Seroprevalence of anti-polio antibodies in children from polio high risk area of Afghanistan: A cross sectional survey 2017

Q: What are the key findings of this study?

Younger children (6-11 months) had higher risk of poliovirus seronegativity than older children, driven by lower PV2 seroprevalence.

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Poliovirus immunity / Poliomyelitis prevention (n=409). Intervention: Younger age group (6-11 months, born after trivalent OPV withdrawal) vs. Older age group (36-48 months, exposed to trivalent OPV). Primary outcome: Seronegativity for at least one poliovirus serotype (PV1, PV2, or PV3; neutralizing antibody titer <=8) (RR 3.6, 95% CI 2.2-5.6).

Q: What does this research mean for the field?

Children in Kandahar, Afghanistan achieved high serological protection against poliovirus types 1 and 3 (93–100%), but younger children aged 6–11 months had lower type 2 seroprevalence (71%) and a higher risk of seronegativity following the withdrawal of trivalent oral polio vaccine. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Imtiaz Hussain; Ondrej Mach; Nasir A. Hamid; Zaid Shakoor Bhatti; Deborah D. Moore; M. Steven Oberste; Shahid Khan; William C. Weldon; Roland W. Sutter; Zulfiqar Ahmed Bhutta; Sajid Bashir Soofi

doi:10.1016/j.vaccine.2018.02.055

March 3, 2018VaccineOpen Access

Seroprevalence of anti-polio antibodies in children from polio high risk area of Afghanistan: A cross sectional survey 2017

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Key result

Younger age linked to ~3.6-fold higher poliovirus seronegativity risk, driven by lower PV2 seroprevalence.

RR 3.6
95% CI 2.2-5.6
n=409

Why the study?

Afghanistan remained one of the wild-poliovirus endemic countries, motivating an evaluation of anti-poliovirus antibody seroprevalence in the high-risk area of Kandahar Province.

Study Design

Type

Cross-Sectional (n=409)

Multicenter

No

PICO

P

Population

409 children aged 6-11 months (n=200) and 36-48 months (n=209), 34% female, visiting Mirwais Regional Hospital in Kandahar, Afghanistan for minor polio-unrelated ailments between June and July 2017.

E

Exposure / Comparator

Younger age group (6-11 months, born after trivalent OPV withdrawal) vs Older age group (36-48 months, exposed to trivalent OPV)

O

Primary Outcome

Seronegativity for at least one poliovirus serotype (PV1, PV2, or PV3; neutralizing antibody titer <=8) — RR 3.6 (2.2-5.6)

Main Result

Relative Risk: 3.6 (95% CI 2.2–5.6)

Limitations

Facility-based survey at a single hospital due to security concerns rather than a community-based survey
Study population may not be representative of the general population and may come from a more privileged background given higher immunization coverage and card retention than national estimates
Most children in the 6-11 month age group were over 9 months old, which may have overestimated seroprevalence in the younger group
Campaign vaccine doses relied on parental recall and were not recorded on vaccination cards

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Abstract

BACKGROUND: Afghanistan is one of the remaining wild-poliovirus (WPV) endemic countries. We conducted a seroprevalence survey of anti-poliovirus antibodies in Kandahar Province. METHODS: Children in two age groups (6-11 months and 36-48 months) visiting Mirwais hospital in Kandahar for minor ailments unrelated to polio were enrolled. After obtaining informed consent, we collected venous blood and conducted neutralization assay to detect poliovirus neutralizing antibodies. RESULTS: A total of 420 children were enrolled and 409/420 (97%) were analysed. Seroprevalence to poliovirus type 1 (PV1) was 97% and 100% in the younger and older age groups respectively; it was 71% and 91% for PV2; 93% and 98% for PV3. Age group (RR = 3.6, CI 95% = 2.2-5.6) and place of residence outside of Kandahar city (RR = 1.8, CI 95% = 1.2-2.6) were found to be significant risk factors for seronegativity. CONCLUSIONS: The polio eradication program in Kandahar achieved high serological protection, especially against PV1 and PV3. Lower PV2 seroprevalence in the younger age group is a result of a withdrawal of live type 2 vaccine in 2016 and is expected. Ability to reach all children with poliovirus vaccines is a pre-requisite for achieving poliovirus eradication.

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Cite This Study

Hussain et al. (2018) conducted a cross-sectional in Poliovirus immunity / Poliomyelitis prevention (n=409). Younger age group (6-11 months, born after trivalent OPV withdrawal) vs. Older age group (36-48 months, exposed to trivalent OPV) was evaluated on Seronegativity for at least one poliovirus serotype (PV1, PV2, or PV3; neutralizing antibody titer <=8) (RR 3.6, 95% CI 2.2-5.6). Younger children (6-11 months) had higher risk of poliovirus seronegativity than older children, driven by lower PV2 seroprevalence.

synapsesocial.com/papers/6add55b5a516181685d5ead4 https://doi.org/10.1016/j.vaccine.2018.02.055

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Seroprevalence of anti-polio antibodies in children from polio high risk area of Afghanistan: A cross sectional survey 2017

Study Design

PICO

Main Result

Limitations

Ask about this paper

Abstract

Discussion

Cite This Study

Seroprevalence of anti-polio antibodies in children from polio high risk area of Afghanistan: A cross sectional survey 2017

Study Design

PICO

Main Result

Limitations

Ask about this paper

Abstract

Discussion

Cite This Study

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