If South Africa does not pursue a rapid vaccination programme to achieve herd immunity, it may face a third wave as a consequence, warned a leading local expert.
Professor Marc Mendelson of UCT’s Division of Infectious Diseases and HIV Medicine at Groote Schuur Hospital made these statements while speaking during a virtual Summer School lecture on Saturday, titled “COVID-19 Insights and Lessons”.
“Without rapid vaccination of at least two thirds of the population, we [South Africa] are not going to get to population immunity, and without that, we will see another wave,” Mendelson warned.
However, he emphasised that much had been accomplished in the battle against COVID. “It is associated with a scientific endeavour that we have never seen before. We’re definitely better off a year down the line, but there are a huge number of things that we need to answer. As a country we still face deep problems with severe issues around vaccine strategy, and we haven’t even talked about vaccine denial,” he said.
Criticism has been directed at the South African government because of its failure to start a vaccination programme, despite its huge case load and status as Africa’s most wealthy nation. A leaked phone call from a Pfizer executive has only added to this, as it was revealed that for months SA health officials had not been responding to requests for vaccine discussions.
Regarding COVID transmission, he said that the virus resided in the upper respiratory tract as well as the lungs, and that it could be expelled in aerosol droplets. The clinical and epidemiological evidence suggested that larger, heavier droplets carried the virus.
“The household infection rates were high. A very large number of cases, the vast majority [in fact], were within families in close proximity [to one another]. This, epidemiologically, suggests that large droplets play a role in transmission.
“If you want to reduce transmission from large droplets, then you need to increase the distance you are from someone. Also, because droplets drop onto surfaces … you will need to clean surfaces and wash your hands well. This is the science behind the use of masks, handwashing, social distancing and ventilation.”
However, he added that a number of studies had found the virus in remote corners of hospitals at a distance from patients, suggesting that it had been carried there by smaller, aerosolised particles.
“If you want to reduce aerosols, one way of doing that is to improve ventilation. The more the air is changed, the [quicker] it will dilute small droplets,” he said.
Source: University of Cape Town
