A four-year-old boy has died from the flu after his mother reportedly treated him with advice offered by members of an anti-vaccine Facebook group, according to reports.

Last week, Geneva Montoya, from Pueblo, Colorado, sought advice from the Facebook group "Stop Mandatory Vaccination" after two of her four children had been diagnosed with the flu, according to NBC News.

Although the youngest child, Najee, had not yet been diagnosed, he had a 102-degree fever and had a seizure when Ms Montoya told the group that the doctor had prescribed Tamiflu, an antiviral medication to treat the flu, but “I did not pick it up”.

“I am in desperate need of help with what to do for my pore (sic) kiddos!” the post reads, according to a screenshot. Ms Montoya concluded the post asking the group’s more than 144,000 members what she could give the children to “help the fever or the symptoms subside”.

According to NBC News, members of the group suggested she try breast milk and thyme and elderberry, which are not medically recommended treatments for the flu.

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“Perfect, I’ll try that,” the mother responded, according to the outlet.

The Colorado Department of Public Health and Environment confirmed the child died from the flu and told NBC News that it did not have records showing whether the boy had been vaccinated.

“The death is the second paediatric flu death in Colorado this season,” the department said in a statement.

Following the four-year-old’s death, his father Najee Jackson Sr explained what happened to his son and spoke out in defence of his family.

“His heart stopped,” he told Fox31. “He wasn’t breathing. They got his heart going back at the hospital in Pueblo.”

The child, who tested positive for Influenza B and Paraflu, was later declared brain dead and taken off life support, according to a GoFundMe page set up by Ms Montoya.

“I would like to sincerely thank everyone who has donated money for me son Najee!” an update posted Thursday read. “It is my deepest sorrow to inform those of you that don’t already know that my son has been taken off of life support and has passed. Myself and all those who love Najee are devastated and broken.”

Regarding criticisms over the family’s association with the anti-vaxx Facebook group, Mr Jackson said: “I don’t look at none of it.

“The negative comments - keep to yourself because at the end of the day, what’s important is that each one of these parents goes home and kisses their kids.”

In a statement to KKTV, Ms Montoya said: "I'm hurting so bad right now and so is his dad and brothers. Our whole family is hurting and it feels like we failed him because we did what we had to do,” but did not comment on whether the child was vaccinated.

According to Mr Jackson, his wife and the couple’s three other sons, including a 10-month-old whose symptoms required hospitalisation, are still battling the flu.

The four-year-old's death comes after a survey from the American Academy of Family Physicians (AAFP) found that 59 per cent of parents said that their child has missed a flu shot at least once due to misinformation or a misunderstanding.