According to research conducted on Indian patients, a single-dose of COVID-19 vaccine may be adequate for protecting patients who have recovered from a mild infection of the virus since the immunological memory that they generate preserves its imprint for a few years, reported The New Indian Express.
The research appears at a time, coherent with the government's plan to vaccinate all eligible persons (over the age of 18) by the end of the year.
Dr Nimesh Gupta's team at the National Institute of Immunology (NII), in association with Dr Ashok Sharma of the Biochemistry Department and Dr Poonam Coshic of the Department of Transfusion Medicine at the All India Institute of Medical Sciences (AIIMS) in New Delhi, discovered that Indian patients who recovered from mild COVID-19 have long-lasting immunological memory embedded in the important arms of protective immunity- T cells and B cells.
The researchers believe that the immunological memory, which can last for a few years, is predominantly associated with the spike protein of the virus.
According to research funded through the Science and Engineering Research Board's (SERB) a statutory body of the Department of Science and Technology (DST), for the Intensification of Research in High Priority Areas (IRHPA) scheme, if the vaccine can prompt the immune response seen in mild patients, it will result in successful and long-standing cellular immunity against SARS-CoV-2.
The study also implicated that nearly 70 percent of observed Indians volunteers possessed high levels of SARS-CoV-2 reactive type of white blood cells which are a crucial part of human immune system (CD4+ T cells). These were present before the COVID-19 pandemic reverberated around the world.
The COVID-19 virus has an intense effect on these previously existent T cells. These pre-existing cross-reactive CD4+ T cells were discovered to not fully terminate the viral infection, but they can significantly lower the viral load and the duration of symptomatic illness.
This will lead to less severe disease and lower rates of hospitalization. These SARS-CoV-2 reactive CD4+ T cells may have originated due to previous exposure to the highly prevalent 'Common Cold' viruses, said the study recently published in the journal 'Frontiers in Immunology'.