A coronavirus outbreak that originated in Wuhan, China, has killed at least 565 people and infected more than 28,000 other people since December. (For the latest case total and death toll, see Business Insider's live updates here.)

At the onset of the outbreak, a Wuhan doctor named Li Wenliang warned some of his contacts from medical school about the virus.

He was reprimanded by the police in Wuhan and required to sign a letter acknowledging that he was "making false comments."

Li caught the coronavirus himself after treating people who had it. Wuhan Central Hospital said at about 4 a.m. local time on Friday that he died after "efforts to save him were ineffective."

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In the past five weeks, a new coronavirus has infected more than 28,000 people and killed at least 565 other people. Among those casualties is Li Wenliang, a 34-year-old doctor who was one of the first people to sound the alarm about the new outbreak.

Li sent a message to his medical-school alumni group on December 30 warning that seven patients had been quarantined at Wuhan Central Hospital after coming down with a respiratory illness that seemed like the SARS coronavirus. The police in Wuhan then reprimanded and silenced Li, requiring him to sign a letter acknowledging that he was "making false comments."

Li died of the coronavirus early on Friday at Wuhan Central Hospital, where he had been in intensive care for three weeks. The hospital confirmed his death in a statement on Weibo at about 4 a.m. local time.

"During the fight against the novel coronavirus outbreak, Li Wenliang, an ophthalmologist at our hospital, was infected. Efforts to save him were ineffective. He died at 2:58 a.m. on Feb. 7. We deeply regret and mourn his death," the post said.

A screenshot of a Weibo post from the Wuhan Central Hospital. Weibo

Li is survived by his wife, who is pregnant, and their first child.

He first checked himself into Wuhan Central Hospital on January 12 and announced on his Weibo account on Saturday that he'd been diagnosed with the novel coronavirus. China News Weekly reported that Li's heart stopped at about 9:30 p.m. local time on Thursday but that he was rescued.

Some reports had incorrectly suggested that Li died on Thursday evening. At 12:38 a.m. on Friday, the hospital said Li was in critical condition.

A warning message gone viral

Earlier this week, Li told The New York Times via text message that Chinese officials could have done better at sharing information about the coronavirus at the beginning of the outbreak.

This image from video, shows a selfie of Dr. Li Wenliang, the Chinese doctor who got in trouble with authorities for sounding an early warning about the coronavirus outbreak. Associated Press

"If the officials had disclosed information about the epidemic earlier," he said, "I think it would have been a lot better. There should be more openness and transparency."

The WeChat message Li sent to his medical-school contacts on December 30 said that the seven quarantined patients had all worked at or visited the Huanan Seafood Wholesale Market.

That day, the Wuhan Municipal Health Commission published a notice that some people had contracted a kind of pneumonia, possibly at the seafood market. But the commission warned that "organizations or individuals are not allowed to release treatment information to the public without authorization," CNN reported.

Screenshots of Li's message, though, had already gone viral.

The closed Huanan Seafood Wholesale Market in Wuhan, China, where health officials think the coronavirus outbreak might have started. NOEL CELIS/AFP via Getty Images

"When I saw them circulating online, I realized that it was out of my control and I would probably be punished," Li told CNN.

Four days later, Li was summoned to a police station. Authorities told him that his WeChat warning was illegal and had "severely disturbed the social order," the BBC reported.

According to the BBC, the letter he was told to sign read: "We solemnly warn you: If you keep being stubborn, with such impertinence, and continue this illegal activity, you will be brought to justice — is that understood?"

Beneath that, Li wrote, "Yes, I do."

A screenshot of a photo that Li shared on his Weibo account on January 31 shows the letter he signed on January 3. Weibo

Li was not detained, and he returned to work at the hospital.

Li continued to speak out and share information while sick

After contracting the coronavirus and checking himself into the hospital for treatment, Li continued to post on his Weibo account and speak out against misinformation.

"I was wondering why [the government's] official notices were still saying there was no human-to-human transmission, and there were no healthcare workers infected," Li wrote on January 31 from his hospital bed, according to CNN.

China's Supreme People's Court on January 28 condemned Wuhan authorities' investigations into people like Li who shared early information about the virus.

"It might have been a fortunate thing for containing the new coronavirus, if the public had listened to this 'rumor' at the time, and adopted measures such as wearing masks, strict disinfection and avoiding going to the wildlife market," the court said, according to CNN.

Update: This story was originally published on February 6 at 2:08 p.m. ET, before Li died. It has been updated with the latest information about his death.