The final stages of the global eradication of polio

A phase Ⅱ, randomized, controlled trial to evaluate the safety and immunogenicity of a Sabin strain-based inactivated polio vaccine

This phase Ⅱ, randomized, controlled trial aimed to evaluate the safety and immunogenicity of a various Sabin IPV preparations. Six hundred infants aged 60 ~ 90 days received one of five different vaccines: low- (group A), medium- (group B) or high-D antigen content (group C) of an experimental Sabin IPV, control Sabin IPV (group D) or control Salk IPV (group E), on a 0-1-2 month schedule. Participants were observed and followed up within 30 days of each dose to assess safety. Serum samples were collected before the first dose and 30 days after the third dose to assess immunogenicity. After three doses, type-1 seroconversion rates of groups A-E were 99.1%, 100.0%, 99.1%, 99.0%, and 93.4%, respectively; type-2 seroconversion rates were 93.5%, 97.1%, 98.1%, 95.1%, and 91.5%, respectively; and type-3 seroconversion rates were 95.4%, 98.1%, 98.1%, 95.1%, and 100.0%, respectively. Only type-1 seroconversion rates differed significantly for group E. The incidences of injection-site redness (A: 21.9%, B: 23.7%, C: 29.4%, D: 16.2%, E: 12.7%), swelling (A: 6.7%, B: 6.8%, C: 5.0%, D: 0.0%, E: 1.7%) and pain (A: 5.0%, B: 6.8%, C: 7.6%, D: 0.0%, E: 0.9%) all were significantly higher for experimental vaccines relative to control groups. No SAEs were detected related to vaccination, and most adverse reactions were mild or moderate in severity. In conclusion, the experimental Sabin IPVs with low-, medium-, and high-D antigen content all revealed good safety and immunogenicity profiles although being more reactogenic than the control vaccines.

Lung function in post-poliomyelitis syndrome: a cross-sectional study

OBJECTIVE:

To compare lung function between patients with post-poliomyelitis syndrome and those with sequelae of paralytic poliomyelitis (without any signs or symptoms of post-poliomyelitis syndrome), as well as between patients with post-poliomyelitis syndrome and healthy controls.

METHODS:

Twenty-nine male participants were assigned to one of three groups: control; poliomyelitis (comprising patients who had had paralytic poliomyelitis but had not developed post-poliomyelitis syndrome); and post-poliomyelitis syndrome. Volunteers underwent lung function measurements (spirometry and respiratory muscle strength assessment).

RESULTS:

The results of the spirometric assessment revealed no significant differences among the groups except for an approximately 27% lower mean maximal voluntary ventilation in the post-poliomyelitis syndrome group when compared with the control group (p = 0.0127). Nevertheless, the maximal voluntary ventilation values for the post-poliomyelitis group were compared with those for the Brazilian population and were found to be normal. No significant differences were observed in respiratory muscle strength among the groups.

CONCLUSIONS:

With the exception of lower maximal voluntary ventilation, there was no significant lung function impairment in outpatients diagnosed with post-poliomyelitis syndrome when compared with healthy subjects and with patients with sequelae of poliomyelitis without post-poliomyelitis syndrome. This is an important clinical finding because it shows that patients with post-poliomyelitis syndrome can have preserved lung function.

The state of polio vaccination in the world: the case for continuing routine vaccination

This article reviews the literature concerning polio vaccination and uses that information to evaluate the World Health Organization's announced plans to end polio vaccination early in the 21st century. The safe elimination of polio vaccination would require the elimination of all polio cases, including paralytic cases, mild, nonparalytic cases, and vaccine-associated cases; proof that polio does not have any nonhuman alternative host; proof that no one alive can still shed the poliovirus; proof that no poliovirus persists in the environment; and proof that no live poliovirus, either the wild type or the vaccine strain, exists in medical or terrorist hands. Because it does not seem possible to ensure that ending vaccination against polio would be safe, and given the fact the polio is a terrible and untreatable disease, it would seem prudent to continue polio vaccination for the foreseeable future.

Epitope mapping: the first step in developing epitope-based vaccines

Antibodies are an effective line of defense in preventing infectious diseases. Highly potent neutralizing antibodies can intercept a virus before it attaches to its target cell and, thus, inactivate it. This ability is based on the antibodies’ specific recognition of epitopes, the sites of the antigen to which antibodies bind. Thus, understanding the antibody/epitope interaction provides a basis for the rational design of preventive vaccines. It is assumed that immunization with the precise epitope, corresponding to an effective neutralizing antibody, would elicit the generation of similarly potent antibodies in the vaccinee. Such a vaccine would be a ‘B-cell epitope-based vaccine’, the implementation of which requires the ability to backtrack from a desired antibody to its corresponding epitope.

In this article we discuss a range of methods that enable epitope discovery based on a specific antibody. Such a reversed immunological approach is the first step in the rational design of an epitope-based vaccine. Undoubtedly, the gold standard for epitope definition is x-ray analyses of crystals of antigen: antibody complexes. This method provides atomic resolution of the epitope; however, it is not readily applicable to many antigens and antibodies, and requires a very high degree of sophistication and expertise. Most other methods rely on the ability to monitor the binding of the antibody to antigen fragments or mutated variations. In mutagenesis of the antigen, loss of binding due to point modification of an amino acid residue is often considered an indication of an epitope component. In addition, computational combinatorial methods for epitope mapping are also useful. These methods rely on the ability of the antibody of interest to affinity isolate specific short peptides from combinatorial phage display peptide libraries. The peptides are then regarded as leads for the definition of the epitope corresponding to the antibody used to screen the peptide library. For epitope mapping, computational algorithms have been developed, such as Mapitope, which has recently been found to be effective in mapping conformational discontinuous epitopes. The pros and cons of various approaches towards epitope mapping are also discussed.

Fatigue and neuromuscular diseases

PURPOSE

To identify the role of fatigue, its evaluation and its causes in the pathophysiology context of acquired or hereditary neuromuscular diseases of the spinal anterior horn cell, peripheral nerve, neuromuscular junction and muscle.

MATERIAL AND METHODS

A literature review has been done on Medline with the following keywords: neuromuscular disease, peripheral neuropathy, myopathy, fatigue assessment, exercise intolerance, force assessment, fatigue scale and questionnaire, then with the terms: Fatigue Severity Scale, Chalder Fatigue Scale, Fatigue Questionnaire, Piper Fatigue Scale, electromyography and the combination of the word Fatigue with the following terms: Amyotrophic Lateral Sclerosis (ALS), Post-Polio Syndrome (PPS), Guillain-Barre Syndrome, Immune Neuropathy, Charcot-Marie-Tooth Disease, Myasthenia Gravis (MG), Metabolic Myopathy, Mitochondrial Myopathy, Muscular Dystrophy, Facioscapulohumeral Dystrophy, Myotonic Dystrophy.

RESULTS

Fatigue is a symptom very frequently reported by patients. Fatigue is mainly evaluated by strength loss after an exercise, by change in electromyographic activity during a given exercise and by questionnaires that takes into account the subjective (psychological) part of fatigue. Due to the large diversity of motor disorders, there are multiple clinical expressions of fatigue that differ in their presentation, consequences and therapeutic approach.

CONCLUSION

This review shows that fatigue has to be taken into account in patients with neuromuscular diseases. In this context, pathophysiology of fatigue often implies the motor component but the disease evolution and the physical obligates of daily life also induce an important psychological component.

Community-acquired poliovirus infection in children with primary immunodeficiencies in Tunisia

The global polio eradication program recommends the use of massive vaccination campaigns with live vaccine through National Immunization Days (NIDs) to displace the wild virus from the community. Immunodeficient patients may be indirectly infected and become chronic excretors and potential reservoirs of polioviruses, a concern for the posteradication era. This prospective study aimed to assess the risk of community-acquired infection of immunodeficient patients following NIDs, the dynamics of viral excretion and the genetic variation of excreted viruses. Sixteen children with various primary immunodeficiencies, who did not receive the vaccine during the campaign, were investigated. Stool samples were collected weekly, shortly after the NIDs, during at least 3 months, and were processed for viral isolation. Isolates were characterized by three intratypic differentiation methods and partial sequencing of the VP1/2A region. Polioviruses were detected in 4 out of 16 patients (serotype 1 in 3 patients and serotype 3 in 1 patient). Sequencing revealed more than 99% homology with homotypic Sabin strains, suggesting recent infection. Duration of viral excretion ranged from 1 to 7 weeks. Nine out of eleven isolates from the three poliovirus serotype 1-infected patients disclosed a non-Sabin-like phenotype by enzyme-linked immunosorbent assay and had recurrent mutations within or close to the neutralizing antigenic sites. In summary, the risk of secondary infection in immunodeficient patients is within the range previously reported for the general population. Although none of the four infected patients developed prolonged viral excretion, particular viral variants were selected and may be of epidemiological significance.

Another look at polio and postpolio syndrome

Polio survivors will likely be accessing the health care system because of acute and/or chronic conditions as they age. Therefore, they will again be interacting with health care professionals, especially orthopaedic and rehabilitation nurses. A comprehensive understanding of polio and postpolio syndrome will give orthopaedic and rehabilitation nurses the knowledge they will need to help polio survivors and their families achieve their highest potential and quality of life.