No credible source has reported such a story. The Pfizer COVID-19 vaccine is proven to be effective for children aged 12 years and above.
This claim is false as there is no evidence to link such a death to the Pfizer COVID-19 vaccine. Apart from the vague age description of the "15 years" and the event occurring in the United States, there is not much that can give credibility to the story. Details like the teenager's name, the hospital he was admitted to, and the locality and state name are missing. The same article has been republished or cited by fake news-spreading websites. The Daily Exposé had published an article referring to it but later took down the article and a tweet about it.
According to the Mayo Clinic, children aged 12 to 15 who received the Pfizer-BioNTech COVID-19 vaccine experienced side effects similar to adults that lasted 1 to 3 days. Other than soreness around the area of the jab, there were very few side effects experienced by this demographic.
The U.S. Food and Drug Administration (FDA) granted emergency use authorization to the Pfizer-BioNTech COVID-19 vaccination for children aged 12 to 15. Furthermore, the FDA examined a study of over 2,200 children aged 12 to 15 in the U.S., which found that the vaccine effectively prevents COVID-19 in this age range.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.