Background: The efficacy of a rotavirus vaccine against severe rotavirus gastroenteritis when coadministered with routine Expanded Program on Immunization (EPI) vaccines including oral polio vaccine (OPV) was evaluated in this study. Methods: Double-blind, randomized (2:1), placebo-controlled study conducted across 6 Latin American countries. Healthy infants (N = 6568) 6 to 12 weeks of age received 2 doses of RIX4414 vaccine or placebo following a 0, 1- to 2-month schedule. Routine vaccines including OPV were coadministered according to local EPI schedule. Vaccine efficacy (VE) against severe rotavirus gastroenteritis caused by circulating wild-type rotavirus from 2 weeks post-Dose 2 until 1 year of age was calculated with 95% confidence interval [CI]. Safety was assessed during the entire study period. Immunogenicity of RIX4414 and OPV was also assessed. Results: During the efficacy follow-up period (mean duration = 7.4 months), 7 and 19 cases of severe rotavirus gastroenteritis were reported in the vaccine and placebo groups, respectively, with a VE of 81.6% (95% CI: 54.4–93.5). VE against severe rotavirus gastroenteritis caused by G1 type was 100% (95% CI: <0–100) and 80.6% (95% CI: 51.4–93.2) against the pooled non-G1 rotavirus types, respectively. There was no difference (P = 0.514) in the incidence of serious adverse events reported in the 2 groups. Antirotavirus IgA seropositivity rate at 1 to 2 months post-Dose 2 was 61.4% (95% CI: 53.7–68.6) in the RIX4414 group; similar seroprotection rates (≥96.0%) against the 3 antipoliovirus types was observed 1 month post-Dose 3 of OPV in both groups. Conclusion: RIX4414 was highly efficacious against severe rotavirus gastroenteritis caused by the circulating wild-type rotavirus (G1 and non-G1) when coadministered with routine EPI vaccines including OPV.
Background: RIX4414(Rotarix, a trademark of GlaxoSmithKline), an oral live attenuated human rotavirus (RV) vaccine has previously been shown to be highly effective against RV gastroenteritis(GE). The efficacy evaluation of RIX4414 administered concomitantly with routine EPI vaccinations including Oral Polio Vaccine(OPV) to healthy infants in a phase III, double-blind, randomized, placebo-controlled and multi-center study (444563/024/NCT00139347) conducted in six countries in Latin-America is presented.Methods: Healthy infants aged 6-12 weeks were enrolled to receive two doses of RIX4414(N = 4376) or placebo(N = 2192) according to a 0,1–2 month schedule, administered concomitantly with Dose 1 and Dose 2 of routine pediatric vaccines including OPV, given respecting the national immunisation guidelines.Vaccine efficacy(VE) was calculated from two weeks post-Dose2 until one year of age. Severe GE was defined as an episode of diarrhea requiring hospitalization and/or re-hydration therapy in a medical facility. Diarrhoeal samples were analyzed for RV by ELISA and typed by RT-PCR based method. Safety data were collected throughout the study. Results: During the efficacy follow-up period (mean duration of 7.4 months) RIX4414 has offered 81.6% (95%CI:54.4;93.5) protection against severe RVGE and 88.3% (95%CI:64.0;97.1) against hospitalization due to RVGE. For severe RVGE, VE against wild-type G1 was 100% (95%CI:<0;100) and 80.6% (95%CI:51.4;93.2) against pooled non-G1 RV types (G2,G9). No clinically meaningful difference between RIX4414 group and the placebo group for serious adverse events were reported. Conclusion: Two doses of RIX4414(Rotarix™)offer high protection against severe RVGE and related hospitalizations when co-administered with specific childhood vaccines including OPV. These results show that co-administration with OPV does not impact the efficacy of Rotarix™ and are in line with the high efficacy against severe RVGE of 85% demonstrated in a large Phase III Latin America study with staggered co-administration of OPV. This finding is of significance for the implementation of RV vaccination programmes in many countries where OPV is still routinely administered.
Abstract Background Incidence data of respiratory syncytial virus–associated lower respiratory tract illness (RSV-LRTI) are sparse in low- and middle-income countries (LMICs). We estimated RSV-LRTI incidence rates (IRs) in infants in LMICs using World Health Organization case definitions. Methods This prospective cohort study, conducted in 10 LMICs from May 2019 to October 2021 (largely overlapping with the coronavirus disease 2019 [COVID-19] pandemic), followed infants born to women with low-risk pregnancies for 1 year from birth using active and passive surveillance to detect potential LRTIs, and quantitative reverse-transcription polymerase chain reaction on nasal swabs to detect RSV. Results Among 2094 infants, 32 (1.5%) experienced an RSV-LRTI (8 during their first 6 months of life, 24 thereafter). Seventeen (0.8%) infants had severe RSV-LRTI and 168 (8.0%) had all-cause LRTI. IRs (95% confidence intervals [CIs]) of first RSV-LRTI episode were 1.0 (.3–2.3), 0.8 (.3–1.5), and 1.6 (1.1–2.2) per 100 person-years for infants aged 0–2, 0–5, and 0–11 months, respectively. IRs (95% CIs) of the first all-cause LRTI episode were 10.7 (8.1–14.0), 11.7 (9.6–14.0), and 8.7 (7.5–10.2) per 100 person-years, respectively. IRs varied by country (RSV-LRTI: 0.0–8.3, all-cause LRTI: 0.0–49.6 per 100 person-years for 0- to 11-month-olds). Conclusions RSV-LRTI IRs in infants in this study were relatively low, likely due to reduced viral circulation caused by COVID-19–related nonpharmaceutical interventions. Clinical Trials Registration NCT03614676.
Abstract We assessed EV‐D68 epidemiology and phylogenetics among children aged ≤9 years hospitalized with severe acute respiratory illnesses at five sites in Panama and El Salvador during 2012‐2013. Respiratory specimens positive for enterovirus or rhinovirus were tested by real‐time RT‐PCR for EV‐D68, and partial VP1 gene sequences were determined. Of 715 enrolled children, 17 from sites in both countries were EV‐D68‐positive and commonly had a history of asthma or wheezing. Phylogenetically, 15 of 16 sequences fell into Clade B1, and one into Clade A2. The Central American EV‐D68s were closely related genetically to contemporaneous strains from North America, South America, and the Caribbean.
Abstract Background Primary intestinal immunity through viral replication of live oral vaccine is key to interrupt poliovirus transmission. We assessed viral fecal shedding from infants administered Sabin monovalent poliovirus type 2 vaccine (mOPV2) or low and high doses of 2 novel OPV2 (nOPV2) vaccine candidates. Methods In 2 randomized clinical trials in Panama, a control mOPV2 study (October 2015 to April 2016) and nOPV2 study (September 2018 to October 2019), 18-week-old infants vaccinated with bivalent oral poliovirus vaccine/inactivated poliovirus vaccine received 1 or 2 study vaccinations 28 days apart. Stools were assessed for poliovirus RNA by polymerase chain reaction (PCR) and live virus by culture for 28 days postvaccination. Results Shedding data were available from 621 initially reverse-transcription PCR–negative infants (91 mOPV2, 265 nOPV2-c1, 265 nOPV2-c2 recipients). Seven days after dose 1, 64.3% of mOPV2 recipients and 31.3%–48.5% of nOPV2 recipients across groups shed infectious type 2 virus. Respective rates 7 days after dose 2 decreased to 33.3% and 12.9%–22.7%, showing induction of intestinal immunity. Shedding of both nOPV2 candidates ceased at similar or faster rates than mOPV2. Conclusions Viral shedding of either nOPV candidate was similar or decreased relative to mOPV2, and all vaccines showed indications that the vaccine virus was replicating sufficiently to induce primary intestinal mucosal immunity.
BackgroundContinued emergence and spread of circulating vaccine-derived type 2 polioviruses and vaccine-associated paralytic poliomyelitis from Sabin oral poliovirus vaccines (OPVs) has stimulated development of two novel type 2 OPV candidates (OPV2-c1 and OPV2-c2) designed to have similar immunogenicity, improved genetic stability, and less potential to reacquire neurovirulence. We aimed to assess safety and immunogenicity of the two novel OPV candidates compared with a monovalent Sabin OPV in children and infants.MethodsWe did two single-centre, multi-site, partly-masked, randomised trials in healthy cohorts of children (aged 1–4 years) and infants (aged 18–22 weeks) in Panama: a control phase 4 study with monovalent Sabin OPV2 before global cessation of monovalent OPV2 use, and a phase 2 study with low and high doses of two novel OPV2 candidates. All participants received one OPV2 vaccination and subsets received two doses 28 days apart. Parents reported solicited and unsolicited adverse events. Type 2 poliovirus neutralising antibodies were measured at days 0, 7, 28, and 56, and stool viral shedding was assessed up to 28 days post-vaccination. Primary objectives were to assess safety in all participants and non-inferiority of novel OPV2 day 28 seroprotection versus monovalent OPV2 in infants (non-inferiority margin 10%). These studies were registered with ClinicalTrials.gov, NCT02521974 and NCT03554798.FindingsThe control study took place between Oct 23, 2015, and April 29, 2016, and the subsequent phase 2 study between Sept 19, 2018, and Sept 30, 2019. 150 children (50 in the control study and 100 of 129 assessed for eligibility in the novel OPV2 study) and 684 infants (110 of 114 assessed for eligibility in the control study and 574 of 684 assessed for eligibility in the novel OPV2 study) were enrolled and received at least one study vaccination. Vaccinations were safe and well tolerated with no causally associated serious adverse events or important medical events in any group. Solicited and unsolicited adverse events were overwhelmingly mild or moderate irrespective of vaccine or dose. Nearly all children were seroprotected at baseline, indicating high baseline immunity. In children, the seroprotection rate 28 days after one dose was 100% for monovalent OPV2 and both novel OPV2 candidates. In infants at day 28, 91 (94% [95% CI 87–98]) of 97 were seroprotected after receiving monovalent OPV2, 134 (94% [88–97]) of 143 after high-dose novel OPV2-c1, 122 (93% [87–97]) of 131 after low-dose novel OPV2-c1, 138 (95% [90–98]) of 146 after high-dose novel OPV2-c2, and 115 (91% [84–95]) of 127 after low-dose novel OPV2-c2. Non-inferiority was shown for low-dose and high-dose novel OPV2-c1 and high-dose novel OPV2-c2 despite monovalent OPV2 recipients having higher baseline immunity.InterpretationBoth novel OPV2 candidates were safe, well tolerated, and immunogenic in children and infants. Novel OPV2 could be an important addition to our resources against poliovirus given the current epidemiological situation.FundingFighting Infectious Diseases in Emerging Countries and Bill & Melinda Gates Foundation.
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