Eight scientists, including SA Medical Research Council head Prof Glenda Gray, have sent a chilling warning about the toll Covid-19 could take as winter sets in.
The scientists compared the virus with the H1N1 outbreak which infected more than 12,000 South Africans and killed 90 between July and October in 2009.
“The incidence of infections declined significantly during the transition from winter to spring, suggesting that winter, which is the typical season for influenza, may have been conducive to the spread of [H1N1],” they said in an SA Medical Journal editorial on Monday.
“Similarly, the colder temperatures in winter may be conducive to the spread of the Sars-Cov-2 virus [which causes Covid-19], as is the case for seasonal influenza.”
Gray and colleagues — including North West University deputy vice-chancellor Nancy Phaswana-Mafuya and the University of Cape Town’s Olive Shisana — said Covid-19 had displayed “extreme heterogeneity” across the world.
This made it critical that models for its transmission should be drawn up “in the context of rapidly changing individual, social and structural determinants in SA”.
The experience with H1N1, another respiratory pathogen, could inform such models, which were limited by “severely restricted” surveillance data on Covid-19.
The scientists said the initial 100 deaths from H1N1 were in the more affluent population and linked to travel, as they were with Covid-19.
Similarly, both outbreaks were most serious in metropolitan areas and moved quickly to lower socio-economic groups due to the difficulties of social distancing in overcrowded settings, the cost of hygiene products, lack of clean water and sanitation, and food insecurity.
“These extreme socio-economic disparities threaten the survival of vulnerable communities and have serious implications for estimating the potential impact of Covid-19,” said the scientists.
HIV and TB were also associated with disease severity and death during the H1N1 outbreak, and the same was likely to be the case with Covid-19.
This would have serious implications since SA had the highest HIV burden in the world with around 71,000 Aids deaths annually, and 63,000 TB deaths.
There were two main risks of the combination of Covid-19 and HIV or TB, the scientists said. The first was that the disease would be more severe in such patients, and the second was that HIV and TB prevention and treatment programmes would be disrupted by the health-care system’s preoccupation with Covid-19.
Integrating these factors into mathematical models was “critical in informing contextually appropriate public health interventions, potential emergency and hospital-care resources, policy and governance”.