Some news at last:
https://focustaiwan.tw/society/202104260016Shorter quarantine for COVID-19-vaccinated arrivals from mid-May: CECC
Taipei, April 26 (CNA) Arrivals in Taiwan who are fully vaccinated against COVID-19 could be allowed to shorten their quarantine from 14 to seven days as soon as mid-May, the Central Epidemic Command Center (CECC) said Monday.
These arrivals would be able to apply to cut their quarantine short if they became fully vaccinated more than one month prior to visiting Taiwan, said Minister of Health and Welfare Chen Shih-chung (陳時中), who also heads the CECC, at a press briefing in Taipei.
Further eligibility requirements include having to present proof of a negative COVID-19 test result before their flight and another negative test for COVID-19 on the seventh day after their arrival.
They must also be tested for antibodies in Taiwan, although the CECC has not yet decided how such a test would be carried out, Chen said.