The Indian Council of Medical Research (ICMR) in its latest study found that vaccination does result in a reduction in hospital admission and mortality. According to the ICMR study, the overall majority (86.09 per cent) of the breakthrough infections were caused by the Delta variant (B.1.617.2) and only 9.8 per cent of the Covid-19 patients required hospitalisation while fatalities were observed in only 0.4 per cent of the cases.
Breakthrough infections are those cases where a person gets infected even after getting vaccinated.
For the study, the ICMR collected 677 clinical samples (throat swabs/nasal swabs) of individuals who had received two doses and one dose of vaccines (Covishield and Covaxin,) and tested positive for Covid-19, from 17 States and Union Territories of the country.
A total of 604 patients had received Covishield vaccine, 71 had received Covaxin and two had received Sinopharm vaccine. In another study, the ICMR found that two doses of Covid-19 vaccine administered to high-risk police personnel were successful in preventing 95 per cent deaths due to coronavirus in the Delta variant-driven second wave.
“To understand the possible reason of 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 study.
A total of 482 cases (71 per cent) were symptomatic with one or more symptoms, while 29 per cent had asymptomatic SARS-CoV-2 infection. Fever (69 per cent) was the most consistent presentation followed by body ache including headache and nausea (56 per cent), cough (45 per cent), sore throat (37 per cent), loss of smell and taste (22 per cent), diarrhoea (6 per cent), breathlessness (6 per cent) and 1 per cent had ocular irritation and redness.
The ICMR said 677 samples were collected from 17 States: Maharashtra, Kerala, Gujarat, Uttarakhand, Karnataka, Manipur, Assam, Jammu and Kashmir, Chandigarh, Rajasthan, Madhya Pradesh, Punjab, Pondicherry, New Delhi, West Bengal and Tamil Nadu.
The study, the largest and first nation-wide study of post-vaccination breakthrough infections from India, said its analysis shows the vaccination does provide reduction in hospital admission and mortality.
Two new SARS-CoV-2 variants Delta AY.1 and AY.2 were also identified in these study samples.
“Delta AY.1 and AY.2 is characterised by the presence of K417N mutation in the spike protein region. K417N, E484K, L452R, and E484Q are the mutations known to disrupt receptor binding domain (RBD) binding capacity and make them more infectious by immune escape mechanisms against the current vaccines. This indicates improved virus fitness to evade immune responses and survive against the vaccines,” the study said.
In another study on police personnel, the ICMR found that two doses of Covid-19 vaccine administered to high-risk police personnel were successful in preventing 95 per cent deaths due to coronavirus in the Delta variant-driven second wave.
The study, presented by NITI Aayog member (Health) Dr V K Paul, was conducted in Tamil Nadu to see the vaccine effectiveness in preventing Covid-19 deaths.
About 1,17,524 police personnel were analysed for the study out of which those unvaccinated were 17,059, while those who received one dose were 32,792 and those fully vaccinated were 67,673.
The study further showed that the number of Covid-19 deaths among unvaccinated police personnel was 20, while among those who received the first dose was 7 and second dose was four.
Moreover, vaccine effectiveness in those who took the first dose was 82 per cent and in those who took both doses was 95 per cent.
“Incidence of Covid-19 deaths per 1,000 was 1.17 among unvaccinated, 0.21 among partially vaccinated and 0.06 in fully vaccinated,” the study showed.
