Intradermal Administration of Fractional Doses of Inactivated Poliovirus Vaccine: A Dose-Sparing Option for Polio Immunization.

A fractional dose of inactivated poliovirus vaccine (fIPV) administered by the intradermal route delivers one fifth of the full vaccine dose administered by the intramuscular route and offers a potential dose-sparing strategy to stretch the limited global IPV supply while further improving population immunity. Multiple studies have assessed immunogenicity of intradermal fIPV compared with the full intramuscular dose and demonstrated encouraging results. Novel intradermal devices, including intradermal adapters and disposable-syringe jet injectors, have also been developed and evaluated as alternatives to traditional Bacillus Calmette-Guérin needles and syringes for the administration of fIPV. Initial experience in India, Pakistan, and Sri Lanka suggests that it is operationally feasible to implement fIPV vaccination on a large scale. Given the available scientific data and operational feasibility shown in early-adopter countries, countries are encouraged to consider introducing a fIPV strategy into their routine immunization and supplementary immunization activities.

Boosting Immune Responses Following Fractional-Dose Inactivated Poliovirus Vaccine: A Randomized, Controlled Trial.

BACKGROUND: Fractional-dose administration of inactivated poliovirus vaccine (fIPV) could increase IPV affordability and stretch limited supplies. We assessed immune responses following fIPV administered intradermally, compared with full-dose IPV administered intramuscularly, among adults with a history of oral poliovirus vaccine (OPV) receipt. METHODS: We conducted a randomized, controlled noninferiority trial in Cuba. fIPV or IPV were administered on days 0 and 28; serum was collected on days 0, 7, 28, and 56 for analysis by a neutralization assay. The primary end point was seroconversion or a ≥4-fold rise in antibody titer. The noninferiority limit was 10%. The secondary end point was safety, assessed by the number and intensity of adverse reactions. RESULTS: A total of 503 of 534 enrolled participants (94.2%) completed all study requirements. Twenty-eight days after the first dose, 94.8%, 98.0%, and 98.0% of fIPV recipients had an immune response to poliovirus types 1, 2, and 3, respectively, compared with 98.1% (P = .06), 98.0% (P = 1.00), and 99.2% (P = .45) in the IPV arm. Noninferiority was achieved on days 7, 28, and 56 for all serotypes. No serious adverse events were reported. CONCLUSION: fIPV induced similar boosting immune responses, compared with full-dose IPV. This suggests that fIPV would be an effective strategy to boost population immunity in an outbreak situation. CLINICAL TRIALS REGISTRATION: ACTRN12615000305527.

Risk factors and short-term projections for serotype-1 poliomyelitis incidence in Pakistan: A spatiotemporal analysis.

BACKGROUND: Pakistan currently provides a substantial challenge to global polio eradication, having contributed to 73% of reported poliomyelitis in 2015 and 54% in 2016. A better understanding of the risk factors and movement patterns that contribute to poliovirus transmission across Pakistan would support evidence-based planning for mass vaccination campaigns. METHODS AND FINDINGS: We fit mixed-effects logistic regression models to routine surveillance data recording the presence of poliomyelitis associated with wild-type 1 poliovirus in districts of Pakistan over 6-month intervals between 2010 to 2016. To accurately capture the force of infection (FOI) between districts, we compared 6 models of population movement (adjacency, gravity, radiation, radiation based on population density, radiation based on travel times, and mobile-phone based). We used the best-fitting model (based on the Akaike Information Criterion [AIC]) to produce 6-month forecasts of poliomyelitis incidence. The odds of observing poliomyelitis decreased with improved routine or supplementary (campaign) immunisation coverage (multivariable odds ratio [OR] = 0.75, 95% confidence interval [CI] 0.67-0.84; and OR = 0.75, 95% CI 0.66-0.85, respectively, for each 10% increase in coverage) and increased with a higher rate of reporting non-polio acute flaccid paralysis (AFP) (OR = 1.13, 95% CI 1.02-1.26 for a 1-unit increase in non-polio AFP per 100,000 persons aged <15 years). Estimated movement of poliovirus-infected individuals was associated with the incidence of poliomyelitis, with the radiation model of movement providing the best fit to the data. Six-month forecasts of poliomyelitis incidence by district for 2013-2016 showed good predictive ability (area under the curve range: 0.76-0.98). However, although the best-fitting movement model (radiation) was a significant determinant of poliomyelitis incidence, it did not improve the predictive ability of the multivariable model. Overall, in Pakistan the risk of polio cases was predicted to reduce between July-December 2016 and January-June 2017. The accuracy of the model may be limited by the small number of AFP cases in some districts. CONCLUSIONS: Spatiotemporal variation in immunization performance and population movement patterns are important determinants of historical poliomyelitis incidence in Pakistan; however, movement dynamics were less influential in predicting future cases, at a time when the polio map is shrinking. Results from the regression models we present are being used to help plan vaccination campaigns and transit vaccination strategies in Pakistan.

Development of inactivated poliovirus vaccine from Sabin strains: A progress report.

The Global Polio Eradication Initiative (GPEI) has seen significant progress since it began in 1988, largely due to the worldwide use of oral poliovirus vaccine (OPV). In order to achieve polio eradication the global cessation of OPV is necessary because OPV contains live attenuated poliovirus, which in rare circumstances could re-gain wild poliovirus (WPV) characteristics with potential to establish transmission. The GPEI endgame strategy for the period 2013-2018 recommends the globally synchronised sequential cessation of the Sabin strains contained in the OPV, starting with type 2 Sabin. The withdrawal of Sabin type 2 took place in April 2016, with the introduction of at least one dose of inactivated poliovirus vaccine (IPV) as a risk mitigation strategy. The introduction of IPV into 126 countries since 2013 has required a rapid scale-up of IPV production by the two manufacturers supplying the global public sector market. This scale-up has been fraught with challenges, resulting in reductions of 40-50% of initial supply commitments. Consequently, 22 countries will not be supplied until 2018, and another 23 countries will experience serious stock-outs. In the last decade repeated calls-for-action were made to the global community to invigorate their vision and investment in developing "new poliovirus vaccines" including the development of IPV from less-virulent strains, such as Sabin-IPV (S-IPV). The conventional Salk-IPV production is limited to high-income industrialized-country manufacturers due to the containment requirements (i.e., high sanitation, low force-of-poliovirus-infection, and high population immunity). The use of Sabin strains in the production of S-IPV carries a lower biosafety risk, and was determined to be suitable for production in developing countries, expanding the manufacturing base and making IPV more affordable and accessible in the long term. Significant progress in the S-IPV has been made since 2006. S-IPV is now licensed as S-IPV in Japan and as standalone S-IPV in China, demonstrating the feasibility of this vaccine. In addition, production process improvements can further reduce the cost of production. The latter are critical to the economic success of this vaccine in the global market. We summarize the progress made to date in S-IPV technology, the scientific data and economic evidence in support of S-IPV development.

Using short-message-service notification as a method to improve acute flaccid paralysis surveillance in Papua New Guinea.

BACKGROUND: High quality acute flaccid paralysis (AFP) surveillance is required to maintain polio-free status of a country. Papua New Guinea (PNG) is considered as one of the highest risk countries for polio re-importation and circulation in the Western Pacific Region (WPRO) of the World Health Organization due to poor healthcare infrastructure and inadequate performance in AFP surveillance. The Government of PNG, in collaboration with WHO, piloted the introduction of short-message-service (SMS) to sensitize pediatricians and provincial disease control officers on AFP and to receive notification of possible AFP cases to improve surveillance quality in PNG. METHODS: Ninety six health care professionals were registered to receive SMS reminders to report any case of acute flaccid paralysis. Fourteen SMS messages were sent to each participant from September 2012 to November 2013. The number of reported AFP cases were compared before and after the introduction of SMS. RESULTS: Two hundred fifty three unique responses were received with an overall response rate of 21 %. More than 80 % of responses were reported within 3 days of sending the SMS. The number of reported AFP cases increased from 10 cases per year in 2009-2012 to 25 cases per year during the study period and correlated with provincial participation of the health care professionals. CONCLUSIONS: Combined with improved sensitization of health care professionals on AFP reporting criteria and sample collection, SMS messaging provides an effective means to increase timely reporting and improve the availability of epidemiologic information on polio surveillance in PNG.

Affordable inactivated poliovirus vaccine: strategies and progress.

After polio eradication is achieved, the use of live-attenuated oral poliovirus vaccine (OPV) must be discontinued because of the inherent risk of the Sabin strains to revert to neurovirulence and reacquire greater transmissibility that could potentially result in the reestablishment of polio transmission. In 2008, the World Health Assembly mandated that the World Health Organization establish a strategy for developing more-affordable inactivated poliovirus vaccine (IPV) options for low-income countries. In 2012, the Strategic Advisory Group of Experts (SAGE) on Immunization recommended universal IPV introduction as a risk-mitigation strategy before the phased cessation of OPV (starting with Sabin type 2) and emphasized the need for affordable IPV options. In 2013, SAGE reiterated the importance of attaining the long-term target price of IPV at approximately $0.5 per immunizing dose and encouraged accelerated efforts to develop lower-cost IPV options. This article outlines the 4-pronged approach that is being pursued to develop affordable options and provides an update on the current status and plans to make IPV affordable for developing-country use.

Lot quality assurance sampling to monitor supplemental immunization activity quality: an essential tool for improving performance in polio endemic countries.

Monitoring the quality of supplementary immunization activities (SIAs) is a key tool for polio eradication. Regular monitoring data, however, are often unreliable, showing high coverage levels in virtually all areas, including those with ongoing virus circulation. To address this challenge, lot quality assurance sampling (LQAS) was introduced in 2009 as an additional tool to monitor SIA quality. Now used in 8 countries, LQAS provides a number of programmatic benefits: identifying areas of weak coverage quality with statistical reliability, differentiating areas of varying coverage with greater precision, and allowing for trend analysis of campaign quality. LQAS also accommodates changes to survey format, interpretation thresholds, evaluations of sample size, and data collection through mobile phones to improve timeliness of reporting and allow for visualization of campaign quality. LQAS becomes increasingly important to address remaining gaps in SIA quality and help focus resources on high-risk areas to prevent the continued transmission of wild poliovirus.

Cluster lot quality assurance sampling: effect of increasing the number of clusters on classification precision and operational feasibility.

BACKGROUND: To assess the quality of supplementary immunization activities (SIAs), the Global Polio Eradication Initiative (GPEI) has used cluster lot quality assurance sampling (C-LQAS) methods since 2009. However, since the inception of C-LQAS, questions have been raised about the optimal balance between operational feasibility and precision of classification of lots to identify areas with low SIA quality that require corrective programmatic action. METHODS: To determine if an increased precision in classification would result in differential programmatic decision making, we conducted a pilot evaluation in 4 local government areas (LGAs) in Nigeria with an expanded LQAS sample size of 16 clusters (instead of the standard 6 clusters) of 10 subjects each. RESULTS: The results showed greater heterogeneity between clusters than the assumed standard deviation of 10%, ranging from 12% to 23%. Comparing the distribution of 4-outcome classifications obtained from all possible combinations of 6-cluster subsamples to the observed classification of the 16-cluster sample, we obtained an exact match in classification in 56% to 85% of instances. CONCLUSIONS: We concluded that the 6-cluster C-LQAS provides acceptable classification precision for programmatic action. Considering the greater resources required to implement an expanded C-LQAS, the improvement in precision was deemed insufficient to warrant the effort.

Effect of buffer on the immune response to trivalent oral poliovirus vaccine in Bangladesh: a community based randomized controlled trial.

BACKGROUND: Polio eradication efforts have been hampered by low responses to trivalent oral poliovirus vaccine (tOPV) in some developing countries. Since stomach acidity may neutralize vaccine viruses, we assessed whether administration of a buffer solution could improve the immunogenicity of tOPV. METHODS: Healthy infants 4-6 weeks old in Sylhet, Bangladesh, were randomized to receive tOPV with or without a sodium bicarbonate and sodium citrate buffer at age 6, 10, and 14 weeks. Levels of serum neutralizing antibodies for poliovirus types 1, 2, and 3 were measured before and after vaccination, at 6 and 18 weeks of age, respectively. FINDINGS: Serologic response rates following 3 doses of tOPV for buffer recipients and control infants were 95% and 88% (P=.065), respectively, for type 1 poliovirus; 95% and 97% (P=.543), respectively, for type 2 poliovirus; and 90% and 89% (P=.79), respectively, for type 3 poliovirus. CONCLUSIONS: Administration of a buffer solution prior to vaccination was not associated with statistically significant increases in the immune response to tOPV; however, a marginal 7% increase (P=.065) in serologic response to poliovirus type 1 was observed. CLINICAL TRIALS REGISTRATION: NCT01579825.

Progress in the development of poliovirus antiviral agents and their essential role in reducing risks that threaten eradication.

Chronic prolonged excretion of vaccine-derived polioviruses by immunodeficient persons (iVDPV) presents a personal risk of poliomyelitis to the patient as well as a programmatic risk of delayed global eradication. Poliovirus antiviral drugs offer the only mitigation of these risks. Antiviral agents may also have a potential role in the management of accidental exposures and in certain outbreak scenarios. Efforts to discover and develop poliovirus antiviral agents have been ongoing in earnest since the formation in 2007 of the Poliovirus Antivirals Initiative. The most advanced antiviral, pocapavir (V-073), is a capsid inhibitor that has recently demonstrated activity in an oral poliovirus vaccine human challenge model. Additional antiviral candidates with differing mechanisms of action continue to be profiled and evaluated preclinically with the goal of having 2 antivirals available for use in combination to treat iVDPV excreters.

Inactivated Poliovirus Vaccine: Recent Developments and the Tortuous Path to Global Acceptance.

Inactivated poliovirus vaccine (IPV), available since 1955, became the first vaccine to be used to protect against poliomyelitis. While the immunogenicity of IPV to prevent paralytic poliomyelitis continues to be irrefutable, its requirement for strong containment (due to large quantities of live virus used in the manufacturing process), perceived lack of ability to induce intestinal mucosal immunity, high cost and increased complexity to administer compared to oral polio vaccine (OPV), have limited its use in the global efforts to eradicate poliomyelitis. In order to harvest the full potential of IPV, a program of work has been carried out by the Global Polio Eradication Initiative (GPEI) over the past two decades that has focused on: (1) increasing the scientific knowledge base of IPV; (2) translating new insights and evidence into programmatic action; (3) expanding the IPV manufacturing infrastructure for global demand; and (4) continuing to pursue an ambitious research program to develop more immunogenic and safer-to-produce vaccines. While the knowledge base of IPV continues to expand, further research and product development are necessary to ensure that the program priorities are met (e.g., non-infectious production through virus-like particles, non-transmissible vaccine inducing humoral and intestinal mucosal immunity and new methods for house-to-house administration through micro-needle patches and jet injectors), the discussions have largely moved from whether to how to use this vaccine most effectively. In this review, we summarize recent developments on expanding the science base of IPV and provide insight into policy development and the expansion of IPV manufacturing and production, and finally we provide an update on the current priorities.

Promoting healthy ageing in the Western Pacific: A mini review of good practices and policy responses.

The Western Pacific Region is experiencing rapid population ageing, which has implications for almost all areas of society. Countries will need to prepare for population ageing by investing in health and optimizing living environments. This requires a whole-of-society approach to healthy ageing. Countries in the Western Pacific Region have been making significant progress in healthy ageing. Since the endorsement of the Regional Action Plan on Healthy Ageing, younger societies have also started preparing for population ageing, focusing on social and health systems transformation, community-based integrated care, social and technological innovations and research, monitoring and evaluation. As more countries are interested in healthy ageing and preparing for necessary social and health systems transformation, the case studies in this article can be an inspiration for Member States to transform their approaches to achieving a society where older adults are healthier and can participate fully.

Strengthening the Acute Flaccid Paralysis (AFP) Surveillance Component of the Polio Eradication Initiative through Short Message Service (SMS) Reminders; Experience from Sokoto State, Nigeria 2014.

Eradication of poliomyelitis remains a public health priority due to the paralytic effects of the virus on children and impact on global health system. However, existing gaps in surveillance can hinder eradication. Improved timeliness of identification and reporting of acute flaccid paralysis (AFP) cases with further confirmation of Wild Poliovirus (WPV) in stool samples, can help Nigeria achieve the performance indicators of non-polio AFP rate of ≥ 2/100,000 population aged < 15 years and ≥80% stool sample collection adequacy. To ascertain the awareness of AFP case definition and detection by health care workers and to evaluate the impact of SMS-based reporting on the AFP surveillance system the study was conducted from November 2013 to July 2014. In Sokoto state, 112 health facilities (focal sites) were operational and participated in this study. All AFP focal points for the 112 facilities were included in the study. In addition to AFP focal points, two clinicians per facility where possible, were included in the study. The study focused exclusively on reports from focal sites. The methodology was a one group pretest-posttest design conducted in 3 phases. 1) Pre-intervention Knowledge, Attitude and Practices (KAP) survey, 2) SMS implementation and 3) Post-intervention KAP. Results were analysed using the independent sample t-test to assess the increase in knowledge, attitudes, or practice scores pre- and post- training. The study showed improved knowledge gap of health care workers on AFP surveillance between pre and post intervention. It shows that this approach of improved surveillance will be effective in countries in hard to reach, access compromised or countries/place without sufficient surveillance staff.

Challenges of vaccine presentation and delivery: How can we design vaccines to have optimal programmatic impact?

Immunization program delivery strategies that enable high vaccine coverage, particularly in inaccessible and remote areas, are critical to achieving optimal vaccine impact. In addition to demonstration of safety and efficacy, there are many factors that influence whether a newly licensed vaccine will be introduced into a country's national immunization program, particularly in resource-constrained environments. This paper describes three case studies of novel approaches that represent the potential for improved programmatic impact by increasing vaccine accessibility in different ways. However, the pathway to regulatory approval, policy recommendation, and program introduction in low- and middle-income countries is complex, requiring engagement with multiple, diverse stakeholders. Consideration of aspects that affect uptake in low- and middle-income countries, during the product development stage, will help better position new or second-generation vaccine products for successful implementation to achieve public health impact.

Satellite imagery technology in public health: analysis of site catchment areas for assessment of poliovirus circulation in Nigeria and Niger.

Environmental surveillance supplements the surveillance of acute flaccid paralysis by monitoring wastewater for poliovirus circulation. Building on previous work, we analysed wastewater flow to optimise selection and placement of sampling sites with higher digital surface model (DSM) resolution. The newly developed 5-m mesh DSM from the panchromatic, remote-sensing instruments for stereo mapping on-board the Japanese advanced land observing satellite was used to estimate catchment areas and flow of sewage water based on terrain topography. Optimal sampling sites for environmental surveillance were identified to maximise sensitivity to poliovirus circulation. Population data were overlaid to prioritise selection of catchment areas with dense populations. The results for Kano City, Nigeria were compared with an analysis based on existing 30- and 90-m mesh digital elevation model (DEM). Analysis based on 5-m mesh DSM was also conducted for three cities in Niger to prioritise the selection of new sites. The analysis demonstrated the feasibility of using DSMs to estimate catchment areas and population size for programme planning and outbreak response with respect to polio. Alternative sampling points in Kano City that would cover a greater population size have been identified and potential sampling sites in Niger are proposed. Comparison with lower-resolution DEMs suggests that the use of a 5-m mesh DSMs would be useful where the terrain is flat or includes small-scale topographic changes not captured by 30-m data searches.

Decay of Sabin inactivated poliovirus vaccine (IPV)-boosted poliovirus antibodies.

INTRODUCTION: We conducted a follow-on study to a phase I randomized, controlled trial conducted in Cuba, 2012, to assess the persistence of poliovirus antibodies at 21-22 months following booster dose of Sabin-IPV compared to Salk-IPV in adults who had received multiple doses of oral poliovirus vaccine (OPV) during childhood. METHODS: In 2012, 60 healthy adult males aged 19-23 were randomized to receive one booster dose, of either Sabin-inactivated poliovirus vaccine (Sabin-IPV), adjuvanted Sabin-IPV (aSabin-IPV), or conventional Salk-IPV. In the original study, blood was collected at days 0 (before) and 28 (after vaccination), respectively. In this study, an additional blood sample was collected 21-22 months after vaccination, and tested for neutralizing antibodies to Sabin poliovirus types 1, 2 and 3. RESULTS: We collected sera from 59/60 (98.3%) subjects; 59/59 (100%) remained seropositive to all poliovirus types, 21-22 months after vaccination. The decay curves were very similar among the study groups. Between day 28 and 21-22 months, there was a reduction of ⩾87.4% in median antibody levels for all poliovirus types in all study groups, with no significant differences between the study groups. CONCLUSION: The decay of poliovirus antibodies over a 21-22-month period was similar regardless of the type of booster vaccine used, suggesting the scientific data of Salk IPV long-term persistence and decay may be broadly applicable to Sabin IPV.

Reactogenicity and immunogenicity of inactivated poliovirus vaccine produced from Sabin strains: a phase I Trial in healthy adults in Cuba.

BACKGROUND: To ensure that developing countries have the option to produce inactivated poliovirus vaccine (IPV), the Global Polio Eradication Initiative has promoted the development of an IPV using Sabin poliovirus strains (Sabin IPV). This trial assessed the reactogenicity and immunogenicity of Sabin IPV and adjuvanted Sabin IPV in healthy adults in Cuba. METHODS: This is a randomized, controlled phase I trial, enrolling 60 healthy (previously vaccinated) male human volunteers, aged 19-23 years to receive one dose of either Sabin IPV (20:32:64 DU/dose), adjuvanted Sabin IPV (10:16:32 DU/dose), or conventional Salk IPV (40:8:32 DU/dose). The primary endpoint for reactogenicity relied on monitoring of adverse events. The secondary endpoint measured boosting immune responses (i.e. seroconversion or 4-fold rise) of poliovirus antibody, assessed by neutralization assays. RESULTS: Sixty subjects fulfilled the study requirements. No serious adverse events reported were attributed to trial interventions during the 6-month follow-up period. Twenty-eight days after vaccination, boosting immune responses against poliovirus types 1-3 were between 90% and 100% in all vaccination groups. There was a more than 6-fold increase in median antibody titers between pre- and post-vaccination titers in all vaccination groups. DISCUSSION: Both Sabin IPV and adjuvanted Sabin IPV were well tolerated and immunogenic against all poliovirus serotypes. This result suggests that the aluminum adjuvant may allow a 50% (or higher) dose reduction.

Safety and immunogenicity of a primary series of Sabin-IPV with and without aluminum hydroxide in infants.

BACKGROUND: An inactivated poliovirus vaccine (IPV) based on attenuated poliovirus strains (Sabin-1, -2 and -3) was developed for technology transfer to manufacturers in low- and middle-income countries in the context of the global polio eradication initiative. METHOD: Safety and immunogenicity of Sabin-IPV (sIPV) was evaluated in a double-blind, randomized, controlled, dose-escalation trial in the target population. Healthy infants (n=20/group) aged 56-63 days, received a primary series of three intramuscular injections with low-, middle- or high-dose sIPV with or without aluminum hydroxide or with the conventional IPV based on wild poliovirus strains (wIPV). Virus-neutralizing titers against both Sabin and wild poliovirus strains were determined before and 28 days after three vaccinations. RESULTS: The incidence of local and systemic reactions was comparable with the wIPV. Seroconversion rates after three vaccinations were 100% for type 2 and type 3 polioviruses (both Sabin and wild strains) and 95-100% for type 1 polioviruses. Median titers were high in all groups. Titers were well above the log2(titer) correlated with protection (=3) for all groups. Median titers for Sabin-2 were 9.3 (range 6.8-11.5) in the low-dose sIPV group, 9.2 (range 6.8-10.2) in the low-dose adjuvanted sIPV group and 9.8 (range 5.5-15.0) in the wIPV group, Median titers against MEF-1 (wild poliovirus type 2) were 8.2 (range 4.8-10.8) in the low-dose sIPV group, 7.3 (range 4.5-10.2) in the low-dose adjuvanted Sabin-IPV group and 10.3 (range 8.5-17.0) in the wIPV group. For all poliovirus types the median titers increased with increasing dose levels. CONCLUSION: sIPV and sIPV adjuvanted with aluminum hydroxide were immunogenic and safe at all dose levels, and comparable with the wIPV. EudraCTnr: 2011-003792-11, NCT01709071.

Safety and immunogenicity of inactivated poliovirus vaccine based on Sabin strains with and without aluminum hydroxide: a phase I trial in healthy adults.

BACKGROUND: An inactivated poliovirus vaccine (IPV) based on attenuated poliovirus strains (Sabin-1, -2 and -3) was developed for technology transfer to manufacturers in low- and middle income countries in the context of the Global Polio Eradication Initiative. METHOD: Safety and immunogenicity of the Sabin-IPV was evaluated in a double-blind, randomized, controlled, phase I 'proof-of-concept' trial. Healthy male adults received a single intramuscular injection with Sabin-IPV, Sabin-IPV adjuvanted with aluminum hydroxide or conventional IPV. Virus-neutralizing titers against both Sabin and wild poliovirus strains were determined before and 28 days after vaccination. RESULTS: No vaccine-related serious adverse events were observed, and all local and systemic reactions were mild or moderate and transient. In all subjects, an increase in antibody titer for all types of poliovirus (both Sabin and wild strains) was observed 28 days after vaccination. CONCLUSION: Sabin-IPV and Sabin-IPV adjuvanted with aluminum hydroxide administered as a booster dose were equally immunogenic and safe as conventional IPV. EudraCTnr: 2010-024581-22, NCT01708720.