Randomized Controlled Clinical Trial of Bivalent Oral Poliovirus Vaccine and Inactivated Poliovirus Vaccine in Nigerian Children.

BACKGROUND: We conducted a trial in Nigeria to assess the immunogenicity of the new bivalent oral poliovirus vaccine + inactivated poliovirus vaccine (bOPV+IPV) immunization schedule and gains in type 2 immunity with addition of second dose of IPV. The trial was conducted in August 2016-March 2017, well past the trivalent OPV-bOPV switch in April 2016. METHODS: This was an open-label, 2-arm, noninferiority, multicenter, randomized, controlled trial. We enrolled 572 infants aged ≤14 days and randomized them into 2 arms. Arm A received bOPV at birth, 6, and 10 weeks, bOPV+IPV at week 14, and IPV at week 18. Arm B received IPV each at 6, 10, and 14 weeks and bOPV at 18 weeks of age. RESULTS: Seroconversion rates for poliovirus types 1 and 3, respectively, were 98.9% (95% confidence interval [CI], 96.7-99.8) and 98.1% (95% CI, 88.2-94.8) in Arm A and 89.6% (95% CI, 85.4-93.0) and 98.5% (95% CI, 96.3-99.6) in Arm B. Type 2 seroconversion with 1 dose IPV in Arm A was 72.0% (95% CI, 66.2-77.3), which increased significantly with addition of second dose to 95.9% (95% CI, 92.8-97.9). CONCLUSIONS: This first trial on the new Expanded Program on Immunization (EPI) schedule in a sub-Saharan African country demonstrated excellent immunogenicity against poliovirus types 1 and 3 and substantial/enhanced immunogenicity against poliovirus type 2 after 1 to 2 doses of IPV, respectively.

Vital Signs: Surveillance for Acute Flaccid Myelitis - United States, 2018.

BACKGROUND: Acute flaccid myelitis (AFM), a serious paralytic illness, was first recognized as a distinct condition in 2014, when cases were reported concurrent with a large U.S. outbreak of severe respiratory illness caused by enterovirus D-68 (EV-D68). Since 2014, nationwide outbreaks of AFM have occurred every 2 years in the United States; the cause for the recent change in the epidemiology of AFM in the United States, including the occurrence of outbreaks and a biennial periodicity since 2014, is under investigation. This report updates clinical, laboratory, and outcome data for cases reported to CDC during 2018. METHODS: Clinical data and specimens from persons in the United States who met the clinical criterion for AFM (acute onset of flaccid limb weakness) with onset in 2018 were submitted to CDC for classification of the illnesses as confirmed, probable, or non-AFM cases. Enterovirus/rhinovirus (EV/RV) testing was performed on available specimens from persons meeting the clinical criterion. Descriptive analyses, laboratory results, and indicators of early recognition and reporting are summarized. RESULTS: From January through December 2018, among 374 reported cases of AFM, 233 (62%) (from 41 states) were classified as confirmed, 26 (7%) as probable, and 115 (31%) as non-AFM cases. Median ages of patients with confirmed, probable, and non-AFM cases were 5.3, 2.9, and 8.8 years, respectively. Laboratory testing identified multiple EV/RV types, primarily in respiratory and stool specimens, in 44% of confirmed cases. Among confirmed cases, the interval from onset of limb weakness until specimen collection ranged from 2 to 7 days, depending on specimen type. Interval from onset of limb weakness until reporting to CDC during 2018 ranged from 18 to 36 days, with confirmed and probable cases reported earlier than non-AFM cases. CONCLUSION: Identification of risk factors leading to outbreaks of AFM remains a public health priority. Prompt recognition of signs and symptoms, early specimen collection, and complete and rapid reporting will expedite public health investigations and research studies to elucidate the recent epidemiology of AFM and subsequently inform treatment and prevention recommendations.

Cold chain and virus-free chloroplast-made booster vaccine to confer immunity against different poliovirus serotypes.

The WHO recommends complete withdrawal of oral polio vaccine (OPV) type 2 by April 2016 globally and replacing with at least one dose of inactivated poliovirus vaccine (IPV). However, high-cost, limited supply of IPV, persistent circulating vaccine-derived polioviruses transmission and need for subsequent boosters remain unresolved. To meet this critical need, a novel strategy of a low-cost cold chain-free plant-made viral protein 1 (VP1) subunit oral booster vaccine after single IPV dose is reported. Codon optimization of the VP1 gene enhanced expression by 50-fold in chloroplasts. Oral boosting of VP1 expressed in plant cells with plant-derived adjuvants after single priming with IPV significantly increased VP1-IgG1 and VP1-IgA titres when compared to lower IgG1 or negligible IgA titres with IPV injections. IgA plays a pivotal role in polio eradication because of its transmission through contaminated water or sewer systems. Neutralizing antibody titres (~3.17-10.17 log2 titre) and seropositivity (70-90%) against all three poliovirus Sabin serotypes were observed with two doses of IPV and plant-cell oral boosters but single dose of IPV resulted in poor neutralization. Lyophilized plant cells expressing VP1 stored at ambient temperature maintained efficacy and preserved antigen folding/assembly indefinitely, thereby eliminating cold chain currently required for all vaccines. Replacement of OPV with this booster vaccine and the next steps in clinical translation of FDA-approved antigens and adjuvants are discussed.

Effect of booster doses of poliovirus vaccine in previously vaccinated children, Clinical Trial Results 2013.

BACKGROUND: Considering the current polio situation Pakistan needs vaccine combinations to reach maximum population level immunity. The trial assessed whether inactivated poliovirus vaccine (IPV) can be used to rapidly boost immunity among children in Pakistan. METHODS: A five-arm randomized clinical trial was conducted among children (6-24months, 5-6years and 10-11years). Children were randomized in four intervention arms as per the vaccines they received (bOPV, IPV, bOPV+vitamin A, and bOPV+IPV) and a control arm which did not receive any vaccine. Baseline seroprevalence of poliovirus antibodies and serological immune response 28days after intervention were assessed. RESULTS: The baseline seroprevalence was high for all serotypes and the three age groups [PV1: 97%, 100%, 96%, PV2: 86%, 100%, 99%, PV3: 83%, 95%, 87% for the three age groups respectively]. There was significantly higher rate of immune response observed in the study arms which included IPV (95-99%) compared with bOPV only arms (11-43%), [p<0.001]; Vitamin A was not associated with improved immune response. Immune response rates in the IPV only arm and IPV+bOPV arm were similar [p>0.5]. CONCLUSION: IPV has shown the ability to efficiently close existing immunity gaps in a vulnerable population of children in rural Pakistan.

Achieving high seroprevalence against polioviruses in Sri Lanka--results from a serological survey, 2014.

The immunization program in Sri Lanka consistently reaches >90% coverage with oral poliovirus vaccines (OPV), and no polio supplementary vaccination campaigns have been conducted since 2003. We evaluated serological protection against polioviruses in children. A cross-sectional community-based survey was performed in three districts of Sri Lanka (Colombo, Badulla, and Killinochi). Randomly selected children in four age groups (9-11 months, 3-4 years, 7-9 years, and 15 years) were tested for poliovirus neutralizing antibodies. All 400 enrolled children completed the study. The proportion of seropositive children for poliovirus Type 1 and Type 2 was >95% for all age groups; for poliovirus Type 3 it was 95%, 90%, 77%, and 75% in the respective age groups. The vaccination coverage in our sample based on vaccination cards or parental recall was >90% in all age groups. Most Sri Lankan children are serologically protected against polioviruses through routine immunization only. This seroprevalence survey provided baseline data prior to the anticipated addition of inactivated poliovirus vaccine (IPV) into the Sri Lankan immunization program and the switch from trivalent OPV (tOPV) to bivalent OPV (bOPV).

Application of bioinformatics in probe design enables detection of enteroviruses on different taxonomic levels by advanced in situ hybridization technology.

BACKGROUND: Enteroviral infections are common, affecting humans across all age groups. RT-PCR is widely used to detect these viruses in clinical samples. However, there is a need for sensitive and specific in situ detection methods for formalin-fixed tissues, allowing for the anatomical localization of the virus and identification of its serotype. OBJECTIVES: The aim was to design novel enterovirus probes, assess the impact of probe design for the detection and optimize the new single molecule in situ hybridization technology for the detection of enteroviruses in formalin-fixed paraffin-embedded samples. STUDY DESIGN: Four enterovirus RNA-targeted oligonucleotide RNA probes - two probes for wide range enterovirus detection and two for serotype-targeted detection of Coxsackievirus B1 (CVB1) - were designed and validated for the commercially available QuantiGene ViewRNA in situ hybridization method. The probe specificities were tested using a panel of cell lines infected with different enterovirus serotypes and CVB infected mouse pancreata. RESULTS: The two widely reactive probe sets recognized 19 and 20 of the 20 enterovirus serotypes tested, as well as 27 and 31 of the 31 CVB1 strains tested. The two CVB1 specific probe sets detected 30 and 14 of the 31 CVB1 strains, with only minor cross-reactivity to other serotypes. Similar results were observed in stained tissues from CVB -infected mice. CONCLUSIONS: These novel in-house designed probe sets enable the detection of enteroviruses from formalin-fixed tissue samples. Optimization of probe sequences makes it possible to tailor the assay for the detection of enteroviruses on the serotype or species level.

Monovalent type-1 oral poliovirus vaccine given at short intervals in Pakistan: a randomised controlled, four-arm, open-label, non-inferiority trial.

BACKGROUND: Supplementary immunisation activities with oral poliovirus vaccines (OPVs) are usually separated by 4 week intervals; however, shorter intervals have been used in security-compromised areas and for rapid outbreak responses. We assessed the immunogenicity of monovalent type-1 oral poliovirus vaccine (mOPV1) given at shorter than usual intervals in Karachi, Pakistan. METHODS: This was a multicentre, randomised, controlled, four-arm, open-label, non-inferiority trial done at five primary health-care centres in low-income communities in and around Karachi, Pakistan. Eligible participants were healthy newborn babies with a birthweight of at least 2·5 kg, for whom informed consent was provided by their parent or guardian, and lived less than 30 km from the study clinic. After receiving a birth dose of trivalent OPV, we enrolled and randomly assigned newborn babies (1:1:1:1) to receive two doses of mOPV1 with an interval of 1 week (mOPV1-1 week), 2 weeks (mOPV1-2 weeks), or 4 weeks (mOPV1-4 weeks) between doses, or two doses of bivalent OPV (bOPV) with an interval of 4 weeks between doses (bOPV-4 weeks). We gave the first study dose of OPV at age 6 weeks. We did the randomisation with a centrally generated, computerised allocation sequence with blocks of 16; participants' families and study physicians could not feasibly be masked to the allocations. Trial participants were excluded from local supplementary immunisation activities during the study period. The primary outcome was non-inferiority (within a 20% margin) between groups in seroconversion to type-1 poliovirus. The primary and safety analyses were done in the per-protocol population of infants who received all three doses of vaccine. This trial is registered with ClinicalTrials.gov, number NCT01586572, and is closed to new participants. FINDINGS: Between March 1, 2012, and May 31, 2013, we enrolled 1009 newborn babies, and randomly assigned 829 (82%) to treatment. 554 (67%) of the 829 babies were included in the per-protocol analysis. Proportions of seroconversion to type-1 poliovirus were 107/135 (79%, 95% CI 72·4-86·1) with mOPV1-1 week, 108/135 (80%, 73·2-86·8) with mOPV1-2 weeks, 129/148 (87%, 80·9-92·0) with mOPV1-4 weeks, and 107/136 (79%, 71·8-85·6) with bOPV-4 weeks. Non-inferiority was shown between groups and no significant differences were noted. Ten participants died during the trial. Seven of these deaths occurred during the lead-in period before randomisation (two from diarrhoea, five from unknown causes). Three infants died from sepsis after random assignment. No deaths were attributed to the procedures or vaccines. Additionally, we noted no events of vaccine-associated paralysis. INTERPRETATION: We identified no significant differences in responses to mOPV1 given with shorter intervals between doses than with the standard 4 week intervals. The short-interval strategy could be particularly beneficial when temporary windows of opportunity for safe access can be granted in areas of conflict--eg, during cease-fire periods. In such situations, we recommend shortening the interval between OPV doses to 7 days. FUNDING: World Health Organization.

Immunogenicity of poliovirus vaccines in chronically malnourished infants: a randomized controlled trial in Pakistan.

Reaching high population immunity against polioviruses (PV) is essential to achieving global polio eradication. Efficacy of oral poliovirus vaccine (OPV) varies and is lower among children living in tropical areas with impoverished environments. Malnutrition found as a risk factor for lower serological protection against PV. We compared whether inactivated polio vaccine (IPV) can be used to rapidly close the immunity gap among chronically malnourished (stunted) infants in Pakistan who will not be eligible for the 14 week IPV dose in routine EPI schedule. A phase 3, multicenter 4-arm randomized controlled trial conducted at five Primary Health Care (PHC) centers in Karachi, Pakistan. Infants, 9-12 months were stratified by length for age Z score into chronically malnourished and normally nourished. Infants were randomized to receive one dose of either bivalent OPV (bOPV) alone or bOPV+IPV. Baseline seroprevalence of PV antibodies and serum immune response to study vaccine dose were assessed by neutralization assay. Vaccine PV shedding in stool was evaluated 7 days after a bOPV challenge dose. Sera and stool were analyzed from 852/928 (92%) enrolled children. At baseline, the seroprevalence was 85.6% (n=386), 73.6% (n=332), and 70.7% (n=319) in malnourished children against PV types 1, 2 and 3 respectively; and 94.1% (n=448), 87.0% (n=441) and 83.6% (n=397) in the normally nourished group (p<0.05). Children had previously received 9-10 doses of bOPV (80%) or tOPV (20%). One dose of IPV+bOPV given to malnourished children increased their serological protection (PV1, n=201, 97.6%; PV2, n=198, 96.1% and PV3, n=189, 91.7%) to parity with normally nourished children who had not received IPV (p=<0.001). Seroconversion and boosting for all three serotypes was significantly more frequent in children who received IPV+bOPV than in those with bOPV only (p<0.001) in both strata. Shedding of polioviruses in stool did not differ between study groups and ranged from 2.4% (n=5) to 7.1% (n=15). In malnourished children the shedding was reduced after bOPV+IPV compared to bOPV only. Chronically malnourished infants were more likely to be unprotected against polioviruses than normal infants. bOPV+IPV helped close the immunity gap better than bOPV alone.

Seroconversion to islet autoantibodies after enterovirus infection in early pregnancy.

Gestational enterovirus (EV) infections have been associated with an increased risk for type 1 diabetes in the offspring. We therefore analyzed non-diabetic mothers for EV exposure in early pregnancy in relation to type 1 diabetes HLA-DQ risk genotypes and seroconversion to islet autoantibodies during pregnancy. Non-diabetic mothers who had islet autoantibodies (n=365) against glutamic acid decarboxylase (GADA), islet antigen-2 autoantibodies (IA-2A), or insulin autoantibodies (IAA), in early pregnancy and at delivery were compared to islet autoantibody-negative mothers (n=1457) matched for age and sampling date. Mothers were genotyped for HLA-DQ and analyzed for both EV-RNA and EV-IgM. EV-IgM, but not EV-RNA, was detected during early pregnancy in 12% of islet autoantibody-positive mothers compared to 11% of the controls. In early pregnancy, mothers with HLA-DQ 2/2 or 2/X genotypes showed an increased risk for islet autoantibodies at delivery (OR 1.85; p=0.001). After adjusting for parity, maternal age, year of birth, and season of early pregnancy, early pregnancy EV-IgM combined with DQ2/2 or 2/X increased the risk for islet autoantibodies (OR 3.10; 95% CI 1; p=0.008). EV-IgM in early pregnancy increased the risk for islet autoantibodies at delivery in non-diabetic mothers with HLA-DQ 2/2 or 2/X type 1 diabetes risk genotypes.

Enterovirus 71 meningoencephalitis complicating rituximab therapy.

We describe a fatal case of proven enterovirus 71 meningoencephalitis complicating monoclonal anti-CD20 antibody therapy for non-Hodgkin's lymphoma. B-cell depletion, an effective treatment strategy in an expanding spectrum of hematological and inflammatory disorders, impairs neutralising antibody-mediated clearance of enterovirus. The global threat of emerging neurotropic viruses such as enterovirus 71 is heightened by an increasing pool of susceptible individuals in non-endemic regions.

Enterovirus no polio de casos con parálisis residual, Colombia, 1992-1995 / Non-polio enterovirus from residual paralysis cases, Colombia, 1992-1995

Las parálisis fláccidas agudas (PFA) tienen una amplia variedad de orígenes y de agentes causales: físicos, fisiopatológicos, tóxicos e infecciosos. Entre estos últimos, el virus salvaje (silvestre) de la poliomielitis y el enterovirus 71(EV71), parecen ser los agentes virales más frecuentes. Habiendo eliminado el poliovirus salvaje autóctono como agente causal de enfermedad paralítica en Colombia desde junio de 1991 y teniendo aislamientos de virus no polio en el 20,8 por ciento del total de casos de PFA notificados anualmente, quisimos conocer el papel que juegan los enterovirus en la incidencia de parálisis fláccida aguda y la dinámica de circulación y distribución de los mismos en Colombia. Se revisó la base de datos de los casos notificados al Programa de Erradicación de la Poliomielitis en Colombia entre el 1º de enero de 1992 y el 31 de diciembre de 1995, al cual se notificaron 856 casos sospechosos de niños menores de 15 años, y se escogieron 69 casos para el estudio pero se recuperaron 57 aislamientos virales por reinoculación en células RD y Hep-2C. Estos se identificaron mediante neutralización con mezclas de antisueros de Lim & Benyesh-Melnick (LBM). Todos ellos fueron sometidos a caracterización molecular mediante reacción en cadena de la polimerasa -PCR-, utilizando iniciadores complementarios a la region VP1 del genoma viral, seguida del análisis de secuencia de nucleótidos de los fragmentos amplificados por PCR. La identificación final del serotipo se realizó por comparación de nucleótidos en auto assembler y el análisis descriptivo de los datos. No se estableció circulación mayor de ningún serotipo específico en región geográfica alguna del país. Tampoco hubo asociación causal a ninguna patología característica con ninguno de los enterovirus aislados. Se describe el hallazgo de EV71 en un caso de PFA con diagnóstico clínico de síndrome de Guillain-Barre. La descripción de 22 serotipos diferentes de enterovirus no polio que circulan en Colombia (19 serotipos identificados por métodos moleculares y 3 por seroneutralización), coincide con los serotipos más frecuentemente descritos en otros estudios. Los serotipos Coxsackievirus B5, B1, B3, Echovirus 6, 7, 13, 20, 30, Coxsackievirus A2, A10, A14, A16, A18, A21, fueron los serotipos de enterovirus más frecuentes en Colombia durante el período 1992-1995