USA (Reuters) – Researchers in the US are warning that Vicks VapoRub, a commonly used product to ease coughs and colds, should never be put under the nose of a child younger than age two. Recent tests on animals show that, if incorrectly applied, the product can cause respiratory problems. The researchers were clear that the manufacturer, Procter & Gambel, warns consumers not to use it this way. Related story: sleeping less than seven hours can increase your risk of catching a cold, new research shows.