Research finds that total antibodies of those inoculated with Sinopharm declined after 12 weeks from 2nd dose

However memory T-cell and B-cell responses persisted

A study conducted by Sri Jayewardenepura University researchers found that while the SARS-CoV-2 specific total antibodies of those inoculated with Sinopharm declined after 12 weeks from the second dose, the memory T cell and B cell responses persisted.

Given below is the press release issued by the University pertaining to the study: “The Sinopharm is an inactivated COVID-19 vaccine, which is currently given emergency use authorization by the WHO and is the main vaccine used in many Asian and Middle East Countries. A new study was carried out to determine the kinetics and persistence of immune responses following the Sinopharm/BBIBP-CorV, by investigating the immune responses in a cohort of Sri Lankan individuals.

“Antibody responses declined in all age groups, especially in those who are more than 60 years after 12 weeks from the second dose, while T cell responses persisted.” Said Prof. Neelika Malavige, Head, Department of Immunology and Molecular Medicine of University of Sri Jayewardenepura.

“USJ researchers including Prof. Neelika Malavige and Dr. Chandima Jeewandara from Allergy Immunology and Cell Biology Unit, Department of Immunology and Molecular Medicine of the University have been studying immune responses to different types of COVID-19 vaccines used in Sri Lanka.

“Results of the current research show that while the SARS-CoV-2 specific total antibodies, and especially neutralizing antibodies and antibodies to the receptor binding domain significantly declined, the memory T cell and B cell responses persisted.

“Since the ACE2 receptor blocking antibodies (neutralizing antibodies that associate with protection) was shown to significantly decline in all age groups and especially in the elderly, it is important to carry out long term efficacy studies to assess the waning of immunity on hospitalization and severe disease in order to decide on booster doses in different populations.” said Prof. Malavige.”