What puts a child at highest risk for severe whooping cough? A new analysis of Chinese children reveals the top five warning signs.

When a child gets whooping cough, parents and doctors want to know: what are the biggest warning signs that this could become a severe, dangerous illness? A new analysis of 24 studies, involving over 5,000 Chinese children, has identified the top five factors most strongly linked to severe pertussis. The analysis compared 839 severe cases to 4,280 non-severe ones. The strongest warning sign was a lung complication called consolidation or atelectasis, which made severe disease over 15 times more likely. The second strongest was a physical sign of breathing difficulty called the 'three concave sign.' High levels of a protein in the blood that signals inflammation (C-reactive protein) was another major red flag. Perhaps most crucially, children who were not vaccinated with the DTP (diphtheria, tetanus, pertussis) vaccine were four times more likely to have severe whooping cough. A very high white blood cell count was also strongly linked to severe illness. The study concludes that spotting these factors early and making sure children get vaccinated are key steps to preventing severe cases.