A video of Gertrude -- she didn't give her last name -- has gone viral with more than 3 million views since it was posted online last Friday, a little more than a week ahead of the December 4 re-run vote.
"It's probably my last election," said the retiree from Vienna.
"There's not much future for me. But the young have all their lives ahead of them and it's up to them to see that they continue to do well. They can only do that if they vote wisely."
The left-leaning Alexander Van der Bellen, an independent candidate backed by the Green Party, posted the video on Facebook
at Gertrude's request. He is challenging Norbert Hofer of the far-right Freedom Party
in the election.
At the age of 16, Gertrude, her parents and two younger brothers were deported to Auschwitz, the German Nazi concentration camp in occupied Poland. Estimates vary, but about one million Jews are believed to have been executed at Auschwitz.
According to the video, Gertrude -- who says she is not religious -- was the only member of the family to survive.
'Shiver ran down my spine'
Gertrude says she is disturbed by the anti-migrant sentiment -- "the insult towards others. The denigration. The badmouthing" -- that she has heard during the campaign by the Freedom Party.
She reminds viewers of a comment made in October by the leader of the Freedom Party, Heinz-Christian Strache, who warned of possible civil war if the influx of migrants to the EU is not stopped.
"When Strache used the word 'civil war,' a cold shiver ran down my spine and I thought that shouldn't even be mentioned, not even be thought of," she says.
"I experienced a civil war as a seven-year-old and I've never forgotten it. It was the first time I saw dead bodies. Regrettably not the last.
"I've never forgotten it. It buried itself so deep in me that I'm still aware of it."