Asian countries that started to feel tentative hope that their responses to the coronavirus pandemic were bearing fruit are now facing possible second waves, brought by a rush of panicked people racing home to beat border closures and quarantine orders.

As daily numbers of confirmed cases start to rise again, and new evidence of asymptomatic cases spark fear of unwitting community transmission, many have now brought in far stricter measures.

Jason Kindrachuk, assistant professor and Canada research chair at Manitoba University’s department of medical microbiology & infectious diseases, said it was hard to know how daily life could return to normal until there was a vaccine and until governments know what the immunity levels are across the population.

“The concern with this virus … is how to reduce social distancing measures and enforcement in such a way that you don’t reignite transmission chains for the virus and find yourself back at square one with trying to get things contained,” he said.

One of the first affected by the virus, Hong Kong had already closed schools and some buildings and parks but never enacted a full lockdown.

It has now banned foreign arrivals, closed venues and restricted gatherings, strengthened testing, opened quarantine centres, and handed out jail sentences for non-compliance. Tracking bracelets ensure people mandatorily isolating don’t leave their homes.

Prof Ben Cowling, an epidemiologist at Hong Kong University’s school of public health, said that while Hong Kong could claim to have prevented an epidemic so far, there was still a risk of one with incoming travellers.

Hong Kong never saw more than 11 cases confirmed in a day during the early stages of the outbreak. After thousands of people flew home the number is now regularly above 50, and the city’s health system is strained.

Taiwan’s response to the pandemic is considered one of the world’s most successful. It maintains a ban on foreign entrants, and with its infection rate still low – around 330 cases – is more focused on a spat with the World Health Organization.

Singapore is also considered to be an example of best practice but is facing a potential second wave. Amid warnings of growing community “complacency”, all four of Singapore’s deaths and more than 60% of its 1,000 or so confirmed cases have been in the past three weeks.

Singapore has introduced fines and jail terms for breaching stay-at-home orders, banned all international short-term visitors and transits, cancelled mass gatherings, and closed venues, places of worship and tuition centres.

This week it announced all long term pass-holders needed approval before entering the country, and cancelled the passport of a citizen who flouted stay-at-home orders.

Japan’s daily case reports grew slowly over January and February, not reaching more than 50 until last month. While it has held off a major outbreak, Tokyo has become a concern, reporting record high case numbers for four consecutive days in late March.

The country’s social distancing and lockdown measures appear far more lax than its neighbours and there has been accusations of under-testing and speculation the number of infected people is far higher than reported.

South Korea was once one of the worst outbreak sites, but after implementing aggressive contact tracing, quarantining and isolation, it appeared to get control. Amid fears of a second wave, however, some health experts are calling for the country to extend its entry ban, currently one of the most lax in the region.

In mainland China the initial outbreak, which killed thousands, has slowed but there remains concern over people who returned home from abroad and foreigners, all of whom have been banned from entering, including those with residency visas. Restrictions have been lifted in Hubei but across the country people’s movements are policed by a colour-coded health app.

This week authorities imposed lockdown on a Chinese county of 600,000 after a woman is thought to have contracted the virus from asymptomatic doctors at a hospital.

A study in the Lancet Public Health Journal said the extreme restrictions on Wuhan helped control the outbreak, and lifting them now could see a second wave by August.

Dozens of new cases are reported daily in mainland China, almost all imported. However, there are accusations of coverups, and it was not until this week that Chinese health authorities included asymptomatic people who tested positive – estimated to be 18-31% of cases – among its reported number.

China’s national health commission said that as of Tuesday, 20,000 people were under observation as possible silent carriers, and the president, Xi Jinping, on a visit to Zhejiang, called for more focus on asymptomatic cases.