The sero-prevalence study began today in Delhi. This second round survey is being conducted in the different areas of the city in the next five days.<br />''<br />''The first phase of the study was conducted from 27th of June to 10th of July in all the 11 districts of Delhi. During the survey, a total of 21 thousand 387 blood samples were collected from selected individuals and were tested for IgG antibodies using the ELISA testing kits.  <br />''<br />''The study showed that only 22.86 per cent of the people are affected due to Corona virus and 77 per cent population is still vulnerable. The study also indicated that a large number of infected persons remain asymptomatic. The tests have been done to identify the presence of antibodies in the general population. It provided information about past COVID-19 infection in individuals who tested positive.<br />''<span style="color: #222222;"><br />''AIR correspondent reports that antibody testing like Sero study provides important evidence for assessing the spread of the pandemic. Depending upon the level of sero-prevalence of infection, appropriate public health interventions can be planned and implemented for prevention and control of the disease. As per the Indian Council of Medical Research, periodic sero-surveys are useful to guide the policy makers to conduct surveys in high risk areas or vulnerable population who have been infected in the past and has now recovered.</span>