Antigenic Changes in Bordetella pertussis Strains Circulating in Taiwan, 1992–2014

DOI: 10.6525/TEB.20160119.32(2).002

Shu-Man Yao^＊, Ying-Yan Chen, Pei-Hsiu Kao, Yi-Lin Wen,Ruei-Siang Chen, Chuen-Sheue Chiang

2016 Vol.32 NO.2

Correspondence Author： Shu-Man Yao^＊

Abstract：

Taiwan government began providing free acellular vaccines (ACVs) in 2010, when whole-cell vaccines(WCVs) have been replaced by ACVs in many other countries. Because of selective pressure of vaccines, genotypes of vaccine-component antigens changed from vaccine strains (ptxA2/prn1 or ptxA4/prn1) to non-vaccine strains (ptxA1/prn2), as well as from ptxP1 to ptxP3 that produces more virulent factors to counteract immunity induced by vaccines. In recent years, pertactin-deficient (PRN-) strains emerged in several countries, resulting in circulation of pertussis. In Taiwan, majority of B. pertussis strains express pertactin whereas occurrence of PRN- strains was sporadic. Since expression of antigens directly affects efficacy of ACVs, the incidence of PRN- strains could be used as a warning index for disease occurrence and a reference for selecting vaccines. Pertussis in infants who are younger than twelve months old remains high in Taiwan. Some studies suggest that ACVs is effective in disease prevention, but not disease transmission. Therefore, immunized preschool children could be potential B. pertussis carriers and transmit pertussis to younger children. It is important to enforce knowledge on pertussis disease and vaccine in order to provide good care for children who are too young to gain full protection from vaccination.