Pressure is building on the Government to give the meningitis B vaccine to all children aged under 11 as the number of signatories to a petition approaches 700,000.
Huge support for the campaign comes after several high-profile cases involving the devastating virus, that can kill its victims or leave them in need of life-changing amputations.
Tragic images of two-year-old Faye Burdett, from Maidstone, Kent, who succumbed to the virus on Valentine's Day, prompted a surge in support for the cause and the petition received a further boost when England rugby hero Matt Dawson revealed his two-year-old son, Sam, was recovering after contracting meningitis C.
By Monday more than 667,000 had signed the parliamentary petition, making it the most popular since their introduction.
Any petition that receives over 100,000 signatures will be considered for debate in Parliament. So far it has eclipsed the petition to ban US presidential hopeful Donald Trump from the UK that attracted around 580,000 and was discussed in the Commons.
Faye's parents, Jenny and Neil, have said the response to the petition since their toddler contracted meningitis B and died has been "overwhelming".
Although his son is now well and back home with his family, Dawson said he felt "absolutely helpless" as Sam lay hooked up to machines in hospital.
Lee Booth, who lives in Newcastle-upon-Tyne, launched the petition last September after one of his two young daughters was deemed too old to have the vaccine on the NHS.
He said previously he was "speechless and overwhelmed" by the "phenomenal" response.
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.
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.