A study conducted by Hyderabad’s AIG Hospital and Asian Healthcare Foundation, sampled swab specimens on 1,636 healthcare workers who were fully vaccinated. The report was aimed at assessing the long-term durability of vaccine immunity with respect to antibody levels.
It was discovered that 30 per cent of individuals had antibody levels below the protective immunity level of 100 AU/ml after six months. “The study aimed to understand the effectiveness of current vaccines over the long-term and see if there are specific population demography who need a booster at the earliest,” explained Dr D Nageshwar Reddy, Chairman, AIG Hospitals.
Researchers involved in the study measured the IgG anti-S1 and IgG anti-S2 antibodies to SARS-CoV-2 in 1,636 individuals. According to Dr Reddy, the nine-month gap for prevention dose benefits only 70 per cent of the population who can retain enough antibody levels beyond six months.
“Those who had antibody levels less than 15 AU/ml were considered antibody negative, which means they didn’t develop any protective immunity against the virus. Any individual with less than 100 AU/ml antibody level is susceptible to getting infected,” explained Dr Reddy.
Of the 1,636 study participants, 93% received Covishield, 6.2% received Covaxin, and less than 1% received Sputnik vaccines. “These individuals were majorly above 40 years with co-morbidities like hypertension and diabetes. Out of the total, 6 per cent did not develop any immune protection at all,” said Dr Reddy who is also amongst the researchers.
The results clearly indicate that younger people have more sustained antibody levels than the elderly population. People above 40 years with co-morbidities like hypertension and diabetes have significantly less antibody response after six months of getting fully vaccinated. The report concluded that this group should be prioritised for a booster dose after six months.
“However, considering the scale of our country, the 30 per cent people especially those with comorbid conditions like Hypertension, Diabetes, etc., who are more prone to develop an infection after six months of getting fully vaccinated should also be considered for the prevention dose,” he further added.
