Serious complications of pertussis happen most often in infants and may include:
- Apnea (breathing stops)
- Convulsions or seizures
- Encephalopathy (brain damage) that may be permanent.
Pertussis starts like a common cold with symptoms such as:
- Runny nose
- Mild fever
- A mild cough
During the next week or two, the cough gets worse, leading to severe coughing spells that often end with a whooping sound before the next breath, especially in young children.
Teenagers and adults may not make the whooping sound.
The cough can last one to two months and occurs more often at night. The cough can make a person gag or spit out mucus and make it hard to take a breath preventing enough oxygen from getting to the brain.