In his post on Facebook, Lee noted that the test performed after returning to his country after traveling to Africa and Asia was positive for COVID-19.
The 71-year-old Prime Minister, who said that he generally felt well, stated that his doctors had advised him to isolate himself until the symptoms disappeared.
Lee said that the last COVID-19 vaccine was in November 2022, and urged Singaporeans to be regularly vaccinated to keep the disease mild.
Lee made an official visit to South Africa on May 14-16 and Kenya on May 17-19. Lee also attended the Association of Southeast Asian Nations (ASEAN) summit held in Indonesia on May 10-11.