Mumbai civic body to ramp up antibody and antigen testing from next week

After facing severe criticism over inadequate testing for almost four months, the Brihanmumbai Municipal Corporation (BMC) is set to expand the screening for Covid-19

After facing severe criticism over inadequate testing for almost four months, the Brihanmumbai Municipal Corporation (BMC) is set to expand the screening for Covid-19 through antibody and rapid antigen testing.

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Starting Monday, the civic body will commence large-scale sero-surveillance to diagnose individuals for antibodies of Sars-CoV-2 virus that causes Covid-19, and monitor the spread of the virus. The survey will be conducted in three wards — M West (Tilak Nagar and Chembur), F North (Matunga, Sion and Wadala) and R North (Dahisar and Mandapeshwar).

During sero-surveillance, residents will undergo blood tests that can detect the presence of IgG antibodies, which develop against Sars-CoV-2.

Sero-surveillance mostly helps in identifying asymptomatic patients. A total of 10,000 blood samples of patients above 12 years of age will be randomly collected from areas in the three civic wards.

“Through this, we will be able to understand the geographical spread of the infection among the population. Our health workers and NGOs will carry house-to-house surveys to collect blood,” said Dr Daksha Shah, deputy health officer, BMC. “With a better understanding on the spread of the virus, we will be able to formulate further policies.”

Meanwhile, BMC also decided to increase daily rapid antigen tests by 2,000 from the current 4,000-5,000 tests, which has shown a case positivity rate of 22%. For the purpose, BMC is in the process of procuring around 1 lakh rapid testing kits from South Korean firm SD Biosensors – the only company approved by the Indian Council of Medical Research (ICMR). Rapid antigen tests detect the presence of molecular pathogens of Sars-Cov-2. The test results are out within 30 minutes, as against eight hours through reverse transcription polymerase chain reaction (RT-PCR) test that is being used currently. Thus, the procedure will help in early detection of symptomatic patients. According to protocol, every positive report from the rapid antigen testing will be treated as ‘true positive’, while negative samples will have to be mandatorily re-tested by RT-PCR process.

“We have over 20,000 suspected patients in government quarantine facilities. With rapid testing, we will be able to identify them faster, which will help in early treatment, faster contact tracing and vacating of beds,” said Dr Shashank Joshi, who is a part of the state Covid-19 task force.

When asked if testing samples twice will increase the burden on RT-PCR labs, Suresh Kakani, additional commissioner, BMC, said, “Since we will mostly test high-risk contacts after five days of getting exposed to the virus, the possibility of finding more positive cases are higher than negative samples and therefore the burden on labs will be less.”