BACKGROUND: Due to global shortage of inactivated poliovirus vaccine and withdrawal of oral vaccine containing poliovirus type 2 (PV2), a PV2-containing vaccine was not used in Vietnam May 2016 to October 2018. We assessed the population immunity gap to PV2. METHODS: A cross-sectional survey in children aged 1-18 months was carried out in January 2018. One blood sample per child was analyzed for presence of poliovirus neutralizing antibodies. In children with detectable anti-PV2 antibodies, a second sample was analyzed 4 months later to distinguish between passive (maternally derived) and active (induced by secondary transmission or vaccination) immunity. RESULTS: Sera were obtained from 1106/1110 children. Seroprevalence of PV2 antibodies was 87/368 (23.6%) at age 1-7 months, 27/471 (5.7%) at 8-15 months, and 19/267 (7.1%) at 16-18 months. Seroprevalence declined with age in the 1-7 months group; in the 8-18 months group there was no significant change with age. Four months later, 11/87 (14%), 9/27 (32%), and 12/19 (37%) remained seropositive in 1-7, 8-15, and 16-18 months age groups, respectively. CONCLUSIONS: We found declining immunity to PV2, suggesting Vietnam is at risk for an outbreak of type 2 vaccine-derived poliovirus following virus importation or new emergence.
BACKGROUND: Due to global shortage of inactivated poliovirus vaccine and withdrawal of oral vaccine containing poliovirus type 2 (PV2), a PV2-containing vaccine was not used in Vietnam May 2016 to October 2018. We assessed the population immunity gap to PV2. METHODS: A cross-sectional survey in children aged 1-18 months was carried out in January 2018. One blood sample per child was analyzed for presence of poliovirus neutralizing antibodies. In children with detectable anti-PV2 antibodies, a second sample was analyzed 4 months later to distinguish between passive (maternally derived) and active (induced by secondary transmission or vaccination) immunity. RESULTS: Sera were obtained from 1106/1110 children. Seroprevalence of PV2 antibodies was 87/368 (23.6%) at age 1-7 months, 27/471 (5.7%) at 8-15 months, and 19/267 (7.1%) at 16-18 months. Seroprevalence declined with age in the 1-7 months group; in the 8-18 months group there was no significant change with age. Four months later, 11/87 (14%), 9/27 (32%), and 12/19 (37%) remained seropositive in 1-7, 8-15, and 16-18 months age groups, respectively. CONCLUSIONS: We found declining immunity to PV2, suggesting Vietnam is at risk for an outbreak of type 2 vaccine-derived poliovirus following virus importation or new emergence.
Authors: Q Sue Huang; Gail Greening; Michael G Baker; Keith Grimwood; Joanne Hewitt; Debbie Hulston; Lisa van Duin; Amanda Fitzsimons; Nick Garrett; David Graham; Diana Lennon; Hiroyuki Shimizu; Tatsuo Miyamura; Mark A Pallansch Journal: Lancet Date: 2005 Jul 30-Aug 5 Impact factor: 79.321
Authors: P Más Lago; V M Cáceres; M A Galindo; H E Gary; M Valcarcel; J Barrios; L Sarmiento; I Avalos; J A Bravo; R Palomera; M Bello; R W Sutter; M A Pallansch; C A de Quadros Journal: Int J Epidemiol Date: 2001-10 Impact factor: 7.196
Authors: Pedro Más Lago; Howard E Gary; Luis Sarmientos Pérez; Victor Cáceres; Julio Barrios Olivera; Rosa Palomera Puentes; Marité Bello Corredor; Patricia Jímenez; Mark A Pallansch; Roberto González Cruz Journal: Int J Epidemiol Date: 2003-10 Impact factor: 7.196
Authors: Ali Faisal Saleem; Ondrej Mach; Mohammad Tahir Yousafzai; Zaubina Kazi; Attaullah Baig; Muhammad Sajid; Vishali Jeyaseelan; Roland W Sutter; Anita K M Zaidi Journal: J Infect Dis Date: 2021-04-08 Impact factor: 5.226