A British coroner says a girl who died after receiving a vaccine against cervical cancer was likely killed by a tumor.

Natalie Morton collapsed Monday about two hours after being given Cervarix, a vaccine which protects against two viruses that can cause cervical cancer.

Deputy coroner Louise Hunt said Thursday at an inquest into the teenager's death "it appears that Natalie died from a tumor in her chest involving her heart and her lungs."

Her mother and stepfather say that Natalie was "kind, fun-loving and had a beautiful smile. We will miss her very much."

Britain's National Health Service began offering the Cervarix vaccine to teenage girls last year. More than 1.4 million doses of the vaccine have been given out so far.