How mainland China's closest neighbors kept coronavirus caseloads so low

Subscribe to Fortune’s Outbreak newsletter for a daily roundup of stories on the coronavirus outbreak and its impact on global business.

Cases of Covid-19 are spiking around the world in regions as far flung from the pandemic’s origin as Italy, with 21,157 infections, and Iran, with 12,729. Yet across the smaller constituents of Greater China—Taiwan, Hong Kong, and Macau—infection rates have remained shockingly low, despite close proximity and intimate ties to the outbreak’s mainland epicenter.

In this series, Fortune examines each region’s coronavirus response:

Taiwan: SARS taught Taiwan how to contain the coronavirus outbreak

Hong Kong: Hong Kong gets thousands of mainland Chinese visitors each day. How it’s kept coronavirus at bay

Macau: 10 cases, 10 recovered: How the world’s most densely-populated region fought off the coronavirus

In Hong Kong, which shares a land border with mainland China, case numbers have only crept to 141 this week with four deaths and 81 recovered. In the densely-populated gambling enclave of Macau, cases peaked at 10, all of which are now clear. Meanwhile in Taiwan, across the 140-mile long Taiwan Strait that separates the island from mainland China, there have been 53 cases to date.

Each of these three regions has reacted in different ways to the virus, but there are parallels in the steps they’ve taken. Border checks have been tightened, events have been cancelled, schools have been closed, surgical masks are vogue. What’s more, they didn’t delay in implementing such measures; they all went into effect relatively soon after cases of the coronavirus started appearing in the mainland.

Another common thread is that the three regions—Taiwan and Hong Kong in particular—share painful memories of a past novel coronavirus outbreak—of so-called Severe Acute Respiratory Syndrome of SARS that gripped Asia in 2003—and appear to have learned from that episode. Perhaps there’s something to be learned from their current responses, too.