Although the COVID-19 pandemic is causing a massive devastation in many countries, within a very short period, many different types of COVID-19 vaccines have been developed and have been given Emergency User License by the WHO. Several types of these vaccines are been used in Sri Lanka. Our department is currently studying the immune responses of these different vaccines in Sri Lankan individuals in order to understand the immune responses to different vaccines, the duration of immunity and the immune responses in comparison to natural infection.
Except for Janssen COVID-19 vaccine, all other COVID-19 vaccines are two dose vaccines and individuals are considered only fully immunized two weeks after receiving both doses of such vaccines. While some individuals may develop antibodies to the first dose of a vaccine, individuals are only fully protected and develop a robust antibody and T cell response after both doses of the vaccines. We have been studying how the immune response evolves following the first and second dose of these different vaccines. The study on the first dose of the Covishield/AZD1222 is completed and the data is available as a preprint: Antibody and T cell responses to a single dose of the AZD1222/Covishield vaccine in previously SARS-CoV-2 infected and naïve health care workers in Sri Lanka | medRxiv
Our Department is also conducting studies on immune responses to the Sinopharm and the Sputnik V vaccine. As the vaccination only started recently, these studies are not yet complete and are currently ongoing. When the studies are complete, we will release the data of these studies.