Immunogenicity of different dosing schedules of the human live attenuate rotavirus vaccine (RV1) in infants and children: a meta-analysis

Neonatal rotavirus vaccine (RV3-BB) immunogenicity and safety in a neonatal and infant administration schedule in Malawi: a randomised, double-blind, four-arm parallel group dose-ranging study

Background

Rotavirus vaccines reduce rotavirus-related deaths and hospitalisations but are less effective in high child mortality countries. The human RV3-BB neonatal G3P[6] rotavirus vaccine administered in a neonatal schedule was efficacious in reducing severe rotavirus gastroenteritis in Indonesia but had not yet been evaluated in African infants.

Methods

We did a phase 2, randomised, double-blind, parallel group dose-ranging study of three doses of oral RV3-BB rotavirus vaccine in infants in three primary health centres in Blantyre, Malawi. Healthy infants less than 6 days of age with a birthweight 2·5 to 4·0 kg were randomly assigned (1:1:1:1) into one of four treatment groups: neonatal vaccine group, which included high-titre (1·0 × 10⁷ focus-forming unit [FFU] per mL), mid-titre (3·0 × 10⁶ FFU per mL), or low-titre (1·0 × 10⁶ FFU per mL); and infant vaccine group, which included high-titre (1·0 × 10⁷ FFU per mL) using a computer generated code (block size of four), stratified by birth (singleton vs multiple). Neonates received their three doses at 0–5 days to 10 weeks and infants at 6–14 weeks. Investigators, participant families, and laboratory staff were masked to group allocation. Anti-rotavirus IgA seroconversion and vaccine take (IgA seroconversion and stool shedding) were evaluated. Safety was assessed in all participants who received at least one dose of vaccine or placebo. The primary outcome was the cumulative IgA seroconversion 4 weeks after three doses of RV3-BB in the neonatal schedule in the high-titre, mid-titre, and low-titre groups in the per protocol population, with its 95% CI. With the high-titre group as the active control group, we did a non-inferiority analysis of the proportion of participants with IgA seroconversion in the mid-titre and low-titre groups, using a non-inferiority margin of less than 20%. This trial is registered at ClinicalTrials.gov (NCT03483116).

Findings

Between Sept 17, 2018, and Jan 27, 2020, 711 participants recruited were randomly assigned into four treatment groups (neonatal schedule high titre n=178, mid titre n=179, low titre n=175, or infant schedule high titre n=179). In the neonatal schedule, cumulative IgA seroconversion 4 weeks after three doses of RV3-BB was observed in 79 (57%) of 139 participants in the high-titre group, 80 (57%) of 141 participants in the mid-titre group, and 57 (41%) of 138 participants in the low-titre group and at 18 weeks in 100 (72%) of 139 participants in the high-titre group, 96 (67%) of 143 participants in the mid-titre group, and 86 (62%) of 138 of participants in the low-titre. No difference in cumulative IgA seroconversion 4 weeks after three doses of RV3-BB was observed between high-titre and mid-titre groups in the neonatal schedule (difference in response rate 0·001 [95%CI −0·115 to 0·117]), fulfilling the criteria for non-inferiority. In the infant schedule group 82 (59%) of 139 participants had a cumulative IgA seroconversion 4 weeks after three doses of RV3-BB at 18 weeks. Cumulative vaccine take was detected in 483 (85%) of 565 participants at 18 weeks. Three doses of RV3-BB were well tolerated with no difference in adverse events among treatment groups: 67 (39%) of 170 participants had at least one adverse event in the high titre group, 68 (40%) of 172 participants had at least one adverse event in the mid titre group, and 69 (41%) of 169 participants had at least one adverse event in the low titre group.

Interpretation

RV3-BB was well tolerated and immunogenic when co-administered with Expanded Programme on Immunisation vaccines in a neonatal or infant schedule. A lower titre (mid-titre) vaccine generated similar IgA seroconversion to the high-titre vaccine presenting an opportunity to enhance manufacturing capacity and reduce costs. Neonatal administration of the RV3-BB vaccine has the potential to improve protection against rotavirus disease in children in a high-child mortality country in Africa.

Funding

Bill & Melinda Gates Foundation, Australian Tropical Medicine Commercialisation Grant.

Evaluation of the decision-making process underlying the initial off-label use of vaccines: a scoping review protocol

INTRODUCTION

Vaccination has become a central part of public health prevention. Vaccines are introduced after licensure by national regulatory authorities, whereas recommendations for use of licensed vaccines are made by national or international advisory committees and may include off-label use. The methodological and decision-making processes that are used to assess novel initial off-label vaccine use are unclear. This review aims to examine the off-label assessment processes to map evidence and concepts used in the decision-making process and present a common approach between all recommendations and specifics of each decision.

METHODS AND ANALYSIS

The methodological framework described at the Joanna Briggs Institute will be applied to this scoping review. A search strategy was developed, in collaboration with an experienced senior health research librarian, by combining Mesgarpour's highly sensitive search strategies. Peer-reviewed and grey literature will be systematically identified using PubMed, Medline and EMBASE; governmental agency and pharmaceutical websites; and search engines, such as Google Scholar. Reports and studies on off-label vaccine use in public health will be included. Screening will be independently undertaken by two reviewers. Data will be extracted using a standard form. Results will be narratively summarised to highlight relevant findings and guide the development of an analytical framework for off-label vaccination recommendations.

ETHICS AND DISSEMINATION

This research does not require ethical approval. This scoping review will provide decision-making elements and a synthesis of knowledge on vaccines off-label use. Findings will be relevant to decision-makers/advisory committees and public health. These will be disseminated through peer-reviewed articles and conferences.

The impact of shared decision making with patient decision aids on the rotavirus vaccination rate in children: A randomized controlled trial

Rotavirus vaccination reduces the incidence and severity of acute gastroenteritis due to rotavirus infection. However, because of a lack of understanding and private payment for the rotavirus vaccine, the rotavirus vaccination rate is still low in some countries. We intended to assess the impact of shared decision-making (SDM) with the assistance of patient decision aids (PDAs) on the rotavirus vaccination rate, and the knowledge, confidence, and congruence of value among baby's parents when decision-making. The study was a two-group, outcome assessor-blind, randomized, controlled trial. The families of 1-month-old infants for routine vaccination were enrolled; they were divided randomly into non-SDM and SDM groups. The influence of SDM on the acceptance of rotavirus vaccination was assessed when their infants were 2 months old. Outcome measures were decisional conflict, decision-making difficulties, and rotavirus vaccine knowledge, and the overall rotavirus vaccination rate. The study enrolled 180 participants. SDM, parents' education level, and rotavirus vaccination of a previous child were variables that influenced acceptance of rotavirus vaccination. The SDM group scored significantly higher for understanding the information on the oral rotavirus vaccine than the non-SDM group, which helped them to decide whether to vaccinate the baby against rotavirus. The rotavirus vaccination rate was 16.7% higher in the SDM group than the non-SDM group. SDM assisted with PDAs gives more information and helps infants' families understand what they need, reduces their decision conflict, and increases their baby's vaccination against rotavirus, which promotes public health. The clinical trial is registered at ClinicalTrials.gov (NCT03804489).

Fifteen years of experience with the oral live-attenuated human rotavirus vaccine: reflections on lessons learned

INTRODUCTION

Rotavirus (RV) disease remains a prominent cause of disease burden in children <5 years of age worldwide. However, implementation of RV vaccination has led to significant reductions in RV mortality, compared to the pre-vaccination era. This review presents 15 years of real-world experience with the oral live-attenuated human RV vaccine (HRV; Rotarix). HRV is currently introduced in ≥80 national immunization programs (NIPs), as 2 doses starting from 6 weeks of age.

AREAS COVERED

The clinical development of HRV and post-marketing experience indicating the impact of HRV vaccination on RV disease was reviewed.

EXPERT OPINION

In clinical trials, HRV displayed an acceptable safety profile and efficacy against RV-gastroenteritis, providing broad protection against heterotypic RV strains by reducing the consequences of severe RV disease in infants. Real-world evidence shows substantial, rapid reduction in the number of RV infections and associated hospitalizations following introduction of HRV in NIPs, regardless of economic setting. Indirect effects against RV disease are also observed, such as herd protection, decrease in nosocomial infections incidence, and a reduction of disease-related societal/healthcare costs. However, not all countries have implemented RV vaccination. Coverage remains suboptimal and should be improved to maximize the benefits of RV vaccination.