A single dose of vaccine is sufficient for those already infected by COVID-19, revealed a study by Hyderabad's AIG Hospitals.

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The hospital announced on 14 June that it conducted a study on 260 healthcare workers who got vaccinated between January 16 and February 5 to assess the immunological memory response in all those patients. All patients were given the Covishield vaccine. Two significant observations came out of the study, which has been published in the International Journal of Infectious Diseases, a peer-reviewed journal. The previously infected group (people who got infected with COVID-19) showed a greater antibody response to a single dose of vaccine compared with those who had no prior infection.

It also revealed that memory T-cell responses elicited by a single dose of vaccine were significantly higher in the previously infected group compared with those who had no prior infection. It was concluded that higher memory T and B-cell responses in addition to higher antibody response with a single dose of vaccine given at 3-6 months after recovery from COVID-19 may be considered at par with two doses of vaccine for individuals already infected with COVID-19.

"The results show that people who got infected with COVID-19 need not take two doses of vaccine yet with a single dose can develop robust antibody and memory cell response at par with two-doses for those who didn't get the infection. This will significantly help at a time when there's a shortage of vaccine in the country and more people can be covered using the saved doses", said Dr. D Nageshwar Reddy, Chairman, AIG Hospitals, and one of the co-authors in the study.

"Once we attain the requisite number of people vaccinated for achieving herd immunity, these patients who got infected and received only one dose can take the second dose of the vaccine. At this point, all our strategies should be directed at the widespread distribution of available vaccines and to include the maximum number of people at least with a single dose," he added.

During the second COVID wave when cases were growing exponentially; the vaccination rate took a downturn. As of April 27, when the growth rate of active infection was 5%, the growth of vaccinated people was just 1.4 per cent. "We need to modify vaccination strategy based on scientific evidence and with the objective that a larger set of the population can be covered in the shortest duration", he said.