Possibly some of them, but reinfection of dengue fever can cause hemorrhagic symptoms and this has been around for a long time. It wasn't even called Dengue until some time in the early to mid 19th century, well before vaccination existed. It is possible that testing the mechanism of dengue with gain of function could have created the Marburg, Ebola and other more modern versions of hemorrhagic fever. The majority of these types of illnesses are actually quite recent. I think Marburg was the first in the mid to late 1960's. At this point, nothing is impossible.