Case No. 605, a male in his 30s, traveled to Myanmar for work in March. He began developing symptoms, including drowsiness, a fever and a loss of smell and taste, on September 6, after which he tested positive for COVID-19.

He was placed in isolation in Myanmar and was released in late September after his symptoms had subsided, without having undergone a second test, Chuang Jen-hsiang, spokesperson for the health ministry’s Central Epidemic Command Center (CECC), told a press briefing on Tuesday.

The individual returned to Taiwan on November 8 and volunteered the fact that he had been diagnosed with coronavirus in the past. He tested negative at the port of entry and was allowed to proceed to his quarantine residence for 14 days of mandatory isolation.

However, Case No. 605 later developed symptoms including a scratchy throat and a mild cough. They worsened on November 13, resulting in another test and finally a positive result on Tuesday, Chuang said.

The individual, who authorities said had infected two other close contacts, is suspected of having “long COVID”—also known as “long-haul COVID”—which is characterised by coronavirus symptoms lasting more than a month.

He is not believed to have been infected a second time, Taiwan’s state-funded Central News Agency reported.

During Tuesday’s press conference, Chuang said the Ministry of Health and Welfare hoped to acquire a COVID-19 vaccine by the middle of next year.

The CECC was monitoring positive progress by vaccine maker Moderna and the Pfizer/BioNTech team, among others, Chuang said. The government had budgeted 11.5 billion New Taiwan dollars ($403 million) for procurement of 1.5 million doses of a vaccine, he added.

Taiwan’s 605 COVID-19 infections include 513 imported cases. The island has not had a confirmed case of local infection since April 12, according to the health authority.

Taiwan’s death toll has remained at seven since May 11.

In August, Hong Kong researchers reported that a 33-year-old local man was the world’s first patient to be reinfected with coronavirus, having previously tested positive in March.

A 25-year-old from Reno, Nevada, is thought to be the first person to be infected twice in the United States. The patient tested positive in April and again in June.