Quick Dips

Post-Polio Syndrome in New Zealand

Jane Chetwynd & Denis Hogan

Polio was the most feared infectious disease in New Zealand in the first half of this century, and it remains a problem for former polio sufferers who are now experiencing post-polio syndrome 30 to 40 years after they first came down with the disease. Until now, there has been little in-depth research into the epidemiology of post-polio syndrome, but a recent study by Christchurch School of Medicine researchers is shedding some light on the victims' experiences.

In the first half of this century, there were six major polio epidemics in New Zealand with each one producing more than 1,000 cases, predominantly in children under the age of 16. Few people died from the illness but most recovered from the acute stage with some residual weakness or partial paralysis. Most went on to live full and active lives. Now, 30-40 years after their initial infection, some polio survivors are becoming disabled again with post-polio syndrome -- a combination of symptoms usually involving increasing weakness, pain and extreme fatigue.

The researchers asked for volunteers to take part in a postal survey concerning their experience of polio and post-polio symptoms, and received 700 responses. The average age of respondents was 59 years and most of them (73%) were under 16 at the age of their infection with polio.

Symptoms of post-polio syndrome were reported by significant numbers of the study sample. Some 38% reported increasing weakness in muscle functioning in one or more areas, generalised muscle weakness was reported by 47%, increasing muscle wastage by 17%. Pain in joints was reported by 60% of the sample and excessive tiredness by 48%.

After controlling for age there was little evidence that the symptoms increased with years since the acute polio infection.

It seems from this study and from the experience gained by other international researchers that somewhere between 30% and 40% of people who experience acute polio infection will go on to develop post-polio symptoms. It is estimated that there are between 3,000 and 5,000 polio survivors in New Zealand who may be suffering post-polio symptoms.

It is important that general practitioners be kept informed about the incidence of, and symptoms of, post-polio syndrome, and that appropriate secondary care facilities at hospitals be made available so as to provide comprehensive assessments and treatments where possible.

Jane Chetwynd, Christchurch School of Medicine
Denis Hogan, Christchurch School of Medicine