Johannesburg - In the future, the Covid-19 virus may end up losing its bite, causing just mild flu-like symptoms in those it infects, a new model has suggested.
However all will depend on the virus circulating in the general population, and exposure in childhood.
The model was developed by scientists from the Emory and Pennsylvania State universities, in the US, and drew on studies of four common cold corona viruses and SARS-CoV-1, which is better known as the SARS virus.
Their findings were published in the latest issue of Science.
By examining these five viruses, the model predicts that the infection fatality ratio for the Covid 19 virus may eventually fall below that of seasonal influenza, which is about 0,1%. In South Africa, the fatality ratio of known coronavirus infections stands at 2,7%.
“We are in uncharted territory, but a key take-home message from the study is that immunological indicators suggest that fatality rates and the critical need for broad-scale vaccination may wane in the near term, so maximum effort should be on weathering this virgin pandemic en route to endemicity," said Ottar Bjornstad, Distinguished Professor of Entomology and Biology at Penn State, in a statement.
The researchers explained that natural infection in childhood does provide immunity that protects them later in life against severe disease. However, this does not prevent periodic reinfection.
"Reinfection is possible within one year, but even if it occurs, symptoms are mild and the virus is cleared from the body more quickly," explained Jennie Lavine, another author on the paper.
“It highlights the need to tease apart the components of immunity to SARS-CoV-2. How long does immunity that prevents pathology last, and how long does immunity that prevents transmission last? Those durations may be very different.”
She further explained that studies were emerging that are providing data on how long antibodies and immune cells, formed to fight Covid 19, last after an infection.
The problem though is that researchers are still in the process of figuring out how all this translates into protecting against the disease or transmission.
“Overall, we're asking: how does SARS-CoV-2 (Covid 19) compare to other viruses such as seasonal influenza or respiratory syncytial virus,” she said. “This model assumes immunity to SARS-CoV-2 works similar to other human coronaviruses. We don't really know what it would be like if someone got one of the other coronaviruses for the first time as an adult, rather than as a child.”
But for Covid-19 to lose its teeth, it will have to become endemic, meaning that it is circulating in the general population.
Vaccines could save hundreds of thousands of lives in the first year or two of the pandemic, but continued mass vaccinations may be less critical, once Covid 19 becomes endemic, the authors said.
Saturday Star