An emergency room doctor has tested positive for COVID-19 just days after receiving the vaccine for the virus.

Josh Mugele, who works at the Northeast Georgia Medical Center in Gainesville received the COVID-19 vaccine on Dec. 20, but nine days later, he had contracted the virus, Business Insider reported.

Mugele, who has openly chronicled his struggles as an ER doctor during the coronavirus pandemic on social media, said it was just “dumb luck” that he got COVID-19 after receiving the first dose of the Pfizer-BioNTech vaccine.

He said in a Twitter post, “For Christmas one of my patients gave me COVID.”

Prior to receiving the vaccine, Mugele told Business Insider, “I had three shifts in a row right up to the vaccine date. I was just really nervous I was going to get exposed before that. I honestly felt really a sense of relief when, on the 20th, I actually was able to get the vaccine, and I thought I'd kind of crossed the finish line.”

Mugele, who had spent 10 months working in the frontlines with COVID patients, tested positive for the virus after coming down with a headache and cough the following Monday, the news outlet said.

In another tweet, Mugele said he was experiencing mild symptoms after testing positive for the virus.

He told Business Insider after finding out he was positive for the virus, he was “angry.”

He said, "I've had maximum exposure, as much as any ER doc in the country, and I've been spared for 10 months, and then to get it right after I got the vaccine is just stupid and frustrating.”

But Mugele is not alone.

A nurse in San Diego also contracted COVID-19 just eight days after receiving the vaccine for the virus.

Experts have said this is “not unexpected” as the first dose of the vaccine only provides about 50% protection against COVID, while the second injection is designed to offer up to 95% effectiveness.

The Pfizer-BioNtech vaccine that Mugele received also is given in two doses 21 days apart, while the Moderna vaccine is given in two doses 28 days apart.

Mugele told the news outlet that he knew there was a chance that he could contract COVID after he received the first inoculation of the vaccine as it takes time for the body to build up an immunity to the virus.

“That first eight days is really critical. People still have to be absolutely isolated. They have to wear their mask, they have to wash their hands, they have to avoid going out before they get the benefit of the vaccine.”

He also stressed that "I happened to be exposed within a few days of getting the vaccine, but this still is the best tool we have for fighting the virus."

Mugele is slated to receive his second dose of the COVID vaccine on Jan. 12, if his COVID symptoms subside, Business Insider said.

Pfizer Vaccine Emergency Use Authorization
The U.S. Food and Drug Administration granted Pfizer and BioNTech’s coronavirus vaccine emergency use authorization, bringing millions of Americans hope that the pandemic will soon end. Initial supplies will be given to health care workers and nursing home residents. The general public would likely be vaccinated in the early spring of 2021. Ethan Miller/Getty Images