Natalie Morton died in hospital following a cervical cancer jab at school
Parents are being urged to carry on getting their daughters vaccinated against cervical cancer.
Senior government health officials have sought to allay fears following the death of a 14-year-old from Coventry.
Natalie Morton fell ill shortly after being given the Cervarix jab, but it has now emerged she had a serious underlying health condition.
Chief nursing officer Christine Beasley urged parents not to lose confidence, saying the jab could save lives.
She said: "My message to parents and to the young girls themselves is this a vaccination which will prevent you getting cervical cancer, which is a horrible disease, even if it is treated."
Public health minister Gillian Merron added: "We hope that girls continue to protect themselves against cervical cancer by having this vaccine."
Natalie was given the vaccination at school as part of the national vaccination programme. It protects against the human papilloma virus (HPV), a sexually transmitted disease linked to most cervical cancers.
Dr Caron Grainger, joint director of public health for NHS Coventry and Coventry City Council, said the results of a preliminary post-mortem examination had "revealed a serious underlying medical condition which was likely to have caused death".
Head teacher Dr Julie Roberts and the Bishop of Coventry on the death of Natalie Morton
"We are awaiting further test results which will take some time," she said. "However, indications are that it was most unlikely that the HPV vaccination was the cause of death."
Coventry postponed its immunisation clinics immediately after the death while the batch of vaccines was quarantined - this batch is now going to be tested by manufacturer GlaxoSmithKline.
In the meantime, Coventry is expecting to restart its clinics soon.
Natalie's death has left schoolmates and staff shocked and saddened, headteacher Dr Julie Roberts said.
She described Natalie as a "happy, easy-going child who worked hard".
A routine programme of vaccinating 12- and 13-year-old girls started in September 2008 using the Cervarix vaccine. A catch-up campaign is now under way for older girls.
It is thought about a million girls have already safely received the jab.
Adverse reactions to Cervarix
Total number of reactions reported between April 2008 and 23 September 2009
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.