NEW DELHI: The country’s first sero survey conducted in a hospital — All India Institute of Medical Science (AIIMS), Delhi — has shown that nearly 20 per cent of the patients hospitalised for non-Covid-19 reasons had antibodies against the deadly virus.
In what could be seen as independent corroboration of the sero surveillance exercise carried out in the national capital, it also showed that over 29 per cent of the patients from Delhi had antibodies, while only 8 per cent among other parts of the country, mainly from Bihar, Uttar Pradesh and Haryana, had previous exposure to the virus.
The study was carried out between June 9 and August 8, among 212 patients who were admitted to the medical wards and ICU in one of the largest government healthcare facilities in the country. Positive serology against Covid-19 was detected in 19.8 per cent patients and residency in Delhi conferred a higher frequency of seropositivity 26.5 per cent as compared to that of other states, which stood at 8 per cent, as per the survey.
The exercise found that seroprevalence of Covid-19 was highest between 40 and 59 years and was calculated to be 22 per cent and 26 per cent for 40-49 and 50-59-year age groups respectively. It was approximately 15 per cent, between 20 to 39 and 19 per cent for patients who were 60 years of age and above.
Since the majority, over 97 per cent of people have had minor or no symptoms attributable to Covid-19, the researchers concluded that viral exposure has led to predominantly asymptomatic infection. Based on the data from this survey, they also calculated the infection fatality rate of Covid-19 to be around 0.084 per cent as 4,082 deaths were reported in Delhi till August 8.
A recent sero surveillance study in Delhi conducted between June 27 and July 20 carried out by the National Centre for Diseases Control in collaboration with the state government had found 23.48 per cent of the population of Delhi to be seropositive for SARS-CoV-2 IgG antibody.