Most people who say they never had it actually do have antibodies against the
virus, showing they had a subacute case. Subgacute means the
virus invaded their bodies and they made antibodies against it, but they never had symptoms.
Once you have Chickenpox the virus lives on forever in the dorsal root ganglia just outside the spinal cord. Sometimes the virus gets activated and travels down a sensory nerve just under the skin and causes the condition known as "Shingles.