Much of the hand washing we do is possibly "worse than useless" and education about the subject is not necessarily helpful because it tries to make the message too simple.
That's the view of a University of Otago senior lecturer in the Department of Primary Health Care and General Practice (Wellington School of Medicine) Dr Ben Gray.
Most of the time when people failed to wash their hands properly, it probably did not matter, but people needed to know how to do it properly and when it was important to do that.
The presence of norovirus in a community was such a time, as was any illness involving vomiting or diarrhoea, handling raw chicken or visiting a neonatal unit.
Last year, a large study of the hand-hygiene practices of 1200 people using toilets in malls in Auckland, Hamilton, Wellington and Christchurch showed that most people did not meet recommendations about the length of washing and drying times and the proportion of men who did any kind of hand washing was lower than that for women.
It was suggested following the study that future hand-hygiene promotion should focus on males, but Dr Gray took issue with that because there was no evidence that the lack of hand washing practised by them had led to illness, he said .
A man who walked into a urinal, urinated and left again had not touched anything apart from himself (and urine was sterile when it came out).
Men who did not wash after such events might not be convinced of the benefits of hand washing, based on their own experience, and they might be right, he said.
Probably only about 1% of the population was obsessive-compulsive about hand washing and did it correctly all the time.
The rest of people thought they were doing it properly because the hand-washing message had been drummed into them, but washing hands slightly without drying them properly after you had touched all the taps could be worse than doing nothing.
The way people washed their hands would also be influenced by why they were doing it.
Some people washed their hands because it was the cultural norm and therefore waving them under the tap sufficed.
No amount of hygiene talk would necessarily change that behaviour.
"Whatever we recommend, we need to study what difference it makes. It may be that the current advice is better than no advice. It may be that the current advice is making things worse."
Ideally, advice should be derived from research based on outcomes.
Dr Gray was not a fan of the general carrying of hand sanitisers for those occasions when ideal hand-washing facilities might not be available.
There could be a reason for it in certain circumstances - a frail elderly man with prostate disease who had to visit five poorly equipped public toilets around town before he got home, for instance.
For most people, however, the degree of risk involved in using a toilet occasionally where there were inadequate hand-washing facilities was not likely to be high.
