"In adults it causes symptoms like common cold." This is not correct!! When I was 23 I had whooping cough. I was coughing and vomiting for close to a month, able to keep very little down. I remember well waking up one morning unable to breath and thumping my chest violently trying to move the phlegm blocking my throat. Most frustrating was that it was not until the 5th doctor or went to see that someone identified the problem. It was only that it was an older doctor who on hearing me cough knew immediately what it was which was then confirmed by a blood sample. At the time I was very fit and healthy, had I not been I would not like to consider the outcome!!