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States show variations in testing contacts, says study

A healthcare worker checks a boy’s temperature with an infrared thermometer at a camp in Dharavi on May 29, 2020.

A healthcare worker checks a boy’s temperature with an infrared thermometer at a camp in Dharavi on May 29, 2020.   | Photo Credit: REUTERS

Kerala tested an average of 40 contacts per confirmed positive case, Maharashtra only eight

States that are grappling with the highest burden of COVID-19 are those that least tested the contacts of persons who were confirmed positive, suggests data from an analysis of nearly 1,00,000 individuals tested for the SARS-CoV-2 coronavirus and published by a core group of Indian Council of Medical Research (ICMR) scientists and independent epidemiologists leading India’s COVID-19 testing.

A large proportion of both — those tested and those found positive — were asymptomatic family contacts.

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Kerala, which is among the States that have contained the initial surge of the pandemic, tested an average of 40 contacts per confirmed positive case. On the other hand, Maharashtra, which on Friday had 38,948 active cases and 1,982 deaths, had tested only eight contacts per positive case. Gujarat, which had 6,599 cases and 960 deaths, only tested 12 contacts per confirmed positive case.

‘Wide variations’

“States demonstrated wide variations in contacts tested per case. It represents the robustness of contact tracing. While exposure to different contacts could vary per case, the reason for this variation needs to be further explored to improve tracing and testing strategies,” says the paper, published on Friday in the Indian Journal for Medical Research.

According to the paper, Karnataka, Tamil Nadu, Kerala, Goa, Odisha, Chhattisgarh, Himachal Pradesh and Uttarakhand were among the States that had tested greater than the 75th percentile of contacts.

Rajasthan, Gujarat, Madhya Pradesh, Uttar Pradesh, Haryana, Delhi were among those with less than 50th percentile of the contacts tested.

States show variations in testing contacts, says study
 

Testing contacts and isolating suspects is a critical aspect of restricting fatalities and ensuring that infections don’t spread rapidly.

For the analysis, the researchers studied individuals who had tested positive between January 22-April 30. Cases in India started to measurably pick up only after March 5, and by March 23, Prime Minister Narendra Modi had declared a lockdown.

Highest proportion

The proportion of positive cases was highest among symptomatic and asymptomatic contacts, two-three-fold higher than among those with severe acute respiratory infections, or those with an international travel history, or among healthcare workers.

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The attack rate (based on the number of positive cases in a category) per million by age was highest among those aged 50-69 years (63.3%) and was lowest among those under 10 years (6.1%). The attack rate, or a fraction of a population testing positive, was higher among males (41.6%) than females (24.3%). The secondary attack rate (based on positive cases among contacts of primary cases) was 6%.

Tests for COVID-19 were conducted in 99% of 736 districts in the country, and 71% of these districts reported positive cases.

Cough and fever

Of the 40,184 positive cases until April, 25.3% were asymptomatic family contacts, 10.6% were symptomatic contacts, and 10.5% were SARI (Severe Acute Respiratory Infection) patients. Among the 12,810 cases with reported symptoms at the time of specimen collection, cough and fever were the most commonly reported symptoms (64.5% and 60%, respectively).

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As on Friday, 1.65 million people in India had tested positive, the highest in Asia.

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Printable version | Jul 16, 2020 5:18:31 PM | https://www.thehindu.com/news/national/states-show-variations-in-testing-contacts/article31705335.ece

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