The World Health Organisation on Friday rebuked in unusually strong terms advice by a Swiss homeopathic doctors association that pregnant women should avoid getting vaccinated against swine flu.
The Swiss Society of Homoeopathic Physicians said pregnant women shouldn't take either of the two vaccines licensed in Switzerland - Novartis' Focetria and GlaxoSmithKline's Pandemrix - claiming the effects on mothers and their unborn children have been insufficiently studied.
"This (advice) may result in putting pregnant women and their foetuses at risk of severe consequences in case of pandemic influenza virus infection," said WHO vaccines chief Marie-Paule Kieny.
WHO considers Focetria and Pandemrix to be safe for pregnant women, Kieny said.
"We ... regret that the recommendation of the Swiss Society of Homoeopathic Physicians does not take WHO recommendations in this matter into consideration," she said.
Homeopathic doctors believe that highly diluted substances made from natural ingredients can be used to treat symptoms and cure diseases, despite lack of scientific evidence to that effect.
Opinion polls in Switzerland, where WHO is based, show significant portions of the population already are reluctant to get vaccinated.
As in neighbouring Germany, there has been public concern recently over the use of adjuvants in vaccines. Both Focetria and Pandemrix contain these additives, which are intended to boost the body's immune response stretch the vaccine's active ingredient so more doses can be made.
No flu vaccines with adjuvants are licensed in the United States, though they are commonly used in Europe.
WHO says pregnant women are at particular risk of developing severe complications from the pandemic strain of flu, known as H1N1, and has urged countries to make pregnant women a priority group for vaccination.
More than 6,000 people around the world have died from swine flu since the disease was identified in April, according to WHO's latest figures.
