Two doses of the Pfizer vaccine reduced the risk of being hospitalised or dying from Covid-19 In South Africa by more than 90% compared to those who have not received the jab. This is one of the main findings of an analysis by Discovery Health in conjunction with researchers from the South African Medical Research Council. It included the data of 1.2 million adult medical scheme members that were vaccinated from the start of the vaccine rollout in May this year to 23 September.

The findings of the ongoing analysis of the trajectory of the COVID-19 pandemic and real-world effectiveness of COVID‑19 vaccines were shared during a webinar hosted by Discovery Health. It corroborated the findings of a study published in The Lancet last month and aimed to answer three questions:

1. What is the real-world effectiveness of the Pfizer-BioNtech (Pfizer) COVID-19 vaccine in protecting against Covid-19-related hospitalisation and death in South Africa and does the 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 and how does the risk of complications from COVID-19 stack up against the risk of adverse events from COVID-19 vaccination?

“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,” says Discovery Health CEO, Dr Ryan Noach.

Within Discovery’s scheme membership, 60% of all adults and almost 80% of those over the age of 60 have received at least one Covid-19 dose.

The Pfizer vaccine’s effectiveness in protecting against COVID-19 admission and mortality was determined by analysing 526 516 pathology test results, 14 673 COVID-19 admissions and 3 441 COVID‑19 deaths from the start of the rollout in May to 23 September.

“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 attributable to more than 95% of infections. 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,” said Dr Noah.

Protection against severe disease and death

The research found that following each dose of the two-dose Pfizer vaccine, there is significant protection against both serious COVID-19 illness and death, 14 days after receiving the second dose with the vaccine being 73% effective in protecting against hospital admission risk 14 days after dose one and 92% effective from 14 days after the second dose. It was also shown to be 79% effective in protecting against COVID-19-related death from 14 days after the first dose and 94% effective from 14 days after dose two.

Encouragingly, in considering the effect of sex, specific chronic conditions, and province/location, little to no variation in vaccine effectiveness in protecting from COVID-19 admission was found. However, there was 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.

“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,” noted Dr Noach.

“Compared to fully vaccinated members, 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,” he added.

Effectiveness of vaccine after infection

Looking at the protective effects of the vaccination in people who have recovered from COVID-19, the research showed that these individuals have a stronger immune response following vaccination, than vaccinated people who have never had a prior COVID-19 infection with a 98% drop in the risk of admission following re-infection in these individuals.  Over the full period of the pandemic, spanning the three waves in South Africa, more than 11 500 Discovery Health members have experienced reinfections

“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,” Dr Noach stressed.

Adverse effects after vaccination

No vaccine-related deaths occurred in the Discovery membership population and the absolute risk of a severe adverse event following vaccination with either the Pfizer or Johnson & Johnson vaccine was 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.

Three adverse events were found to have a statistically significant risk of occurrence following vaccination, though they are extremely rare. They are lymphadenopathy, myositis and paraesthesia. Lymphadenopathy occurred in 31 of every 100 000 doses administered (0.031% of vaccinations), myositis in nine of every 100 000 doses administered (0.009% of vaccinations) and 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. They also occur with higher excess frequency in people who have COVID-19 than following COVID-19 vaccination,” adds Dr Noach.

Referring to the risks of myocarditis, which is a commonly cited, rare adverse event linked to Pfizer vaccination, particularly in teenage males, Dr Noach said this complication did not show up as statistically relevant in the analysis.

“The risk–benefit consideration of being vaccinated against COVID-19 is undoubtedly strongly in favour of vaccination. The analysis spans a sizeable medical scheme member base, representative of all South Africans, and shows 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,” Dr Noach observed.