Now that the government has finally begun mass testing across the country, public health experts say all suspects should be tested for Covid-19 as the recently started rapid tests are likely to discover more cases.

Although officials had initially said rapid test kits imported from China would not be employed without being tested for efficacy, the government on April 9 decided to move ahead with rapid testing while confirming all positive cases with a polymerase chain reaction test. Since the test was rolled out on April 10, seven new cases of Covid-19 have been confirmed, bringing the tally to 16.

“It is clear that positive cases are being detected in places where authorities are performing tests,” said Dr Anup Subedee, a consultant infectious disease physician. “All those who’ve returned from abroad should now be tested,” said Subedee adding that this was important as officials still didn’t know to what extent the disease has spread.

Rapid testing identified at least five new cases of Covid-19 on Monday alone. Among the people who tested positive on Monday were three people from the same family living in Sun City Apartments in Pepsicola, Bhaktapur.

“Two out of the three people [from Pepsicola] who were sent to isolation have tested positive,” said Dr Bikash Devkota, spokesperson for the health ministry, at a regular press briefing on Tuesday. “Samples from the third person are being verified again.”

As of Tuesday, 6,607 rapid diagnostic tests have been conducted across the country, with 1,316 done in the last 24 hours alone, according to the health ministry. The polymerase chain reaction (PCR) method has also been employed 6,299 times.

While rapid diagnostic tests, which give results in a matter of minutes, look for antibodies in blood that the human body produces in response to a virus infection, the PCR method is used to look for signs of the virus in the patient’s swab. According to scientists, a recovered patient can still test positive with the rapid diagnostic test.

The three people from Sun City had returned from London on March 18 and were only identified when authorities began testing everyone who had returned from abroad using the 75,000 rapid diagnostic test kits imported from China. Health officials said that they have now started tracing those who could have come in contact with the infected persons. All residents of Sun City will also be tested.

The health ministry, which earlier purchased 75,000 rapid diagnostic kits from China, has sent the kits to all 77 districts for testing people in quarantine.

The World Health Organization has long been asking countries to step up testing in order to identify active cases but the Nepal government has been slow to act as it was itself mired in a corruption scandal involving the procurement of medical supplies.

The UN body’s recommendations are also endorsed by Nepali public health experts. They believe that mass testing is especially important because a large proportion of carriers are believed to be asymptomatic, meaning they do not show any symptoms, but spread the disease. Studies show that 25 to 50 percent of people infected don’t show any symptoms at all.

Dr Mingmar Gyelgen Sherpa, former director of the Department of Health Services, said that the government has no option but to increase the range of tests. “A single positive patient can infect many others,” said Sherpa. “We should trace all who have come in contact with infected people, regardless of their travel history.”

Most Covid-19 patients identified so far have mild symptoms, said Sherpa. “This is risky because those with mild symptoms may not seek treatment.” But, such people can infect others but again. We don’t have any option but to increase testing,” he said.

Testing is even more important if the government plans to gradually lift the lockdown, said Sherpa. “Tests will help identify risky areas that need to be placed under continued lockdown.”

Dr Subedee said that governments should also start “active case finding”, which involves testing everyone suffering from fever and cough. “Rapid tests should also be performed on random samples in communities.”