Even four months after first jab antibodies generated by Covishield vaccine remain active – expert

By Rathindra Kuruwita

A significant amount of antibodies created by the Covishield COVID-19 vaccine remained even 16 weeks after receiving the first jab, Dr. Chandima Jeewandara of the Allergy, Immunology and Cell Biology Unit, Department of Immunology Molecular and Molecular Medicine of the University of Sri Jayewardenepura said yesterday.

“We studied this because it was a serious issue due to hundreds of thousands of people have not received the booster doses yet. Our research shows that a significant amount of antibodies remains in those who received the first dose. This is good news and I think we can give them the second dose. But we have to conduct tests.”

Dr. Jeewandara said they would soon release a report on antibodies that developed due to the Sputnik-V vaccine, and a similar report on the Moderna vaccine too would be released in a month or two.

Dr. Jeewandara said that 500 Sputnik-V recipients and 600 Moderna recipients were being studied.

Commenting on a recent study by the department on the development of antibodies by those given the Sinopharm vaccine where it was found that vaccine induced antibody responses in over 95% of individuals, similar to levels seen following natural COVID-19 illness, Dr. Jeewandara said that the study had addressed a key concern people had about Sinopharm.

“One of the biggest problems is that we have little data on Sinopharm. This study tries to fill that,” he said.

Dr. Jeewandara said that the university had started measuring efficacy and antibodies from vaccines since Sri Lanka started administering them. The first vaccine they started studying was Covishield, he said.

“Let me explain the process. We take a blood sample before vaccination. We do that to identify antibody levels before vaccination. In Sri Lanka most people who contract COVID19 don’t develop symptoms. So we do this as a baseline blood test. Then we get a second sample before the second jab is given and a third sample at a time the manufacturer recommends as the best time to check antibodies.”

In the case of Sinopharm, the third sample was taken two weeks after the second jab. The researchers look at the level of antibodies and T-cell response because they are the two main tools to fight or prevent the virus or prevent serious illness, he said. A person can either get antibodies from contracting the virus or through vaccination, Dr. Jeewandara said.

“These are not efficacy tests. Efficacy is measured in a controlled clinical trial and is based on how many people who got vaccinated developed the ‘outcome of interest’ (usually the disease) compared with how many people who got the placebo (dummy vaccine) developed the same outcome. What we did was to test antibodies but this hints at vaccine efficacy too. Immunity and protection tend to be similar in both tests.”

Dr. Jeewandara said that Sri Lanka was an interesting case study because most Sri Lankans were genetically similar and that one variant usually dominates the country. However, Sri Lanka used several vaccines, giving the country an excellent opportunity to find out what vaccine was best.

“We also studied Covishield and over 90% of people vaccinated with it had developed antibodies,” he said.