Fig. 2
From: Hospital-based prospective study of pertussis in infants and close contacts in Tehran, Iran

Distribution of primary (a) and secondary (b) cases with respect to the index case among positive contacts. yo, years old
From: Hospital-based prospective study of pertussis in infants and close contacts in Tehran, Iran
Distribution of primary (a) and secondary (b) cases with respect to the index case among positive contacts. yo, years old