Skip to content
Discovery Health shares unequivocal data on protective effects of COVID 19 vaccination and low risk of vaccine-related adverse events

Press release -

Discovery Health shares unequivocal data on protective effects of COVID 19 vaccination and low risk of vaccine-related adverse events

Today, Discovery Health shared the latest data from its actuarial team’s ongoing analysis of the trajectory of the COVID-19 pandemic and real-world effectiveness of COVID‑19 vaccines.

The new research answers three main questions – addressing themes that are highly relevant in the context of South Africa’s efforts to quickly vaccinate as many eligible individuals as possible:

  1. What is the real-world effectiveness of the Pfizer-BioNtech (Pfizer) COVID-19 vaccine? How well does it protect against hospitalisation and death? Does the reported high effectiveness reduce in the context of the Delta variant?
  2. Do people who get fully (Pfizer) vaccinated after recovering from a COVID-19 infection, benefit from added protection?
  3. Are adverse events from COVID-19 vaccines (Pfizer and Johnson & Johnson) a concern, posing significant health risks? How does the risk of complications from COVID-19 stack up against the risk of adverse events from COVID-19 vaccination?

Discovery Health’s analytics team has collaborated with leading scientists and clinicians to deploy global best-practice methodologies in the research undertaken,” says CEO of Discovery Health, Dr Ryan Noach. “We are delighted by the unequivocal conclusion emerging from the evidence, that vaccination with the two-dose Pfizer vaccine is safe and highly effective for Discovery Health-administered members, here in South Africa.”

What inspired this analysis?

South Africa has procured sufficient COVID-19 vaccine doses for around 80% of the population. Furthermore, the National Department of Health has set targets to vaccinate 70% of the adult population by December 2021. Based on current vaccinated population levels and projections, it is unlikely that South Africa will meet these targets, and will most likely finish the year with slightly more than 50% of the adult population vaccinated.

“The demand for vaccination has unfortunately slowed,” says Dr Noach. “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 1.2m Discovery Health-administered medical scheme members.”

“People want to understand the true, real-world nature of the protective effects of COVID-19 vaccines. Also, people want to know their risk of experiencing side effects post vaccination – and whether they are at higher risk of an adverse event post vaccination or complications from COVID-19. Our analysis answers these questions.”

Dr Noach goes on to say, “In addition, what this research clarifies is our pathway to resuming a productive new normal, whilst protecting lives and livelihoods.”

High levels of COVID-19 vaccine penetration evident in medical scheme member base

“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,” says Dr Noach. “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 allows 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.”

1. What is the real-world effectiveness, in South Africa, of the two-dose Pfizer COVID-19 vaccine in protecting against COVID-19 admission and mortality?

“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,” adds Dr Noach.

“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 of SARS-CoV-2 (the virus that causes COVID-19) attributable to more than 95% of infections. This Delta variant is more contagious than previous variants and consequently was responsible for a substantial wave, with much morbidity. The fact that vaccine effectiveness during a Delta wave has not been widely reported on in large global studies makes Discovery Health’s research even more relevant, on a global basis.”

“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.”

In summary

  1. The Pfizer vaccine is 73% effective in protecting against COVID-19 admission risk 14 days after dose one and 92% effective from 14 days after dose two.
  2. The Pfizer vaccine is 79% effective in protecting against COVID-19 mortality risk from 14 days after dose one and 94% effective from 14 days after dose two.
  3. 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.
  4. Encouragingly, in considering the effect of sex, specific chronic conditions, and province/location, we observe little to no variation in vaccine effectiveness in protecting from COVID-19 admission. There is,however, a 5% to 7% decline in vaccine effectiveness in protecting against admission in people over the age of 80, and in individuals who live with three or more chronic conditions.
  5. Globally, studies are being conducted to establish the durability of the vaccine-mediated immune response, ie how long vaccine effectiveness lasts. To date, Discovery Health’s data shows no waning in vaccine effectiveness in protecting against COVID-19 admission and death, in the three-month data interval following the second dose. We will continue to track this and follow up for longer periods.
  6. Relative to members fully vaccinated with Pfizer-BioNTech, the unvaccinated member population has a five times higher risk of COVID-19 infection; and 20 times the risk of dying from the complications of a COVID-19 infection. Importantly, there have been zero vaccine-related deaths recorded in the Discovery Health administered scheme member population.

To read the full detail on this analysis, please refer to the Discovery Health Insights Hub article on this data set.

2. The powerful, protective effects of COVID-19 vaccination after recovering from COVID-19

To what extent are people who have recovered from COVID-19 and then been vaccinated, protected from future admission to hospital to treat COVID-19?

In some circles, it’s being referred to as “super immunity” – people who have previously recovered from COVID-19 have a stronger immune response following vaccination, than vaccinated people who have never had a prior COVID-19 infection.

“Our examination of super-immunity within Discovery Health-administered medical scheme members reveals the stunning protective effect of piggybacking vaccine-induced immunity onto immunity following a COVID-19 infection,” says Dr Noach.

In summary

  • For people who have both recovered from COVID-19 and are fully vaccinated (Pfizer two-dose vaccine), there is a 98% drop in the risk of COVID-19 admission.

Dr Noach adds: “It is important to mention that whilst immunity following an infection provides some protection from future COVID complications, the risk of reinfection remains. Over the full period of the pandemic, spanning the three waves of COVID-19 in South Africa, more than 11 500 Discovery Health-administered members have experienced reinfections.”

Dr Noach emphasises that being vaccinated is extremely important considering these reinfections and the very high likelihood of exposure to COVID-19 for all of us. “Contracting COVID-19 carries a far higher risk of experiencing complications than getting vaccinated for COVID-19 does. This data clearly reinforces the call for COVID-19 vaccination, even in people who have had a prior COVID-19 infection.”

- To read the full detail on this analysis, please refer to the Discovery Health Insights Hub article on this data set.

    3. Are scheme members more likely to experience adverse events post COVID‑19 vaccination or in dealing with COVID-19?

    “We are encouraged to see that, within the Discovery Health client base, the risk of experiencing any adverse event following vaccination is low. And even more importantly, the risk of a severe adverse event is extremely low - in fact, rare. To reiterate, there have been zero vaccine-related deaths recorded in the Discovery Health administered scheme member population.”

    “Importantly, the absolute risk of a severe adverse event following vaccination for COVID-19 with either the Pfizer or Johnson & Johnson (J&J) COVID-19 vaccine is significantly lower than the risk of complications following infection with COVID-19.”

    To conduct this analysis, a list of 179 clinically relevant conditions was compiled. This list consisted of medical conditions that could potentially follow COVID-19 vaccination and included all conditions that had been mentioned in peer-reviewed, published research and others that are of immune-mediated origin.

    • Mild vaccine-related adverse events such as fever, malaise and local injection-site reactions were excluded from the analysis (which focused specifically on understanding any severe side effects of vaccination).

    In summary

    Three conditions (adverse events) were found to have a statistically significant risk of occurrence following COVID-19 vaccination, though they are extremely rare. They are lymphadenopathy (a benign enlargement of lymph nodes), myositis (inflammation of the muscles presenting as general muscle pain) and paraesthesia (a tingling sensation). “These were fortunately easily treated,” says Dr Noach.

    What is the risk (comparing vaccinated to unvaccinated people) of experiencing these three very rare conditions post vaccination?

    • Lymphadenopathy (a benign enlargement of lymph nodes) occurred in 31 of every 100 000 doses administered (0.031% of vaccinations).
    • Myositis (inflammation of the muscles presenting as general muscle pain) occurred in nine of every 100 000 doses administered (0.009% of vaccinations).
    • Paraesthesia (a tingling sensation) occurred in three of every 100 000 doses administered (0.003% of vaccinations).

    “Our analysis shows that the complications of COVID-19 illness are significantly more common and serious than vaccine-related adverse events. For example, lymphadenopathy, myositis and paraesthesia are all known complications of COVID-19. They also occur with higher excess frequency in people who have COVID-19 than following COVID-19 vaccination,” adds Dr Noach.

    Relative to these rare and manageable adverse events, the complications of COVID-19 are significant and potentially fatal. In terms of absolute risk relating to COVID-19 infection:

    • There is a 40-fold increased risk of pulmonary embolism (40 times higher chance of experiencing pulmonary embolism after a COVID-19 infection)
    • There is a 22-fold increased risk of myocarditis
    • There is a 16-fold increased risk of acute kidney injury.

    - Did the analysis reveal any information around the risks of myocarditis (a commonly cited, rare adverse event linked to Pfizer vaccination)?

    “Whilst myocarditis is important to keep in mind as a potential adverse event following vaccination – particularly in teenage males – 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,” says Dr Noach.

    - To read the full detail on this analysis, please refer to the Discovery Health Insights Hub article on this data set.

    “The risk–benefit consideration of being vaccinated against COVID-19 is undoubtedly strongly in favour of vaccination”

    “We are very encouraged to share our findings that, in the sizeable population under review – just over 1.2 million members of Discovery Health-administered medical schemes – COVID-19 vaccination has proven effective and very safe,” says Dr Noach.

    “Discovery Health’s rigorous analysis spans a sizeable medical scheme member base, representative of all South Africans, and concludes unequivocally that vaccination with the Pfizer COVID-19 vaccine is extremely safe and is highly effective at preventing COVID-19 complications and mortality. The complications of COVID-19 infection are severe and in some cases are fatal. The risk–benefit consideration of being vaccinated against COVID-19 is undoubtedly strongly in favour of vaccination.”

    “The data also reinforce reports of substantial protection from COVID-19 vaccination available to people who recovered from a previous COVID-19 infection.”

    “Furthermore, the complications following COVID-19 infection significantly outweigh the risks of COVID-19 vaccination with either the J&J or Pfizer COVID-19 vaccines.”

    - Visit the new Discovery Health Insights hub: Articles relating to all of the above-mentioned findings have been published on the new Discovery Health Insights hub, on Discovery’s website. This new hub has been created to feature the latest in data analysis and research from Discovery Health’s actuarial team and to shares insights into a wide array of healthcare topics. These insights have the potential to inform and transform our understanding and decision making in navigating the healthcare landscape.


    • Vaccine “efficacy” refers to a vaccine’s protective capacity under tightly controlled (clinical trial) conditions.
    • Vaccine “effectiveness” refers to its real-world protective effects – how a vaccine fares once rolled out to the public – and may differ from efficacy due to real-world factors not present when the trial was carried out.



    Discovery information

    About Discovery

    Discovery Limited is a South African-founded financial services organisation that operates in the healthcare, life assurance, short-term insurance, banking, savings and investment and wellness markets. Since inception in 1992, Discovery has been guided by a clear core purpose – to make people healthier and to enhance and protect their lives. This has manifested in its globally recognised Vitality Shared-Value insurance model, active in over 35 markets with over 20 million members. The model is exported and scaled through the Global Vitality Network, an alliance of some of the largest insurers across key markets including AIA (Asia), Ping An (China), Generali (Europe), Sumitomo (Japan), John Hancock (US), Manulife (Canada) and Vitality Life & Health (UK, wholly owned). Discovery trades on the Johannesburg Securities Exchange as DSY. 

    Follow us on Twitter @Discovery_SA


    Nthabiseng Chapeshamano

    Nthabiseng Chapeshamano

    Press contact Senior Reputation Manager Invest, Cogence, Long & Short Term Insurance, and Sustainability
    Karishma Jivan

    Karishma Jivan

    Press contact Senior Reputation Management Consultant Healthcare & Sustainability