Interactions of viruses
Another thing that may be driving the different behavior of viruses is that the SARS-CoV-2 virus could somehow be interacting with other respiratory viruses, Dr. Schaffner says. “And if so, what sort of interactions?”
Many researchers are looking into that, and how coinfections with other respiratory diseases, including the common cold and flu, may affect the course of COVID-19. Some studies have found that the T cells – a source of deeper, cellular immunity in people – generated after a common cold “may also provide cross-protection in some people against COVID-19.”
But another study found immunity against common cold–causing coronaviruses might make COVID-19 more severe.
When researchers in the United Kingdom studied nearly 7,000 patients infected with COVID-19, including 583 also infected with RSV, flu, or adenoviruses (causing flulike or coldlike illness), those with flu or adenovirus, compared with the others, were at higher risk of death.
To be continued …
Exactly how COVID-19 will be changing what we know of other viruses is yet to be determined, too.
Even before the pandemic, Dr. Martinello says, there were already some shifts in RSV. Florida, for instance, has an RSV season longer than the rest of the country, mimicking the pattern in the tropics.
Will the atypical patterns continue? “My guess is that this will settle out,” he says, with some sort of pattern developing. At this point, there are many unknowns. “We still can’t answer whether there will be some seasonality to COVID.”
A version of this article first appeared on WebMD.com.