Having failed to find a match in their local community, the family took their search across the US and even into Israel, France and Mexico.
Mr Krief's wife, Leah, explained: "On that first day at our synagogue, we got about 600 people registered. Things just catapulted from there.
"Adam's cousins abroad started mobilising an international drive. In Israel, 2,000 people have been swabbed and the government has agreed to a national campaign on September 28. The last time they did something on this scale, 16,000 people registered on a single day."
The movement has also gained celebrity backing, with comedian Ellen DeGeneres, retired basketball player Shaquille O'Neal and model Kendall Jenner tweeting their support.
