Antigen test shows 7.46% positivity rate in containment zones

DELHI IS THE FIRST STATE TO ROLL OUT ANTIGEN-BASED TESTING AS CASES IN THE CITY SURGE, MAKING IT IMPERATIVE TO CONDUCT LARGESCALE QUICK TESTING

nNEWDELHI: Of the 99,274 people surveyed using the rapid antigen test, which began in containment zones and neighbouring areas on June 18, 7,414 tested positive for the coronavirus disease (Covid-19) till June 26, suggesting a positivity rate of 7.46%,a senior Delhi government official said on Monday.

Experts said the rapid antigen tests are providing a better picture of the spread of the infection since so far only those with symptoms in containment zones were being tested. With random sampling in containment zones and areas around them, and rapid testing, the outcome of these tests provide a more representative picture, they said.

The rapid antigen test, a much faster way to confirm positive cases, was started as part of the Centre’s and the state government’s efforts to ramp up testing in Delhi. “We are conducting close to 7,000-12,000 rapid tests per day. These tests are being done mostly in containment zones and its neighbouring areas. It is also being done in some other areas. It is helping us isolate positive cases early, as the test results are out within 30 minutes,” said a senior Delhi government official with the revenue department, which is compiling the testing data.

The results, a district magistrate said, were used to identify new clusters of Covid-19 cases and redraw boundaries of the containment zones. On Sunday, the Delhi government increased the number of containment zones from 280 to 421.

Tests that detect presence or absence of an antigen in the body are called antigen detection tests. An antigen is a foreign molecule that induces an immune response , especially the production of antibodies, and detecting its presence determines infection.

Delhi is the first state to roll out antigen-based testing as Covid-19 cases in the city have seen unusual surge, making it imperative to conduct large-scale quick testing to trace, treat and isolate the infected individuals. Till Monday, Delhi reported 85,161 cases 2,680 deaths due to the infection.as many as 20,080 people were tested on Sunday.

“The antigen test helps us understand the prevalence of the infection. We could identify clusters where the number of cases is more and have redrawn the boundaries and added new areas accordingly,” a district magistrate said.

Dr T Jacob John, professor emeritus and former head of the department of virology at Christian Medical College, Vellore, “The positivity rate reflects the situation at the ground. If it is 7.46% in containment zones and neighbouring areas, then chances are that the positivity rate in non-containment areas would be far less.”