Who gets the first Covid-19 vaccines? Prof Shabir Madhi weighs in
Who will be the first South Africans to get Covid-19 vaccines?
This was the question after SA committed R500m to the global Covax distribution scheme, signing up for a purchase that will cover 10% of the population.
The department of health would not comment, but Wits University professor of vaccinology Shabir Madhi said SA would probably adhere to the guidelines of the World Health Organisation (WHO), since it was a co-leader of the Covax initiative to provide vaccines in low- and middle-income countries.
“That is a small number of vaccines, so there will definitely have to be prioritisation,” said Madhi. “The WHO recommendation is that first and foremost, health-care workers receive protection. Second is people over the age of 65, and after them are the people with comorbidities.”
This means diabetes, hypertension and other conditions that create much higher risk for those who contract Covid-19.
So far, there are three promising candidate vaccines:
- The first to announce high efficacy was Pfizer/BioNTech, but a drawback for SA is that this vaccine has to be stored at -70°C;
- The next, from Moderna, claims 95% efficacy but also requires low-temperature storage; and
- The latest is from Oxford/AstraZeneca, and it might go down as a lucky accident.
Preliminary results, according to Nature, showed the vaccine was 70% effective. But analysis of trial data “found a striking difference in efficacy, depending on the amount of vaccine delivered to a participant”.
Nature added: “A regimen consisting of two full doses given a month apart looked to be just 62% effective. But, surprisingly, participants who received a lower amount of the vaccine in a first dose and then the full amount in the second dose were 90% less likely to develop Covid-19, compared with participants in the placebo arm.”
As it turned out, the administration of a lower dose was a mistake.
“The data is intriguing and was collected inadvertently in the UK,” said Madhi.
He said a vaccine that could give up to 90% protection would go a long way towards achieving herd immunity and, unlike the other two, the AstraZeneca vaccine does not have to be stored at low temperatures.