ICMR study on SARI patients with COVID-19 hints at community transmission in India

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ICMR study on SARI patients with COVID-19 hints at community transmission in India

In what may be an indication that community transmission of COVID-19 may have begun in India, a new study conducted by the Indian Council of Medical Research (ICMR) on patients who first had Severe Acute Respiratory Illness (SARI) and then tested positive for the novel coronavirus in India, shows that 40% of these patients did not report any contact history nor any international travel. 

According to ICMR’s study, which was published on Thursday evening, a total of 5,911 SARI patients were tested, out of which 104 (1.8%) tested positive for COVID-19. These cases were reported from 52 districts in 20 states and Union Territories. ICMR analysed the SARI surveillance data from February 15 to April 2, 2020, to calculate the weekly COVID-19 positivity.

965 SARI patient samples were tested retrospectively between February 15- 29, 2020 and March 19, 2020, out of which two (0.2%) were positive for COVID-19. “When the COVID testing strategy was expanded to include all SARI patients, a total of 4,946 samples yielded 102 (2.1%) cases,” the study says.

More significantly, the study showed that of the 102 COVID-19 positive SARI patients, 40 (39.2%) did not report any history of contact or international travel, two (2.0%) reported contact with a confirmed case and one (1.0%) reported a recent history of international travel. The data on exposure history is not available for 59 (57.8%) cases.

“About a third of COVID-19 positive SARI cases did not have any history of contact with a laboratory-confirmed case or international travel, and such cases were reported from 36 Indian districts in 15 states. These districts need to be prioritized to target COVID-19 containment activities,” the study states.

The study showed that COVID-19 positivity was higher among males and patients aged above 50 years, the study showed. The median age of COVID-19 positive SARI patients was 54 years (interquartile range: 44-63), and 85 (83.3%) were males; 83 (81.4%) of the affected patients were more than 40 years of age. 

COVID-19 cases among SARI patients were detected from 52 districts of the 20 states. The majority of the SARI patients were tested from Gujarat (792), Tamil Nadu (577), Maharashtra (553) and Kerala (502) with COVID-19 positivity. COVID-19 positive SARI patients were detected from eight districts in Maharashtra, six in West Bengal and five each in Tamil Nadu and Delhi.

The study says that the trend of COVID-19 positivity among SARI patients could provide reliable information about its spread in the area. It adds that the diagnosis of COVID-19 positive SARI patients could have been missed due to false-negative results of laboratory tests based on RT-PCR.

RT-PCR (or real-time reverse transcription-polymerase chain reaction) is the test that can detect the SARS-CoV-2 virus that causes the disease COVID-19. Tests are carried out on nasal or throat samples.  

India began testing of SARI patients for COVID-19 on March 15, 2020. At the time, India had around 110 confirmed cases of COVID-19. As of April 10, the number of confirmed cases in India has crossed 6,000 and around 200 deaths have been recorded across the country.