NEW DELHI: Single-dose immunization with Covid-19 vaccine may be sufficient for protecting patients who have recovered from mild bouts of the disease, as the immunological memory that they develop keeps its imprint for a few years, says a study conducted on Indian patients.
The study comes when the country is looking at vaccinating everyone above 18 by year end. The vaccine is considered as the most effective preventive measure to protect from the pandemic that has become a major threat globally.
However, how long the vaccine will protect, whether it will protect against all recently circulating and future variants of the virus, and what should be the vaccination schedule and dosage for individuals recovered are questions that need answers for successful implementation of vaccination.
A study by Dr Nimesh Gupta’s group at the National Institute of Immunology in collaboration with Dr Ashok Sharma, Biochemistry Department, and Dr Poonam Coshic, Department of Transfusion Medicine at the All India Institute of Medical Sciences (AIIMS), New Delhi, reveals that Indians recovered from mild Covid have durable immunological memory in most important arms of protective immunity — T cells and B cells.
The team believes the immunological memory, which can last a few years, is predominantly associated with the Spike protein of the virus. These responses are mainly targeted at the Spike protein, and it also gives high hopes to the current vaccines.
The research supported under the Intensification of Research in High Priority Areas (IRHPA) scheme of the Science and Engineering Research Board (SERB), a statutory body of the Department of Science and Technology (DST), says if the vaccine can induce the immune response like seen in mild patients, then we will have an effective and long-lasting cellular immunity against SARS-CoV-2.
The study also indicated that almost 70 per cent of the examined Indian cohort had high to very high levels of SARS-CoV-2 reactive type of white blood cells that are an essential part of the human immune system (CD4+ T cells).