Immune Deficiencies Foundation board member, sufferer, and mother of a sufferer, Laura Hannah, said "more and more" people chose not to vaccinate, and this put at risk those who were unable to gain full benefits from immunisation.
Mrs Hannah had to be extremely careful of her own health, as a dose of a pneumonia could be fatal.
While those with immune deficiency could have some vaccines, depending on the type of vaccine and their illness, they usually did not receive its full effect, while they were at greater risk from routine illness.
The so-called "herd immunity" of the rest of the population was crucial to the one in 400 New Zealanders with immune deficiencies, she said.
Mrs Hannah said she had reluctantly had to pull back from some members of her social circle, because of their unvaccinated children.
Vaccination was a hot topic in the foundation's Dunedin support group.
"Within our Dunedin group, we find that illnesses which keep a healthy child away from school for a few days to a week land one of our members in the hospital, or with weeks of ongoing illness."
Payments - or linking the vaccination schedule to benefits - was a solution to low vaccination rates suggested by a Health Select Committee report, the Government's official response to which is due on June 22.
Mrs Hannah said she supported paying people, if that was what it took.
Bronagh Quinn, whose son has an immune deficiency, said it was unfortunate many parents thought of the issue purely in terms of their own children rather than the wider community.
