Strategies for elimination of poliomyelitis in different parts of the world with use of oral poliovirus vaccine

Re-imagining world: From human health in the world to 'all-world health'

This article explores the concept of 'world' as it frequently appears across health studies; specifically largely humanistic and phenomenological variations in use of 'the world' and 'lifeworld' are considered as they have helped cast knowledge on health and care. Looking forward, it is argued that world might be reimagined post-humanistically and post-phenomenologically as a vital emergent material entity and property. This is a reimagination that pays dividends by drawing attention to all-world processes and productions, hence to 'all-world health'. On one level, all-world health involves consideration of the healths of all the world's material and biological entities (all parts of the world). On another level, all-world health involves understanding what an entity gains from its total surround as it moves through life (all parts of its world). Together these levels provide a more processual, relational and holistic understanding of health than that provided by traditional notions of human health states, determinants or meanings, and even by some environmental (ist) ideas on health. All-world health arguably provides a vision of interrelatedness on which greater unity, cooperation and care might be built.

M cell targeting engineered biomaterials for effective vaccination

Vaccines are one of the greatest medical interventions of all time and have been successful in controlling and eliminating a myriad of diseases over the past two centuries. Among several vaccination strategies, mucosal vaccines have wide clinical applications and attract considerable interest in research, showing potential as innovative and novel therapeutics. In mucosal vaccination, targeting (microfold) M cells is a frontline prerequisite for inducing effective antigen-specific immunostimulatory effects. In this review, we primarily focus on materials engineered for use as vaccine delivery platforms to target M cells. We also describe potential M cell targeting areas, methods to overcome current challenges and limitations of the field. Furthermore, we present the potential of biomaterials engineering as well as various natural and synthetic delivery technologies to overcome the challenges of M cell targeting, all of which are absent in current literature. Finally, we briefly discuss manufacturing and regulatory processes to bring a robust perspective on the feasibility and potential of this next-generation vaccine technology.

Cross-sectional serologic assessment of immunity to poliovirus infection in high-risk areas of northern India

INTRODUCTION

The objectives of this survey were to assess the seroprevalence of antibodies to poliovirus types 1 and 3 and the impact of bivalent (types 1 and 3) oral poliovirus vaccine (bOPV) use in immunization campaigns in northern India.

METHODS

In August 2010, a 2-stage stratified cluster sampling method identified infants aged 6-7 months in high-risk blocks for wild poliovirus infection. Vaccination history, weight and length, and serum were collected to test for neutralizing antibodies to poliovirus types 1, 2, and 3.

RESULTS

Seroprevalences of antibodies to poliovirus types 1, 2, and 3 were 98% (95% confidence interval [CI], 97%-99%), 66% (95% CI, 62%-69%), and 77% (95% CI, 75%-79%), respectively, among 664 infants from Bihar and 616 infants from Uttar Pradesh. Infants had received a median of 3 bOPV doses and 2 monovalent type 1 OPV (mOPV1) doses through campaigns and 3 trivalent OPV (tOPV) doses through routine immunization. Among subjects with 0 tOPV doses, the seroprevalences of antibodies to type 3 were 50%, 77%, and 82% after 2, 3, and 4 bOPV doses, respectively. In multivariable analysis, malnutrition was associated with a lower seroprevalence of type 3 antibodies.

CONCLUSIONS

This study confirmed that replacing mOPV1 with bOPV in campaigns was successful in maintaining very high population immunity to type 1 poliovirus and substantially decreasing the immunity gap to type 3 poliovirus.

Paralytic poliomyelitis associated with Sabin monovalent and bivalent oral polio vaccines in Hungary

Historical records of patients with vaccine-associated paralytic poliomyelitis (VAPP) in Hungary during 1961-1981 were reviewed to assess the risk of VAPP after oral polio vaccine (OPV) administration. A confirmed VAPP case was defined as a diagnosis of paralytic poliomyelitis and residual paralysis at 60 days in a patient with an epidemiologic link to the vaccine. Archived poliovirus isolates were retested using polymerase chain reaction and sequencing of the viral protein 1 capsid region. This review confirmed 46 of 47 cases previously reported as VAPP. Three cases originally linked to monovalent OPV (mOPV) 3 and one case linked to mOPV1 presented after administration of bivalent OPV 1 + 3 (bOPV). The adjusted VAPP risk per million doses administered was 0.18 for mOPV1 (2 cases/11.13 million doses), 2.96 for mOPV3 (32 cases/10.81 million doses), and 12.82 for bOPV (5 cases/390,000 doses). Absence of protection from immunization with inactivated poliovirus vaccine or exposure to OPV virus from routine immunization and recent injections could explain the higher relative risk of VAPP in Hungarian children. In polio-endemic areas in which mOPV3 and bOPV are needed to achieve eradication, the higher risk of VAPP would be offset by the high risk of paralysis due to wild poliovirus and higher per-dose efficacy of mOPV3 and bOPV compared with trivalent OPV.

Future of polio vaccines

Over the past half-century, global use of highly effective vaccines against poliomyelitis brought this disease to the brink of elimination. Mounting evidence supports the argument that a high level of population immunity must be maintained after wild poliovirus circulation is stopped to preserve a polio-free status worldwide. Shifting factors in the risk-benefit-cost equation favor the creation of new poliovirus vaccines for use in the foreseeable future. Genetically stable attenuated virus strains could be developed for an improved oral poliovirus vaccine, but proving their safety and efficacy would be impractical owing to the enormous size of the clinical trials required. Novel versions of inactivated poliovirus vaccine that could be used globally should be developed. An improved inactivated poliovirus vaccine must be efficacious, inexpensive, safe to manufacture and easy to administer. Combination products containing inactivated poliovirus vaccine and other protective antigens should become part of routine childhood immunizations around the world.

M cell-targeted delivery of vaccines and therapeutics

BACKGROUND

M (microfold or membranous) cells are specialised epithelial cells responsible for antigen sampling at the interface of mucosal surfaces and the environment. Their high transcytotic ability make M cells an attractive target for mucosally delivered vaccines and therapeutics.

OBJECTIVE

This brief review discusses the current state of M cell-targeted mucosal delivery systems and the potential of such delivery systems for the development of new vaccines and therapeutics against mucosal infectious and inflammatory diseases.

SCOPE

A variety of synthetic microparticles/nanoparticles have been developed and tested as vehicles for M cell-targeted mucosal drug and vaccine delivery. beta1 integrins, pathogen recognition receptors, specific carbohydrate residues and other M cell surface antigens have been exploited as potential targets for the delivery of mucosal vaccines and therapeutics.

CONCLUSION

Despite a considerable body of literature, much work still needs to be done before an effective M cell-targeted vaccine or therapeutic is developed.

Mass vaccination campaigns for polio eradication: an essential strategy for success

Effective vaccines against poliomyelitis became available in the mid-1950s and early 1960s. Mass campaigns were an integral part of early control efforts. Thereafter, polio vaccines were used largely in routine childhood programs. The resolution in 1988 to eradicate polio globally led to the development of appropriate strategies to achieve this goal, including mass vaccination campaigns (i.e., national immunization days, sub-national immunization days and mop-up activities), to achieve the highest possible coverage in the shortest possible time. Unlike other vaccines, mass campaign use of oral poliovirus vaccine enhances the immunogenicity of this vaccine, primarily due to: (1) the decrease in the prevalence of other enteroviruses that potentially interfere with seroconversion; and (2) the secondary spread of vaccine virus from vaccinees to close contacts, resulting in seroconversion of some unvaccinated contacts. To reach the highest possible coverage, detailed planning, meticulous execution, careful supervision and standardized monitoring are critical. A number of innovative approaches to improve the quality and/or coverage have become the 'standard' of supplemental immunization activities. These mass campaigns have led to dramatic decreases in the incidence of polio. This chapter reviews the scientific, operational and programmatic data on mass campaign use of polio vaccines, and summarize the lessons learnt from implementing the mass vaccination strategies used to eradicate poliomyelitis globally.

Analysis of the accumulation of mutants in Sabin attenuated polio vaccine viruses passaged in Vero cells

To confirm the safety of oral poliomyelitis vaccine (OPV) cultured in Vero cells, the genetic stability of cultured polio vaccine viruses was analysed by MAPREC (mutant analysis by PCR and restriction enzyme cleavage). The rates of mutant accumulation of the viruses passaged in Vero cells under a low multiplicity of infection (MOI) condition (approximately 10(-3.5)CCID50/cell; the same as under usual OPV production conditions) were higher than those passaged in secondary cultured monkey kidney cells. However, the rates of mutant accumulation were restrained when the viruses were cultured under a high MOI condition (approximately 10(-1.5)CCID50/cell) in Vero cells. Furthermore, neurovirulence of the passaged viruses in pollovirus susceptible transgenic mice PVR-Tg21 was shown to correlate highly with the results of MAPREC. It is expected that our results will contribute to the large scale preparation of safe and effective OPV using Vero cells.

Recent advances with recombinant bacterial vaccine vectors

Bacille Calmette-Guerin (BCG), Listeria monocytogenes, Salmonellae and Shigellae have shown promise as vaccine vectors in experimental animal models. Although disappointing results in humans and non-human primates stalled the development of this vaccination strategy, interest in this approach was reinvigorated recently by the development of bacterial DNA-vaccine-vectors. The purpose of this review is to highlight the strengths and weaknesses of bacterial vaccine vectors, and to discuss the future prospects of these vaccine delivery systems.

The use of mass campaigns in the expanded program on immunization: a review of reported advantages and disadvantages

The use of mass immunization campaigns (MICs) has been and remains controversial. To evaluate these campaigns, the authors review the literature relating to their effectiveness, sustainability, and cost-effectiveness in controlling diseases and raising immunization coverage levels, and their impact on the subsequent development of routine immunization services. Well-conducted campaigns have increased vaccine coverage levels and decreased disease morbidity and mortality. Their use in the Americas has been associated with the apparent elimination of poliomyelitis. However, unless health care infrastructure is improved, or campaigns are repeated, gains in coverage levels may not be sustained. Studies suggest that MICs are often not as cost-effective for raising coverage as the delivery of vaccines through routine services, but the use of coverage as the only outcome measure is questionable. Mass immunization campaigns can increase awareness of vaccination and may be appropriate in situations where new programs are to be initiated, in refugee situations where people congregate into areas with little infrastructure, and in disease eradication efforts when specific time goals are set. Little information is available on whether MICs strengthen or interfere with the development of routine services. To be successful, MICs require a well-coordinated and planned effort on the part of national authorities with the identification of specific goals, intensive social promotion, and strong management. In addition, research is needed to clarify how MICs should be evaluated.

Polio eradication--target 2000

Poliovirus an enterovirus is of 3 types (1, 2 & 3). The 1 poliovirus is most often the cause of paralysis. Poliomyelitis can be eradicated from human soil as man is the only reservoir of this infection and effective vaccines are also available for its control. Inactivated poliovirus vaccine (IPV) confers mainly the humoral immunity in comparison to oral polio vaccine (OPV) which gives the intestinal immunity as well. OPV has been recommended by the WHO as the vaccine of choice for global eradication of polio because of its superior ability to inhibit spread of wild polio virus, low cost and its ease of administration. 70-90% of polio cases occur in children less than 3 year of age. Each paralytic case which is the tip of an iceberg probably represents 100 to 1,000 infected persons in the community. The incidence of poliomyelitis is on the decline with 145 of 213 countries today report 0 case of polio. Central Africa & South Asia are the principal reservoirs of wild poliovirus with nearly two thirds of cases being reported from Indian subcontinent. Components of eradication strategy are: sustained high levels of immunisation, annual mass vaccination campaigns of OPV to all children under 5 years of age, establishment of extremely sensitive surveillance systems and targeted immunisation to areas and populations where poliovirus transmission is likely to persist. The task of global eradication of poliomyelitis is uphill but well within our reach. A strong will and political commitment by the Government of India is leading the nation to the goal of polio-free world by the year 2,000.

Effect of diarrhea on the humoral response to oral polio vaccination

OBJECTIVE

The purpose of this study was to measure the effect of concurrent diarrheal illness on seroconversion to trivalent oral polio vaccine (OPV).

METHODS

Six- to 16-week-old infants with acute diarrhea and age-matched controls received single doses of OPV at enrollment, 4 weeks after enrollment and 8 weeks after enrollment. Serum specimens were obtained at enrollment, before the second OPV dose and 4 weeks after the third OPV dose for measurement of antibody titers to polio virus by the microneutralization assay.

RESULTS

Four weeks after the first OPV dose, the serologic responses to poliovirus types 2 and 3 in the case cohort were lower by 26 and 34%, respectively, than in the control cohort (P < 0.002 for both comparisons). Poliovirus type 2 and 3 geometric mean antibody titers in the diarrhea cohort were approximately 50% of the geometric mean antibody titers in the control cohort (235 (95% confidence interval (CI) 154 to 359) vs. 446 (95% CI 350 to 569) and 64 (95% CI 45 to 90) vs. 112 (95% CI 88 to 143), respectively, P < 0.01 for both comparisons). After the third OPV dose the seroconvertion rates to poliovirus types 2 and 3 each remained about 10% lower in the case cohort than in the control cohort, but the differences were not statistically significant.

CONCLUSION

Concurrent acute diarrhea adversely affects seroconvertion rates of type 2 and 3 polioviruses among infants in Bangladesh receiving the first dose of trivalent OPV.

Perspectives on rapid elimination and ultimate global eradication of paralytic poliomyelitis caused by polioviruses

Poliomyelitis caused by polioviruses has already been eradicated from industrialized countries of North America, Europe, Asia and Oceania, but the procedures by which this eradication was achieved are not adequate for the poor tropical and subtropical countries. The major challenge now is first to eliminate it rapidly from Asia and Africa where an estimated 250,000 cases and 25,000 deaths currently occur annually. The great progress toward eradication of "wild" polioviruses from poor tropical and subtropical countries in Latin America was achieved not by the procedures still recommended by the WHO Expanded Program on Immunization (EPI) but by the independently organized annual, national days of antipolio vaccination - all based on the use of large armies of well-trained non-professional, community volunteers - first used in Cuba (1962), Brazil (1980), Nicaragua (1981), Dominican Republic (1983), Paraguay (1985), and Mexico (1986). This novel approach, described in some detail in this communication, is recommended for the rapid elimination of wild polioviruses from Asia and Africa, and for ultimate global eradication with the help of a special cadre within the EPI of WHO. The extensive use by the Pan American Health Organization (PAHO) of highly sophisticated regional virus laboratories has led to the recognition that, in areas from which poliomyelitis caused by polioviruses has been largely eliminated, there are thousands of cases of acute flaccid paralysis, previously clinically diagnosed as "probable poliomyelitis", that have no viral etiology, a phenomenon previously reported by Dr. Manuel Ramos Alvarez in Mexico City in 1967.

Measles, killer of millions in developing countries: strategy for rapid elimination and continuing control

Measles, which is still killing about two million children a year in poor countries, was mostly eliminated within two to three months after the conclusion of a special, national mass vaccination campaign in which all children of a selected age group received measles vaccine subcutaneously during a period of days to months, regardless of a history of previous vaccination or measles. This strategy was tested in the Dominican Republic in 1985, in Cuba in 1986-87, and in the State of São Paulo, Brazil May 11-June 10, 1987. Subsequent control was maintained by different procedures in the three states. A simple, rapid indirect immunofluorescent test for IgM measles antibody, used in Greater São Paulo, was more efficient in confirming concurrent infection with measles virus than the hemagglutination inhibition test for IgG antibody, and only one blood specimen taken during the course of the rash was needed to confirm the etiologic diagnosis in 97.5% of 240 cases confirmed by IgM. In Greater São Paulo and Cuba, it was found that over 90% of the small number of suspect measles cases reported during the first year after the mass campaign, were not caused by measles virus. The cost of disposable syringes and needles in the State of São Paulo, where 8,565,230 children were vaccinated in 10,527 centers in 30 days, was U.S. $2,057,753 or 63% of the total. Immunization by aerosol could have vaccinated this number of children more easily and effectively in one day if each of the vaccination centers had been supplied with one plastic foot or hand pressure pump and nebulizer at a cost of only about U.S. $300,000.

Impact of annual immunisation programme with oral polio vaccine on the prevalence of paralytic poliomyelitis

Lameness survey was conducted in a rural community development block of Haryana in 1985. Enumerators contacted school teachers, anganwadi workers and several key informants in the community to identify lame children in 1-11 years age-group. Physician verified 219 lame cases to be due to poliomyelitis. Prevalence of poliomyelitis lameness was 7.3/1000 children born in 1974-76, 7.7/1000 children born in 1977-1980 and 2.3/1000 children born in 1981-1984 (expected to increase to 3.1/1000 when all children born in 1981-84 cross 5th year of life). Immunisation coverage with 3 doses of oral polio vaccine (OPV) was less than 10% during 1974-80 when immunisation was a clinic based activity. Coverage increased from 50 to 80% during 1981-85 when OPV was given in annual immunisation campaign. The results indicate that prevalence of paralytic poliomyelitis dropped at least by 60% after giving OPV in annual immunisation campaigns.

Strategy for construction of live picornavirus vaccines

A number of recombinant viruses between the virulent Mahoney and the attenuated Sabin 1 strains of type 1 poliovirus were constructed in vitro using their infectious cDNA clones. Monkey neurovirulence tests on these recombinant viruses revealed that the surface structure of the virion particle had a little correlation with the neurovirulent phenotype, and that the strong neurovirulence determinant(s) resided in the 5' noncoding sequence. These results in turn led to two possible strategies for constructing live attenuated picornavirus strains. One is to use the Sabin 1 strain as a vector carrying foreign antigenicities. The other is the construction of the attenuated picornaviruses by introducing mutations into the 5' noncoding sequences. The antigenicity of the Sabin 1 strain was successfully changed to those of other poliovirus serotypes without loss of vaccine quality. Furthermore, it was proved that introduction of deletion mutation into the 5' noncoding sequence of genomes of the Sabin 1 and Mahoney strains resulted in construction of viruses with a less neurovirulent phenotype.

An infectious cDNA clone of the poliovirus Sabin strain could be used as a stable repository and inoculum for the oral polio live vaccine

Viruses were recovered from HeLa S3 cells and African green monkey kidney (AGMK) cells transfected with an infectious cDNA clone of poliovirus vaccine Sabin 1 strain. The viruses recovered from the different DNA-transfected cells were tested for the biological characteristics of temperature sensitivity (rct marker), plaque size, and bicarbonate concentration dependency (d marker). The results revealed that the above properties were similar to those obtained from tests on the Sabin 1 vaccine reference strain. The recovered viruses and the vaccine reference virus were passaged in AGMK cells at an elevated temperature of 37.5 degrees, and the passaged isolates were tested for the rct marker. The virus recovered from AGMK cells had the most stable rct phenotype while the virus from HeLa S3 cells had a similar stability to that of the reference virus, suggesting that the virus from AGMK cells would be more suitable as a vaccine strain than the other two viruses. Furthermore, an infectious cDNA clone of high specific infectivity, constructed by introducing SV40 large T antigen into the plasmid, was used for production of high titers of virus after transfection. The results of in vitro biological tests on the recovered virus suggested that virus produced in the transfected AGMK cells also had the high quality that is desirable in vaccine stocks. Monkey neurovirulence tests performed with these recovered viruses revealed that the recovered viruses were weakly neurovirulent, similar to the vaccine reference virus. The infectious cDNA clone of the poliovirus vaccine strain could therefore be used to generate a possible inoculum of the oral polio live vaccine. Our findings strongly suggest that an infectious cDNA clone of poliovirus RNA may be used to preserve the constancy and quality of the present seed viruses of the Sabin 1 vaccine strain.

Strategy for rapid elimination and continuing control of poliomyelitis and other vaccine preventable diseases of children in developing countries

Estimates of a recent yearly incidence of 400 000 cases of paralytic poliomyelitis, 2.5 million deaths from measles and its complications, over 1 million deaths from neonatal tetanus, and 735 000 deaths from pertussis in Asia, Africa, and Latin America now pose a greater challenge for new action than did the worldwide eradication of smallpox several years ago. By virtue of the conditions obtaining in the developing countries mere expansion or acceleration of what is being done now--even with modifications that may achieve a temporary increase in vaccine coverage--cannot achieve the desired rapid elimination and continuing control of these diseases. A new strategy--namely, bringing the vaccine to the people during annual national days of vaccination--has already been used successfully in some small and large developing countries of Latin America for the rapid elimination and continuing control of polio. This strategy could be adapted to include vaccination against measles, pertussis, and neonatal tetanus by additional training of community volunteers in the large auxiliary health armies that work with the existing health services each year.

Natural variants of the Sabin type 1 vaccine strain of poliovirus and correlation with a poliovirus neutralization site

Independent substitution mutations have been detected in capsid polypeptide VP1 of the type 1 oral poliovirus vaccine isolated from normal infant vaccine recipients. These mutations map at amino acid residues 142 and 147 of VP1, a region only minimally hydrophilic. A synthetic peptide, corresponding to residues 141 to 147 of VP1 was synthesized, conjugated to a carrier polypeptide of bovine serum albumin. The conjugate was found to elicit a weak poliovirus neutralizing antibody response. It was also capable of priming the immune system for the production of IgG-type antibodies able to neutralize greater than 99.999% of infectious type 1 virus. It is suggested that region 141 to 147 of VP1 may be involved in neutralization of the virus and that the mutants may have accumulated by antibody selection.