Prof Salim Abdool Karim Weekly COVID-19 UPDATES

3 April 2023

Great to be back in South Africa though a challenge coming back to a huge backlog. Japan and Singapore were amazing. 

As I previously said I would, I have now moved the weekly Covid-19 update slides to the back of email. So, today’s missive starts with polio.

If I mentioned “iron lung machine”, I wonder how many of you would know what I am talking about? For those of my generation, you may remember these metal tubular machines that were used to help patients with polio to breathe. Polio was a devastating disease, with drawings by the Egyptians showing people with polio as far back as 1500 BC. President Roosevelt had polio – it was his personal struggle with polio that led to the creation of the National Foundation for Infantile Paralysis, better known as March of Dimes. 

For those not familiar with the “March of Dimes”, its name comes from primary fundraising campaign to collect a dime (10 cents) from each family in the USA to fight polio. It was a pun on the newsreel of that time called, “The March of Time”. March of dimes undertook polio vaccine research and scale up, leading to the elimination of polio in the U.S. in 1994. 

In 1985, Rotary International launched a global effort to immunize the world’s children against polio and in 1988 the Global Polio Eradication Initiative was established as a partnership between WHO, Rotary, US CDC, UNICEF, GAVI and Gates Foundation. Its goal is to eradicate polio worldwide. 

Note that 2 of the 3 types of poliovirus have been completely eradicated – only Type 1 poliovirus continues in circulation. Unfortunately, this polio virus continues to be transmitted in 2 countries – Afghanistan and Pakistan (see the diagram on the left in Figure 1).

In the early 1990s, the South African government established a Polio Expert Committee tasked with undertaking the monitoring to enable the country to be declared polio free. Professor Barry Schoub, Director of the country’s National Institute of Virology was the first chair of this committee. I succeeded him as the next chair of this committee. It was a huge effort – each case of clinical paralysis had to be investigated and a determination made as to whether it was likely to be due to polio, be a case of vaccine associated paralytic polio (VAPP) or some other unrelated cause, mostly Guillian-Barre syndrome. The last case of polio in South Africa was in 1989 and the country and Africa was declared polio free in 2006.

However, Africa is now dealing with a resurgence of polio, principally due to vaccine-strains. VAPP, as we used to call it, was part of the surveillance for polio eradication certification. It can be a severe illness and continues to occur in Africa (see the diagram on the right in Figure 1). 


This situation demands some changes to our overall polio eradication strategy. Some of the changes needed were captured in the NEJM editorial in Figure 2. A key element is the switch from oral polio vaccine to the injectable vaccine to avoid replication in the gut that leads to viral shedding, that is readily picked up in sewer virus surveillance.  

Regarding the global Covid-19 situation (Figure 3), there were 76,409 (3 weeks ago it was 127,571) reported Covid-19 cases and 606 deaths across the world last Friday. The overall 7-day average number of cases and deaths has continued to drop from the week before. 

In South Africa, the trends in reported cases show no significant changes, under-reporting notwithstanding (Figure 4). The daily number of reported cases remained low overall. 

XBB.1.5 continues its unchallenged dominance, accounting for most of the viruses sequenced in South Africa last week. Figure 5, which comes from the National Genomic Surveillance group, shows quite strikingly how fast XBB.1.5 became dominant in this coverage – look at how quickly the pink comes to dominate. 


Have a great week.


Salim S. Abdool Karim, FRS
Director: CAPRISA
CAPRISA Professor of Global Health: Columbia University