I think it is a joke.

US noses out China in math meet:

https://www.chinadaily.com.cn/world/2015-07/27/content_21418690.htm

"Team USA won the first place at this year's International Mathematical Olympiad (IMO) held in Chiang Mai, Thailand, reclaiming the crown after 21 years."

There is no 30-year winless span for the USA in this list:

https://en.wikipedia.org/wiki/International_Mathematical_Olympiad

Team members for 2015:

https://www.imo-official.org/team_r.aspx?code=USA&year=2015

Edit: Yes, I did laugh.

Another news report . . .

https://www.maa.org/news/us-team-takes-first-place-at-international-mathematical-olympiad