Hexavalent vaccines: characteristics of available products and practical considerations from a panel of Italian experts

Combination vaccines represent a valuable technological innovation in the field of infectious disease prevention and public health, because of their great health and economic value from the individual, societal, and healthcare system perspectives. In order to increase parents' and healthcare professionals' confidence in the vaccination programs and maintain their benefits to society, more information about the benefits of innovative vaccination tools such as combination vaccines is needed. Purpose of this work is an examination of available hexavalent vaccines, that protect against Diphtheria, Tetanus, Pertussis, Poliomyelitis, Hepatitis B and Haemophilus influenzae type b infections. From the epidemiological updates of vaccine preventable diseases to the vaccine development cycle, from the immunogenicity of antigenic components to the safety and co-administration with other vaccines, several aspects of available hexavalent vaccines are discussed and deepened. Also a number of practical considerations on schedules, age of employment, strategies for vaccination recovery, vaccination in at-risk births are issued, based on the recommendations of Italian Ministry of Health, Italian Society of Pharmacology (SIF), Italian Society for Pediatrics (SIP), Italian Federation of Family Paediatricians (FIMP) and Italian Society of Hygiene, Preventive Medicine and Public Health (SItI).

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.

Communications, Immunization, and Polio Vaccines: Lessons From a Global Perspective on Generating Political Will, Informing Decision-Making and Planning, and Engaging Local Support

The requirements under objective 2 of the Polio Eradication and Endgame Strategic Plan 2013-2018-to introduce at least 1 dose of inactivated poliomyelitis vaccine (IPV); withdraw oral poliomyelitis vaccine (OPV), starting with the type 2 component; and strengthen routine immunization programs-set an ambitious series of targets for countries. Effective implementation of IPV introduction and the switch from trivalent OPV (containing types 1, 2, and 3 poliovirus) to bivalent OPV (containing types 1 and 3 poliovirus) called for intense global communications and coordination on an unprecedented scale from 2014 to 2016, involving global public health technical agencies and donors, vaccine manufacturers, World Health Organization and United Nations Children's Fund regional offices, and national governments. At the outset, the new program requirements were perceived as challenging to communicate, difficult to understand, unrealistic in terms of timelines, and potentially infeasible for logistical implementation. In this context, a number of core areas of work for communications were established: (1) generating awareness and political commitment via global communications and advocacy; (2) informing national decision-making, planning, and implementation; and (3) in-country program communications and capacity building, to ensure acceptance of IPV and continued uptake of OPV. Central to the communications function in driving progress for objective 2 was its ability to generate a meaningful policy dialogue about polio vaccines and routine immunization at multiple levels. This included efforts to facilitate stakeholder engagement and ownership, strengthen coordination at all levels, and ensure an iterative process of feedback and learning. This article provides an overview of the global efforts and challenges in successfully implementing the communications activities to support objective 2. Lessons from the achievements by countries and partners will likely be drawn upon when all OPVs are completely withdrawn after polio eradication, but also may offer a useful model for other global health initiatives.

'An American tragedy'. the Cutter incident and its implications for the Salk polio vaccine in New Zealand 1955-1960

During the United States polio immunisation campaign in 1955 a number of children immunised with Cutter Laboratories vaccine were stricken with the disease, halting the programme. This event, the Cutter Incident, had major repercussions in the United States but also in many other countries such as New Zealand, Britain, and Australia. In New Zealand scarcity of vaccine left children exposed to the 1955-6 epidemic and the Department of Health's planned immunisation campaign at the mercy of erratic supply. This paper examines how the consequences of the Cutter Incident shaped the New Zealand polio immunisation programme. The New Zealand experiences with the polio vaccine are set in an international context in order to give an appreciable understanding of the events that occurred.

Decision analysis in planning for a polio outbreak in the United States

OBJECTIVE

Global eradication of poliomyelitis may soon be achieved, but circulating polioviruses could reemerge years after eradication by reversion of live attenuated oral vaccine virus to a virulent form, laboratory stock mishandling, or bioterrorism. If a poliomyelitis outbreak occurs in the United States, access to a vaccine stockpile to interrupt viral spread will be necessary. Options for the stockpile include the inactivated polio vaccine and the live-attenuated trivalent and monovalent oral poliovirus vaccines. With differences in immunogenicity, adverse effects, availability, and other issues, the optimal vaccine choice for the stockpile is not clear. We sought to compare vaccine interventions for poliomyelitis outbreak control.

DESIGN

We applied decision analysis to 8 strategies for outbreak control: no intervention, 1 or 2 inactivated polio vaccine doses, 1 or 2 trivalent oral poliovirus vaccine doses, 1 or 2 monovalent oral poliovirus vaccine doses, and sequential inactivated polio vaccine-monovalent oral poliovirus vaccine. Historical data from outbreaks in developed countries were used to estimate the risk of paralytic disease after a hypothetical reintroduction of circulating polioviruses. The outcome measure was cases of paralytic poliomyelitis.

RESULTS

Monovalent oral poliovirus vaccine provided optimal outbreak control in most scenarios because of high seroconversion rates with 1 dose. Control provided by trivalent oral poliovirus vaccine and inactivated polio vaccine was equivalent at high vaccine coverage rates. At low intervention rates, trivalent oral poliovirus vaccine produced fewer paralytic cases than inactivated polio vaccine in highly immune populations but more cases than inactivated polio vaccine in poorly immunized groups because of secondary transmission of oral poliovirus vaccine virus and vaccine-derived viruses.

CONCLUSIONS

This model suggests that monovalent oral poliovirus vaccine would be the most advantageous vaccine for outbreak control. If a monovalent oral poliovirus vaccine stockpile is impractical, the optimal vaccine choice depends on the previous immunity and the anticipated intervention rates.

Effect of a national vaccine shortage on vaccine coverage for American Indian/Alaska Native children

OBJECTIVES

We determined the effect of national vaccine shortages on coverage with 4 doses of diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine for American Indian/Alaska Native (AIAN) children.

METHODS

Data on DTaP coverage for children aged 19 to 27 months were abstracted from Indian Health Service (IHS) immunization reports. Coverage with the fourth DTaP dose (DTaP4) was compared for different periods to determine coverage levels before, during, and after the shortage. Data were stratified geographically to determine regional variation.

RESULTS

AIAN children experienced a significant decline (14.8%) in DTaP4 coverage during the shortage. Considerable variation was seen among IHS regions (declines ranged from 4.5% to 26.5%).

CONCLUSIONS

AIAN children included in IHS immunization reports experienced a greater decline in DTaP4 coverage during the shortage than the decline reported nationally for children receiving vaccine at public clinics (14.8% vs 6%). Variations in the decline in coverage highlight possible inequities in vaccine supply and distribution and in implementation of vaccine shortage recommendations. We must identify ways to ensure more equitable vaccine distribution and consistent implementation of vaccine recommendations to protect all children from vaccine-preventable diseases.

Preventive strategies against poliomyelitis

Successful poliomyelitis prevention depends upon the epidemiological characteristics of the infection and the immune status of the population in the area. Presently available polio vaccines may prove very useful for progress with polio control, provided the prevention programme has been adequately chosen and the limitations of the vaccine used have been taken into consideration. In the present and near future, polio prevention should aim at the containment and local elimination of the paralytic disease, which can be obtained with either OPV or E-IPV. The vaccine-associated disease remains an unsolved issue in an OPV programme. The association of OPV and E-IPV offers a clear advantage over the immunization with a single vaccine, particularly with OPV alone. Global eradication of polio, possible in principle, will be difficult to achieve by the year 2000, because of the present global dimensions of polio infection and the unequal environmental development of the world.

Eradication of poliomyelitis: progress in the Americas

In the span of 5 years since the eradication initiative was launched and only 3 years since external funds were made available, PAHO has been able to develop and implement a comprehensive program strategy for polio eradication that includes the following components: achievement and maintenance of high immunization levels (which include the supplemental strategies of national immunization days and mop-up operations); effective surveillance to detect all new cases; and a rapid response to the occurrence of new cases. Despite yearly increases in the number of cases of acute flaccid paralysis reported to the surveillance system, a decline in reported confirmed cases of polio has occurred since 1986 to record low levels in 1989. Cases in 1989 were reported from only 0.7% of the counties in the Americas. The occurrence of 24 wild-type virus isolates in 1989 were limited to only three geographic areas: northwestern Mexico; the northern Andean Region; and northeastern Brazil. At this writing the clock is ticking with only 3 months left to achieve the goal of interrupting transmission by the end of 1990. If the current level of effort is sustained and special efforts are directed at the remaining foci of infection, the eradication of the transmission of wild-type poliovirus from the Americas can be achieved. Continued external financial support will be critical if the effort is to succeed. The prospect of poliomyelitis eradication in the Americas led the 41st World Health Assembly of WHO to adopt a resolution in May, 1988, to eradicate the indigenous transmission of wild-type poliovirus from the world by the year 2000.(ABSTRACT TRUNCATED AT 250 WORDS)

Recommendations for a national policy on poliomyelitis vaccination

Declining numbers of adequately vaccinated persons, new data about the comparative safety and effectiveness of live, attenuated and killed poliomyelitis-virus vaccines, increased consumer awareness of adverse reactions and pressure from manufacturers seeking protection from liability were factors leading the Institute of Medicine to re-examine poliomyelitis vaccination programs. The relative merits of live and killed virus vaccines as immunizing agents were reviewed within the context of the 60 to 70 per cent level of poliomyelitis vaccination now reached in the United States. Until about 90 per cent of persons are adequately immunized, the continued use of live-virus vaccines for infants is recommended, with provision that certain categories of persons receive killed-virus vaccine. Vaccination with attenuated live virus of children 11 to 12 years old is suggested to reduce vaccine-associated disease when they become parents of vaccinated infants. Recommendations are made on education, research, liability and informed consent as they pertain to prevention of polyomyelitis.