A 13-year-old boy has died in his sleep just three days after he received his second dose of the coronavirus vaccine.
Jacob Clynick died on June 16 at his home in the US state of Michigan after he was given the Pfizer jab.
His aunt Tami Burages told the the Detroit Free Press he was an otherwise healthy teen with no underlying medical issues.
He had however complained of symptoms in the two days following his second dose of the vaccine, reporting a fever and fatigue.
The night before he died the teen also complained of a stomach ache but it wasn't drastic enough to cause concern.
But that night, Jacob went to bed and died at his home in the middle of the night.
His aunt wrote on Twitter preliminary autopsy results found the teen's heart was enlarged when he died and there was fluid around the organ.
On June 23, a Centres for Disease Control and Prevention (CDC) advisory committee said there was a likely association between the risk of heart problems in young people and the Pfizer and Moderna vaccines.
The CDC is investigating Jacob's death and told local media in a statement it would look at a correlation between his death and the vaccine.
"The health department continues to encourage families to speak with their physicians to weigh their own risks and benefits of vaccination," the statement said.
An obituary for the teen following his death said he loved gaming and Pokemon and was known for his jokes and having a meme for every occasion.
"But, what he really loved most was his family," the obituary said.
Teen in Singapore critical after Pfizer shot
Following Jacob's death, a 16-year-old boy in Singapore suffered a cardiac arrest after lifting weights six days after receiving his first dose of Pfizer.
The Ministry of Health said on Monday the boy had been transferred to the National University Hospital where he remains in a critical condition.
The ministry added he was lifting "very heavy weights which were above his body weight". It is investigating the incident.
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