40% of patients with severe respiratory illness lacked travel history, suggest ICMR scientists

There was evidence for community transmission — or instances of coronavirus (COVID-19) in patients who had no established contact with someone who had picked up the disease from abroad — from as early as March 22, suggests a research study in the Indian Journal of Medical Research, authored by several ICMR scientists — including its head Balram Bhargava — and made public late Thursday.

On March 24, Prime Minister Narendra Modi imposed a nationwide lockdown for three weeks. The ICMR’s official position continues to be that there is no evidence for community transmission. With the case load increasing on an average of 500 per day for nearly a week, the Health Ministry and the States have stepped up surveillance and testing at hotspots and announced indefinite extensions of the 21-day lockdown.

The ICMR’s testing strategy has been to check those who showed symptoms of the disease — cough, fever and laboured breathing — in those with international travel history, their contacts and health-workers tending to those with Severe Acute Respiratory Illness (SARI-a syndrome of COVID-19).

To check whether there was a wider prevalence of COVID-19, it began to randomly test samples of hospitalised SARI patients from February 15, and from March 20, all patients who exhibited the syndrome.

“When the COVID testing strategy was expanded to include all SARI patients (from March 21), a total of 4,946 samples yielded 102 (2.1%) cases. The positivity increased from zero during the initial weeks to 2.6% in the 14th week,” the report notes. One hundred and two of these cases were from samples gleaned from March 22 to April 2. “Of the 102 COVID-19 positive SARI patients, 40 (39.2%) did not report any history of contact or international travel,” the study underlines. Only 2 of the samples from February 15 to March 20 later turned positive.

Details of the States from which these cases were emerging also point to why certain districts are under increased surveillance. In 15 States, more than 1% of SARI patients were COVID-19 positive. About a third of the COVID-19 positive SARI cases did not have any history of contact with laboratory-confirmed cases or international travel, and such cases were reported from 36 districts in 15 States. These districts need to be prioritised to target COVID-19 containment activities, the study underlines. 2.3% of those SARI patients who tested positive were male, and positivity among women was only 0.8%.

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The 50-59 age group was most likely to test positive for the infection.

A majority of the SARI patients were tested from Gujarat (792), Tamil Nadu (577), Maharashtra (533) and Kerala (503). These are also the States with the highest prevalence overall of COVID cases. “Tracking the spread of COVID-19 is critical to inform response activities, including testing, containment and mitigation measures. The current SARI testing strategy will complement and strengthen the routine COVID-19 surveillance activities,” the study added.

In the last two weeks as cases have ballooned, the ICMR has significantly increased testing and roped in more laboratories — state and private — for assessment. It has increased testing, and has tested 1.3 million samples (including repeats) in the last month. On Wednesday alone, it has tested 13,000 samples, and between 1% and 3% of the samples have turned positive. India has nearly 6,000 confirmed COVID positive cases and lost about 190 to the pandemic as on Thursday.