77 pc Delhi's population still susceptible to catch COVID-19 infection: Sero-survey
Jul 21, 2020
By Priyanka Sharma
New Delhi, 21 July : While 23.48 per cent population is affected with coronavirus in the national capital as per the findings revealed by the Delhi's sero-survey, at least 77 per cent population is still vulnerable to catch the infection, said the Union Health Ministry official on Tuesday.
Out of the total 11 districts in Delhi, 8 districts have shown the prevalence of infection by more than 20 per cent.
The study was done by the National Center for Disease Control (NCDC) in collaboration with the Delhi government and Central government. The survey was conducted from June 27 to July 10 in all the 11 districts of the city in about 21,387 households.
Dr Sujeet Singh, Director of the National Centre for Disease Control (NCDC) said: "Our objective was to identify the coronavirus infection prevalence among the general community in Delhi. The sero-survey showed an overall prevalence of about 23.48 per cent. This is an adjusted prevalence. Out of the total 11 districts in Delhi, 8 districts have prevalence more than 20 per cent. Some of the high caseload districts include: Central (27.86), North East (27.7), Shahdara (27.61) and North (25.26) South East (22.12) New Delhi (22.87) South West (12.95) North East (27.7) East (23.9) South (18.61) West (19.13). And this indicates that almost 27 per cent populations in these districts are affected with the virus."
"We should also notice that--it has been over six months since the COVID-19 pandemic has started and only 23.48 per cent population is exposed. But, more importantly, the remaining 77 per cent population is still vulnerable and are susceptible to catch the infection. The high-risk population like elderly, co-morbid people needs to take extra care," Singh said adding that the containment measures need to continue with the same rigour.
The present sero-survey is a follow up of sero-surveillance survey undertaken by ICMR (in containment zone - South East District in Delhi), said the official.
This can be attributed to the efforts taken up for preventing the spread of infection through lockdown and other containment measures, he added.
The official further stated that the as best hygiene practices such as physical distancing, use of face mask/cover, hand hygiene, cough etiquette must be followed strictly to combat COVID19.
According to the Central Government, there are two types of tests for coronavirus to detect response of the virus. (i) Antigen response, (ii) Antibody response, respectively.
"This is very important for us to understand in the case of COVID-19. First, we look for antigen response in the body for which we do RT-PCR tests and Rapid Antigen Test (RAT) to detect active infection of COVID-19 infection among individuals. These tests are used for guiding the treatment/ management of an individual."
"Second, we look for antibody response in the body for which antibody detection tests are done. It is performed during sero-survey studies to primarily assess the prevalence of infection at the community level," he said adding that these test performed is not a diagnostic test but only provides information about past infection due to SARSCoV-2 in individuals who test positive.
Antibody testing repeatedly done over time i.e. sero-surveillance, generates important evidence for assessing the spread of the pandemic from time to time, said the official.
Methodology: 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 Indian Council for Medical Research (ICMR). It is one of the largest sero-prevalence studies conducted in the country using the ELISA testing having sensitivity (92.1 per cent) and specificity (97.7 per cent).
