**3. Clinical case definition**

The clinical case definition used is based on CDC/WHO clinical criteria (www.cdc.gov/ncphi/ disss/nndss/casedef/pertussis\_current.htm, www.who.int/entity/immunization\_monitoring/ diseases/pertussis\_surveillance/en/index.html) that refers to a person with a cough illness lasting at least 2 weeks with one of the following symptoms/signs: coughing paroxysms, inspiratory whoop, or post-tussive vomiting. In patients younger than 6 months of age, cyanosis and apneas could also be present, and, for this reason, these symptoms are also included for pertussis clinical diagnosis. The different countries have considered adaptations in clinical criteria including age stratification and cough duration [43].
