The recent Covid-19 outbreak in Taiwan is a lesson that a containment strategy that targets zero local transmission may not be sustainable in the long term, a public health professor said Tuesday.

Before the recent explosion in cases, Taiwan had reported very few Covid infections for over a year – and most were imported. This allowed daily activities to continue largely normally and the island received international praise for its containment measures.

But it made Taiwan “completely vulnerable” to new variants of the coronavirus that are more communicable and potentially more serious, said Benjamin Cowling, professor and head of the epidemiology and biostatistics department at the University of Hong Kong’s School of Public Health.

“Probably less than 1% of their population have a natural infection, and therefore natural immunity, and … less than 1% have been vaccinated – so they are almost entirely susceptible,” Cowling told CNBC’s Squawk Box Asia.

Taiwan, with a population of around 24 million, has reported more than 8,500 confirmed Covid cases and 124 deaths as of Monday, official data showed.

It is a warning to other parts of Asia that this strategy of elimination is also trying, it is not necessarily sustainable in the long run.

Benjamin Cowling

Hong Kong University School of Public Health

Cowling said Taiwan will have a hard time controlling the recent outbreak. Authorities may need tougher social distancing measures as testing capacity hasn’t been ramped up enough and the island’s vaccination progress has been slow, he added.

“It is a warning to other parts of Asia that are also trying this elimination strategy, it is not necessarily sustainable in the long term,” said the professor.

Asian economies have generally shown lower tolerance to Covid infection compared to their competitors in other regions.

Governments in Hong Kong and Singapore, for example, have been quick to tighten measures to curb small upward movements in cases. Meanwhile, countries like the US and UK are still reporting thousands of cases every day, but faster vaccination has allowed countries to lift restrictions.

Like many of its regional competitors in Asia, Taiwan faced challenges in securing Covid vaccines, Cowling said. Part of Taiwan’s hurdle is politics, the professor said.

Taiwan President Tsai Ing-wen said in a Facebook post last week that the government had bought vaccines developed by AstraZeneca and Moderna. She accused China Blocking of a deal with Germany’s BioNTech, which has developed a vaccine together with US pharmaceutical company Pfizer.

Beijing rejects Tsai’s allegations.

China claims Taiwan as a runaway province that will one day have to be reunited with the mainland – if necessary by force. The Chinese Communist Party has never ruled Taiwan, which is a democratic, self-governing island.

“There are a lot of policies out there when it comes to getting vaccines into Taiwan,” Cowling said. “I think they will do it, but right now they won’t be able to vaccinate enough people to stop the current outbreak. They have to use social distancing and bans to deal with it.”