Are we still vaccinating to reach herd immunity?

Prof Shabir Madhi says reaching herd immunity is not the reason for vaccinating people against Covid-19.

Madhi, who sits on the Covid-19 ministerial advisory committee and is also heading the SA vaccine trials, said people must get jabbed to prevent severe illness and death.

“We need to stop talking about herd immunity because it’s not going to materialise with Covid-19. That is not the reason we are vaccinating. To achieve herd immunity, about 85% of the population would need to develop immunity against infection, not against severe disease, and that is extremely unlikely.

“But that doesn’t mean we shouldn’t get people vaccinated. The main reason for vaccinating people is to protect them from severe disease and death from Covid-19.” 

According to the World Health Organisation, “herd immunity” or “population immunity” means “the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection” .

Madhi said it is crucial to vaccinate high-risk individuals, like those who are 60 years and older and those with comorbidities.

“The vaccines provide more than 90% protection against severe disease. When it comes to mild infection and transmitting the coronavirus, the vaccines reduce that by about 50%. Even if there’s a 50% reduction in the transmission of the virus when compounded, that will result in a massive number of fewer cases of Covid-19 transpiring,” he said.

Madhi said this is not herd immunity.

“It’s not herd immunity, which usually means the virus has been eliminated and can’t continue transmitting in a community. Even a 50% reduction in the ability to transmit the virus results in large numbers of cases being prevented,” said Madhi.