At 5am Mark rang for an ambulance, and Henry was rushed to hospital. "Within about 20 minutes of us arriving at resus they told us he wasn't going to make it," said Mark. "It was that quick."
Henry had an extremely rare bacterial infection, Haemophilus Influenzae Type F, which led to meningitis. He never developed a rash. The strain of the infection is not covered by the MenB vaccine or the Hib jab.
Mark said: "Just because you've had the jab doesn't mean you can't catch another strain. For us we thought like everybody else - that something like this couldn't happen to our family.
"The main thing is you should always err on the side of caution. Don't wait for a rash."
His family have now planned a series of events to raise money for the charity Meningitis Now, in Henry's memory.
Mark told the Peterborough Telegraph: "We've had a few donations from friends and people saying 'I'm sorry it can't be more'. It's not about the money, it's about keeping his memory alive and wanting something positive to come out of something that doesn't seem to have any positives."
ABOUT MENINGITIS
1 Meningitis is an infection of the protective membranes that surround the brain and spinal cord. It can be caused by a bacteria or a virus
2 Babies and young children are most at risk of developing bacterial meningitis
It is more serious than viral meningitis. The symptoms usually begin suddenly and get worse rapidly
3 Symptoms include a high fever with cold hands and feet, vomiting and refusal to feed, drowsiness, floppiness, grunting or rapid breathing, convulsions or seizures, dislike of bright lights and pale or blotchy skin with a red rash that doesn't fade when a glass is rolled over it
4 Most people with viral meningitis will have mild flu-like symptoms, such as headaches, fever and generally not feeling well
5 Symptoms may also include neck stiffness, muscle or joint pain, nausea and vomiting, diarrhoea and sensitivity to light
6 Unlike bacterial meningitis, viral meningitis does not usually lead to septicaemia (blood poisoning)
7 Clinical tests are needed to distinguish between the two types of meningitis