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Explained: Virus testing in India, elsewhere

On Friday, the Indian Council of Medical Research (ICMR) announced that it would start testing influenza patients without any travel history or contact with novel coronavirus disease (COVID-19) for signs of community transmission, terming it “inevitable”.

Last week itself, the Health Ministry had announced that India had recorded its first cases of community transmission, though officials later clarified it had meant “local transmission in the community”.

Various countries have adopted various models for addressing community transmission, or for preventing it. India’s decision also raises the question: will the larger number of tests open up testing at private facilities?

What is community transmission?

It is one of the levels of transmission defined by the World Health Organization (WHO). Simply put, community transmission means that a virus is circulating in the community and can affect people with no history of travel to affected areas or of contact with an infected person. That is what ICMR is trying to find out by testing over 1,000 samples from people suffering from influenza-like symptoms but with no history of such travel or contact. India’s current emphasis on social distancing and discouragement of public gatherings, too, is aimed at checking community transmission.

Once community transmission begins, it is more difficult to trace contacts. One unknown source of infection can wreak havoc — one woman in South Korea, who refused to take the test, has been found to have ended up infecting over 160 people.

What is known about the level of transmission in India?

So far, most of the cases in India have had a history of travel abroad — for example, the Kerala and Delhi patients — or have contracted the disease from somebody around them — for example, the Italian tourist in Jaipur who ended up infecting 17 in the group including their Indian driver. On the other hand, some of the cases in Agra had neither any history of foreign travel nor had they come directly in contact with an infected person.

In a statement last week, the Health Ministry had said: “Since, in addition to COVID 19 cases related to travel, some cases of community transmission have also been observed, it has been decided to involve district collectors and States have been asked to form rapid response teams as the district, block and village levels.” Later, joint secretary Lav Agarwal clarified that this means local transmission at community level.

Local transmission, another level defined by WHO, happens through direct contact with an infected person within the country. In Agra, after two people with travel history to Italy infected their families, door-to-door  searches were undertaken within a 3-km radius.

Another level is imported transmission, for which the protocol is vigilance at the borders and airports, such as thermal screening and quarantine if required, like India began early on. India has also suspended visas to foreign nationals and the facility of visa-free travel to OCI card-holders.

So, does India’s latest move mean opening up testing to the private sector?

While the government is working with private hospitals to develop standard operating procedures for treatment and isolation of patients, there is no move yet for the testing process to be opened up for the private sector.

The possibility of profiteering is one concern. The primary reason for the government seeking to retain its control on the testing regime, however, is fear of wider exposure.

“It is not a question of technology; allowing the private sector would mean possible patients will be going to such a large number of places where adherence to infection control norms would be crucial to prevent spread of infections. Designated laboratories mean that we streamline everything, including the exposure of the medical staff and laboratory technicians,” said a senior official of the National Centre for Disease Control.

For now, the tests ICMR is doing are free for patients. Were they to pay, the two tests would have cost them about Rs 5.000. So, even if the government did open it up to private laboratories, it would mean not everyone would be able to afford the test. Rather than open up testing to the private sector and risk exposing more people, India has chosen to wait a bit longer for test reports while the patient is in isolation.

How does India’s model for testing for the virus — and combating it — compare with those of other countries?

Among the countries where community transmission seems to have begun are China (over 80,000 cases), Italy (over 21,000) and South Korea (8,000). For the time being, India has chosen to follow the Italian model of lockdown, rather than the South Korean model of free testing.

Italy, the epicentre of the outbreak in Europe, has imposed a nationwide lockdown, especially given its ageing population. Stores and restaurants have been closed and restrictions put on individual movement. Spain too has announced plans to lock down its citizens, while France has shut down several places. Cases are still climbing in these countries.

South Korea, meanwhile, has been testing lakhs of people and tracking potential carriers — like detectives, according to a Reuters report — by using cell phone and satellite technology. Mass free testing and treatment, and identification of transmission sources, have brought down daily new cases, from 909 on February 29 to less than 100 on March 15.

For India, massive free testing in a country of 135 crore would need humongous resources. India currently has reagents for about 1 lakh tests, has done a little over 6,000 tests so far, and is in the process of procuring 2 lakh more test kits. But if mass testing were to be done, all this would be a drop in the ocean.

What are countries besides these doing?

China adopted a graded approach, and the number of new cases are gradually declining. It has locked down Hubei, the epicentre, for 50 days now. Elsewhere, it enforced social distancing measures during the crucial phase of the Chinese New Year.

“As part of these social distancing policies, the Chinese Government encouraged people to stay at home; discouraged mass gatherings; cancelled or postponed large public events; and closed schools, universities, government offices, libraries, museums, and factories. Only limited segments of urban public transport systems remained operational and all cross-province bus routes were taken out of service,” The Lancet wrote earlier this month.

The US has partnered with a Google subsidiary to develop a website which will help determine whether a test is warranted.

What else is in India’s strategy?

India is relying on social distancing and cluster containment. According to the containment plan developed by the Health Minister: “The cluster containment strategy would be to contain the disease within a defined geographic area by early detection, breaking the chain of transmission and thus preventing its spread to new areas. This would include geographic quarantine, social distancing measures, enhanced active surveillance, testing all suspected cases, isolation of cases, home quarantine of contacts, social mobilization to follow preventive public health measures.”

Quarantine and isolation help by breaking the chain of transmission. More than 43,000 persons are now under community surveillance by the Integrated Disease Surveillance Programme, and contact tracing is still on.

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