Your Covid-19 questions answered

What percentage of efficiency must vaccines have to be approved?

A Covid-19 vaccine needs to have at least 50% effectiveness for approval.
A Covid-19 vaccine needs to have at least 50% effectiveness for approval.
Image: 123rf/pitinan

A Covid-19 vaccine needs to have at least 50% effectiveness against the various strains of the virus to be approved.

This is according to SA Health Products Regulatory Authority (Sahpra) chair, Prof Helen Rees, who was briefing parliament’s health committee on Covid-19 vaccine licensing, efficacy rates, and the latest research this week.

According to Reese, the effectiveness of all the Covid-19 vaccines can drop, as new variants are discovered.

“As we know there are very few vaccines in the world that are 100% effective. Many vaccines are partially effective and many vaccines act by reducing the severity of disease or preventing symptoms developing even if you have a low-grade infection, but 100% vaccines are a rare thing indeed.

“The bar that we have set for ourselves, which is the international standard, is to say 50% effectiveness is the minimum that we would expect,” said Reese.

She emphasised that none of the Covid-19 vaccines are 100% effective.

“The different vaccines we are looking at will have a different level of efficacy. Importantly, for the vaccines that are at the most advanced stage, with all of the early clinical trials, all of these vaccines showed that they prevent severe disease, hospitalisation and death.