Omicron had a lower impact in India than in the United States and the United Kingdom, according to a recent study, due to the presence of hybrid immunity among its population. The researchers explain hybrid immunity as immunity developed when a person who has already been infected with the virus is vaccinated.
The human body gains immunity through natural infection or vaccination, explained Dr Padmanabha Shenoy, clinical immunologist and rheumatologist, who headed the research, as quoted by news agency PTI, and further added: Hybrid immunity is the immunity generated when a person with prior infection receives a vaccine.
As more than 70% of Indians were infected with Delta during the second wave and India has vaccinated 95% of eligible population, at least with one dose, so close to three-fourths of India’s population has hybrid immunity. This hybrid immunity wall is the reason India had a relatively minor third wave.
About 65% of patients, who had received a single dose of Covishield following an infection, were able to neutralise Omicron. The researchers are currently decoding the impact of Covaxin on generating hybrid immunity and its effect on Omicron.
The study further revealed, 60% of people who had received two vaccine doses were able to neutralise the original Wuhan strain of virus, 90% of them with hybrid immunity could neutralise the original strain. Even in Delta variant also, the figures were almost similar.
The research included about 2,000 patients with auto-immune rheumatic diseases at the Centre for Arthritis & Rheumatism Excellence (CARE). It was found during the initial studies that hybrid immunity generated antibody levels 30 times higher than those who have received two doses of vaccines. Dr Sakir Ahmed of Kalinga Institute of Medical Sciences, Bhubaneswar, was co-researcher for the study.
