[cs702]

If tests indeed have such a high false-positive rate, then all estimates of fatality rate calculated by dividing over the number of individuals identified as "infected" are too low, i.e., by implication the virus is actually deadlier than naively estimated.

EDIT: All else remaining the same. See AnthonyMouse's comment below for important clarifications and corrections.

[AnthonyMouse]

That's assuming a large fraction of the people who have been tested are asymptomatic, otherwise a high false positive rate among asymptomatic people would have minimal effect on the numbers because they aren't being tested to begin with.

Meanwhile you also have the opposite happening for the same reason -- if even a small percentage of asymptomatic people are actually infected but not being tested, a small percentage of "asymptomatic people" (i.e. nearly the entire population) could represent a very large proportion of those infected and cause the fatality rate estimates to be much higher than the true number.

[cs702]

True. I updated my comment.