Economic analysis of prevaccination serotesting compared with presumptive immunization for polio, diphtheria, and tetanus in internationally adopted and immigrant infants

Review of poliovirus modeling performed from 2000 to 2019 to support global polio eradication

INTRODUCTION

Over the last 20 years (2000-2019) the partners of the Global Polio Eradication Initiative (GPEI) invested in the development and application of mathematical models of poliovirus transmission as well as economics, policy, and risk analyses of polio endgame risk management options, including policies related to poliovirus vaccine use during the polio endgame.

AREAS COVERED

This review provides a historical record of the polio studies published by the three modeling groups that primarily performed the bulk of this work. This review also systematically evaluates the polio transmission and health economic modeling papers published in English in peer-reviewed journals from 2000 to 2019, highlights differences in approaches and methods, shows the geographic coverage of the transmission modeling performed, identified common themes, and discusses instances of similar or conflicting insights or recommendations.

EXPERT OPINION

Polio modeling performed during the last 20 years substantially impacted polio vaccine choices, immunization policies, and the polio eradication pathway. As the polio endgame continues, national preferences for polio vaccine formulations and immunization strategies will likely continue to change. Future modeling will likely provide important insights about their cost-effectiveness and their relative benefits with respect to controlling polio and potentially achieving and maintaining eradication.

Assessment of the Clinical and Economic Impact of Different Immunization Protocols of Measles, Mumps, Rubella and Varicella in Internationally Adopted Children

The appropriate immunization of internationally adopted children (IAC) is currently under debate and different approaches have been suggested. The aim of this study is to evaluate the clinical and economic impact of different strategies of measles, mumps, rubella, and varicella (MMRV) immunization in IAC in Italy. A decision analysis model was developed to compare three strategies: presumptive immunization, pre-vaccination serotesting and vaccination based on documentation of previous immunization. Main outcomes were the cost of strategy, number of protected IAC, and cost per child protected against MMRV. Moreover, the incremental cost-effectiveness ratio (ICER) was calculated. The strategy currently recommended in Italy (immunize based on documentation) is less expensive. On the other hand, the pre-vaccination serotesting strategy against MMRV together, improves outcomes with a minimum cost increase, compared with the presumptive immunization strategy and compared with the comparator strategy. From a cost-effectiveness point of view, vaccination based on serotesting results in being the most advantageous strategy compared to presumptive vaccination. By applying a chemiluminescent immunoassay test, the serology strategy resulted to be clinically and economically advantageous. Similar results were obtained excluding children aged <1 year for both serology methods. In conclusion, based on our analyses, considering MMRV vaccine, serotesting strategy appears to be the preferred option in IAC.

Systematic review shows that immunising internationally adopted children is a major challenge for primary health care

AIM

This systematic review aimed to provide an overview of the immunisation of internationally adopted children and to discuss possible vaccination strategies.

METHODS

A literature search was performed covering papers published in English from 1988 to 15 June 2018 using the Ovid MEDLINE, EMBASE and Cochrane Library databases. This identified 749 studies and 41 full texts were evaluated.

RESULTS

Overall, 19 studies conducted between 1988 and 2016 fulfilled our inclusion criteria. These covered 7663 children aged 1.1-5.7 years adopted from Asia, Eastern Europe, Africa and South and Central America. Tetanus protective antibody levels ranged from 35 to 95%, and similar data were reported for diphtheria. A higher percentage of adoptees had protective antibody levels for polio (50-93%) and measles (62-95%). More than a third (35%) did not have protective antibody titres for hepatitis B. Only one study investigated adoptees with protective antibodies against haemophilus influenza, and it reported that this was around 66%.

CONCLUSION

The appropriate immunisation of internationally adopted children is a major challenge for primary health care and a number of different approaches have been suggested, with no clear conclusions. Further studies on the cost-effectiveness of different approaches should be performed to optimise screening strategies and develop recommendations.

Interventions to Improve Vaccination Uptake and Cost Effectiveness of Vaccination Strategies in Newly Arrived Migrants in the EU/EEA: A Systematic Review

Newly arrived migrants to the EU/EEA (arrival within the past five years), as well as other migrant groups in the region, might be under-immunised and lack documentation of previous vaccinations, putting them at increased risk of vaccine-preventable diseases circulating in Europe. We therefore performed a systematic review conforming to PRISMA guidelines (PROSPERO CRD42016045798) to explore: (i) interventions that improve vaccine uptake among migrants; and (ii) cost-effectiveness of vaccination strategies among this population. We searched MEDLINE, Embase, CINAHL, and Cochrane Database of Systematic Reviews (CDSR) between 1 January 2006 to 18 June 2018. We included three primary intervention studies performed in the EU/EEA or high-income countries and one cost effectiveness study relevant to vaccinations in migrants. Intervention studies showed small but promising impact only on vaccine uptake with social mobilization/community outreach, planned vaccination programs and education campaigns. Targeting migrants for catch-up vaccination is cost effective for presumptive vaccination for diphtheria, tetanus, and polio, and there was no evidence of benefit of carrying out pre-vaccination serological testing. The cost-effectiveness is sensitive to the seroprevalence and adherence to vaccinations of the migrant. We conclude that scarce but direct EU/EEA data suggest social mobilization, vaccine programs, and education campaigns are promising strategies for migrants, but more research is needed. Research should also study cost effectiveness of strategies. Vaccination of migrants should continue to be a public heath priority in EU/EEA.

Tetanus immunity as a surrogate for past diphtheria-tetanus-pertussis immunization in migrant children

BACKGROUND

Data on vaccination coverage in recently arrived refugee children are essential to formulate catch-up recommendations. "Overimmunizing" is costly and associated with risks of hyperimmunization, whereas assuming up-to-date immunizations may be misleading.

METHODS

We retrospectively collected data from 92 migrant children referred to our hospital between January 2009 and May 2010.

RESULTS

According to our guidelines, 68 (73.9%) children without evidence of up-to-date immunizations received a booster dose of an age-appropriate tetanus-containing vaccine. As a surrogate for diphtheria-tetanus-pertussis-poliomyelitis immunity, tetanus antibodies were measured by enzyme-linked immunosorbent assay 1 month later in 55 of 68 (80.8%) children 6 months to 16 years of age (median, 7 years) from 23 countries. All but 2 children (3.6%) had reached high antibody titers (>1.0 IU/mL) and required no further booster. Unnecessary additional tetanus immunizations thus were avoided in 53 of 55 (96.4%) patients.

CONCLUSION

Assessing antitetanus antibody responses in migrant children allows individual vaccination schedules and avoids the risks of hyperimmunization.

The seroepidemiology of tetanus in Catalonia, Spain

Titres of anti-tetanus toxin antibodies > or = 0.1 IU/ml were determined using an enzyme linked immunosorbent assay in representative samples of the juvenile and adult population of Catalonia. The prevalence obtained in 1,316 juveniles and 1,296 adults was 99.4 and 68.3%, respectively. In adults, the prevalence in males (76.5%) was higher (P < 0.001) than in females (61.7%), fell with increasing age and was higher in subjects born in Catalonia (72.5%) than in those born outside Catalonia (57.9%) (P < 0.001). These results show that routine vaccination of children is successful. In adults aged > or = 45 years, the prevalence is inadequate and efforts should be made to increase vaccination.