Gaskins later deleted the photo and issued an apology.
"In NO WAY did I intend to trivialise the Star of David or disrespect what happened to millions of people. That is not who I am & what I stand for," Gaskins wrote. "My intent was not to exploit or make a profit. My hope was to share my genuine concern & fear, and to do all that I can to make sure that nothing like that ever happens again. I sincerely apologise for any insensitivity."
The photo was shared widely on social media with the hashtag "hateworks" and prompted hat maker Stetson to announce that it was pulling its products from the store. Hat maker Goorin Bros of San Francisco said on Instagram that it was "horrified" by the patch.
"To make a mockery of the Holocaust in any form is unacceptable and completely insensitive," owner and company president Ben Goorin said. "We are looking at all options to fix and address this unfortunate circumstance."
The photo also prompted small protests outside the shop on Saturday. One sign at a protest read: "The Holocaust is not a marketing op."
Ivo H Daalder, the US ambassador to Nato from 2009 to 2013, denounced the photo on Twitter.
"As a young school girl in Holland, my mother was forced to wear a yellow star by the Nazis to identify her as a Jew," Daalder wrote. "It's beyond grotesque to sell this evil symbol to proclaim one's not vaccinated. Where does this end?"
- Associated Press