One Dose of Vaccine Sufficient For COVID Recovered People: Study

A single dose of COVID vaccine provides sufficient protection in those previously infected with COVID-19, finds a study conducted by AIG Hospital, Hyderabad.

The study has also found that COVID vaccines elicited a higher neutralising antibody response, and higher memory cell response in COVID recovered people.

What the Study Found

According to Dr D Nageshwar Reddy, Chairman, AIG Hospitals, and one of the co-authors of the study, it was designed to assess the immunological memory response in all those patients.

The study was conducted on 280 healthcare workers who were vaccinated between 16 January and 5 February.

All participants were given both doses of the COVISHEILD vaccine with a gap of 28 days.

Side effects for all the participants were noted between the doses, and blood samples were tested for neutralising antibodies and memory cells.

Of these, 131 participants were previously infected with COVID with mild to moderate disease, and 50 required hospital admission.

All 131 were noted to have an overall seropositivity of 46.78, and the rest 149 were seronegative prior to the first vaccination dose.

The study also found that all the previously seropositive and seronegative participants developed neutralizing antibodies by day 28 after the first dose of COVISHIELD.

Higher Memory Cells

A single dose of the vaccine was found to elicit a much higher memory T cell and B cell responses in those previously infected by COVID, than those who weren't.

The study concluded that this, combined with the higher antibody response following a single dose of vaccine for previously infected patients (given at 3-6 months after recovery from COVID-19) may be considered at par with two doses of vaccine for individuals not infected with COVID-19.

Dr D Nageshwar Reddy, Chairman, AIG Hospitals, and one of the co-authors of the study, in a press release, said,

“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.”

Dr D Nageshwar Reddy, Chairman, AIG Hospitals

"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," he added.

The study authors hope that these findings would help optimise vaccine usage at a time of shortage, and that such a strategy may help cover a larger population when it comes to public immunisation.

"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,” said Dr Reddy.