NEW DELHI (BLOOMBERG) - Vaccines targeting Covid-19 are able to curb deaths and hospitalisation in patients substantially, including those infected by the highly transmissible Delta variant that drove India's devastating second wave and is now triggering curbs from Los Angeles to Melbourne.
About 0.4 per cent died among those who got infected after inoculation - called breakthrough infections - while nearly 10 per cent needed hospitalisation, according to a new study by researchers led by Indian Council of Medical Research's Dr Nivedita Gupta.
The study, which analysed genome sequencing data of 677 Covid-19 patients, found 86 per cent of the fully vaccinated cases were infected by the Delta variant.
The findings underscore the crucial role of shots in preventing extreme outcomes among Covid-19 sufferers and allays doubts around vaccine efficacy, especially with respect to the Delta variant that has rapidly spread to at least 104 countries.
First detected in India last October, this variant has emerged as the dominant strain in Britain, the United States and Australia, forcing public health officials to double down on social distancing measures.
"This clearly suggests that vaccination reduces severity of disease, hospitalisation and mortality," said the study. "Therefore, enhancing the vaccination drive and immunising the populations quickly would be the most important strategy to prevent further deadly waves of Covid-19 and would reduce the burden on the healthcare system."
Among those analysed in the study, which is still to be peer reviewed, 592 people had received both vaccine doses while 85 had only one dose. India has predominantly injected people with AstraZeneca's Covishield - a traditional vector-based shot whose efficacy against the Delta variant has been dogged with concerns compared with the highly effective messenger RNA vaccines from Pfizer and Moderna.
Possibly the largest and first nationwide study of post-vaccination breakthrough infections from India, the research also detected evidence of two new mutations of Delta - Delta AY.1 and Delta AY.2 - in some samples besides older variants, Alpha and Kappa.
India saw daily infections breach record 400,000-levels in early May during the Delta-driven second wave which overwhelmed hospitals and crematoriums. Shortages of essential supplies led to citizens' pleas flooding social media platforms for hospital beds, oxygen cylinders and Covid-19-related medicines.
The country has so far fully vaccinated only 5.7 per cent of its 1.3 billion population, according to Bloomberg's vaccine tracker.
Infections are on the rise again in some Indian states including Maharashtra and Kerala, stoking fears of an incoming third wave. India's Prime Minister Narendra Modi told state chiefs during a briefing on Friday that effective steps were urgently needed to curb the outbreak from flaring up again.
The study also has policy prescriptions for India as it seeks to avert another wave of Covid-19 infections.
It emphasised the need for constant genome sequencing as well as tracking these breakthrough infections.
"Such monitoring will help us to understand the need to adequately tweak the available vaccines and also develop new vaccines with enhanced potential to protect against variant strains of Sars-CoV-2," it said.