The man behind the most-signed online petition in parliamentary history has said a price should not be put on a child's life, ahead of a high-level debate on his meningitis B vaccine campaign.
Lee Booth, 44, said it would be more cost-effective for the NHS to vaccinate all children up to at least the age of 11 rather than treating meningitis survivors for the rest of their lives.
He spoke after the Government rejected calls for the meningitis B vaccine to be given to all children, with officials saying the NHS budget is a "finite resource".
The Department of Health this month said its priority is to vaccinate those children considered most at risk from meningitis B.
It said it is following guidance from the Joint Committee on Vaccination and Immunisation (JCVI), which advises the Government on the cost-effectiveness of vaccinations.
But ahead of the first of two public evidence sessions in Parliament starting on Tuesday, father-of-two Mr Booth said ministers should consider the cost implications of not vaccinating all children.
British Gas worker Mr Booth, who lives in Newcastle-upon-Tyne, said: "What price can you put on saving a child's life?
"What do we deem cost-effective to save a child? The actual cost to look after someone who has survived meningitis is extremely high.
"There are the drugs, the therapy, the changes to that person's home. You are looking at about £3 million over the course of that child's lifetime.
"The maths soon add up and it would be more cost-effective to have this vaccination programme instead, I would say."
Mr Booth launched the petition last September after one of his two young daughters was deemed too old to have the vaccine on the NHS.
The campaign attracted around 900 signatures until two-year-old Faye Burdett, from Maidstone, Kent, caught the infection and died on Valentine's Day after an 11-day battle.
A flood of support followed after a harrowing picture of Faye covered in a rash and lying in a hospital bed just before she died was shared by her family.
Now more than 823,000 people have signed the petition. After it gained more than 100,000 signatures, a debate was guaranteed to be held in Parliament.
Faye's parents Jenny and Neil are due to speak in Parliament at the first session on Tuesday, along with Mr Booth and ex-England rugby captain Matt Dawson, whose two-year-old son Sam battled, and survived, meningitis C.
Mr Booth said: "823,000 is an awful lot of people who agree with what I'm saying. I don't think anyone should be held to ransom but it's a large voice that cannot be ignored."
A vaccine to protect against meningitis B is available on the NHS for babies aged two months, followed by a second dose at four months and a booster at 12 months.
But parents who wish to have older children vaccinated must pay privately, although a worldwide shortage of the vaccine Bexsero means stocks are very low.
Manufacturer GlaxoSmithKline (GSK) hopes to have increased stocks in the UK by the summer. The NHS programme is unaffected.
A Department of Health spokesman said: "MenB is a terrible disease that can be devastating for families. This is why we looked so carefully at the evidence for a free vaccination programme for infants and why in 2015 became the first - and to date only - country in the world to introduce this programme.
"We understand people's concerns and all vaccination programmes are kept under constant review, but we have to be guided by the very best scientific advice and we will continue to protect the children who are most at risk."