As per the latest pan-India study, after two doses of vaccine, fewer hospitalisations (9.8%) and deaths (0.4%) were recorded in people who tested positive for COVID-19 mostly caused by the Alpha variant in north India and the Delta variant elsewhere. This highlights the fact that vaccination does reduce the chances of hospital admission and mortality.
The study conducted by the Indian Council of Medical Research (ICMR) during the peak of the second wave between April and June 2021, is the largest nationwide study of post-vaccination breakthrough infections from India with more than 600 clinical samples.
“During March to June 2021, India has experienced a deadly second wave of Covid-19 with an increased number of post-vaccination breakthrough infections reported across the country. To understand the possible reason for these breakthroughs, we collected 677 clinical samples (throat swab/ nasal swabs) of individuals who had received two doses (n=592) and one dose (n=85) of vaccines (Covishield and Covaxin,) and tested positive for Covid-19, from 17 states/Union Territories of country,” said the paper.
With telephonic interviews and clinical data of the subjects, out of the 677 cases, 593 contracted COVID after both doses and 84 after one dose.
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A total of 482 cases (71%) were symptomatic with one or more symptoms, while 29% were asymptomatic. Fever (69%) was the most consistent presentation followed by body ache including headache and nausea (56%), cough (45%), sore throat (37%), loss of smell and taste (22%), diarrhoea (6%), breathlessness (6%) and ocular irritation and redness (1%).
“This study indicated that majority of the clinical cases in the breakthrough were infected with the Delta variant and only 9.8% cases required hospitalisation while fatality was observed in only 0.4% cases. This clearly suggests that the vaccination does provide a reduction in hospital admission and mortality,” finds the study.
The goal of the study was to address fears regarding vaccinations and the growing suspicion on the level of protection offered by these vaccines after the emergence of ‘variants of concern’ and reduced real-world effectiveness of certain vaccine candidates against the variants.
The network of Viral Research and Diagnostic Laboratories (VRDLs) was utilised by ICMR’s Department of Health Research (ICMR-DHR) to track breakthrough infections.
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“It was observed 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. The northern and central regions reported such infections due to Alpha, Delta and Kappa variants; however, cases due to Alpha variant predominated in the northern region. The overall majority (86.09%) of the breakthrough infections were caused by the Delta variant (B.1.617.2) of SARS-CoV-2 in different regions of India except in the northern region where the Alpha variant predominated,” the study added.