Cases Of Paralytic Poliomyelitis Research Articles

Vaccine-Derived Polioviruses

The attenuated oral poliovirus vaccine (OPV) has many properties favoring its use in polio eradication: ease of administration, efficient induction of intestinal immunity, induction of durable humoral immunity, and low cost. Despite these advantages, OPV has the disadvantage of genetic instability, resulting in rare and sporadic cases of vaccine-associated paralytic poliomyelitis (VAPP) and the emergence of genetically divergent vaccine-derived polioviruses (VDPVs). Whereas VAPP is an adverse event following exposure to OPV, VDPVs are polioviruses whose genetic properties indicate prolonged replication or transmission. Three categories of VDPVs are recognized: (1) circulating VDPVs (cVDPVs) from outbreaks in settings of low OPV coverage, (2) immunodeficiency-associated VDPVs (iVDPVs) from individuals with primary immunodeficiencies, and (3) ambiguous VDPVs (aVDPVs), which cannot be definitively assigned to either of the first 2 categories. Because most VDPVs are type 2, the World Health Organization's plans call for coordinated worldwide replacement of trivalent OPV with bivalent OPV containing poliovirus types 1 and 3.

Progress in research on vaccine derived polio virus related polio case

Objective To understand the incidence of vaccine derived polio virus (VDPV) related polio and related factors and provide evidence for VDPV related polio prevention and control. Methods Literature review on oral polio vaccine (OPV) caused polio was conducted to understand the incidence of VDPV related polio, population distribution and virus types. Results Vaccine associated paralytic poliomyelitis cases have been reported in the world, which were mainly caused by polio virus typeⅡ and type Ⅰ. VDPV were the result of the gene mutation and genetic recombination of vaccine strain virus. Persons who are immune defect are prone to be affected by VDPV. Conclusion VDPV eradication is essential in the late stage of polio eradication. Some scholars have suggested to use inactivated polio vaccine (IPV) instead of OPV, or the combination of OPV and IPV.

Expert Review on Poliovirus Immunity and Transmission

Successfully managing risks to achieve wild polioviruses (WPVs) eradication and address the complexities of oral poliovirus vaccine (OPV) cessation to stop all cases of paralytic poliomyelitis depends strongly on our collective understanding of poliovirus immunity and transmission. With increased shifting from OPV to inactivated poliovirus vaccine (IPV), numerous risk management choices motivate the need to understand the tradeoffs and uncertainties and to develop models to help inform decisions. The U.S. Centers for Disease Control and Prevention hosted a meeting of international experts in April 2010 to review the available literature relevant to poliovirus immunity and transmission. This expert review evaluates 66 OPV challenge studies and other evidence to support the development of quantitative models of poliovirus transmission and potential outbreaks. This review focuses on characterization of immunity as a function of exposure history in terms of susceptibility to excretion, duration of excretion, and concentration of excreted virus. We also discuss the evidence of waning of host immunity to poliovirus transmission, the relationship between the concentration of poliovirus excreted and infectiousness, the importance of different transmission routes, and the differences in transmissibility between OPV and WPV. We discuss the limitations of the available evidence for use in polio risk models, and conclude that despite the relatively large number of studies on immunity, very limited data exist to directly support quantification of model inputs related to transmission. Given the limitations in the evidence, we identify the need for expert input to derive quantitative model inputs from the existing data.

A Sri Lankan infant with vaccine associated acute flaccid paralysis

Global incidence of poliomyelitis has reduced by more than 99% since the Global Polio Eradication Initiative was launched in 1988 [1]. In par with the global trend, Sri Lanka has achieved great success with no reported cases since 1993, but still is not declared as a country which has eradicated polio due to prevalence of polioyomyelitis in neighbouring countries [2]. Countries which have eradicated polio use killed injectable polio vaccine (IPV), mainly because oral polio vaccine (OPV) can result in paralytic poliomyelitis. In literature review, we could not find any reported cases of paralytic poliomyelitis following vaccination in Sri Lanka. We report a case of acute flaccid paralysis following immunisation with first dose of OPV.

Vaccine-associated paralytic poliomyelitis in Japan

Despite WHO's recommendation to switch the poliomyelitis vaccine from oral polio vaccine (OPV) to inactivated polio vaccine (IPV) in countries where polio elimination has been achieved, Japan has continued to use OPV. In Japan, OPV is given twice to children aged from 3 to 18 months.1 More than 10 years after the elimination of wild polio virus, tragic cases of vaccine-associated paralytic poliomyelitis (VAPP) continue to be reported every year—most recently in May, 2011. The Ministry of Health, Labour and Welfare claims that IPV is still being developed by Japanese vaccine companies and that it will not be available until the end of 2012 at the earliest. The growing tension between the Government, which persists with domestically produced OPV, and the parents, who request IPV to avoid VAPP, has evoked huge media attention.

History of polio vaccination

Poliomyelitis is an acute paralytic disease caused by three poliovirus (PV) serotypes. Less than 1% of PV infections result in acute flaccid paralysis. The disease was controlled using the formalin-inactivated Salk polio vaccine (IPV) and the Sabin oral polio vaccine (OPV). Global poliomyelitis eradication was proposed in 1988 by the World Health Organization to its member states. The strategic plan established the activities required for polio eradication, certification for regions, OPV cessation phase and post-OPV phase. OPV is the vaccine of choice for the poliomyelitis eradication program because it induces both a systemic and mucosal immune response. The major risks of OPV vaccination are the appearance of Vaccine-Associated Paralytic Poliomyelitis cases (VAPP) and the emergence of Vaccine Derived Polioviruses strains. The supplementary immunization with monovalent strains of OPV type 1 or type 3 or with a new bivalent oral polio vaccine bOPV (containing type 1 and type 3 PV) has been introduced in those regions where the virus has been difficult to control. Most countries have switched the schedule of vaccination by using IPV instead of OPV because it poses no risk of vaccine-related disease. Until 2008, poliomyelitis was controlled in Romania, an Eastern European country, predominantly using OPV. The alternative vaccination schedule (IPV/OPV) was implemented starting in September 2008, while beginning in 2009, the vaccination was IPV only. The risk of VAPP will disappear worldwide with the cessation of use of OPV. The immunization for polio must be maintained for at least 5 to 10 years using IPV.

Economic analysis of the global polio eradication initiative

The global polio eradication initiative (GPEI), which started in 1988, represents the single largest, internationally coordinated public health project to date. Completion remains within reach, with type 2 wild polioviruses apparently eradicated since 1999 and fewer than 2000 annual paralytic poliomyelitis cases of wild types 1 and 3 reported since then. This economic analysis of the GPEI reflects the status of the program as of February 2010, including full consideration of post-eradication policies. For the GPEI intervention, we consider the actual pre-eradication experience to date followed by two distinct potential future post-eradication vaccination policies. We estimate GPEI costs based on actual and projected expenditures and poliomyelitis incidence using reported numbers corrected for underreporting and model projections. For the comparator, which assumes only routine vaccination for polio historically and into the future (i.e., no GPEI), we estimate poliomyelitis incidence using a dynamic infection transmission model and costs based on numbers of vaccinated children. Cost-effectiveness ratios for the GPEI vs. only routine vaccination qualify as highly cost-effective based on standard criteria. We estimate incremental net benefits of the GPEI between 1988 and 2035 of approximately 40–50billion dollars (2008 US dollars; 1988 net present values). Despite the high costs of achieving eradication in low-income countries, low-income countries account for approximately 85% of the total net benefits generated by the GPEI in the base case analysis. The total economic costs saved per prevented paralytic poliomyelitis case drive the incremental net benefits, which become positive even if we estimate the loss in productivity as a result of disability as below the recommended value of one year in average per-capita gross national income per disability-adjusted life year saved. Sensitivity analysis suggests that the finding of positive net benefits of the GPEI remains robust over a wide range of assumptions, and that consideration of the additional net benefits of externalities that occurred during polio campaigns to date, such as the mortality reduction associated with delivery of Vitamin A supplements, significantly increases the net benefits. This study finds a strong economic justification for the GPEI despite the rising costs of the initiative.

Distribution of wild poliovirus genotypes in India

In order to study the genetic relationships and epidemiological links between strains circulating in the Vellore region of India, 70 wild type poliovirus strains isolated from paralytic poliomyelitis cases were sequenced at the VP1-2A junction region of the viral genome. This showed that three genotypes of types 1 and 2 and four genotypes of type 3 poliovirus were circulating in India at least since 1985. Different clusters were identified within wild genotypes. This study demonstrates the endemic circulation and wide genetic variation of all three serotypes in Southern India. Knowledge of wild poliovirus distribution before NIDs beginning could be helpful for a critical monitoring of poliomyelitis control and further evaluation of the NIDs impact on wild poliovirus transmission in India. Key words: Poliovirus, poliomyelitis, genotype, molecular epidemiology, eradication, surveillance.

Two decades of battle against polio: opening a window to examine public health in China

During a two-decade battle against polio, the Chinese government has saved more than one million children from physical disability caused by wild poliovirus infection. Today, the Chinese government still faces an arduous task in (1) preventing the entry and transmission of wild poliovirus from surrounding polio-endemic countries, (2) finding and stopping the outbreak of polio caused by the recycling of vaccine-derived poliovirus, (3) reducing vaccine-associated paralytic poliomyelitis (VAPP) cases, and (4) improving the State compensation system. The scientific monitoring system established in China and the immunity strategy implemented not only allow children in China to avoid lifelong disability or premature death due to polio infection, but also provide success stories for the World Health Organization that can be used for the specification of quality control indices for monitoring polio, classification and diagnosis criteria for acute flaccid paralysis cases, and identification and emergency treatment principles for imported wild poliovirus.

A Case of Paralytic Poliomyelitis Associated with Poliovirus Vaccine Strains in Hokkaido, Japan

Hokkaido Institute of Public Health, Sapporo 060-0819; 1School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501; 2Sorachi Public Health and Social Welfare Office, Iwamizawa 068-8558; 3Kamikawa Public Health and Social Welfare Office, Asahikawa 079-8610; 4Iburi Public Health and Social Welfare Office, Muroran 051-8555; 5Department of Health and Welfare, Hokkaido Government, Sapporo 060-8588; and 6Department of Virology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan

Impacto económico de la introducción de la vacuna inactivada inyectable contra la poliomielitis en Colombia

Evaluate the cost-effectiveness of introducing the injectable inactivated polio vaccine (IPV) in Colombia versus the current system based on the use of the oral vaccine (OPV). A Markov model was designed, based on a hypothetical cohort of newborns that would receive the IPV or the OPV vaccine, with a two-year follow-up and monthly estimates of the number of cases of vaccine-associated paralytic poliomyelitis (VAPP) that would emerge. The cost was analyzed from the perspective of the insurer (costs throughout life) and society (cases of VAPP and disability-adjusted life years [DALYs] prevented). From 1988 to 1998, some 22.5 million doses of OVP were administered in Colombia and nine cases of VAPP were detected, for a rate of 4.0 yen 10-7 dose. According to the model, 2 to 4 cases of VAPP could be anticipated in the following two years. The cost of treating the VAPP cases would total US$302,008, with the cost of vaccination with OPV coming to US$737,037 and with IPV, US$5,527,777. Vaccination with IPV would prevent 64 DALYs, at a cost of US$71,062 per DALY prevented; preventing one case of VAPP by substituting OPV with IPV would cost between US$1.8 and US$2.2 million. Substituting OPV with IPV is not a cost-effective measure in Colombia, even if the cellular vaccine against whooping cough currently in use were replaced with an acellular vaccine combined with an IPV.

Switching from OPV to IPV: are we behind the schedule in Latin America?

Oral polio vaccine (OPV) has been an effective strategy since it was initiated almost five decades ago. However, concern regarding its collateral effects has been increasing in recent years among the scientific and policymaker community, since it has proved to be of risk for immunocompetent and immunocompromised individuals by causing cases and even outbreaks of poliomyelitis disease in countries where the virus is not circulating. Enhanced-potency inactivated polio vaccine (IPV), a safer, effective and inexpensive vaccine, has been available for the past couple of decades. Different points of view have emerged regarding stopping the use of OPV to start routine general IPV but, despite the evidence of OPVs derived and associated with unnecessary poliomyelitis cases, Central and South America are still lacking a strategy in place to make the switch from OPV to IPV, and there are no leading efforts to start this strategy. This review gives some evidence-based elements to help raise criteria regarding the best vaccine to choose and highlights the current need for strategic planning in Latin America to avoid more vaccine-associated paralytic poliomyelitis cases.

Molecular characterization of poliovirus isolates from children who contracted vaccine-associated paralytic poliomyelitis (VAPP) following administration of monovalent type 3 oral poliovirus vaccine in the 1960s in Hungary

Hungarian children were immunized with monovalent oral poliovaccine (mOPV) delivered at 6-week intervals in the order Sabin 1, Sabin 3, Sabin 2, from 1959 until 1992. During that period, 90 cases of vaccine-associated paralytic poliomyelitis (VAPP) were reported, 52 of which were associated with Sabin 3-related virus (76% of VAPP cases with virologic data). Because of renewed interest in type 3 mOPV (mOPV3), molecular methods were used to reanalyze 18 of the Sabin 3-related isolates from 15 VAPP patients, confirming the original identification. All isolates had the U472C 5'-untranslated region (5'-UTR) substitution associated with reversion to neurovirulence, and from zero to seven nucleotide substitutions in the virus protein 1 (VP1) region. No evidence was found for prolonged mOPV3 replication in the VAPP patients or for spread of Sabin 3-related viruses beyond close vaccinee contacts. The VAPP diseases were prevented by a single dose of inactivated poliovirus vaccine from 1992 to 2006 in Hungary, as proved by continuous surveillance of acute flaccid paralysis.

Vaccine-associated paralytic poliomyelitis in an infant with perianal abscesses

We describe a case of vaccine-associated paralytic poliomyelitis (VAPP) in a 7-month-old infant with perianal abscesses. The infant had suffered from perianal abscesses from 3weeks after birth. The abscesses repeatedly developed and spontaneously drained through the orifice. Twenty-seven days before admission, a live attenuated oral poliovirus vaccine (OPV) was given to the infant for the first time for routine immunization. His body temperature rose to 38°C 19days after receiving the OPV and fell 4days later. Flaccid paralysis of the right leg appeared 26days after receipt of the OPV. A Sabin type 3 poliovirus was isolated from a stool obtained at admission. The DNA sequences of the VP1 region of the isolated virus were more than 99% identical with those of the vaccine strain. Mild muscle atrophy with moderate motor impairment in the right leg persisted at 18months of age. One VAPP case provoked by a perianal abscess has been reported from the United Kingdom. Database search revealed that one of nine VAPP cases reported during 2003-2008 in Japan had a perianal abscess. Taken together, these reports and our case imply that we should give OPV with caution to infants with a perianal abscess.

Outbreak of poliomyelitis in Finland in 1984–85 – Re-analysis of viral sequences using the current standard approach

In 1984, a wild type 3 poliovirus (PV3/FIN84) spread all over Finland causing nine cases of paralytic poliomyelitis and one case of aseptic meningitis. The outbreak was ended in 1985 with an intensive vaccination campaign. By limited sequence comparison with previously isolated PV3 strains, closest relatives of PV3/FIN84 were found among strains circulating in the Mediterranean region. Now we wanted to reanalyse the relationships using approaches currently exploited in poliovirus surveillance. Cell lysates of 22 strains isolated during the outbreak and stored frozen were subjected to RT-PCR amplification in three genomic regions without prior subculture. Sequences of the entire VP1 coding region, 150 nucleotides in the VP1-2A junction, most of the 5′ non-coding region, partial sequences of the 3D RNA polymerase coding region and partial 3′ non-coding region were compared within the outbreak and with sequences available in data banks. In addition, complete nucleotide sequences were obtained for 2 strains isolated from two different cases of disease during the outbreak. The results confirmed the previously described wide intraepidemic variation of the strains, including amino acid substitutions in antigenic sites, as well as the likely Mediterranean region origin of the strains. Simplot and bootscanning analyses of the complete genomes indicated complicated evolutionary history of the non-capsid coding regions of the genome suggesting several recombinations with different HEV-C viruses in the past.

Three cases of paralytic poliomyelitis associated with type 3 vaccine poliovirus strains in Bulgaria

Oral poliovirus vaccine (OPV) can cause, in extremely rare cases vaccine-associated paralytic poliomyelitis in recipients, or contacts of vaccinees. Three cases of vaccine-associated paralytic poliomyelitis (two contacts and one recipient) occurred in the Bourgas region of Bulgaria in the spring of 2006. The first two cases, notified as acute flaccid paralysis, were 55 days old unvaccinated twin brothers, having been in contact with vaccinees. The third case concerned a 4-month-old infant who had received the first OPV dose 37 days prior to the onset of illness. Complete clinical, epidemiological, virological, serological and molecular investigations of the children with paralysis and their contacts were undertaken. In all the three cases type 3 polioviruses were isolated from fecal samples and characterized as Sabin-like poliovirus strains. Type 3 polioviruses isolated from the twin brothers demonstrated by sequence analysis U-to-C back mutation at nt 472 of the 5' UTR, known to correlate with neurovirulence, and mutation in the VP1 region. Type 3 poliovirus isolated from the third child demonstrated in the 3D sequenced region a recombination with Sabin type 1 poliovirus. In the latter region, three silent mutations and one, resulting in amino acid substitution, were also observed. The clinical, epidemiological and virological data and the neurological sequelae observed 60 days following the onset of paralysis, confirmed the diagnosis of vaccine-associated paralytic poliomyelitis in all the three patients.

Effectiveness of Immunization against Paralytic Poliomyelitis in Nigeria

The number of cases of paralytic poliomyelitis has declined in Nigeria since the introduction of newly licensed monovalent oral poliovirus vaccines and new techniques of vaccine delivery. Understanding the relative contribution of these vaccines and the improved coverage to the decline in incident cases is essential for future planning. We estimated the field efficacies of monovalent type 1 oral poliovirus vaccine and trivalent oral poliovirus vaccine, using the reported number of doses received by people with poliomyelitis and by matched controls as identified in Nigeria's national surveillance database, in which 27,379 cases of acute flaccid paralysis were recorded between 2001 and 2007. Our estimates of vaccine coverage and vaccine-induced immunity were based on the number of doses received by children listed in the database who had paralysis that was not caused by poliovirus. The estimated efficacies per dose of monovalent type 1 oral poliovirus vaccine and trivalent oral poliovirus vaccine against type 1 paralytic poliomyelitis were 67% (95% confidence interval [CI], 39 to 82) and 16% (95% CI, 10 to 21), respectively, and the estimated efficacy per dose of trivalent oral poliovirus vaccine against type 3 paralytic poliomyelitis was 18% (95% CI, 9 to 26). In the northwestern region of Nigeria, which reported the majority of cases during the study period, coverage with at least one dose of vaccine increased from 59 to 78%. Between 2005 and 2007, vaccine-induced immunity levels among children under the age of 5 years more than doubled, to 56%. The higher efficacy of monovalent type 1 oral poliovirus vaccine (four times as effective as trivalent oral poliovirus vaccine) and the moderate gains in coverage dramatically increased vaccine-induced immunity against serotype 1 in northern Nigeria. Further increases in coverage in Nigerian states with infected populations are required to achieve the levels of vaccine-induced immunity associated with the sustained elimination achieved in other parts of the country.

Characterization of mutations in the VP 1 region of Sabin strain type 1 polioviruses isolated from vaccine-associated paralytic poliomyelitis cases in Iran

Background The live-attenuated oral polio vaccine used to interrupt poliovirus transmission is genetically unstable. Reversion of some attenuating mutations, which normally occurs during vaccine strain replication in some recipients, and can rarely cause vaccine-associated paralytic poliomyelitis (VAPP). The poliovirus eradication program designed by the World Health Organization (WHO) includes immunization with OPV in addition to careful surveillance of all acute-flaccid paralysis (AFP) cases. Objectives In Iran we last isolated imported wild poliovirus in 2000 and the immunization coverage was 100% in 2002. During 2001, there were three AFP cases with residual paralysis from which Sabin-like type 1 polioviruses were isolated in our national polio laboratory. Study design The complete VP 1 region of the three isolates was sequenced and amino acid substitutions associated with these neurovirulent isolates were recorded. Results These isolates had either 4, 2 or 1 nucleotide substitution(s) in the VP 1 region, corresponding to amino acid change in the VP 1 of isolate 1 of either ( H ⟶ 149 Y ), ( T ⟶ 106 A ) or ( I ⟶ 90 L ), respectively. Conclusions Surveillance of the VAPP cases in countries where endemic transmission has recently ceased increases our understanding of the important neurovirulent mutations in vaccine-strain isolates and assists in planning the next step in the eradication program in these countries.

The HPV Vaccine

In 1999, the Morbidity and Mortality Weekly Report (MMWR) identified the ten most significant public health achievements of the last 100 years (Table 1). (1) First on the list of accomplishments was vaccination, a biomedical and public health success story responsible for saving millions of lives and preventing untold misery from infectious diseases. Both life expectancy and quality of life have improved because of vaccines that have eradicated diseases such as smallpox, and virtually eliminated childhood diseases such as measles, diphtheria and pertussis (whooping cough). A particularly good example of the impact of vaccines are ones developed to combat infantile paralysis (polio), first by Salk, and later, by Sabin. Between 1951 and 1954, immediately prior to the widespread dissemination of Salk's polio vaccine, there were over 16,000 cases of paralytic poliomyelitis, and an average of 1900 U.S. deaths annually from polio. (2) The Salk vaccine was licensed in the U.S. in 1955, and cases of the disease dropped precipitously to fewer than 1000 per year until 1962, when the Sabin vaccine was licensed and administered on a widespread basis. (2) By the end of 1962, fewer than 100 cases were seen annually. There has not been a naturally occurring case of polio in the United States since 1979. (3) Concerted efforts by health and non-profit organizations to disseminate the polio vaccine have reduced the global burden of polio from approximately 350,000 cases per year in the late 1980s to 1200 cases in 2005, the 50th anniversary of the development of the vaccine. (4) A new vaccine has been developed and released for use against a leading cause of death in women worldwide--cervical cancer. The human papillomavirus, or HPV, a species-specific DNA virus with over 100 types identified to date, has been recognized as the causal agent in the development of cervical cancer. It also is associated with other cancers (e.g., anal, penile, vulvar, vaginal, and oral-pharyngeal). Over 30 types of HPV are anogenital, and approximately half of those are oncogenic. If left untreated, they have the ability to progress to invasive cancers. Other anogenital HPV types, known as low-risk types, are responsible for genital warts. Whereas genital warts are benign, they are visible and may be a source of embarrassment. HPV is common--a recent U.S. study concluded that overall prevalence among 14-24 year-old women, an age group included in the age range targeted for the HPV vaccine, is 33.8%, and that: This prevalence corresponds with 7.5 million females with HPV infection, which is higher than the previous estimate of 4.6 million prevalent HPV infections among females in this same age group in the United States. (5(p817)) Furthermore, the lifetime likelihood of acquiring HPV is estimated to be 75% or more. (6) Fortunately, infection with HPV also is transient, and in most cases, will clear up through the body's own immune response. According to the National Cancer Institute, about 10% of women have an oncogenic HPV infection at a given time, and they are more common in young women than in older women. Most cervical infections, including ones involving oncogenic types of HPV, clear on their own without causing cancer. (7) In the U.S., cervical cancer incidence and deaths have significantly decreased because of a well-designed and effective screening program, with an estimated number of 11,150 invasive cervical cancer cases, and 3670 deaths forecast for 2007. (8) Globally, the picture is grim as more than 250,000 women die annually from cervical cancer, making it the second most common cause of cancer death in women. Moreover, the World Health Organization anticipates a 25% increase in cervical cancer deaths over the next decade if significant interventions do not occur. (9) In addition, 80% of the approximately half million women who will be diagnosed with cervical cancer worldwide live in resource-poor developing countries that do not have the infrastructure to provide cytology screening for the disease. …

Eradication versus control for poliomyelitis: an economic analysis

Worldwide eradication of wild polioviruses is likely to yield substantial health and financial benefits, provided we finish the job. Challenges in the four endemic areas combined with continuing demands for financial resources for eradication have led some to question the goal of eradication and to suggest switching to a policy of control. We developed a dynamic model, based on modelling of the currently endemic areas in India, to show the importance of maintaining and increasing the immunisation intensity to complete eradication and to illustrate how policies based on perception about high short-term costs or cost-effectiveness ratios without consideration of long-term benefits could undermine any eradication effort. An extended model assesses the economic implications and disease burden of a change in policy from eradication to control. Our results suggest that the intensity of immunisation must be increased to achieve eradication, and that even small decreases in intensity could lead to large outbreaks. This finding implies the need to pay even higher short-run costs than are currently being spent, which will further exacerbate concerns about continued investment in interventions with high perceived cost-effectiveness ratios. We show that a wavering commitment leads to a failure to eradicate, greater cumulative costs, and a much larger number of cases. We further show that as long as it is technically achievable, eradication offers both lower cumulative costs and cases than control, even with the costs of achieving eradication exceeding several billion dollars more. A low-cost control policy that relies only on routine immunisation for 20 years with discounted costs of more than $3500 million could lead to roughly 200 000 expected paralytic poliomyelitis cases every year in low-income countries, whereas a low-case control policy that keeps the number of cases at about 1500 per year could cost around $10 000 million discounted over the 20 years. Focusing on the large costs for poliomyelitis eradication, without assessing the even larger potential benefits of eradication and the enormous long-term costs of effective control, might inappropriately affect commitments to the goal of eradication, and thus debate should include careful consideration of the options.