Vaccine-Derived Polioviruses Burns, Cara C.; Diop, Ousmane M.; Slitter, Roland W. ...
The Journal of infectious diseases,
11/2014, Letnik:
210, Številka:
suppl 1
Journal Article
Recenzirano
Odprti dostop
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.
Although there have been no cases of serotype 2 wild poliovirus for more than 20 years, transmission of serotype 2 vaccine-derived poliovirus (VDPV2) and associated paralytic cases in several ...continents represent a threat to eradication. The withdrawal of the serotype 2 component of oral poliovirus vaccine (OPV2) was implemented in April 2016 to stop VDPV2 emergence and secure eradication of all serotype 2 poliovirus. Globally, children born after this date have limited immunity to prevent transmission. Using a statistical model, we estimated the emergence date and source of VDPV2s detected between May 2016 and November 2019. Outbreak response campaigns with monovalent OPV2 are the only available method to induce immunity to prevent transmission. Yet our analysis shows that using monovalent OPV2 is generating more paralytic VDPV2 outbreaks with the potential for establishing endemic transmission. A novel OPV2, for which two candidates are currently in clinical trials, is urgently required, together with a contingency strategy if this vaccine does not materialize or perform as anticipated.
Abstract Background The use of 2 live attenuated vaccines (LAV) is recommended to be simultaneous or after an interval of at least four weeks between injections. The primary objective of this study ...was to compare the humoral response to yellow fever (YF) and measles vaccines among children vaccinated against these two diseases, either simultaneously or separated by an interval of 7–28 days. Subjects and methods A prospective, multicenter observational study was conducted among children aged 9–15 months. The primary endpoint was the occurrence of positive yellow fever antibodies after YF vaccine by estimating the titers of neutralizing antibodies from venous blood samples. Children vaccinated against YF 7–28 days after receiving the vaccine against measles (test group) were compared with children vaccinated the same day against these two diseases (referent group). Results Analysis was performed on 284 children. Of them, fifty-four belonged to the test group. Measles serology was positive in 91.7% of children. Neutralizing antibodies against YF were detected in 90.7% of the test group and 92.9 of the referent group ( p =0.6). In addition, quantitative analysis of the immune response did not show a lower response to YF vaccination when it took place 1–28 days after measles vaccination. Discussion In 1965, Petralli showed a lower response to the smallpox vaccine when injected 4–20 days after measles vaccination. Since then, recommendations are to observe an interval of four weeks between LAV not injected on the same day. Other published studies failed to show a significant difference in the immune response to a LAV injected 1–28 days after another LAV. These results suggest that the usual recommendations for immunization with two LAV may not be correct. Conclusion In low income countries, the current policy should be re-evaluated. This re-evaluation should also be applied to travelers to yellow fever endemic countries.
Objectif: Décrire les caractéristiques épidémiologiques et les modalités de prise en charge préventive des patients.
Résultats : Cent cinquante-deux (152) patients ont consulté suite à une exposition ...au risque d'infection rabique principalement à la suite d'une morsure par un chien (133cas/152). Aucun animal mordeur n'a été mis en observation. La majorité (90%) provenait de Dakar. L'âge médian était de 22 ans 1 - 90 ans et les hommes étaient les plus touchés avec un sex ratio (H/F) de 1,8. Les blessures de catégorie II étaient les plus fréquentes (100 cas). Près de deux tiers des personnes exposées ont été prises en charge dans les 48 heures. La quasi-totalité des patients avaient bénéficié du protocole Zagreb mais environ 41% d'entre eux avaient abandonné leur prophylaxie post exposition (PPE) en cours de suivi, soit un taux de complétude de 59%.
Conclusion : Composante essentielle de la lutte contre la rage, la prophylaxie post exposition doit être améliorée par la sensibilisation et la collaboration avec les services vétérinaires. Tout ceci dans l'esprit du one health ou santé unique ainsi que l'amélioration de l'accessibilité financière des vaccins et des immunoglobulines antirabiques
Abstract The burden of influenza disease is to a large extent unknown for the African continent. Moreover, the interaction of influenza with common infectious diseases in Africa remains poorly ...described. Solid scientific evidence on the influenza disease burden in Africa is critical for the development of effective influenza vaccine policies. On 1st and 2nd June 2010 in Marrakech, Morocco, over eighty surveillance and influenza experts from 22 African countries as well as Europe and America met at the ‘Afriflu’ conference to discuss influenza challenges and solutions for the continent. During the meeting, participants exchanged their experiences and discussed a wide variety of topics related to influenza in Africa, including diagnosis, surveillance, epidemiology, and interventions. The meeting concluded with a pledge to improve influenza knowledge and awareness in Africa, with an emphasis on accurate determination of disease burden to help orient public health policies.
Summary
Background Infective dermatitis (ID) is a rare dermatological condition of childhood that has been linked to human T‐cell leukaemia/lymphoma virus type 1 (HTLV‐1). Most cases have been ...reported in the Caribbean. Although several million people are estimated to be infected by HTLV‐1 in sub‐Saharan Africa, no case of ID has been reported in this area.
Objectives To identify and to describe cases of HTLV‐1‐associated ID in Senegal, West Africa.
Methods Over a 3‐year period, a serological test for HTLV‐1 was performed at a dermatological centre in Dakar, Senegal, in children who presented with a picture suggestive of ID. Complementary haematological, immunological and virological investigations were performed in infected children and in their mothers.
Results Five patients with typical HTLV‐1‐associated ID were identified, of ages 17, 5, 4, 3 and 3 years; two patients belonged to the same family. They all presented with repeated flares of superinfected dermatitis involving typical sites of ID (mainly the scalp, external ears, nares and eyelids), associated with nasal discharge, and less commonly with a nonspecific papular rash on the face or trunk. Although oral antibiotic therapy always gave effective control of the symptoms, recurrences were constant. A persisting dry dermatitis of the retroauricular folds was common between flares. Infection in the oldest patient was associated with a chronic adult T‐cell leukaemia/lymphoma. The mothers of three patients, and the grandmother of another, were all infected by HTLV‐1 strains belonging to the Cosmopolitan molecular subtype, with a perfect nucleotide identity of long‐terminal repeat and env gp21 genomic regions within each family.
Conclusions We present the clinical and virological features of the first reported African cases of HTLV‐1‐associated ID. When compared with data from the Caribbean, infectious features seemed particularly prominent. ID appears to be overlooked in sub‐Saharan Africa, where it might be easily confused with common pyoderma. Breast feeding appears to be the origin of HTLV‐1 contamination of the children.
In 2005, a serological study was carried out on horses in five ecologically contrasted zones of the Senegal River basin (Senegal) to assess West Nile virus (WNV) transmission and investigate ...underlying environmental risk factors. In each study zone, horses were randomly selected and blood samples taken. A land-cover map of the five study areas was built using two satellite ETM+ images. Blood samples were screened by ELISA for anti-WNV IgM and IgG and positive samples were confirmed by seroneutralization. Environmental data were analysed using a principal components analysis. The overall IgG seroprevalence rate was 85% (n=367; 95% CI 0·81–0·89). The proximity to sea water, flooded banks and salted mudflats were identified as protective factors. These environmental components are unfavourable to the presence of Culex mosquitoes suggesting that in Senegal, the distribution of the vector species is more limiting for WNV transmission than for the hosts' distribution.
Despite substantial progress, global polio eradication has remained elusive. Indigenous wild poliovirus (WPV) transmission in 4 endemic countries (Afghanistan, India, Nigeria, and Pakistan) persisted ...into 2010 and outbreaks from imported WPV continued. By 2013, most outbreaks in the interim were promptly controlled. The number of polio-affected districts globally has declined by 74% (from 481 in 2009 to 126 in 2013), including a 79% decrease in the number of affected districts in endemic countries (from 304 to 63). India is now polio-free. The challenges to success in the remaining poliò-endemic countries include (1) threats to the security of vaccinatore in each country and a ban on polio vaccination in areas of Afghanistan and Pakistan; (2) a risk of decreased government commitment; and (3) remaining surveillance gaps. Coordinated efforts under the International Health Regulations and efforts to mitigate the challenges provide a clear opportunity to soon secure global eradication.
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