When it wasn't just the fly on Mike Pence's head during the Vice Presidential debate on Wednesday night, it was his pink eye that caught the viewer's attention.
Pink eye, or conjunctivitis is fairly common: It's an irritation or inflammation of the conjunctiva, which covers the white part of the eyeball. It can be caused by allergies or a bacterial or viral infection.
So while people watching the debate alleged that Pence's pink eye could be a sign of Covid-19, which is a viral infection, and has affected US President Donald Trump as well as several aides in the White House.
Could Pence too, perhaps, then be showing a rare symptom of the virus?
While not a lot is known about how Covid-19 affects our eyes, studies have found that the overall rate of conjunctivitis was 1.1% in severe cases of Covid-19, and up to 3% of people with COVID-19 develop ophthalmological symptoms (symptoms which affect the eye).
In August, two JAMA Ophthalmology studies detailed cases of conjunctivitis in hospitalized children and adults with COVID-19 in Wuhan, China, one of them finding that nearly a quarter of pediatric patients had this condition.
Another study, published in the British Journal of Ophthalmology that looked at one person with COVID-19 found that eye symptoms occurred in the middle stages of infection.
The other associated and more common symptoms of virus, which are cough, cold and fever were probably not visible on Pence, if he at all, has the virus.
Pence and Kamala Harris debated separated by a plexiglass, one which experts have said isn't enough to stop the virus.
Neither of them had tested positive for the coronavirus before the debate,according to the latest information -- but that doesn't exclude the possibility they were infected after their last test or even before that, since the virus isn't always picked up before it's risen to a high enough level.
SARS-CoV-2 isn't as contagious as some other pathogens over long distances, such as the measles virus, but it can spread this way in the right circumstances, like prolonged time in an enclosed space.
Experts had also come to the conclusion that the safest option would be for all participants to remain masked.