This report in the journal New Scientist emphasis's that the costs in terms of the consequences for the health of people living in a flooded area extend to months or possible years after the water has gone. In the past statistics for hospital admissions were not recorded (i.e. noted as being due to flooding) once the flooding is gone, but once we start to look at figures for the period after the flood we can see a significant rise in admissions (admissions double) over the next year, whereas those in nearby none flooded areas saw no rise. Deaths apparently rise 50% in flooded areas after the waters subside.
A review by the World Health Organisation (WHO) reports similar findings in other parts of the world eg in China and in homes following Hurricane Katrina, but other similar, more recent studies fail to confirm this finding.
Quoting from the article
However, Bettina Menne, co-editor of the WHO review, says people affected by flooding often subsequently move house, possibly to a different, less flood-prone postcode. If more of them later died than would have normally, this would muddy the data, by cutting the apparent death-rate among the flooded and boosting it among the non-flooded. There's also the fact that people's health overall will have improved since 1968. The problem, Menne says, is that "a study like the one in Bristol, directly comparing people we know were flooded with people who weren't, has never been done again, anywhere".
One way of finding out for sure would be to set up a health registry of people flooded this time, so the health of those affected can be compared with those who weren't. Virginia Murray of Public Health England called for such a registry in January, and said a protocol for setting one up was nearly ready. But no decision to fund one has yet been taken, she says.
Still, the standard medical surveillance of people whose homes have been flooded is reassuring. "Nothing worrying is happening," says Murray. But what happens in six months to people fleeing floodwaters these past weeks, we may never know.