While breakthrough COVID-19 infections have been recorded in vaccinated individuals, signs are beginning to emerge that inoculations were reducing the risk of serious illness and hospitalisation.
This was on Thursday revealed by South African Health Products Regulatory Authority (SAHPRA) chairperson, Professor Helen Rees, during a webinar on the process of vaccine approval.
The authority's mandate is to ensure that all health products comply with regulatory principles of safety, quality and efficacy. This includes medical devices, complementary medicines, and veterinary and human medicines.
Despite breakthrough infections, it was critical for the country to obtain and distribute as many jabs as possible.
The country last week entered into the third wave of the COVID-19, with new infections reaching 17 493 on Wednesday.
"Although we are seeing breakthrough infections, it would appear if we look at the (unpublished) J&J data; it does appear that although we are seeing breaks [in] infections many of those infections is mild to moderate disease. In fact we are seeing a reduction in severe disease."
This, she said, was also the trend with the Pfizer vaccine.
SAHPRA is also monitoring development and experiences around the world.
"But because we have the Beta variant - which we share with many other African countries - South Africa's in an unfortunate position, but at an important position in that we can generate this data to look at breakthrough infection in the context of this particular variant."
She reiterated that it was important for the country to obtain and distribute as many vaccines as it possibly can.
"Because if we can reduce the severity of disease, take that terrible burden off the hospitals and we'll reduce the access mortality [which] will come with that surge of infection and serious diseases," Rees said.
"So the question is 'why are we still continuing to immunise?' Well, the first thing to say is that with a new disease like this, all of these vaccines are brand new, so when you approve [vaccines] what you have is varying degrees or clinical data that tell you how effective the vaccine is likely to be."
Among the authority's challenges, is that South Africa has had relatively little clinical data.
"There is some... clinical data about how some of the vaccines perform in the context of the Beta (dominant) variant, but it's limited, at best. So we have to go on the cumulative knowledge that we have from laboratories data about antibodies and about the clinical data."
Even if the Johnson & Johnson and Pfizer vaccines - jabs currently in use in the country - were not effective in preventing middle to moderate disease, it was hoped they would avert severe illness and hospitalisation.
"We also know that every single vaccine has been rendered less effective in the context of the variant. What we are doing is that we are monitoring these breakthrough infections. There's a national strategy to look at the breakthrough infections and to evaluate them.
The strategy evaluates if the affected person has had a vaccine, and if yes, which vaccine.
"Secondly, does the person have other comorbidities? Who is this person? Are they over 60? Do they have any other risk factor? Thirdly, what is the severity of the disease? Is it middle, moderate or severe? Are they hospitalized?" she remarked.
The authority was increasingly looking at which virus had caused the breakthrough infection.
SAHPRA Pharmacovigilance Commitee chairperson, Proffesor March Blockman concurred with Rees, saying early data was showing "good" vaccine efficacy, which is often very important".
"For me it is absolutely critical - 100% efficacy against severe disease [is needed] because that means going to hospital and requiring oxygen," he said.
Blockman added that at this moment in time, the two vaccines are highly effective against serious disease from COVID-19.
"However, it's a pandemic and a roll out must occur and we must continue to accumulate data to make sure that it continues to be consistent," he said.