A 12-year-old schoolgirl missed out on a life-saving vaccination jab just two weeks before her death.
Olivia Diamond died suddenly of acute myocarditis - a type of heart infection - earlier this month, just four days after falling ill with the flu.
The condition causes heart muscles to inflame and is usually caused by a virus.
Olivia, from Accrington, was just 12 days away from being given a nasal spray vaccination against flu as part of a county-wide pilot scheme to vaccinate Year Seven and Eight children.
Her distraught mum, Angela said: "If Olivia had a flu vaccine, she would not have died.
"The message I want to get out is that every child needs that vaccine whether they meet criteria or not.
"Olivia is the prime example of this."
Health professionals now plan to visit Olivia's former school, Accrington Academy, to offer the vaccines next week after the Department of Health decided to extend the national flu programme.
The visit has been planned for a while and is not in response to Olivia's death, the school said.
Principal Andy O'Brien said: "The project was started in conjunction with NHS Lancashire six weeks ago and the students will be getting the vaccinations next week."
All children from the age of two to 17 will be offered vaccinations in the future, the government said, with the extension to the flu programme being phased in, although the timescale depends on how efficient the pilot is.
Angela said she plans to "go down every route available" in her fight to see free widespread vaccinations introduced as quickly as possible.
Local Councillor Peter Britcliffe added: "It's so sad, and it's tragic to think Olivia just missed the opportunity the school was providing with flu vaccinations."