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Covishield Produces More Antibodies Than Covaxin, Study Finds | India News


NEW DELHI: The Covishield vaccine produces more antibodies than Covaxin, although both generate a “good immune response,” says a pan-Indian study of healthcare workers who had received both doses of the preventatives.
The yet-to-publish study, published on the MedRxiv prepress repository on June 4, covered 515 HCWs, 305 men and 210 women, from 22 cities in 13 states.
Covishield, from the Oxford-AstraZeneca stable, is manufactured by the Serum Institute of India in Pune. Covaxin is the indigenous vaccine manufactured by Hyderabad-based Bharat Biotech, in collaboration with ICMR and the National Institute of Virology (NIV).
Blood samples from those who participated in the study were analyzed to determine the amount of antibodies produced and the levels of specific antibodies that target the spike protein of the virus, which is considered a surrogate for protection.
“Both vaccines elicited a good immune response after two doses, although seropositivity rates and antibody levels were significantly higher in Covishield compared to Covaxin,” said Awadhesh Kumar Singh, lead study author and consultant endocrinologist, GD Hospital and Diabetes Institute, Kolkata, in a tweet.
Seropositivity was observed in a greater number of people vaccinated with Covishield compared to those immunized with Covaxin.
“Among the 515 TS, 95% were seropositive after two doses of both vaccines. Of the 425 Covishield recipients and 90 Covaxin recipients, 98.1% and 80% respectively were seropositive,” the study authors said. .
Seropositivity refers to the production of antibodies in an individual.
The study was conducted by researchers from various institutes including Ahmedabad Vijayratna Diabetes Center, Kolkata GD Hospital and Diabetes Institute, Dhanbad Heart and Diabetes Research Center and Rajasthan Hospital and Hospital and Mahatma Gandhi Medical College in Jaipur.
The rise in anti-spike antibodies was also “significantly greater in Covishield versus the Covaxin receptor” at 127 absorbance units per milliliter (AU / mL) and 53 AU / mL respectively, the authors noted.
AU is the unit for measuring antibody levels.
In addition to finding greater seropositivity among Covishield recipients, the study found that the seropositivity rate was “significantly higher” in participants aged 60 and younger compared to those older than 60.
While factors such as gender, body mass index (BMI), and other comorbidities made no difference, the rate of seropositivity or antibodies in people with type 2 diabetes was found to be significantly lower.
The researchers also compared the post-vaccination immune responses of all participants with those with a history of Covid-19 and those without.
It found that participants who had recovered from Covid-19 at least six weeks prior to the first dose of both vaccines, and then took both injections, were 100% seropositive and had higher antibody levels compared to others.
“Past history of SARS-CoV-2 infection resulted in a significantly higher mean antibody titer compared to SARS-CoV-2 naïve cohorts, regardless of the type of vaccine received,” the researchers noted.
According to the study authors, progressive infections, defined as SARS-CoV-2 infection for two weeks after the second dose, were reported in 4.9 percent of cases after both vaccines.
Such infections were seen in 5.5 percent of people in Covishield and 2.2 percent of Covaxin recipients, they said.
Covaxin is an inactivated vaccine that contains the killed virus. Preliminary data from phase 3 trials show that Covaxin has an 81 percent efficacy rate. The duration between the two doses is 28 days.
Covishield is built on the viral vector platform and is made from a weakened version of a chimpanzee common cold virus. The two doses of Covishield are given 12 weeks apart. It is more than 70 percent efficient.

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