Midnight arrived first on the islands closest to the International Date Line in the Pacific Ocean, including Kiritimati (Christmas Island), Tonga and New Zealand
Vanuatu, the Solomon Islands, the Marshall Islands, Samoa and now Micronesia have lost their virus-free status, although none have so far reported community transmission.
"It makes it a little tricky to know exactly how close Yasa will get to Fiji -- direct hit is the current thinking," Weatherwatch managing director Philip Duncan said.