On Sunday, new evidence emerged about Covishield’s inability to stop “advanced infections” caused by the Delta variant of SARS-CoV-2 in fully vaccinated individuals, with a group of Indian researchers who reported an unexpectedly large proportion of Covid-19 infections among vaccine receptors.
In a study of health workers at five hospitals in Delhi and its satellite cities, they found signatures of Delta infection in 25% of 92 people who received two shots and in 48% of 82 people vaccinated with a single dose of Covishield.
The study, conducted jointly by scientists from the Institute of Genomics and Integrative Biology and Max Hospital doctors, came days after doctors at Delhi’s Gangaram Hospital reported that a single dose of Covishield offered no protection against “symptomatic results or no results of interest.”
“Advances in Delta vaccination are much more common than those made so far. A corollary of advances in asymptomatic vaccination that are very common in healthcare workers is that masking will continue to be critical in reducing the risks of transmission in high-risk environments, ”tweeted IGIB Director Anurag Agrawal.
The advancement of Delta vaccination is much more common than has been done so far. See this collaborative work from @IGIBSocial @ ShantanuSengu14 @MaxHealthcare which illuminates why we don’t see much herd effect just by vaccination. https://t.co/Lu5xSyFPBD
– Anurag Agrawal (@AnuragAgrawalMD) August 28, 2021
Infection rates – reported by the IGIB-Max team – are higher than the 9% observed at Christian Medical College in Vellore and the 1.6-2.6% reported by the Postgraduate Institute of Education and Research Medical, Chandigarh, earlier this year.
Read also: 84-day gap between Covishield blows for more efficiency: Center tells Kerala HC
“The main goal of protection against serious illness is well met by vaccines, here in Covishield. There was no serious illness or death among this cohort (group) of vaccinated health workers, even during one of the worst climbs. of the delta, ”Agrawal said in reference to India’s fierce second-wave Covid-19 during the period April to May.
Worryingly, they found that 48% of people receiving a single dose developed the infection. “This is unacceptably high,” the team reported in a document, which has not yet been reviewed in pairs, but has been published in an online archive.
The large proportion of advanced infections and the 48% infection rate among single-dose recipients underscores the importance of reviewing current vaccination policies, including the gap between the two doses of Covishield. Currently, the gap is 12 to 16 weeks.
Such a high level of innovative infections reinforces the evidence of suggestions that existing vaccines might not help reach the so-called immunity threshold in the herd and stop the epidemic, now fed primarily by the Delta variant.
But the data indicate the urgency of exploring routes to more effective use of vaccines. In populations with high seropositivity, a single dose can offer considerable protection, but in areas where the Delta variant circulates, it can help shorten the gap as two doses offer much higher level protection.