Coronavirus | A problematic testing strategy

Kerala’s rationale for revising its COVID-19 testing guidelines could prove counterproductive

Updated - March 17, 2020 12:24 am IST

Published - March 17, 2020 12:15 am IST

Thermal screening of visitors at Allahabad High Court on March 16, 2020.

Thermal screening of visitors at Allahabad High Court on March 16, 2020.

Even as the World Health Organization has been urging countries that have reported many laboratory-confirmed COVID-19 cases to become more aggressive in testing, India continues to have among the lowest testing rates in the world. In India, only those people with a travel history to high-risk COVID-19 affected countries or with close contacts to laboratory confirmed COVID-19 cases and with symptoms of the disease are being tested.

Also read:Coronavirus | Experts say India still in second transmission stage

Criteria for testing

If this does not instil confidence, Kerala, seen as a role model in India in containing highly pathogenic outbreaks, has further narrowed down the criteria for testing. On March 12, the Kerala Health Ministry issued revised testing guidelines based on current risk assessment. According to the guidelines, people with mild symptoms (low grade fever, mild sore throat, cough, rhinitis or diarrhoea) who have come from countries with ongoing COVID-19 local transmission and contacts of confirmed/suspect cases will not be tested for the virus.

“Testing is not going to change either the clinical course or management of the patient with mild symptoms,” the guidelines say. The rationale that testing people with mild symptoms that are non-specific would delay the testing of more deserving cases is problematic and may prove counterproductive.

According to Dr. Nivedita Gupta of the Indian Council of Medical Research, the maximum number of samples that the National Institute of Virology (NIV) unit in Alappuzha received in a single day was around 100. It is as low as 10 on some days. In a day or two, two more labs in the State will begin confirming cases without sending samples to the NIV unit in Alappuzha. One more lab is set to start screening samples early this week. Given that Kerala now has the capacity to test more samples each day, it is unclear why it has issued these revised guidelines. If this is an attempt to keep the numbers artificially low, it will prove counterproductive.

Also read: Explained | When can people transmit the novel coronavirus?

If the number of samples of people with mild symptoms to be tested each day is indeed delaying testing those with more severe symptoms at this early stage of the pandemic, it is worrying to imagine what the situation would look like if and when community spread becomes widespread in Kerala.

Since about 80% of those with COVID-19 exhibit only mild symptoms and recover without special treatment, not testing them would mean that a vast majority of cases will go undetected. This is wrong from the epidemiological point of view as the true case load will not be recorded. In fact, with the rest of the country looking up to Kerala in containing the spread of the virus, the State was expected to adopt a more expansive testing strategy — i.e., testing all contacts soon after being traced immaterial of clinical manifestation.

Fear of spread

As people with mild symptoms will not be tested now, the real danger of allowing them to spread the virus cannot be dismissed. A few studies as well as the experience of many countries show that infected people start spreading the virus even before symptoms show up. The infectiousness only increases when people start exhibiting symptoms. Though the guidelines say that contacts and people with travel histories should be under “strict home isolation”, the false sense of security when not tested might increase the likelihood of such people not following home isolation strictly. In fact, stricter quarantining would be needed for symptomatic people.

Also read:Coronavirus | India shares two SARS-CoV-2 genome sequences

When the State displays great rigour in tracing contacts and insists on home isolation for 14 days, not testing them when they show symptoms goes against the grain of the contact tracing strategy. There will be great danger of contact tracing backfiring when people who willingly self-isolate are not tested when symptoms show up. This is unethical too. Kerala cannot claim that there are no new cases and the pandemic is under control in the State when it does not test people in quarantine exhibiting mild symptoms.

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