THE MASK SLIPS
What never worked against Covid, and what is still worth doing
● Non-pharmaceutical interventions (NPIs) have left a footprint on our daily lives that will stand us in good stead. But if you think they’re still preventing the spread of Covid, think again.
Taking temperatures at venue doors is described as “a complete waste of time, and always has been”, and sanitising may prevent other diseases but isn’t doing much against Covid.
Masks still have their place — when worn correctly — and social distancing hasn’t been that possible in SA.
In sum, “with Covid-19 transmission at a low point now, NPIs need no longer be mandated”, Sheetal Silal, the director of the Modelling and Simulation Hub Africa at the University of Cape Town, told the Sunday Times this week.
“Most of these NPIs had some value in reducing Covid transmission when implemented correctly,” she said, though this was often not the case with temperature readings.
Because airborne transmission is far greater than surface transmission, the effectiveness of sanitising for controlling the virus that causes Covid was “reduced”, but it has “benefits for other disease prevention — especially in the absence of running water”, Silal said.
“Reasonable measures at this stage would include public communication that encourages good, voluntary hygiene practices such as handwashing for all, and wearing masks and socially distancing for those with symptoms of any airborne infectious disease, including ’flu and colds caused by other coronaviruses.”
Health minister Joe Phaahla hinted on Friday that the requirement to wear masks outdoors will be dropped when the national coronavirus command council meets next week, as will travellers entering SA being required to present a negative test result.
Phaahla said the health department was ready to manage Covid after the state of disaster is lifted, and Stellenbosch University virologist Wolfgang Preiser said he hopes the rules will still require masks indoors and in crowded outdoor settings.
For example, being maskless at an openair theatre is fine if you’re sitting on the lawn, but when you use the bathrooms or fetch food, a mask should be worn.
Preiser said sanitising has only a “minor role” in preventing the spread of Covid, but it has led to “an improved level of general hygiene — for example in the case of regular wiping of trolley handles, which is likely beneficial for other reasons”.
Hand-spraying, however, is “probably quite useless”, and the least efficient measure of all is taking temperatures. Its only possible benefit is to “increase awareness about Covid rather than screening out infectious people”.
Social distancing might be useful “in critical areas like public transport” but it is already not implemented nor enforced, said Preiser, adding that he “would not want to be in a very crowded indoor space even now” but there is a negative economic implication if limitations on occupancy continue.
According to Gesine Meyer-Rath, associate professor of health economics at Boston and Wits universities, it is important that NPIs can be reintroduced at short notice.
“Since none of us knows what future SARS CoV-2 variants might look like, and the virus has surprised us a number of times, it would be important to now work on a mechanism to switch restrictions back on in case there is a signal for a new variant causing sufficient levels of severe disease,” she said.
“Both the signal and the level of disease severity that would define it would need to be agreed on by the government.”
Shabir Madhi, dean of health at Wits University and a professor of vaccinology, said NPIs were “particularly useful when we were trying to limit the rate of infections in the context of very limited immunity against the severe sequelae of Covid-19, including death”.
But many of them were conceptualised and advocated “before we had a full understanding of the major mechanism of transmission of the virus”.
We now know it is airborne and is not primarily spread through direct droplets from person to person or contaminated surfaces.
“Consequently, whereas some of the NPIs could be useful to prevent other diseases, they have little value in preventing Covid,” Madhi said.
Implementation and adherence had been poor in any event, as evidenced by 85% of the population having been infected, so it was “highly questionable” whether regulations on NPIs achieved much.
Sanitising should become a “permanent fixture” because it protects against enteric diseases — those related to the intestines.
Taking temperatures at venue doors “is a complete waste of time” and always has been, while “social distancing has very limited use unless in the case of a symptomatic infected person”.
Most of these NPIs had some value in reducing Covid transmission when implemented correctly
Sheetal Silal
Taking temperatures at venue doors “is a complete waste of time” and always has been, while “social distancing has very limited use unless in the case of a symptomatic infected person”
Shabir Madhi
As for limiting capacity indoors, Madhi said “there is a possible case to be made” when transmission is high, but it should not be routine.
“We have extensive population protection against infection [from past infection and vaccines], and it would be foolish to still believe that we are trying to prevent infections,” he said.
Measures are needed to protect high-risk groups when there is heightened intensity of virus transmission, and these include “ensuring they and others are adequately vaccinated”. — Additional reporting by Amanda Khoza