Firdose Moonda is ESPNcricinfo's South Africa correspondent
This is the first instance of the Covid substitution protocol being used in international cricket after Covid replacement incidents in the Plunket Shield and County Championship. It is just the second instance of two substitutes for a team in the same match in international cricket - Bangladesh had two concussion subs against India in 2019.
It wasn't all unexpected. The series is being played in a managed environment rather than a bio-bubble, which means that players are not limited to their hotel rooms and are allowed to go out - with the advice being that they should stick to open-air restaurants and the outdoors - as well as mingle with other people.
"This is an unfortunate situation, but not unexpected after the decision was made to have this tour under the Managed Event Environment (MEE) protocol, rather than the strict Bio-safe Environment (BSE) Protocol as was previously the case," Dr Shuaib Manjra, CSA's chief medical officer said. "This is in line with the country's policy in revoking the Disaster Management Act with reference to the pandemic, as well the huge mental strain that a bubble environment induces."
South Africa is no longer under any form of lockdown, with all restrictions apart from mask-wearing in indoor spaces and limitations on the number of people at gatherings, lifted.
This is the third instance of the series being affected by Covid-19. As reported by ESPNcricinfo, Bangladesh's coach Russell Domingo has not been able to attend the Test after contracting Covid-19 last week while South Africa's bowling coach Charl Langeveldt and security officer Zunaid Wadee are also not at the match after testing positive on Friday.