Hong Kong, Nov 27 : The Hong Kong government has announced that the boarding and quarantine requirements for those arriving from eight countries in southern Africa will be tightened from Saturday. These eight countries include Botswana, Lesotho, Malawi, Mozambique, Namibia and Zimbabwe, as well as South Africa, which is already a specified high-risk place, Xinhua news agency reported, citing a government press release. "The mutant variant B.1.1.529 has been detected in South Africa and Botswana. Although scientists are not fully certain of its potential effects on the epidemic situation or whether the relevant mutations would affect the efficacies of vaccines, we have to stay vigilant," a government spokesperson said. With the eight southern African countries above specified as Group A specified places, non-Hong Kong residents (including visitors) who have stayed there within 21 days are not allowed to enter Hong Kong. For Hong Kong residents, they can only board a flight for Hong Kong if they have been fully vaccinated and hold a recognised vaccination record. Upon arrival they have to undergo compulsory quarantine in a designated quarantine hotel for 21 days. /IANS