Survey of poliovirus antibodies in Borno and Yobe States, North-Eastern Nigeria

Abstract

BackgroundNigeria remains one of only three polio-endemic countries in the world. In 2016, after an absence of 2 years, wild poliovirus serotype 1 was again detected in North-Eastern Nigeria. To better guide programmatic action, we assessed the immunity status of infants and children in Borno and Yobe states, and evaluated the impact of recently introduced inactivated poliovirus vaccine (IPV) on antibody seroprevalence.Methods and findingsWe conducted a facility-based study of seroprevalence to poliovirus serotypes 1, 2 and 3 among health-seeking patients in two sites each of Borno and Yobe States. Enrolment was conducted amongst children 6–9 and 36–47 months of age attending the paediatrics outpatient department of the selected hospitals in the two states between 11 January and 5 February 2016. Detailed demographic and immunization history of the child was taken and an assessment of the child’s health and nutritional state was conducted via physical examination. Blood was collected to test for levels of neutralizing antibody titres against the three poliovirus serotypes. The seroprevalence in the two age groups, potential determinants of seropositivity and the impact of one dose of IPV on humoral immunity were assessed. A total of 583 subjects were enrolled and provided sufficient quantities of serum for testing. Among 6-9-month-old infants, the seroprevalence was 81% (74–87%), 86% (79–91%), and 72% (65–79%) in Borno State, and 75% (67–81%), 74% (66–81%) and 69% (61–76%) in Yobe States, for serotypes-1, 2 and 3, respectively. Among children aged 36–47 months, the seroprevalence was >90% in both states for all three serotypes, with the exception of type 3 seroprevalence in Borno [87% (80–91%)]. Median reciprocal anti-polio neutralizing antibody titers were consistently >900 for serotypes 1 and 2 across age groups and states; with lower estimates for serotype 3, particularly in Borno. IPV received in routine immunization was found to be a significant determinant of seropositivity and anti-polio neutralizing antibodies among 6-9-month-old infants for serotypes 1 and 3, but demonstrated a non-significant positive association for serotype 2. Children receiving IPV through SIAs demonstrated significantly higher anti-polio neutralizing antibodies for serotypes 1 and 3.ConclusionsThe seroprevalence to poliovirus remains suboptimal in both Borno and Yobe States in Nigeria. The low seroprevalence facilitated the continued transmission of both wild serotype 1 and serotype 2 circulating vaccine-derived poliovirus detected in Borno State in 2016. Further efforts are necessary to improve the immunity status of these populations to ensure sufficient population immunity to interrupt transmission.

Poliovirus immunity among children under five years-old in accessible areas of Afghanistan, 2013

“…Overall, findings in this study show that titers and seropositivity in Afghanistan were higher for types 1 and 2 compared to type 3, a finding supported by similar poliovirus antibody seroprevalence studies conducted in Pakistan, Nigeria and the United States [14][15][16]. However, these results need to be interpreted with caution for several reasons.…”

Community-based survey to assess seroprevalence of poliovirus antibodies in far-north Cameroon in 2020

“… [14] Moreover, median titers for serotype 1 were high for all age groups and increased with age for serotype 2, again consistent with studies in Chad, Borno, and Yobe provinces of Nigeria. [13] , [14] , [15] .…”

Historical reconstruction of inaccessibility status in Local Government Areas (LGAs) of Borno and Yobe States, Nigeria, 2010-2020

“…Prior to discovery of ongoing, previously undetected transmission of WPV1 there was evidence of the suboptimal seroprevalence to poliovirus in accessible areas, and a large pool of susceptible infants in both Borno and Yobe States [ 21 ]. The last reported cases of WPV in Nigeria and the entire WHO African Region occurred in four children liberated from trapped inaccessible locations and tested in IDP areas of Borno, Nigeria in 2016 [ 2 ].…”