A new study claims that no antibodies were found against Delta in 16% samples after both doses of Covishield

Dr. T Jacob John of Christian Medical College, Vellore has said “not observed is not equivalent to not present.”


A study conducted by the researchers from the Indian Council of Medical Research (ICMR) has claimed that no neutralizing antibodies were found against the Delta variant i.e. B1.617.2 in 58.1 and 16.1 percent of serum samples after the first and second doses of SII-manufactured Covishield respectively.

The former head of the department of microbiology at Vellore’s Christian Medical College Dr. T Jacob John has stated that not observed is not the same as not present, the neutralizing bodies level could be significantly low so it failed to detect, it might still be present and protect the person against infection as well as severe disease.

He continued, “Also, there would be some cell-mediated protective immunity as well that can protect against infection and severe disease.”

In addition, he said with an assumption that the serum used for the study was from healthy persons, the proportion of individuals with levels of neutralizing bodies that are unobserved will be higher among individuals who are old, comorbid, have chronic illnesses since their immune response is lower. In simpler terms, men and women above the age of 65 years, people with diabetes, hypertension, chronic heart, lung, kidney diseases, or those undergoing cancer treatment should be provided with a third dose.

According to the report, the titers of the neutralizing antibodies, the ones that specifically target the virus that causes COVID-19 called Sars-CoV-2 along with killing or preventing it from entering human cells were also found to be lower against the Delta variant in comparison to the B1 variant which causes the first fave of COVID-19 infections in the country.