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" Children who are overly-protected from exposure to bacteria or viruses could be at a heightened risk of developing asthma, the findings of new research suggest. Up until now the idea that &amp;#039;wrapping children in cotton wool&amp;#039; could cause more health problems than it prevents has largely been perceived wisdom. However, a team working at the Harvard Medical School in Boston has reported their research shows that mice infected with the influenza A virus at the start of their lives then grow into adults protected against induced symptoms of the disease. In comparison, those mice that were protected from the virus at an early age were seen to develop into adults at heightened risk of a range of conditions, including asthma, with a lack of development of natural killer T-cells (NKT cells) blamed for this. Writing up the findings in the Journal of Clinical Investigation, lead researcher Dr Dale Umetsu said: &amp;#039;Our results suggest that infection with certain micro-organisms can prevent the subsequent development of asthma and allergy by expanding the relative proportion of a specific subset of NKT cells, thus providing an immunological mechanism for the hygiene hypothesis.&amp;#039; According to the charity Asthma UK, some 5.4 million people in the UK are now receiving treatment for asthma.\u00A0 "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.netdoctor.co.uk/conditions/allergy-and-asthma/news/a20396/protecting-children-from-viruses-could-increase-asthma-risk/>