Delta variant found to be a major factor for breakthrough Covid-19 infections

Delta variant (B.1.617.2), a variant of concern that became the predominant cause of Covid cases in Delhi from March onwards. (Photo courtesy: National Herald)

(, Jun27’21) – The Delta variant of the Covid-19 coronavirus has been found to be a major factor for breakthrough infections — Covid infection in persons who have received one or both doses of the vaccine — among healthcare workers at the Institute of Liver and Biliary Sciences (ILBS) in south Delhi, reported the Jun 27.

Despite the Covishield injection, hospital officials disclosed, nearly 10% of the employees tested positive for Covid. When a genomic analysis of the swab samples of the infected healthcare workers was completed recently, it was found that 70% of the infections were caused by the Delta variant (B.1.617.2), a variant of concern that became the predominant cause of Covid cases in Delhi from March onwards, the report said.

“It shows that the variants can breach the antibodies generated by the vaccines and the vaccines currently being administered may not offer sufficient protection against new mutant strains,” Dr S K Sarin, director of ILBS, has warned. “There may be a need for strict double masking by healthcare workers despite vaccinations.”

Unvaccinated and single dose recipients had a higher risk of infection compared with those who had received both the doses, Dr Pratibha Kale, associate professor, department of microbiology, ILBS, has said. She has added that fully vaccinated staff were better protected with higher humoral immune response.


The latest data from India’s Ministry of Health and Family Welfare show that the number of daily new cases in the country had increased by 1,342 to 50,040, while the daily new deaths had increased by 75 to 1,258 in the past 24 hours recorded on Jun 27 at 8 AM, taking their cumulative totals to 30,233,183 cases and 395,751 deaths respectively.

The country reported its highest ever daily new cases of 4,14,188 on May 7.

Total recoveries have continued to improve to reach over 29.25 million (29,251,029 or 96.75%) while active cases have further declined to reach over .58 million (586,403 or 2.91%).

The case fatality rate was 1.31%.

The daily positivity rate has increased to 2.82% while the weekly rate had incrased to 2.91%.

Only Maharashtra ((+549), Kerala (+876) Manipur (+12), Tripura ((+22), Meghalaya (+3), and Arunachal Pradesh ((+23) have reported increases in active cases.

Kerala (12,118) continued to be the only state to report more than 10,000 daily new cases this morning.

Only three states continue to have more than 100,000 active cases, namely Maharashtra, Karnataka, and Kerala, with the rest having less than 47,000 active cases.

India is currently the country with the world’s second highest total number of Covid-19 cases after the USA, and the third highest total number of deaths after the USA and Brazil.


The cumulative total of Covid-19 cases among Tibetans in India and Nepal has remained unchanged for the second day at 5,084, according to the tally of the Central Tibetan Administration (CTA) on its website Jun 27. Of them 4,530 had recovered while 423 were active. Three more have died, taking the total to 131.


Across the world the number of Covid-19 cases totaled nearly 180.8 million (180,796,678) and the deaths over 3.9 million (3,917,369), according to the tally of Johns Hopkins University as of Jun 27, 2021 at 1:51 PM.


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