With 37,724 new coronavirus cases in the last 24 hours, India is rapidly inching towards the grim milestone of 12 lakh. Besides Maharashtra and Tamil Nadu, Delhi is one of the worst affected places in the country with a total of 1.24 lakh cases so far. However, the capital has seen a downward trend in the number of positive cases in July (from 3400 cases per day in June to 1,400-1000 cases per day in the last week). And now, according to the serological survey conducted in Delhi, indicates that around one-fourth of the capital has already been exposed to the novel coronavirus. Shocking, right? But the government says it’s a good thing!
The sero-survey or the serological survey involves testing of blood samples to determine the prevalence of antibodies against infection, indicating that they had been exposed to coronavirus in the past. The survey conducted by the National Centre For Disease Control (NCDC) along with the Delhi government showed that 23.48% of Delhiites already have COVID-19 antibodies.
The study was conducted between June 27 to July 10 across 11 districts of Delhi using the Indian Council For Medical Research-approved kit, COVID KAVACH ELISA (Enzyme-Linked Immunosorbent Assay). A total of 21,387 samples were randomly collected, which were then divided into two groups -- of less than 18-year-olds and people older than 18 years of age.
NCDC Director Dr Sujeet Kumar Singh said that eight of the 11 districts in Delhi have reported over 20% of the seroprevalence. The findings are based on the number of people selected from each district being proportionate to the population of that area.
A statement issued by the Ministry of Health and Family Welfare said, “The study also indicates that a large number of infected persons remain asymptomatic. Nearly six months into the epidemic, only 23.48% of the people are affected in Delhi, which has several pockets of dense population. This can be attributed to the proactive efforts taken by the government to prevent the spread of infection including prompt lockdown, effective containment and surveillance measures, contact tracing and tracking, as well as citizen’s compliance to COVID-appropriate behaviours.”
However, the ministry warned that a significant proportion of the population is still vulnerable and precautions should be taken to avoid contracting the virus. The government also plans to conduct sero-surveillance every month. Earlier in May, the ICMR had conducted a pilot sero-survey across 83 districts in 21 states, and the results found out that the percentage of the population infected in the past was 0.73%, with urban areas showing a prevalence of 1.09%.
On June 18, Delhi began to use the rapid antigen tests (point-of-care testing that directly detects the presence or absence of an antigen) along with the already existing RT-PCR test (standard test to detect coronavirus). Daily tests more than doubled from one week to the next and so did the number of cases. According to the Delhi government website, positive COVID-19 cases stood at 38% on June 13 whereas on July 7, the figure came down to 9%. While the government also claims that the worst might be over, it’s too soon to say that Delhi has crossed its peak. Just a reminder, we are still living in the middle of a global health crisis and we still need to take precautions.