Over 77 per cent of the people in Delhi are still susceptible to the deadly coronavirus, a serological survey commissioned by the Union Health Ministry revealed on Tuesday.

The cross-sectional survey was conducted by the National Centre for Disease Control in collaboration with the Delhi government to estimate the prevalence of the infection in the general community of the national capital.

Addressing a press conference, Sujeet Kumar Singh, Director, National Centre for Disease Control, said, "Nearly six months into the pandemic, 22.86 per cent people are affected, while 77 per cent of the population are still susceptible."

The study was conducted from June 27 to July 10 in the capital city on people of two age groups -- below and above 18 years. As many as 21,387 samples were collected. The tests will help identify the presence of antibodies in the general population.

Singh said that out of the eleven districts, eight have sero-prevalence of more than 20 per cent. "In Central, North-East, North and Shahdara districts, the sero-prevalence is 27 per cent," he said.

Survey teams were formed for all the 11 districts of Delhi, blood samples were collected from selected individuals after taking written informed consent and then their sera were tested for IgG antibodies and infection using 'COVID KAVACH ELISA' approved by the Indian Council for Medical Research (ICMR).

Delhi's South-West area has 12.95 per cent sero-prevalence, the least in the city, followed by South and West Delhi at 18.61 per cent and 19.13 per cent, respectively.

"This shows the picture of the third week of June, when Delhi was recording more than 3,000 cases every day. This is robust data which will be used in disease control," said V.K. Paul, Member, Niti Aayog.

He added that much of the population is safe, which can be attributed to the systematic ways of contact tracing, testing, containment, isolation and quarantine.

Paul, however, warned that the figures do not give anyone the licence to stop wearing masks, ignore physical distancing or cough etiquettes. "We have to be more vigilant," he added.

The results of the sero-survey came as the city is recording a higher rate of recoveries and lower rate of new infections and casualties.

Delhi recorded the lowest number of fresh cases in over a month on Monday at 954. On June 23, the city had witnessed the highest single-day spike of 3,947 cases, but the number has come down steadily since then despite the number of tests increasing.

On being asked if the capital has achieved the peak, the officials at the press conference said, "We cannot say that it has peaked because there is still a lot of susceptible population left."

Rajesh Bhushan, Officer on Special Duty of the Health Ministry, said that from June 18 to July 21, 3.63 lakh antigen test samples were collected in Delhi, out of which only 6.33 per cent were found to be positive.

Antibody testing repeatedly done over time generates important evidence for assessing the spread of the pandemic from time to time.

This test is not a diagnostic test, but only provides information about past infection due to SARSCoV-2 in individuals who test positive.

This is one of the largest sero-prevalence studies conducted in the country using the enzyme-linked immunosorbent assay (ELISA) testing.