Paralysis case and contact spread of recombinant vaccine-derived poliovirus, Spain.
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ABSTRACT:
SUBMITTER: Avellon A
PROVIDER: S-EPMC2630745 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Sabin strains used in the manufacture of oral polio vaccine (OPV) replicate in the human organism and can give rise to vaccine-derived polioviruses. The increased neurovirulence of vaccine derivatives has been known since the beginning of OPV use, but their ability to establish circulation in communities has been recognized only recently during the latest stages of the polio eradication campaign. This important observation called for studies of their emergence and evolution as well as extensive surveillance to determine the scope of this phenomenon. Here, we present the results of a study of vaccine-derived isolates from an immunocompromised poliomyelitis patient, the contacts, and the local sewage. All isolates were identified as closely related and slightly evolved vaccine derivatives with a recombinant type 2/type 1 genome. The strains also shared several amino acid substitutions including a mutation in the VP1 protein that was previously shown to be associated with the loss of attenuation. Another mutation in the VP3 protein resulted in altered immunological properties of the isolates, possibly facilitating virus spread in immunized populations. The patterns and rates of the accumulation of synonymous mutations in isolates collected from the patient over the extended period of excretion suggest either a substantially nonuniform rate of mutagenesis throughout the genome, or, more likely, the strains may have been intratypic recombinants between coevolving derivatives with different degrees of divergence from the vaccine parent. This study provides insight into the early stages of the establishment of circulation by runaway vaccine strains.
| S-EPMC538583 | biostudies-literature
Project description:Pathogenic circulating vaccine-derived polioviruses (cVDPVs) have become a major obstacle to the successful completion of the global polio eradication program. Most cVDPVs are recombinant between the oral poliovirus vaccine (OPV) and human enterovirus species C (HEV-C). To study the role of HEV-C sequences in the phenotype of cVDPVs, we generated a series of recombinants between a Madagascar cVDPV isolate and its parental OPV type 2 strain. Results indicated that the HEV-C sequences present in this cVDPV contribute to its characteristics, including pathogenicity, suggesting that interspecific recombination contributes to the phenotypic biodiversity of polioviruses and may favor the emergence of cVDPVs.
| S-EPMC2519664 | biostudies-literature
Project description:BackgroundAs long as oral poliovirus vaccine (OPV) is used, the potential risk for the emergence of vaccine-related polioviruses remains.Case summaryWe report a case of Sabin-like type 1 poliovirus infection in an immunocompetent 17-mo-old child after receiving four scheduled doses of OPV. Somehow, the four doses did not confer full protection, possibly because of interference created by other enteroviruses.ConclusionThe surveillance of vaccine-related polioviruses has important implications for improving health policies and vaccination strategies. Missed cases of vaccine-related poliovirus infection might pose a potential risk to global poliovirus eradication. Therefore, the global withdrawal of OPV and a shift to the inclusion of only inactivated poliovirus vaccine in the vaccination schedule is the main objective of the polio eradication program.
| S-EPMC8465515 | biostudies-literature
Project description:If the world can successfully control all outbreaks of circulating vaccine-derived poliovirus that may occur soon after global oral poliovirus vaccine (OPV) cessation, then immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) from rare and mostly asymptomatic long-term excretors (defined as ⩾6 months of excretion) will become the main source of potential poliovirus outbreaks for as long as iVDPV excretion continues. Using existing models of global iVDPV prevalence and global long-term poliovirus risk management, we explore the implications of uncertainties related to iVDPV risks, including the ability to identify asymptomatic iVDPV excretors to treat with polio antiviral drugs (PAVDs) and the transmissibility of iVDPVs. The expected benefits of expanded screening to identify and treat long-term iVDPV excretors with PAVDs range from US$0.7 to 1.5 billion with the identification of 25-90% of asymptomatic long-term iVDPV excretors, respectively. However, these estimates depend strongly on assumptions about the transmissibility of iVDPVs and model inputs affecting the global iVDPV prevalence. For example, the expected benefits may decrease to as low as US$260 million with the identification of 90% of asymptomatic iVDPV excretors if iVDPVs behave and transmit like partially reverted viruses instead of fully reverted viruses. Comprehensive screening for iVDPVs will reduce uncertainties and maximize the expected benefits of PAVD use.
| S-EPMC5197684 | biostudies-literature
Project description:This report describes emergency response following an imported vaccine derived poliovirus (VDPV) case from Myanmar to Yunnan Province, China and the cross-border collaboration between China and Myanmar. Immediately after confirmation of the VDPV case, China disseminated related information to Myanmar with the assistance of the World Health Organization.A series of epidemiological investigations were conducted, both in China and Myanmar, including retrospective searches of acute flaccid paralysis (AFP) cases, oral poliovirus vaccine (OPV) coverage assessment, and investigation of contacts and healthy children.All children <2 years of age had not been vaccinated in the village where the VDPV case had lived in the past 2 years. Moreover, most areas were not covered for routine immunization in this township due to vaccine shortages and lack of operational funds for the past 2 years.Cross-border collaboration may have prevented a potential outbreak of VDPV in Myanmar. It is necessary to reinforce cross-border collaboration with neighboring countries in order to maximize the leverage of limited resources.
| S-EPMC4308939 | biostudies-literature
Project description:BackgroundVaccine derived poliovirus (VDPV) remains a major barrier to polio eradication, and recent growing emergences are concerning. This paper presents the global epidemiology of circulating VDPV (cVDPV) by exploring associations between demographic and socioeconomic factors with its recent rise.MethodsData on reported cVDPV cases and isolates between January 1 2016 and June 30 2021 were compiled from EPIWATCH, an open-source observatory for outbreak scanning and analysis, the World Health Organisation (WHO) and ProMed, and analysed descriptively. Reports containing cVDPV case information were included while duplicates and defective links were excluded. Data collection occurred from April 5 2021 to July 16 2021. To identify factors associated with cVDPV, a retrospective case-control study comparing socioeconomic profiles of countries which reported cVDPV with those that did not was undertaken with weighted logistic regression analysis.FindingscVDPV caused by serotype 2 poliovirus was the predominant strain (95%) of 1818 total human cVDPV cases reported. Of 40 countries reporting cVDPV cases or isolates, 22 (55%) had polio vaccination coverages below 80%. Low vaccination coverage (Adjusted OR = 83·41, 95% CI: [5·01, 1387·71], p = 0·0020) was found to be associated with increased odds of reporting cVDPV after adjusting for confounding effects of GDP per capita, female adult literacy rates, maternal mortality rate, and Global Peace Index.InterpretationOur findings reinforce the importance of maintaining high levels of vaccination, as risk of re-emergence rises when immunity wanes. Interventions to increase vaccination and standards of living in developing countries, coupled with robust surveillance are required if humanity hopes to eradicate polio in the near future.FundingThis research was supported by the MRFF 2021 Frontier Health and Medical Research Grant (ID RFRHPI000280), Department of Health, the Australian Government.
| S-EPMC9240990 | biostudies-literature
Project description:Reversion and spread of vaccine-derived poliovirus (VDPV) to cause outbreaks of poliomyelitis is a rare outcome resulting from immunisation with the live-attenuated oral poliovirus vaccines (OPVs). Global withdrawal of all three OPV serotypes is therefore a key objective of the polio endgame strategic plan, starting with serotype 2 (OPV2) in April 2016. Supplementary immunisation activities (SIAs) with trivalent OPV (tOPV) in advance of this date could mitigate the risks of OPV2 withdrawal by increasing serotype-2 immunity, but may also create new serotype-2 VDPV (VDPV2). Here, we examine the risk factors for VDPV2 emergence and implications for the strategy of tOPV SIAs prior to OPV2 withdrawal. We first developed mathematical models of VDPV2 emergence and spread. We found that in settings with low routine immunisation coverage, the implementation of a single SIA increases the risk of VDPV2 emergence. If routine coverage is 20%, at least 3 SIAs are needed to bring that risk close to zero, and if SIA coverage is low or there are persistently "missed" groups, the risk remains high despite the implementation of multiple SIAs. We then analysed data from Nigeria on the 29 VDPV2 emergences that occurred during 2004-2014. Districts reporting the first case of poliomyelitis associated with a VDPV2 emergence were compared to districts with no VDPV2 emergence in the same 6-month period using conditional logistic regression. In agreement with the model results, the odds of VDPV2 emergence decreased with higher routine immunisation coverage (odds ratio 0.67 for a 10% absolute increase in coverage [95% confidence interval 0.55-0.82]). We also found that the probability of a VDPV2 emergence resulting in poliomyelitis in >1 child was significantly higher in districts with low serotype-2 population immunity. Our results support a strategy of focused tOPV SIAs before OPV2 withdrawal in areas at risk of VDPV2 emergence and in sufficient number to raise population immunity above the threshold permitting VDPV2 circulation. A failure to implement this risk-based approach could mean these SIAs actually increase the risk of VDPV2 emergence and spread.
| S-EPMC4934862 | biostudies-literature
Project description:Since 2004, a total of 131 isolates of Streptococcus pneumoniae multidrug-resistant invasive serotype 8 have been detected in Spain. These isolates showed resistance to erythromycin, clindamycin, tetracycline, and ciprofloxacin. All isolates were obtained from adult patients and shared a common genotype (sequence type [ST]63; penicillin-binding protein 1a [pbp1a], pbp2b, and pbp2x gene profiles; ermB and tetM genes; and a ParC-S79F change). Sixty-eight isolates that required a ciprofloxacin MIC ≥16 μg/mL had additional gyrA gene changes. Serotype 8-ST63 pbp2x sequences were identical with those of antimicrobial drug-susceptible serotype 8-ST53 isolates. Serotype 8-ST63 pbp2b sequences were identical with those of the multidrug-resistant Sweden 15A-ST63 clone. Recombination between the capsular locus and flanking regions of an ST53 isolate (donor) and an ST63 pneumococcus (recipient) generated the novel 15A-ST63 clone. One recombination point was upstream of pbp2x and another was within pbp1a. A serotype 8-ST63 clone was identified as a cause of invasive disease in Spain.
| S-EPMC4214286 | biostudies-literature
Project description:We determined nucleotide sequences of the VP1 and 2AB genes and portions of the 2C and 3D genes of two evolving poliovirus lineages: circulating wild viruses of T geotype and Sabin vaccine-derived isolates from an immunodeficient patient. Different regions of the viral RNA were found to evolve nonsynchronously, and the rate of evolution of the 2AB region in the vaccine-derived population was not constant throughout its history. Synonymous replacements occurred not completely randomly, suggesting the need for conservation of certain rare codons (possibly to control translation elongation) and the existence of unidentified constraints in the viral RNA structure. Nevertheless the major contribution to the evolution of the two lineages came from linear accumulation of synonymous substitutions. Therefore, in agreement with current theories of viral evolution, we suggest that the majority of the mutations in both lineages were fixed as a result of successive sampling, from the heterogeneous populations, of random portions containing predominantly neutral and possibly adverse mutations. As a result of such a mode of evolution, the virus fitness may be maintained at a more or less constant level or may decrease unless more-fit variants are stochastically generated. The proposed unifying model of natural poliovirus evolution has important implications for the epidemiology of poliomyelitis.
| S-EPMC112258 | biostudies-literature
Project description:Circulating vaccine-derived polioviruses (cVDPVs) can emerge in areas with low poliovirus immunity and cause outbreaks* of paralytic polio (1-5). Among the three types of wild poliovirus, type 2 was declared eradicated in 2015 (1,2). The use of trivalent oral poliovirus vaccine (tOPV; types 1, 2, and 3 Sabin strains) ceased in April 2016 via a 1-month-long, global synchronized switch to bivalent OPV (bOPV; types 1 and 3 Sabin strains) in immunization activities (1-4). Monovalent type 2 OPV (mOPV2; type 2 Sabin strain) is available for cVDPV type 2 (cVDPV2) outbreak response immunization (1-5). The number and geographic breadth of post-switch cVDPV2 outbreaks have exceeded forecasts that trended toward zero outbreaks 4 years after the switch and assumed rapid and effective control of any that occurred (4). New cVDPV2 outbreaks have been seeded by mOPV2 use, by both suboptimal mOPV2 coverage within response zones and recently mOPV2-vaccinated children or contacts traveling outside of response zones, where children born after the global switch are fully susceptible to poliovirus type 2 transmission (2-4). In addition, new emergences can develop by inadvertent exposure to Sabin OPV2-containing vaccine (i.e., residual response mOPV2 or tOPV) (4). This report updates the January 2018-June 2019 report with information on global cVDPV outbreaks during July 2019-February 2020 (as of March 25, 2020)† (2). Among 33 cVDPV outbreaks reported during July 2019-February 2020, 31 (94%) were cVDPV2; 18 (58%) of these followed new emergences. In mid-2020, the Global Polio Eradication Initiative (GPEI) plans to introduce a genetically stabilized, novel OPV type 2 (nOPV2) that has a lower risk for generating VDPV2 than does Sabin mOPV2; if nOPV2 is successful in limiting new VDPV2 emergences, GPEI foresees the replacement of Sabin mOPV2 with nOPV2 for cVDPV2 outbreak responses during 2021 (2,4,6).
| S-EPMC7188410 | biostudies-literature