According to N1 https://rs.n1info.com/svet/a670761-drzave-bez-koronavirusa/ there are 6 countries in the world, which do not have coronavirus cases for now. Out of a total of 193 countries that are full members of the United Nations, and according to the World Health Organization (WHO), there are no official coronavirus cases in 6 countries.
Those countries are: Turkmenistan, North Korea, Kiribati, Tuvalu, Tonga, and Nauru. The last four mentioned countries are island countries in the tropical Pacific (the most populous of them is Kiribati, which has around 120 000 inhabitants, while the smallest one is Nauru, which has around 12 000 inhabitants).