A national cross-sectional study for poliovirus seroprevalence in the Republic of Korea in 2012: implication for deficiency in immunity to polio among middle-aged people

Abstract

BackgroundA worldwide poliomyelitis eradication program was initiated in 1988; however, strains of wild poliovirus (WPV) are still endemic in some countries. Until WPV transmission is eradicated globally, importation and outbreaks of WPV are alarming possibilities. This study is the first report to document the polio immunity after 2004, when an inactivated polio vaccine (IPV) was introduced in the Republic of Korea.MethodsA total of 745 serum samples from randomly selected patients ranging from 6 to 84 years of age were used for neutralization tests, performed in the World Health Organization polio national reference laboratory.ResultsAmong the 745 tested sera, 439 (58.9%) were seropositive and 19 (2.6%) were seronegative to all PV serotypes. In all age groups, PV3 showed the lowest level of seroprevalence, at 509 cases (68.3%), compared to 616 (82.7%) for PV1 and 685 (91.9%) for PV2. In the 6–10-year age group, which included IPV-immunized children, the highest seropositive rate was observed and the difference in seroprevalence between PV3 and other serotypes was the lowest compared to the other age groups immunized with oral PV vaccines (OPV). In addition, the seronegative rates of all three PV types in children aged 6–10 in this study were found to be lower than those in OPV-immunized children reported in a previous study from the Republic of Korea. Meanwhile, middle-aged subjects (41–60 years) had the lowest seroprevalence and geometric mean titer.ConclusionsThis study indicates a deficiency in immunity to PV in middle-aged individuals, and low seroprevalence to PV3 in all age groups. In addition, due to the ongoing risk of importing PV, middle-aged people should consider PV vaccination before visiting a PV-endemic country. Our findings provide data to assist those involved in deciding future national polio vaccination strategies for the maintenance of a polio-free status in Korea.

Polio Seroprevalence in Thailand: Assessment of Outbreak Risk by Age Cohorts

“…The low percentage of protective antibody against poliovirus type 3 was also similar to other studies [20][21][22] . This might be explained by low sero-conversion rate or potency of OPV type 3.…”

“…This result was similar to the Republic of Korea's seroprevalence data which immunity is lower among middle-aged population. 20 The proportion of the population with protective antibody also increased among later birth cohorts as polio vaccination coverage increased.…”

Non-Polio Enteroviruses from Acute Flaccid Paralysis Surveillance in Korea, 2012–2019

“…The polio vaccine was introduced to the national immunization program (NIP) in 1983, and a four-dose polio vaccine schedule was recommended at 2, 4, and 6 months and at 4–6 years of age [ 3 ]. Due to the risk of vaccine-associated paralytic poliomyelitis and vaccine-derived polioviruses, OPV was withdrawn from the NIP in 2004 [ 4 ].…”

Seroepidemiology: an underused tool for designing and monitoring vaccination programmes in low‐ and middle‐income countries

“…In settings where infections are eliminated or near elimination and there are very few disease notifications, serosurveillance can detect immunity gaps before outbreaks occur. Causes of immunity gaps include failure to vaccinate certain population groups , in‐migration of unvaccinated persons , reduced vaccine effectiveness or waning vaccine‐induced immunity . Ideally, immunity gaps are identified in time to prevent outbreaks.…”