Introducing new vaccines in the poorest countries: what did we learn from the GAVI experience with financial sustainability?

This paper reviews the experience of the Global Alliance for Vaccines and Immunization (GAVI) in introducing hepatitis B and Haemophilus influenzae type b vaccines in the poorest countries, and explores how financing for immunization has changed since GAVI Fund resources were made available during its first wave of support between 2000 and 2006. The analysis of Financial Sustainability Plans in 50 countries allowed for some of the original funding assumptions of the GAVI approach to be tested against the realities in a wide set of countries, and to highlight implications for future immunization efforts. While the initial GAVI experience with financial sustainability has proved successful through the development of plans, and many countries have been able to both introduce new vaccines and mobilize additional financing for immunization, for future GAVI supported vaccine introduction, some country co-financing of these will be needed upfront for the approach to be more sustainable.

Strengthening immunization in a West African country: Mali

OBJECTIVES AND CONTEXT: This paper describes the preliminary outcomes of a collaborative capacity-building initiative performed in Mali to strengthen the immunization program.

METHODS

We conducted baseline assessments, training and post-training assessments in four programmatic areas: vaccine management, immunization safety, surveillance, and vaccine coverage, using adapted World Health Organization (WHO) tools. Impact assessment was done by evaluation of trainee performance, programmatic impact and sustainability.

RESULTS

Qualitative and quantitative improvement of trainee performance was seen after the training interventions: some knowledge improvement, greater compliance with vaccine management practices and improved vaccine coverage. Deficiencies in information transfer to the periphery were identified.

CONCLUSIONS

The program involves shared responsibility for planning, implementation and financing with national stakeholders while emphasizing the training of leaders and managers to ensure sustainability. Although short-term gains were measured, our initial assessments indicate that sustained impact will require improvements in staffing, financing and guidelines to ensure delivery of information and skills to the periphery.

Ensuring vaccine safety in immunization programmes--a WHO perspective

Ever since vaccines were firstly used against smallpox, adverse events following immunization have been reported. As immunization programmes expand to reach even the most remote communities in the poorest countries, it is likely that many more events will be temporally linked with vaccine administration. Furthermore, the profound shift in the general public and media interest in adverse events may lead to undue concerns and allegations which may ultimately jeopardize immunization programmes world-wide. While the health professional has understood this issue for some time, the public and the media have now also become all too aware of the significance of vaccine-related adverse events. The familiar vaccines, well-tested over decades, have not changed--but the perception regarding their safety has shifted. Claims outrageous or reasonable are being made against both the old and the newly-introduced vaccines. At the same time, the immunological and genetic revolution of the last decade may well bring to our notice some hypothetical risks that need to be addressed at pre-clinical level. WHO has been at the leading edge to guarantee vaccine safety for the last 30 years and will continue to do so. The Organization's plans for the next decade and beyond include the Safe Injection Global Network (SIGN), the development and introduction of safer technologies, and the prevention, early detection and management of AEFIs. The new technologies include needle-containing injection devices such as the autodisable syringe, as well as mucosal and transcutaneous immunization. Training will continue to be at the centre of WHO's efforts, limiting human error to a minimum. Mechanisms have been set in place to detect and respond to new and unforeseen events occurring. Above all, there is a willingness to respond to new climates and new technologies so that the Organization is in the best position to ensure safe immunization for all the world's children.

Developing a national system for dealing with adverse events following immunization

Although vaccines are among the safest of pharmaceuticals, the occasional severe adverse event or cluster of adverse events associated with their use may rapidly become a serious threat to public health. It is essential that national monitoring and reporting systems for vaccine safety are efficient and adequately coordinated with those that conventionally deal with non-vaccine pharmaceuticals. Equally important is the need for an enlightened and informed national system to be in place to deal with public concerns and rapid evaluation of the risk to public safety when adverse events occur. Described in this article is the outcome of efforts by the WHO Global Training Network to describe a simple national system for dealing with vaccine safety and with emergencies as they arise. The goals of a training programme designed to help develop such a system are also outlined.

New challenges in assuring vaccine quality

In the past, quality control of vaccines depended on use of a variety of testing methods to ensure that the products were safe and potent. These methods were developed for vaccines whose safety and efficacy were based on several years worth of data. However, as vaccine production technologies have developed, so have the testing technologies. Tests are now able to detect potential hazards with a sensitivity not possible a few years ago, and an increasing array of physicochemical methods allows a much better characterization of the product. In addition to sophisticated tests, vaccine regulation entails a number of other procedures to ensure safety. These include characterization of starting materials by supplier audits, cell banking, seed lot systems, compliance with the principles of good manufacturing practices, independent release of vaccines on a lot-by-lot basis by national regulatory authorities, and enhanced pre- and post-marketing surveillance for possible adverse events following immunization. These procedures help assure vaccine efficacy and safety, and some examples are given in this article. However, some contaminants of vaccines that can be detected by newer assays raise theoretical safety concerns but their presence may be less hazardous than not giving the vaccines. Thus risk-benefit decisions must be well informed and based on scientific evidence.

Alternatives and developing countries

Alternative tests have a role in vaccine testing, especially to confirm production consistency. Given the characteristics of these alternative tests and of the products for which they may be used, there are several factors which will influence their use. These include a good understanding of the test and the product to be tested, strong national regulatory infrastructure, a laboratory run in accordance with the principles of laboratory quality systems, and the ability to validate the alternative method. This means that national regulatory authorities will need strong expertise in epidemiology and quality assurance to complement laboratory experience.

Auto-disable syringes for immunization: issues in technology transfer

WHO and its partners recommend the use of auto-disable syringes, "bundled" with the supply of vaccines when donor dollars are used, in all mass immunization campaigns, and also strongly advocate their use in routine immunization programmes. Because of the relatively high price of auto-disable syringes, WHO's Technical Network for Logistics in Health recommends that activities be initiated to encourage the transfer of production technology for these syringes as a means of promoting their use and enhancing access to the technology. The present article examines factors influencing technology transfer, including feasibility, corporate interest, cost, quality assurance, intellectual property considerations, and probable time frames for implementation. Technology transfer activities are likely to be complex and difficult, and may not result in lower prices for syringes. Guidelines are offered on technology transfer initiatives for auto-disable syringes to ensure the quality of the product, the reliability of the supply, and the feasibility of the technology transfer activity itself.

Development of a more thermostable poliovirus vaccine

In 1991, a goal of improved thermostability of oral poliovirus vaccine (OPV) was set, and the Product Development Group was established under the Children's Vaccine Initiative to achieve this goal. Several initial research strategies were unsuccessful. The substitution of deuterium oxide for water in the final blending stage of vaccine production resulted in a significantly more stable product at temperatures of > or = 37 degrees C. A large body of clinical data shows the safety of deuterium at the dosage that would be given with this vaccine. However, reservations about the public acceptability of the vaccine, combined with the progress achieved in polio eradication with the current vaccine and the availability of vaccine vial monitors to indicate time and temperature exposure of every vial of OPV, have resulted in a recommendation that vaccine development cease. This product development activity has been instructive for the process of introduction of new vaccines.

Global DTP manufacturing capacity and capability. Status report: January 1995

A recently completed survey of 63 manufacturers of diphtheria-tetanus-pertussis (DTP) vaccine and its components in 42 countries shows that there is potentially a large excess installed capacity for DTP production. However, many manufacturers are not producing to capacity, and demand and supply for this vaccine are not matched in individual countries. About half of all countries producing DTP vaccine and its components do not have fully functional national control systems, and some countries are performing none of the critical functions for an effective control of quality. Thus, potential for export of excess capacity is limited. The data collected indicate much homogeneity in the preparation of diphtheria and tetanus toxoids. Nearly all manufacturers use the same seeds and similar purification methods, but there is variability in whether purification is done before or after conversion of toxin to toxoid. About 10% of all manufacturers do not meet WHO-defined standards of purity for these toxoids. There is much more heterogeneity in the pertussis seed strains and the methods of purification used. The formulation of DTP vaccine differs considerably among producers. Potency testing is not being done by the WHO-recommended method by about 50% of manufacturers on lots of diphtheria and tetanus toxoids for release. Testing of irreversibility of conversion of toxin to toxoid, a WHO-specified safety test, is also not being done on each lot of diphtheria toxoid by 15% of manufacturers surveyed nor on each lot of tetanus toxoid vaccine by 30% of manufacturers surveyed. Access to technology to develop new DTP-based combination vaccines will be delayed if these manufacturers cannot ensure consistent high quality vaccine for their target populations. The results and conclusions suggest areas for future activities to strengthen the supply and quality of DTP and DTP-based combination vaccines.

Performance and potency of tetanus toxoid: implications for eliminating neonatal tetanus

Neonatal tetanus (NT) is a major cause of mortality in developing countries, with over 400,000 deaths estimated to occur annually. WHO has adopted the goal of eliminating NT worldwide, and a major strategy for its prevention is the administration of at least two properly spaced doses of tetanus toxoid (TT) to women of childbearing age in high-risk areas to protect passively their newborns at birth. In certain countries the locally produced TT vaccine has been shown to be subpotent, while other countries have reported NT among infants born to vaccinated women. An extensive review of production and quality control procedures was carried out between 1993 and 1995 in 8 of 22 TT-producing countries that also report NT cases, with a more superficial assessment being carried out in the remaining 14 countries. Only 4 of the 22 countries have a functioning national control authority to monitor TT production and vaccine quality. A total of 80 TT lots from 21 manufacturers in 14 of the 22 NT-reporting countries were tested for potency. Of these, 15 lots from eight manufacturers in seven countries had potency values below WHO requirements. TT potency can also be compromised by improper vaccine handling. To eliminate neonatal tetanus worldwide requires assurance that all doses of TT meet WHO production and quality requirements and that the field effectiveness of TT is monitored through systematic NT case investigations and assessment of coverage.

The crisis in vaccine supply: a framework for action

Immunization programmes, having made significant progress in protecting over 80% of the world's children against six vaccine-preventable diseases, are now facing a crisis in funding for their vaccine supply. Contributing to this situation are changing donor priorities, rising prices, increased needs for vaccines. The Task Force on Situation Analysis for Vaccine Supply (TFSA) of the Children's Vaccine Initiative (CVI) has developed a framework which provides a logical division of countries into groups that might share similar vaccine supply systems. This framework provides a basis on which to analyse the needs and potential solutions for vaccine supply in countries based on their populations, national wealth, and current ability to produce vaccine. This framework has facilitated the development of strategies to strengthen national vaccine supply systems. It has also provided guidance for governments, donors and development agencies on the most appropriate actions for assuring the objective of sustainable vaccine supply.

Paralytic poliomyelitis: seasoned strategies, disappearing disease

With more than 2 years having elapsed since the last case of paralytic poliomyelitis occurred in the Western Hemisphere, significant progress has been made towards the global eradication of wild polioviruses. Poliomyelitis is disappearing from Europe, North Africa, Southern Africa, the Middle East, China, and the Pacific. Reported poliomyelitis cases declined to 15,587 cases in 1992. Current eradication strategies recommended by the World Health Organization include national mass campaigns administering oral poliovaccine to all children under 5 years of age, enhanced surveillance to detect cases of acute flaccid paralysis, creating a network of laboratories for viral diagnosis, and targeted immunisation to areas and populations where poliovirus transmission is likely to persist. The major obstacles to eradication include inadequate political support for eradication and insufficient funding, especially for the purchase of vaccine. With additional support for the international eradication effort, epidemics of poliomyelitis will cease in developing countries, and industrialised countries will be able to save the large sums spent each year on poliovaccine and rehabilitation.

The thermostability of vaccines. Technologies for improving the thermostability of the oral poliovirus vaccine

Technologies that promise to enhance the stability of vaccines are likely to be determined by the product-specific physical structure and biological functions of the specific vaccine immunogens. Research may define the extent to which the stability of oral poliovirus vaccine may be improved by the addition of certain antiviral components that bind to the poliovirus capsid or by the application of novel drying technologies.

The WHO-EPI initiative for the global eradication of poliomyelitis

Since the development of attenuated oral polio vaccine, Dr Albert Sabin consistently maintained that the global eradication of wild poliovirus was possible, but that to achieve polio eradication in developing countries would require the mass administration of the oral vaccine. Experience in Cuba and Czechoslovakia proved the effectiveness of this technique, but it was only with its deployment in Brazil in 1980 that its role in eradicating the virus from a broad geographical area started to be realized. With the declaration in 1985 of a target of regional polio eradication, extension of this policy, allied with the development of effective surveillance of acute flaccid paralysis in children, with laboratory confirmation of diagnosis rapidly led to apparent interruption of wild poliovirus transmission throughout the Americas. The World Health Assembly in 1988 committed WHO to the global eradication of poliomyelitis. Based on experience in the Americas and building on the solid foundation established by the Expanded Programme on Immunization, WHO has defined the strategies through which the global target could be achieved. Progress is encouraging and where the advocated strategies have been fully implemented, the incidence of poliomyelitis has declined dramatically. Significant geographical areas in Western Europe, the Maghreb, the Arabian peninsula, the Pacific basin and Southern Africa, each incorporating several countries, are now thought to be free of the disease caused by wild poliovirus. The target of a world free of polio by the year 2000 can be achieved.

Quality control of BCG vaccine by WHO: a review of factors that may influence vaccine effectiveness and safety

WHO oversees the quality control of BCG vaccine via a system that includes regular testing of products by in vitro methods and clinical trials. Three parent strains of BCG (Glaxo-1077, Tokyo-172, and Pasteur-1173P2) account for over 90% of the vaccines currently in use worldwide. Important characteristics of the vaccine preparations are summarized here, along with their physical-chemical properties. In instances where diagnostic criteria for tuberculosis are stringent, there is no evidence that when administered to newborns different preparations of BCG vaccine exhibit different efficacies; however, the incidence of BCG-associated adverse reactions does correlate with the type of preparation. Other factors, including dose, administration technique, and recipient characteristics are also important in determining vaccine-associated reactions.

Neonatal anuria with maternal angiotensin-converting enzyme inhibition

The use of angiotensin-converting enzyme inhibitors as antihypertensives has increased rapidly since the introduction of captopril in 1981. Seven cases of neonatal renal failure have been reported in patients with exposure to angiotensin-converting enzyme inhibitors that continued to the time of delivery. Two cases resulted in death of the newborn; the other five patients recovered after peritoneal dialysis. Because the relative frequency of normal outcomes is unknown, these data are insufficient for incidence-rate estimates or risk/benefit analyses. However, given the potential neonatal morbidity and mortality associated with late-pregnancy exposure to angiotensin-converting enzyme inhibitors, alternative therapies in the third trimester should be given consideration. If these drugs must be used in this context, the clinician should be prepared to deal with renal failure and hypotension in the newborn. The Food and Drug Administration invites reports of adverse pregnancy outcomes associated with such exposure.

Postmarketing surveillance for neurologic adverse events reported after hepatitis B vaccination. Experience of the first three years

In 1982, the Centers for Disease Control, the Food and Drug Administration, and the manufacturer created a surveillance system to monitor spontaneous reports of adverse events occurring after inoculation with the new plasma-derived hepatitis B vaccine (Heptavax-B, Merck Sharp and Dohme, West Point, PA). In the three years between June 1, 1982 and May 31, 1985, an estimated 850,000 persons received the vaccine. During that period, a total of 41 reports were received for one of the following neurologic adverse events: convulsions (five cases), Bell's palsy (10 cases), Guillain-Barré syndrome (nine cases), lumbar radiculopathy (five cases), brachial plexus neuropathy (three cases), optic neuritis (five cases), and transverse myelitis (four cases). Half of these occurred after the first of three required vaccine doses. There were no deaths. Calculation of the relative risks of these illnesses after hepatitis B vaccination was highly dependent on diagnostic classification of the cases, estimates of the size of the vaccinated population, background incidence of the diseases, and the length and distribution of the hypothetical at-risk interval used in the analysis. Other factors important in judging the results of the study could not be measured, including underreporting. In some analyses, Guillain-Barré syndrome was reported significantly more often than expected (p less than 0.05, Poisson probability distribution). However, no conclusive epidemiologic association could be made between any neurologic adverse event and the vaccine. Even if such an association did exist, the preventive benefits of the vaccine in persons at high risk for hepatitis B would unequivocally outweigh the risk of any neurologic adverse event.

Adverse reactions reported following receipt of Haemophilus influenzae type b vaccine: an analysis after 1 year of marketing

An analysis of adverse reactions occurring after receipt of Haemophilus influenzae type b vaccine and reported to the Food and Drug Administration during the first year of marketing of the product was performed. During the period April 1985 to May 1986, adverse reaction reports on 152 patients, excluding those of vaccine failure and concurrent infection, were received. Several adverse reactions not previously recognized, including convulsions, allergic reactions such as anaphylactoid-like and serum sickness-like reactions, and vomiting were received. The vast majority of adverse reactions were benign. Because there are many biases that result in the reporting of or failure to report an adverse reaction, it is not possible to derive a rate of reactions from these data. Furthermore, causality cannot be inferred from any single report. The data, however, indicate that, in light of widespread use of the vaccine, its use appears to be safe.

Food and Drug Administration monitoring of adverse drug reactions

Food and Drug Administration requirements for reporting adverse drug reactions (ADRs), processing of ADR reports, and actions in response to these reports are described. FDA requires that drug manufacturers report ADRs to the FDA Division of Epidemiology and Surveillance; 90% of the ADR reports received are from manufacturers. Of the remaining 10%, one third are from pharmacists. FDA regulations were revised in 1985 to specifically define reportable ADRs and procedures for reporting; manufacturers are required to report within 15 days reactions that are serious and unlabeled. For newly approved drugs, reports on ADRs must be submitted quarterly for three years; subsequently, annual reporting is required. Any increase in the frequency of serious, labeled reactions must be reported. Serious reactions not listed in the product labeling must be reported for products marketed before 1962 for which new drug applications or abbreviated new drug applications were not filed. ADR information received by FDA is coded into standard terms and entered in a computerized database for evaluation by reviewers. If an important reaction is suspected, the report is entered in a tracking system for further monitoring. ADR reports may result in requirements for changes in product labeling, "Dear Doctor" letters, requirement of further study by the manufacturer, or withdrawal of the product. Information about ADRs is communicated to health-care practitioners in product labeling and in the literature. Pharmacists are encouraged to report suspected serious and unlabeled reactions to FDA so that the medical community and the public can benefit from current information about drug safety.

Cell-free synthesis of measles virus proteins

Polyadenylated mRNA extracted from cytoplasm of measles virus-infected Vero cells was translated in a cell-free system. Three of the polypeptides obtained corresponded to nucleocapsid protein, phosphoprotein, and membrane protein of measles virions. A fourth polypeptide, present in measles virus-infected cells, could be generated by addition of Vero cytoplasmic extract and was identified as a cleavage product of the nucleocapsid protein.

Characterization of an RNA-dependent RNA polymerase activity associated with measles virus

An RNA-dependent RNA polymerase activity has been found copurifying with measles virus infectivity and complement-fixing antigen in three Vero cell-grown variants of measles virus: the attenuated Edmonston B strain, the natural non-attenuated Edmonston strain, and a subacute sclerosing panencephalitis isolate, IP-3. Incubation of purified measles virions with immunoglobulin G derived from sera of monkeys hyperimmunized against measles specifically removes activity sedimenting in the density region of measles virions. The requirements of the reaction, which is RNase sensitive, are similar to those reported for other paramyxovirus-associated activities, including detergent, divalent cation, ribonucleoside triphosphates, and a reducing agent. The size classes of RNA synthesized correspond to those found in measles-infected cells, including 50, 35, and 16 to 20S. The product RNA of the Edmonston B virus-stimulated reaction was rendered RNase resistant by annealing with RNA extracted from purified Edmonston B virions. RNA from uninfected Vero cells was ineffective in the annealing reaction.

Correlation of virus polypeptide structure with attenuation of poliovirus type 1

Several avirulent samples of poliovirus type 1 derived in the process attenuating the neurovirulent Mahoney strain show an altered virus capsid polypeptide, VP-1, on polyacrylamide gel electrophoresis of sodium dodecyl sulfate-disrupted virions.

Bacteriophages in live virus vaccines: lack of evidence for effects on the genome of rhesus monkeys

Four juvenile rhesus monkeys were inoculated with 10(12) plaque-forming units of the bacteriophage phiV1 isolated from live virus vaccines. After phiV1 had been cleared from the blood, DNA's were isolated from the livers and kidneys and analyzed for the presence of bacteriophage by plaque assays, and for the presence of phiV1 DNA by DNA-DNA reassociation kinetics. No evidence was found for persistence of the bacteriophage or for replication of the phage genome in these rhesus monkeys.

Tests for RNA tumor viruses in cell substrates used in virus vaccine production

Test to detect RNA tumor viruses in cell substrates were reviewed with respect to advantages and disadvantages. Viral induction, electron microscopy, reverse transcriptase assays, density gradient centrifugation, and radioimmunoassays were performed on several cell substrates now in use or being considered for use in vaccine production. RNA tumor viruses were not detected by any of the methods except in the positive control cultures.

Safety of viral vaccine cell substrates: a reevaluation

Primary cultures of African green monkey kidney and rabbit kidney as well as diploid cell lines WI-38 and DBS-FRhL-2 were examined for evidence of tumorigenicity and latent RNA tumor viruses. Cells inoculated into immunosuppressed newborn hamsters and rhesus monkeys were not tumorigenic. Cells treated with 2'-deoxy-5-iodouridine to induce the production of latent viruses were examined by electron microscopy, density gradient centrifugation, and the reverse transcriptase enzyme assay. No evidence was found for RNA tumor viruses by the biochemical or biophysical methods used. The results indicated that each type of mammalian cell currently used in the production of virus vaccines would be acceptable for these parameters of safety if similar control procedures were applied at the time the vaccines were manufactured.

Screen for type-C ribonucleic acid viruses in vaccines using the ribonucleic acid-dependent deoxyribonucleic acid polymerase assay

The ribonucleic acid-dependent deoxyribonucleic acid polymerase assay was used to detect type-C viruses in live virus vaccines. Conditions were first established to maximize the sensitivity of the assay. Vaccines tested included live poliomyelitis, rubella, measles, mumps, and yellow fever. Only yellow fever and measles vaccines known to have been produced in avian leukosis-contaminated cells showed evidence of type-C viruses using the assay. The result of the survey show that the assay has direct practical application to the problem of detecting latent agents in biological products intended for human use.

Reassortment of simian virus 40 DNA during serial undiluted passage

Alterations occur in the supercoiled form of viral DNA after the serial undiluted passaging of simian virus (SV) 40. We have identified a portion of the viral genome which is amplified during this process. These SV40 DNA sequences represent about 30% of the viral genetic information and are present in a reiterated form in twisted circular molecules prepared from purified virions. In addition, reiterated and unique green monkey DNA sequences are incorporated into supercoiled viral DNA. The cellular DNA appears to be inserted at numerous locations in the DNA I molecules.

An oligonucleotide affinity column for RNA-dependent DNA polymerase from RNA tumor viruses

Columns of (dT)(12-18)-cellulose provide a one-step enrichment procedure for RNA-dependent DNA polymerase. The enzyme of the virus from RD-114 cells, as well as that from Rauscher murine leukemia virus, have been purified in this way. The preference of viral as compared to cellular DNA polymerases for (dT)(12-18) as a primer is reflected in the fact that the DNA polymerases of uninfected cells do not bind to this column. Viral enzymes have been purified and identified from crude cellular extracts.