In some ways, immunisation is a victim of its own success.
It has been so long since scourges such as polio or smallpox cruelly smote their way through New Zealand that it is all too easy to become complacent.
Even measles is relatively uncommon these days.
Vaccinating against disease, however, is one of the wonders of modern medicine. Along with sanitation and clean water, the public health benefits have been extraordinary and incalculable.
How much better, too, to prevent diseases rather than have to treat them. It has been estimated vaccinations prevent 2.5 million deaths a year across the world.
New Zealand's rates are reasonable but still fall well short of a goal of 95% of the population.
Coverage last year at the milestone age of 5 for receiving the appropriate immunisations was 81%, dragged down by the Lakes (Rotorua, Taupo and the central North Island) 68%, Counties Manukau and Waikato (73%) and Northland and Bay of Plenty (75%).
The figure for the Southern District Health Board is 89%, meaning in the South there is also room for improvement.
The link to poorer communities, and areas with larger Maori or Pacific Island populations is obvious, and good work has been carried out to raise levels among these groups. There is also another fringe group, estimated about 2%, which refuses to immunise their children, and they have that right. A review in Australia shows these parents often have ''alternative'' interests and outlooks, many are sceptical of Western medicine and want to live a ''natural'' lifestyle. While these people largely piggy-back the herd immunity from everyone else - if a critical mass are immunised, disease has a lesser chance of spreading - their children are more vulnerable. And although these parents are often educated and read widely, pseudo-science and misinformation abounds, ready to be lapped up by those so inclined.
A little scepticism about conventional wisdom and officialdom should not do harm. However, the rejection of immunisation is unhealthy and misguided. Although it should not be forgotten or brushed over that vaccinations can cause adverse reactions, the benefits to individuals and the community overwhelm the risks. The autism scare from a false 1998 paper refuses to die, even though it has been thoroughly discredited. Diseases that have disappeared can return and children's immune systems fight far greater challenges every day than dealing with vaccines.
Measles is far from the most serious of the diseases on the immunisation schedule, although it still kills people.
It is, though, an illness that should have disappeared from New Zealand. But that is far from the case because of low historic vaccination levels and because some children continue to miss out. One of the worst outbreaks was in 2011 when about 500 people were affected and 80 needed hospital care. All this came from one infectious visitor. All those who became ill had no or only one vaccination.
Measles at Westlake Boys' High School, Auckland, last year affected 52 students, teachers and others. Again, almost everyone infected had not had the proper immunisation. This outbreak then spread to Waikato and Northland.
Last week, it was reported a child from a flight from Kuala Lumpur to Auckland had been diagnosed with measles and earlier in the month a measles case in a 4-year-old in Christchurch was notified. The child had not completed measles, mumps and rubella (MMR) vaccinations. The first dose had been given at 15 months but the child was still too young for the follow-up at age 4.
In the wake of this case, Canterbury Medical Officer of Health Daniel Williams said: ''People who choose not to vaccinate their children against infectious diseases are putting not only their own children at risk, but also other people's children.''
Whooping cough epidemics, although preventable, still take place every few years, and infant deaths still occur. Tetanus is no longer common but those not immunised are at risk of nasty consequences, and cases still arise.
The message is clear. Immunisations have brought huge health gains, and parents should immunise their babies and children according to the recommended schedule.
