Less hospitalisations and deaths were reported in people having experienced breakthrough Covid-19 infection after two doses of vaccine. A pre-print study has highlighted the fact that vaccination does reduce hospital admission and mortality.
A study conducted by the Indian Council of Medical Research (ICMR) during the phase of second-wave between April and June 2021, is likely the largest and first nationwide study of post-vaccination breakthrough infections from India with 677 clinical samples.
The vaccines used for the study were Bharat Biotech’s Covaxin and Serum Institute of India’s Oxford-AstraZeneca vaccine that it is locally producing as Covishield. The study further suggests, “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,”
The study further found, “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,”
The aim of this study is to allay fears regarding vaccination with growing questioning of the protection offered by vaccines following the emergence of variants of concern and reduced real-world effectiveness of certain candidate vaccines against these variants.
The Indian Council of Medical Research -Department of Health Research (ICMR-DHR) utilised a network of Viral Research and Diagnostic Laboratories (VRDLs) to track breakthrough infections.
Breakthrough cases are defined as the detection of SARS-CoV-2 RNA or antigen in a respiratory sample collected from a person 14 days after receipt of all recommended doses of a Covid-19 vaccine.
The study found “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 for the northern region where the Alpha variant predominated,”
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