According to the FDA in a safety statement released, it has reviewed 35 reports of seizures among e-cigarettes users, especially teens and young adults. They indicate that there may be connection between vaping and seizures caused by severe nicotine poisoning, which can cause seizures, convulsions, vomiting and even brain injury.
The FDA also wants to be clear...
"We can’t yet say for certain that e-cigarettes are causing these seizures. We’re sharing this early information with the public because as a public health agency, it’s our job to communicate about potential safety concerns associated with the products we regulate that are under scientific investigation by the agency. This also helps encourage the public to voluntarily report additional adverse events that can better inform our work."
Speaking of reporting, they are encouraging anyone who has experienced any ill effects from vaping. To report to the FDA's "Safety Reporting Portal"