Can I test positive for Covid-19 if I have been vaccinated?

President Cyril Ramaphosa testing positive for Covid-19 has sparked a debate on social media, with many questioning how fully vaccinated people are still contracting the virus. 

On Sunday, the presidency announced that Ramaphosa was receiving treatment for mild symptoms.

Ramaphosa, who is fully vaccinated, started feeling unwell after leaving the state memorial service in honour of former deputy president FW de Klerk in Cape Town. He is currently in self-isolation in the city. 

On social media many questioned how Ramaphosa contracted Covid-19 when he is vaccinated against the virus. 

The US Center for Disease Control and Prevention (CDC) has defined contracting Covid-19 after being fully vaccinated as a “vaccine breakthrough infection”.

What is a ‘vaccine breakthrough infection’?

The centre said a vaccine breakthrough infection happens when a fully vaccinated person gets infected with Covid-19 and people with vaccine breakthrough infections may spread the virus to others.

“Vaccine breakthrough infections are expected. Covid-19 vaccines are effective at preventing most infections. However, like other vaccines, they are not 100% effective,” said the CDC. 

“Fully vaccinated people with a vaccine breakthrough infection are less likely to develop serious illness than those who are unvaccinated and get Covid-19.

“Even when fully vaccinated people develop symptoms, they tend to be less severe symptoms than unvaccinated people. This means they are much less likely to be hospitalised or die than people who are not vaccinated.”

Last month, former head of the ministerial advisory committee on Covid-19 Prof Salim Abdool Karim raised concerns about the increase in Covid-19 cases, saying “risky” indoor events should only be attended by vaccinated people.

He said this was based on the fact that vaccinated people are less likely than unvaccinated people to develop severe illness from Covid-19.

“Even though we are likely to see reinfections and breakthrough infections, vaccinated people are less likely to have severe Covid-19. So one of the things is to restrict risky situations, particularly indoors, to vaccinated people only,” said Abdool Karim.