“Kung Flu” (kung fu + flu) became a popular term during the 2019–20 coronavirus outbreak (first identified in Wuhan, Hubei, China), but the term is from the 1970s. The 1968 flu pandemic was called the “Hong Kong flu.” Kung fu martial arts movies became popular in the early 1970s, and Kung Fu, an American action-adventure martial arts western drama television series starring David Carradine, ran from October 14, 1972 until April 26, 1975.
 
“He was referring to ‘Five Fingers of Death,’ the fabulously successful karate flick that has generated a film business stampede or, if you prefer a worldwide epidemic of Asian kung-flu” was printed in the Chicago (IL) Tribune on May 13, 1973. “DAVE BARRY, who closed last night as Wayne Newton’s comedy star at the Sands, says he’s fighting a strange Asian virus called ‘Kung flu’—and it’s fighting back!” was printed in the Las Vegas (NV) Review-Journal on November 1, 1973. “The flu epidemic has gotten so bad around these parts that even David Carradine has come down with Kung flu” was printed in Marilyn Beck’s syndicated Hollywood column on January 31, 1074.
 
“What idiot decided to call it coronavirus and not Kung Flu?” was posted on Twitter by Former Deadspin Commenter on January 23, 2020. “kung flu Another name for the Wuhan coronavirus” was entered in the Urban Dictionary on January 25, 2020.
 
         
Wikipedia: 1968 flu pandemic
The Hong Kong Flu (also known as 1968 flu pandemic) was a category 2 flu pandemic whose outbreak in 1968 and 1969 killed an estimated one million people all over the world. It was caused by an H3N2 strain of the influenza A virus, descended from H2N2 through antigenic shift, a genetic process in which genes from multiple subtypes reassorted to form a new virus.
 
The 1968–1969 pandemic
The first record of the outbreak in Hong Kong appeared on 13 July 1968.
 
Wikipedia: 2019-20 coronavirus outbreak
The 2019–20 coronavirus outbreak is an ongoing global outbreak of coronavirus disease 2019 (COVID-19) caused by the SARS coronavirus 2 (SARS-CoV-2). The disease was first identified in Wuhan, Hubei, China on 1 December 2019, spreading to every province-level administrative division of the country by 29 January 2020. On 30 January, the World Health Organization declared the outbreak a Public Health Emergency of International Concern following an increase in the number of cases outside China.
     
Newspapers.com—headline on section cover
Newspapers.com
13 May 1973, Chicago (IL) Tribune, “Click, chop, ring, chop, chop…go the ribs and the register” by Gene Siskel, sec. 6, pg. 4, col. 3:
(Also, a pg. E1 headline for this article: “An epidemic of Asian Kung-flu.”—ed.)
He was referring to “Five Fingers of Death,” the fabulously successful karate flick that has generated a film business stampede or, if you prefer a worldwide epidemic of Asian kung-flu.
   
29 October 1973, San Francisco (CA) Chronicle, Herb Caen column, second sec., pg. 21, col. 1:
Brian Oakes’ name for the new Asiatic virus hitting people so hard: kung flu.
 
1 November 1973, Las Vegas (NV) Review-Journal, “The Duke of Las Vegas” by Forest Duke, pg. 10, col. 1:
DAVE BARRY, who closed last night as Wayne Newton’s comedy star at the Sands, says he’s fighting a strange Asian virus called “Kung flu”—and it’s fighting back!
       
Google Books
Views Letter,
Volume 3, Issue 4
Publications Company
1973
Pg. 19:
The Asiatic virus is with us once again. This season, however, some witty physician calls it, “Kung flu.”
   
Newspapers.com
31 January 1974, The Sun (San Bernardino, CA), Marilyn Beck syndicated Hollywood column, pg. C-18, col. 8:
The flu epidemic has gotten so bad around these parts that even David Carradine has come down with Kung flu.
 
That’s not the truth, not really.
 
Newspapers.com
9 February 1974, Detroit (MI) Free Press, “Crime Rates as Top School Problem” by Bob Talbert, pg. 15-A, col. 3:
THAT NEW type of Asiatic virus that seems to be paralyzing lots of people could well be called “Kung Flu.”
 
Google Books
The World’s Best Sports Riddles and Jokes
By Joseph Rosenbloom
New York, NY: Sterling Publishing Company, Inc.
1988
Pg. 35:
What sickness did Bruce Lee get every winter?
Kung Flu.
   
Google Books
Big Bad Classroom Jokes
By Sandy Ransford
London, UK: Robinson Publishing
1998
Pg. ?:
What’s the most common disease in China?
Kung flu
 
Urban Dictionary
kung-flu
kung-flu:a flu of asian origin, thats so bad, it makes you stay in bed for a couple of days. more deadlier than the bird flu, or the dreaded panda flu
“has anybody seen seth in the past couple of days, last i heard he was dying in bed, because he had a case of the kung-flu
#kung-flu#flu#kung-fu#asian#sick
by arvin santiago December 12, 2005
       
Twitter
Former Deadspin Commenter
@AltDeadspin
What idiot decided to call it coronavirus and not Kung Flu?
11:35 AM · Jan 23, 2020·Twitter for iPhone
 
Twitter 
Anthony Brian Logan (ABL)
@ANTHONYBLOGAN
Somebody said the Wuhan coronavirus should be called the Kung Flu
2:25 PM · Jan 24, 2020·Twitter Web App
 
Urban Dictionary
kung flu
Another name for the Wuhan coronavirus
I’m trying to protect myself and my family from this kung flu.
#flu#virus#kung fu#wuhan#china#coronavirus#health
by WorldHealthOrganizashun January 25, 2020
     
Twitter
Paul Sperry
@paulsperry_
CBP officers are internally referring to the coronavirus as the “Kung Flu” for short
5:37 PM · Jan 29, 2020·Twitter Web App
 
Twitter
The Winegasm
@TheWinegasm
Who called it coronavirus and not kung flu?
12:03 PM · Feb 2, 2020·Twitter for iPhone
 
YouTube
Kellyanne Conway confronted over WH official allegedly using term ‘Kung Flu’: ‘Tell us who it was’
Mar 18, 2020
The Hill
Speaking to a press gaggle, Kellyanne Conway was asked about a White House allegedly using the phrase ‘Kung Flu’ in reference to the Coronavirus, and while condemning the term asked for the name of the person who said it.
     
Business Insider 
Trump brushes off ‘kung-flu’ remark and claims Asian Americans would agree with calling it the ‘Chinese coronavirus’
David Choi Mar 18, 2020, 2:34 PM
. President Donald Trump said he did not believe the term “kung-flu” and other discriminatory phrases would put Asian Americans at risk of xenophobic attacks amid the coronavirus pandemic.
. The disparaging term was privately used by a White House official to CBS News reporter Weijia Jiang, a Chinese American, on Tuesday morning.
 
Daily Beast
Trevor Noah Destroys Trump Admin’s ‘Kung-Flu’ Coronavirus Racism From His Couch
“The Daily Show” was the latest late-night show to start broadcasting remotely. And Trevor Noah did not hold back.
Matt Wilstein
Senior Writer
Updated Mar. 19, 2020 2:07AM ET / Published Mar. 19, 2020 1:56AM ET

(...)
“You know Trump is the only person who could hold a press conference about a pandemic and then turn it into a fight about racism,” Noah said. “Who does that?” He imitated Trump urging Americans to “stay calm,” and then five minutes later saying, “Kung-Flu is a term of respect, ask any Asian!”