TAIPEI (Taiwan News) — An infectious disease expert believes that Taiwan should reimpose its quarantine requirements on arriving passengers from China to prevent a "tsunami" of cases infected with the Omicron subvariant BF.7.

Hwang Kao-pin (黃高彬), a professor at China Medical University in Taichung City, was cited by ETtoday as saying that Taiwan should impose a three-day quarantine for arrivals from China through the mini-three links because the BF.7 subvariant has such a high R number that one case can infect as many as 18 people. 

There has been debate over Taiwan's reopening the mini-three links (小三通), which refer to postal, transportation, and trade links between the cities of Xiamen, Mawei and Quanzhou in China's Fujian Province, and Taiwan's Kinmen and Matsu islands.

Hwang said that reopening of the mini-three links must be accompanied by supporting measures and strict testing standards because of the dangers of transmitting the new subvariant to Taiwan. He pointed out that BF.7 is rapidly spreading in China, and it is a sub-lineage of the Omicron variant BA.5, with a shorter incubation period, stronger immune escape ability, and faster transmission.

Hwang said though it is mainly mild, because of its strong immune escape ability, people who were previously infected with BA.1 or BA.5 may be reinfected and there are reports the R value for BF.7 is 10 to 18, meaning that one case can transmit the virus to at as many as 18 people, putting it on a par with measles. R is short for the basic reproduction number (R0) and in the absence of herd immunity, R measures the average number of persons one individual with the virus can infect.

As for the supporting measures, Hwang said that in addition to on-arrival tests, regardless of whether it is the opening of the mini-three links or airport flights from China, he recommends controls be placed on the number of arrivals. In addition, Hwang suggested that Taiwan also "resume preliminary quarantine measures" for those returning to Taiwan from China.

Hwang recommended that passengers from China arriving on the outer islands should undergo three days of quarantine. He said these measures should be announced in advance and the quarantine bed capacity of Matsu and Kinmen should be used as the guideline for the number of passengers allowed to enter each day.

Hwang said that China will usher in an "epidemic tsunami." He added that Wang Guangfa (王廣發), a doctor in the Respiratory Department of Peking University First Hospital, said that with the lifting of zero-COVID restrictions, there will be a peak of severe cases within one to two weeks, meaning a big wave of cases in January.

Therefore, Hwang reasoned, if Taiwan wants to keep the mini-three links open during this period, it should impose a quota on the number of people allowed to arrive per day and a three-day quarantine for those who do enter.