On November 26, the Central Epidemic Command Center (CECC) announced that the 16th round of vaccinations for appointments on the COVID-19 Vaccination Registration and Reservation system (https://1922.gov.tw/, "the System") will offer the second dose of the Pfizer-BioNTech (BNT), Moderna, and AstraZeneca (AZ) vaccines. In the 16th round, eligibility for a second dose of BNT or Moderna will be opened to people who have received a first dose of BNT or Moderna for four weeks and people who have received a first dose of AZ for eight weeks. Details about eligibility and schedules are listed below.

A. Eligibility: individuals who registered (mix-and-match approach included) on the System before 12 p.m. on November 25 and meet any of the following criteria:
1. The second dose of the BNT vaccine: people aged 18 and older (born on December 31, 2003, or earlier) who received their first dose of BNT before November 4 (inclusive).
2. The second dose of the Moderna vaccine: people aged 18 and older (born on December 31, 2003, or earlier) who received their first dose of Moderna before November 4 (inclusive).
3. The second dose of the AZ vaccine: people aged 18 and older (born on December 2, 2003, or earlier) who received their first dose of AZ before October 7 (inclusive).
4.Mixing of AZ with a second dose of the BNT or Moderna vaccine: people aged 18 and older (born on December 2, 2003, or earlier) who received their first dose of AZ before October 7 (inclusive).

B. Time slots for scheduling appointments:
1. The BNT vaccine: from 10 a.m. on November 29 to 12 p.m. on November 30.
2. The AZ and Moderna vaccines: from 2 p.m. on November 29 to 12 p.m. on November 30.

C. Vaccination: from December 2 to December 8.