Early strains of COVID-19 caused a range of symptoms, many of them serious or unusual — high fever, for instance, or loss of taste and smell. Why has that morphed to relatively minor and commonplace symptoms like a runny nose?
One reason is that most people have developed some level of immune protection against COVID due to prior infection, vaccination, or both, says Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security in Baltimore.
“There is so much immunity in the population now that COVID symptoms have tended to be milder,” he says.
Virus mutations over the past six years may also be a factor. The currently dominant virus type, Omicron, affects the body differently than its predecessors.
“There is some evidence that the Omicron variants are evolutionarily better suited for the upper respiratory tract versus the lower respiratory tract,” Dr. Adalja says.
As a result, current variants are more likely than previous ones to lead to upper respiratory tract issues like a runny nose, sore throat, and cough, rather than problems affecting the lower respiratory tract, like bronchitis and pneumonia.
Read the full article here
