Low risk of severe complications following Covid vaccination, says Discovery Health

Three studies by Discovery Health actuaries have concluded that the benefits of being vaccinated against Covid-19 “undoubtedly” outweigh the risks.

The research was based on data from members of medical schemes administered by Discovery Health. It addresses the following three questions:

1. How effective is the Pfizer vaccine at protecting against hospital admission and death?
2. Do people who are fully (Pfizer) vaccinated after recovering from a Covid-19 infection benefit from added protection?
3. How does the risk of complications from Covid-19 compare to the risk of complications following vaccination?

“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. 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,” Discovery Health chief executive Dr Ryan Noach said.

“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. How effective is the Pfizer vaccine at protecting against Covid-19 hospital admission and death?

Discovery Health’s actuaries concluded:

• Unvaccinated members have a five times higher risk of Covid-19 infection relative to fully vaccinated members, and they are at 20 times the risk of dying from the complications of a Covid-19 infection.
• No vaccine-related deaths have been recorded among members of schemes administered by Discovery Health.
• The vaccine is 73% effective at protecting against the risk of being admitted to hospital 14 days after dose one and 92% effective from 14 days after dose two.
• The vaccine is 79% effective at protecting against the risk of Covid-19 mortality from 14 days after dose one and 94% effective from 14 days after dose two.
• 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.
• There is little to no variation in vaccine effectiveness in protecting against hospital admission when considering the effect of sex, specific chronic conditions, and province/location.
• There is a 5% to 7% decline in vaccine effectiveness in protecting against admission in people over the age of 80 and in individuals with three or more chronic conditions.
• Three is no waning in vaccine effectiveness in protecting against Covid-19 admission and death in the three-month data interval following the second dose.

“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,” said Dr Noach.

You can read the full details of Discovery’s analysis here.

2. Do people who are fully vaccinated after recovering from Covid-19 benefit from added protection?

Discovery’s actuaries found that scheme members who have both recovered from Covid-19 and are fully (Pfizer) vaccinated have a 98% lower risk of being admitted to hospital with Covid-19, compared with 85% for those who have recovered from Covid-19 but are not fully vaccinated.

You can read the full details of Discovery’s analysis here.

3. How does the risk of complications from Covid-19 compare to the risk of complications following vaccination?

The absolute risk of a severe health condition following vaccination with either the Pfizer or the Johnson & Johnson vaccine is significantly lower than the risk of complications following infection with Covid, according to Discovery Health.

Discovery’s actuaries compiled a list of 179 medical conditions that could potentially follow Covid-19 vaccination and included all the conditions that have been mentioned in peer-reviewed, published research and others that are of immune-mediated origin. The analysis excluded vaccine-related events such as fever, malaise and local injection-site reactions.

Discovery found that three conditions have a significant risk of occurring following Covid-19 vaccination, although they are extremely rare.

They are lymphadenopathy (a benign enlargement of the lymph nodes), myositis (inflammation of the muscles presenting as general muscle pain) and paraesthesia (a tingling sensation). “These were fortunately easily treated,” said Dr Noach.

Discovery said the risk (comparing vaccinated to unvaccinated people) of experiencing these three conditions after vaccination was:

• Lymphadenopathy occurred in 31 of every 100 000 doses administered (0.031% of vaccinations).
• Myositis occurred in nine of every 100 000 doses administered (0.009%).
• Paraesthesia occurred in three of every 100 000 doses administered (0.003%).

“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,” said Dr Noach.

Discovery said that relative to these rare and manageable conditions, the complications following 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 after a Covid-19 infection;
• There is a 22-fold increased risk of myocarditis; and
• There is a 16-fold increased risk of acute kidney injury.

Myocarditis (inflammation of the heart muscle) is a commonly cited, although rare, side-effect linked to Pfizer vaccination, particularly in male teenagers.

Dr Noach said myocarditis did not show up as statistically relevant across the 1 207 760 vaccinated Discovery Health scheme members included in the 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.”

You can read the full details of Discovery’s analysis here.