The Takeaway: The combination of closing borders, tightly regulating travel, effective quarantine of all exposed people using cell phone data for enforcement, and universal mask wearing contributed to effectively keeping COVID-19 from infecting most of Taiwan's population.
The claim: Closing borders early, tightly regulating travel, contact tracing, technology-enforced quarantine, universal mask wearing, and Taiwan's previous deadly experience with SARS resulted in control of SARS-CoV-2 in Taiwan.
The evidence: The earlier COVID-19 cases are stopped from entering a country, the fewer cases will be present to spread the disease to others. To illustrate, it is easier to stop a trickle of water than to try to dam up a flood and easier to extinguish a candle than a forest fire. Taiwan closed its borders on January 23rd, 2020 (1). The Philippines closed their borders on February 2nd, 2020 (2). Tightly regulating travel will help to stop cases before they enter the country. Effective quarantining the few cases and contacts of the cases which do enter a country is critical to preventing the spread of the disease within the country. Taiwan used mobile telephone data to enforce quarantine (1). Without quarantine, each infected person will spread COVID-19 to 2-6 additional people based on the R0 (3, 4). Universal masking will help slow the spread of disease (5). Previous experience with controlling a deadly disease will most likely increase compliance to methods to control the disease.
Per Our World in Data website, Taiwan had one of the least stringent government responses to COVID-19 (6). The biweekly number of COVID-19 cases in Taiwan was 23 on October 29, 2020 (7). Neighboring countries had biweekly COVID-19 cases of 372 (China), 28,644 (Philippines), 11,871 (Malaysia), 51 (Vietnam), and 8,142 (Japan). These neighboring countries had more stringent government responses to COVID-19 (6).
Sources:
1) https://focustaiwan.tw/society/202001230011
2)https://www.pharmaceutical-technology.com/features/coronavirus-affected-countries-philippines-measures-impact-tourism-economy/#:~:text=The%20government%20announced%20earlier%20on,barred%20from%20entering%20the%20country.
3) https://pubmed.ncbi.nlm.nih.gov/32234343/
4) https://pubmed.ncbi.nlm.nih.gov/32097725/
5) https://www.nature.com/articles/s41591-020-1132-9#annotations:7jRWRheWEeuY8x_rXDuRjg
6) https://ourworldindata.org/grapher/covid-stringency-index
7) https://ourworldindata.org/grapher/biweekly-confirmed-covid-19-cases