisation of 9.8% of such cases and fatality observed in 0.4% of cases, according to the results of a nationwide study conducted by the Indian Council of Medical Research (ICMR) on breakthrough COVID-19 infection.
A breakthrough infection is a case of illness in which a vaccinated individual becomes sick from the same illness that the vaccine is meant to prevent.
For the study, “Clinical characterisation and Genomic analysis of COVID-19 breakthrough infections during second wave in different States of India’’, ICMR collected 677 clinical samples of individuals who have been partially or fully vaccinated but contracted the infection.
The samples were collected from 17 States and Union Territories, including Maharashtra, Kerala, Gujarat, Uttarakhand, Karnataka, Manipur, Assam, Jammu and Kashmir, Chandigarh, Rajasthan, Madhya Pradesh.
‘71% symptomatic’
The study found that a total of 482 cases (71%) were symptomatic with one or more symptoms, while 29% had asymptomatic SARS-CoV-2 infection. “Fever (69%) was the most consistent presentation followed by bodyache, including headache and nausea (56%), cough (45%), sore throat (37%), loss of smell and taste (22%), diarrhoea (6%), breathlessness (6%) and 1% had ocular irritation and redness,’’ it noted .
The southern, western, eastern and north-western regions predominantly reported breakthrough infection mainly from Delta and then the Kappa variant. Alpha was predominant behind reinfection in the northern region, it stated.
Though this was not a study on the effect of the vaccines, it had been noted that among the 677, 604 received Covishield, 71 Covaxin and two got China’s Sinopharm, it pointed out.
Between March and June, there was “high community transmission” of the Delta variant, followed by the Alpha and Kappa variants, it added.
