South Africa informed the WHO that it considered that travellers from countries with low risk of YF transmission still pose a risk of YF importation into the country and that proof of YF vaccination will be required from all travellers (unless in possession of a valid waiver certificate) coming from YF risk countries - including Sao Tome and Principe, Somalia, the United Republic of Tanzania and Zambia. Also, all travellers transiting airports in these countries (within the last 10 days) will have to show proof of YF vaccination at entry in the Republic of South Africa. (Reference)