No, flurona is not some scary new variant of the coronavirus. And — do we really need to say this? — it is not an actual scientific term.
But the phenomenon of “coinfection” with influenza and the coronavirus is real and, to those in the medical community, not the least bit surprising. A person can be infected with multiple viruses at the same time — or with a virus and some other type of pathogen, such as bacteria or parasites.
So far in the pandemic, these coinfections seem to have been fairly uncommon — especially last winter, when the rate of flu cases was unusually low (a trend that experts attributed to all the social distancing). But with flu on the rise again this winter, physicians say that’s all the more reason to engage in sensible precautions. Both viruses are transmitted through the air, so with both, the risk can be reduced by avoiding crowded, poorly ventilated spaces and by wearing masks.
And in both cases, there are effective vaccines. As in most years, this season’s flu shot is not a perfect match for the strains in circulation, but that’s no reason not to get an injection, says Thomas Fekete, a professor at Temple University’s Katz School of Medicine. Every layer of defense helps the individual, as well as those who may be more vulnerable.
“Whatever you do to reduce your risk,” he said, “you’re also protecting people around you.”
Though infections with more than one virus are common, the details of how the immune system responds are complicated, depending on such factors as timing and the types of viruses.
For a crash course, we spoke to Sara Cherry, a professor of pathology and laboratory medicine at the University of Pennsylvania Perelman School of Medicine.
How can you be infected with two viruses?
The same way you can be infected with just one virus: exposure.
If a person is in a place where viruses are circulating — that is, in any place where other people are present — then two or more viruses can cause infection at the same time.
Ideally, someone who feels sick is able to stay home, reducing the risk of becoming infected with a second virus. But viruses have incubation periods, multiplying for a day or more inside the body before the person starts to feel sick. So it is easy for someone to pick up more than one bug before feeling sick enough to retreat to the bedroom, Cherry said.
COVID in particular has a long presymptomatic period, up to four days, though the omicron variant of the virus seems to come on faster. If you’re out in a lot in crowds, a double whammy with flu is certainly possible.
“If you’re out doing things without a mask, then you’re more likely probably to get both,” she said.
These respiratory viruses commonly enter through the nasal passages. Often, they are trapped safely in mucus, which is then swallowed and dissolved harmlessly in the stomach. But when they manage to latch on to cells in the airways, the viruses penetrate the cell membrane, hijack its inner machinery, and begin to copy themselves — the definition of an infection.
Flu viruses latch onto substances on the cell surface called sialic acids. The coronavirus, on the other hand, latches onto a “receptor” called ACE-2. Though they may be infecting cells in the same part of the body, neither is likely to fully crowd out the other, Cherry said. Generally, there is plenty of real estate to go around.