Strength in small doses

The radically life-altering wonder of vaccines

April 09, 2025

It is the United Nations’ World Health Day this week. In fact, it was celebrated on Monday (9th of April).  We’ve been looking for an excuse to write about a health topic for a while now and here it is 😊. 

Since 1974, vaccines are estimated to have prevented the deaths of 154 million people—146 million of them children under the age of five[1] . Over the past 50 years, the World Health Organization’s Expanded Programme on Immunization (EPI) is estimated to be the single most impactful initiative for improving infant survival during the last 50 years[2] .

Spotlight

In a time where there is great skepticism about the protective abilities of childhood vaccines, we thought to spotlight the journey that the polio childhood vaccine has followed globally, but also in South Africa since the 1950s.

What does polio do to the body? Polio (poliomyelitis) is a viral disease caused by the poliovirus that primarily affects the nervous system - especially the spinal cord - and can lead to muscle weakness, paralysis, and in severe cases, death. The majority of people will experience no symptoms or mild viral symptoms (fever, headache, fatigue, sore throat, fatigue, upset stomach or nausea). In about one in 200 cases, the virus would leave the digestive system and enter the nervous system where it then attacks motor neurons in the spinal cord or brain, causing paralysis.

It was the latter, more extreme cases that caused children to be paralysed and could severely affect even breathing, requiring support from the “iron lung” (more on this later).

The childhood polio vaccine evolution

We created a timeline infographic tracing the evolution of the childhood polio vaccine, drawing on a range of data sources to highlight key milestones in its development and rollout - locally in South Africa, across Africa, and around the world. Although the first polio vaccines were developed in 1954, the disease continued to spread due to challenges in widespread distribution. In 1974, South Africa recorded 168,000 cases. By 2020, however, the African continent was declared polio-free, following at least four consecutive years without a single reported case.

Showcase

Unintended (positive) side effects of vaccines

Some vaccines may have broader immune responses that result in important, yet positive side effects. A groundbreaking study published last week[3] provides evidence that the vaccine originally developed to reduce the occurrence of shingles (herpes zoster virus), may also have a dementia-preventing or dementia-delaying effect.

It was found that the zoster vaccine reduced the probability of a new dementia diagnosis by approximately one-fifth (20%) over a seven-year follow-up period. These effects on dementia were found to differ between women and men, with women benefitting more than men. 

With significant effects and relatively low production costs, the (live-attenuated) zoster vaccine may provide a much more cost-effective solution to preventing or delaying dementia than existing pharmaceutical interventions.

While Africa has had a young population for many years, the burden of dementia is now rising on the continent and additional strains on dementia care are developing. The cost of dementia for Sub-Saharan Africa was estimated as USD 6.2 billion in 2015, of which 70% was attributable to the cost of informal care provided by relatives and families of those living with dementia[4]. The continent needs alternative solutions and to take advantage of global advancements in preventive, therapeutic and rehabilitative care of the condition[5]. Can the zoster vaccine offer such a cost-effective solution?

  1. Data visualisaton: While we were writing this newsletter, Nature published 5 charts showing “the power of vaccines”. Have a look at some of these images here (others are behind a journal paywall).

  2. Art and storytelling: The value of vaccines—especially childhood vaccines—has been powerfully portrayed through visual art over the years. Few images capture the terror of childhood polio as vividly as photographs of the “iron lung,” a so-called negative pressure respirator that helped children with polio breathe. GAVI’s Vaccines Work site has chronicled, detailing its widespread use in the 1950s and its crucial role in supporting children (and some young adults) who struggled with respiratory failure due to polio.

  3. Music: To end this newsletter on a highlight, for some 80’s moving-the-body inspiration, have a look at Bonnie Tyler singing Holding Out for a Hero.

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