President Cyril Ramaphosa said his COVID-19 infection should serve as a caution to South Africans to be vaccinated and remain vigilant against exposure.
Ramaphosa tested positive for COVID-19 on Sunday and is receiving treatment for mild symptoms.
The presidency said he started feeling unwell after the state memorial service of apartheid's last president FW De Klerk in Cape Town.
"Many wondered why we want a memorial at a state level for FW De Klerk and we said we will have it… because he is one person who played a role in the evolution of our new democracy whether we like it or not."
These were Ramaphosa's words just before he went into isolation after testing positive for COVID-19.
The Presidency said that while all COVID-19 protocols were followed at De Klerk's memorial service on Sunday, those who attended or came into contact with Ramaphosa should monitor for symptoms.
Ramaphosa recently returned from a tour to four West African countries. but was tested for COVID-19 in all countries.
The president, who is fully vaccinated, is in self-isolation and has delegated all responsibilities to Deputy President David Mabuza for the next week.