‘Extremely promising findings’: Discovery releases results of study into efficacy of Pfizer vaccine

In a “real-world” study that analysed the medical aid data of Discovery Health clients, analysts at the company have shown that the two-dose Pfizer vaccine is very effective in protecting against serious illness or death from Covid-19. 

Relative to members fully vaccinated with the Pfizer vaccine, the unvaccinated member population has a five times higher risk of Covid-19 infection, and 20 times the risk of dying from Covid-19 complications, the study revealed. 

“By 3 November 2021, more than 22 million vaccine doses had been administered in South Africa, with 2.5 million vaccine doses given to Discovery Health-administered medical scheme members,” said Dr Ryan Noach, the CEO of Discovery Health. 

“Within our administered medical scheme members, more than 60% of all adults and almost 80% of those over the age of 60 have received at least one Covid-19 vaccine dose. 

“The high vaccine uptake to date within the Discovery Health client base allowed us to examine the relevance and impact of the two Covid-19 vaccines being rolled out in South Africa. 

“Considering the time frame required for a person to become fully vaccinated, we have three months’ worth of data on fully vaccinated medical scheme members included in our analysis. All in all, 1,734,276 data points were reviewed over this period, ensuring extreme rigour in the analysis, and leveraging Discovery Health’s extensive clinical database. Our analysis includes just over 1.2 million vaccinated medical scheme adult members vaccinated up to 23 September 2021. 

“We are delighted to share extremely promising findings around the Pfizer Covid-19 vaccine’s real-world effectiveness, analysed here in South Africa during the third wave of Covid-19, which was dominated by the Delta variant,” Noach said. 

“We determined the Pfizer vaccine’s effectiveness in protecting against Covid-19 admission and mortality by analysing 526,516 pathology test results, 14,673 Covid-19 admissions and 3,441 Covid-19 deaths. All of these occurred between 17 May 2021 (the start of South Africa’s mass vaccination campaign) and 23 September 2021. 

“This period is very important as it coincides with South Africa’s third wave of Covid-19, which was fuelled by the Delta variant. This Delta variant is more contagious than previous variants and consequently was responsible for a substantial wave, with much morbidity.” 

Noach said there has been a “precipitous drop in demand” for the Covid-19 vaccine with a few upticks when the vaccination programme was opened up for children between 12 and 17. 

“Covid-19 vaccine hesitancy is a key deterrent to vaccine uptake and is fuelled in large part by misinformation, which drives confusion and fear. Our analysis definitively addresses this misinformation, through carefully constructed and evidence-based research on more than 1.2 million Discovery Health-administered medical scheme members.” 

He said they used data from their Vitality programme, clinical information from patients on their medical aids and vaccination data from members. 

This had led to an analysis that created “unique real-world insights”.  

Noach said their analysis showed that the Pfizer vaccine is working very well against the Delta variant, the current dominant variant of the coronavirus in South Africa. 

“The findings are striking and extremely encouraging. We have shown that following each dose of the two-dose Pfizer vaccine, there is significant protection against both serious Covid-19 illness (relative risk of admission to hospital) and death — of course, most notable for those who are fully vaccinated, 14 days after receiving the second dose,” Noach said. 

Shirley Collie, the head of health analytics for Discovery, said they found the Pfizer vaccine is 73% effective in protecting against the risk of admission to hospital from Covid-19 from 14 days after the first dose and 92% effective from 14 days after the second dose. 

The vaccine is 79% effective in protecting against Covid-19 mortality from 14 days after the first dose and 94% effective from 14 days after the second dose. 

“There is a stabilisation in vaccine effectiveness protecting against Covid-19 admissions and mortality at 28 days after Dose One and at 14 days after Dose Two,” she said. 

There was a 5% to 7% decline in vaccine effectiveness in protecting against admission to hospital in people over the age of 80, and in individuals with three or more chronic conditions. 

Collie said unvaccinated people who had a prior Covid-19 infection had a lower relative risk of hospital admission. People who had had Covid-19 and got vaccinated, she said, developed a 98% protection against the virus. 

Collie said 11,500 members of their medical schemes had tested positive for Covid-19 twice more than 90 days apart and 37 members had tested positive for Covid-19 three times. 

Dr Ronald Whelan, the head of Discovery’s Covid-19 task team, said of the three statistically significant side effects reported to them, swelling of the lymph nodes was the most prevalent, followed by inflammation of arm muscles and tingling in hands and feet. 

He said people who contracted Covid-19 were more likely to experience these symptoms than those who had the vaccine. 

Whelan added that potentially fatal Covid-19 complications like pulmonary embolism (blood clot in the lungs), acute kidney injury, anaemia, heart rhythm disturbances and myocarditis (inflammation of the heart muscle) were also more prevalent in people with Covid-19 than as a side effect of the vaccine.  

Whelan said there were very few adverse vaccine-related events reported at the Discovery sites and no vaccine-related deaths. 

Noach said that, “Myocarditis is important to keep in mind as a potential adverse event following vaccination — particularly in teenage males — [but] this complication did not show up as statistically relevant across the 1,207,760 vaccinated Discovery Health scheme members included in this analysis. This is not unexpected, considering that myocarditis remains extremely rare, and that younger males were not eligible for vaccination in South Africa during the period of this analysis. 

“The risk/benefit consideration of being vaccinated against Covid-19 is undoubtedly strongly in favour of vaccination.” DM/MC