The use of anti-Asian hashtags skyrocketed on Twitter last year in the days after then-President Donald Trump used the term “Chinese virus” for the first time in a tweet, a study found.

The study was conducted by researchers at the University of California San Francisco and published Thursday in the American Journal of Public Health.

The researchers analyzed nearly 700,000 tweets containing nearly 1.3 million hashtags from the week before Trump’s tweet and the week after. They compared the hashtags "#covid19" and "#chinesevirus" to see what sort of other hashtags accompanied them.

The study found that more than half the tweets (50.4%) that included the "#chinesevirus" hashtag also included hashtags that were hostile toward Asians; demonstrated fear, mistrust or hatred toward them; supported restrictions on Asian immigration; used derogatory language or condoned punishments toward Asian countries or their people. About a fifth of tweets that used "#covid19" were accompanied with such hashtags.

The volume of both hashtags climbed sharply after the Trump tweet, the study found. But the number of anti-Asian hashtags soared by 17,400% when paired with "#chinesevirus" as compared to 797% with "#covid19."

“These results may be a proxy of growth in anti-Asian sentiment that was not as prevalent as before,” said Yulin Hswen, an assistant professor of epidemiology and biostatistics at UCSF and one of the authors of the study. “Using racial terms associated with a disease can result in the perpetuation of further stigmatization of racial groups.”

The researchers said they focused on hashtags rather than the full content of a tweet "because previous research indicates that hashtags are related to the formation of hate groups and hate crimes and because hashtags can be predictive of behaviors."

Since 2015, the World Health Organization has cautioned against using locations or ethnicity when describing diseases because they can "provoke a backlash against members of particular religious or ethnic communities." The global public health agency recommended in February 2020 that people refer to the disease caused by the novel coronavirus as "COVID-19."

However, on March 16, 2020, Trump tweeted: "The United States will be powerfully supporting those industries, like Airlines and others, that are particularly affected by the Chinese Virus. We will be stronger than ever before!"

Trump’s Twitter account was permanently suspended following the Jan. 6 Capitol riot, but searches on the website Trump Twitter Archive found more than 60 mentions of "China virus" or some variation of it, including eight in the week after his first tweet.

The president also often used terms such as “China virus," or other variations on the same theme, during speeches and news conferences. He issued a statement as recently as last week that also used the term "China virus."

The UCSF findings come amid a surge in reported anti-Asian attacks in the United States. According to Stop AAPI Hate, 3,795 hate incidents were reported to the advocacy group from March 19, 2020, to Feb. 28, 2021 — more than 600 of them from March 19 to 25, 2020. The organization believes those incidents represent only a fraction of the true number.

“Although we were unable to assess the relationship between hateful hashtags and hate crimes, our results provide a plausible connection because many tweets and hashtags implied violence,” the study said.

On Tuesday night, a suspected gunman opened fire at three Atlanta-area spas, killing eight people, mostly women Asian descent, police said. The shooting spree has heightened fears about anti-Asian crime, although authorities are still investigating and have not labeled the killings as racially motivated.

Trump’s office has not responded to a request for comment from Spectrum News on the UCSF study. 

On March 18, 2020, two days after his initial "Chinese virus" tweet, Trump defended using the term.

"It’s not racist at all," he said at a White House news conference. "No, not at all."

"Because it comes from China," he added. "That’s why. I want to be accurate."

The researchers say their findings indeed suggest that the names of diseases can have consequences. 

"Everyone — scientists, community members, and politicians — should use neutral, nonjudgmental language to avoid stigmatizing communities and perpetuating discrimination," the study advised.