Covid vaccines currently in use in India reduce chance of hospitalisation or mortality in case of breakthrough infections (or infections that occur after at least one dose of the vaccine), according to the results of an ICMR-funded study of 677 samples recorded during the second wave.
The study (which is in pre-print status, or pending peer review), comes amid some concern that existing COVID-19 vaccines may be less effective against newer (more aggressive) variants of the virus – such as the ‘delta’ and ‘delta plus’ that have been reported from across the country.
This underlines what Dr VK Paul, India’s Covid task force chief, said last month; Dr Paul told news agency PTI there is, as yet, no data that says vaccines are less effective against newer variants.
The study found that 677 RT-PCR samples collected from 17 states/UTs tested positive for COVID-19 after receiving at least one dose of a Covid vaccine – either Covishield or Covaxin. Specifically, 592 were infected after receiving both doses and 85 after getting one dose.
The authors conducted telephonic interviews to establish 9.8 per cent, or 67 individuals, required hospitalisation, and only 0.4 per cent, or three cases, resulted in fatalities.
“This clearly suggests vaccination provides reduction in hospital admission and mortality,” the authors concluded, adding, “… continuous monitoring of post-vaccination breakthrough infections with clinical severity of disease must be adopted as essential component of vaccine roll-out by all countries.”
Of the total samples, 527 were from people who had received both doses of Covishield and 63 had received both doses of Covaxin.
Of the remaining 85 samples, 77 were from people who had received one dose of Covishield and eight were from those who had received one dose of Covaxin.
There were two samples that had received both doses of the Chinese vaccine Sinopharm.
The study also revealed a majority of the breakthrough infections were of the ‘delta’ variant.
Of the total Covid-positive samples, 86.69 per cent were found to be infected with the ‘delta’ variant or its sub lineages, including ‘delta AY.1’ and ‘delta AY.2’, or ‘delta plus’, which a government panel yesterday said are “unlikely” to be more transmissible than the parent ‘delta’ strain.
Other variants found included ‘alpha’ and ‘kappa’.
71 per cent of the positive samples were from symptomatic individuals with at least one symptom.
The rest reported no COVID-19 symptom, or at least none that is currently recognised as such.
Samples were collected from were Maharashtra, Kerala, Gujarat, Uttarakhand, Karnataka, Manipur, Assam, Rajasthan, Madhya Pradesh, Bengal, Tamil Nadu and Punjab.
Samples were also collected from the UTs of Jammu and Kashmir, Chandigarh and Pondicherry, as well as the national capital, New Delhi.
India has administered around 39.5 crore doses of Covid vaccines so far.
This morning 38,949 new COVID-19 cases and 542 deaths were reported from the past 24 hours.