HYDERABAD: A cross-sectional study by AIG Hospitals along with the Asian Healthcare Foundation, involving 1,636 fully-vaccinated healthcare and other workers of the hospital, has suggested the need to administer a booster dose six months after administering the second dose — especially for those aged above 40 with co-morbidities.
The study showed that 6.2 per cent of those who were selected for the study were negative for antibodies six months after taking the second dose and that 30 per cent were at the risk of SARS-COV-2 infection on exposure.
The study, in which long-term durability of vaccine immunity was assessed with respect to the antibody levels, was corroborated with similar research done in US, UK and Israel.
“The aim of the study was to understand the effectiveness of current vaccines over long-term and see if there are any specific population demographics which need a booster at the earliest,” said Dr D Nageshwar Reddy, Chairman, AIG Hospitals.
93% took Covishield
Of the 1,636 study participants, 93 per cent had received Covishield, 6.2 per cent received Covaxin and less than 1 per cent received Sputnik.
Researchers involved in the study measured the IgG anti-S1 and IgG anti-S2 antibodies to SARS-CoV-2 in those 1,636 individuals. Those who had antibody-levels less than 15 AU/ml were considered ‘antibody negative,’ which meant they didn’t develop any protective immunity against the virus.
Further, it was estimated that antibody-level of 100 AU/ml was the minimum level for protection against the virus, which meant that any individual with less than 100 AU/ml antibody level was susceptible to infection. “Our study results found that almost 30 per cent of individuals had antibody levels below protective immunity level of 100 AU/ml after six months of being vaccinated. These individuals were majorly above 40 years with co-morbidities like hypertension and diabetes. Out of the total, six per cent didn’t develop any immune protection at all,” Dr Nageshwar observed.
He pointed to a similar study in Israel, which had reported decline in neutralising antibody titres up to 42-46 per cent in persons of 65 years of age or above and in those aged above 45, where they had found that administering the booster dose had demonstrated protection against Covid-19.
He further suggested the enumeration of antibody titres at six months of vaccination especially in those with co-morbidities, which could help in prioritising such individuals for booster doses.
TS sees 3,557 Covid cases, 3 deaths
EVEN as the State is witnessing a surge in Covid-19 cases, hospitalisations remained low on Wednesday. Of the total 11,994 ICU beds in the State, only 658 beds have been occupied. Similarly, just 1,091 of the total 22,122 oxygen beds and 924 of the total 22,279 regular beds have been occupied. The number of positive cases on Wednesday was 3,557, with 1,773 patients recovering at a recovery rate of 96.06 per cent. There were three casualties on the day, with a case fatality rate of 0.57 per cent. A total of 2,673 persons have occupied hospital beds out of the total 24,253 cases in the state under treatment and isolation. Of the 3,557 cases reported on the day, the GHMC accounted for 1,474 cases followed by Medchal-Malkajgiri (321) and Rangareddy (275)