The first rotavirus vaccine and the politics of acceptable risk

Intussusception and Other Adverse Event Surveillance after Pilot Introduction of Rotavirus Vaccine in Nam Dinh and Thua Thien Hue Provinces-Vietnam, 2017-2021

Rotavin-M1 (POLYVAC) was licensed in Vietnam in 2012. The association of Rotavin-M1 with intussusception, a rare adverse event associated with rotavirus vaccines, and with adverse events following immunization (AEFI) have not been evaluated and monitored under conditions of routine use. From February 2017 to May 2021, we conducted a pilot introduction of Rotavin-M1 into the routine vaccination program in two provinces. Surveillance for intussusception was conducted at six sentinel hospitals. AEFI reports at 30 min and 7 days after vaccination were recorded. Among 443 children <12 months of age admitted for intussusception, most (92.3%) were children ≥ 6 months. Of the 388 children who were age-eligible to receive Rotavin-M1, 116 (29.9%) had received ≥1 dose. No intussusception cases occurred in the 1-21 days after dose 1 and one case occurred on day 21 after dose 2. Among the 45,367 children who received ≥1 dose of Rotavin-M1, 9.5% of children reported at least one AEFI after dose 1 and 7.3% after dose 2. Significantly higher AEFI rates occurred among children given Rotavin-M1 with pentavalent vaccines (Quinvaxem®, ComBE Five®) compared to Rotavin-M1 without pentavalent vaccines. There was no association between intussusception and Rotavin-M1. The vaccine was generally safe when administered alone and when co-administered with other vaccines.

A risk science perspective on vaccines

Vaccines can be seen as one of the greatest successes in modern medicine. Good examples are the vaccines against smallpox, polio, and measles. Unfortunately, vaccines can have side effects, but the risks are considered by the health authorities and experts to be small compared to their benefits. Nevertheless, there are many who are skeptical of vaccination, something which has been very clearly demonstrated in relation to the COVID-19 disease. Risk is the key concept when evaluating a vaccine, in relation to both its ability to protect against the disease and its side effects. However, risk is a challenging concept to measure, which makes communication about vaccines' performance and side effects difficult. The present article aims at providing new insights into vaccine risks-the understanding, perception, communication, and handling of them-by adopting what is here referred to as a contemporary risk science perspective. This perspective clarifies the relationships between the risk concept and terms like uncertainty, knowledge, and probability. The skepticism toward vaccines is multifaceted, and influenced by concerns that extend beyond the effectiveness and safety of the vaccines. However, by clarifying the relationships between key concepts of risk, particularly how uncertainty affects risk and its characterization, we can improve our understanding of this issue.

Measuring indirect transmission-reducing effects in tuberculosis vaccine efficacy trials: why and how?

Tuberculosis is the leading bacterial cause of death globally. In 2021, 10·6 million people developed symptomatic tuberculosis and 1·6 million died. Seven promising vaccine candidates that aim to prevent tuberculosis disease in adolescents and adults are currently in late-stage clinical trials. Conventional phase 3 trials provide information on the direct protection conferred against infection or disease in vaccinated individuals, but they tell us little about possible indirect (ie, transmission-reducing) effects that afford protection to unvaccinated individuals. As a result, proposed phase 3 trial designs will not provide key information about the overall effect of introducing a vaccine programme. Information on the potential for indirect effects can be crucial for policy makers deciding whether and how to introduce tuberculosis vaccines into immunisation programmes. We describe the rationale for measuring indirect effects, in addition to direct effects, of tuberculosis vaccine candidates in pivotal trials and lay out several options for incorporating their measurement into phase 3 trial designs.

Safety biomarkers for development of vaccines and biologics: Report from the safety biomarkers symposium held on November 28-29, 2017, Marcy l'Etoile, France

Vaccines prevent infectious diseases, but vaccination is not without risk and adverse events are reported although they are more commonly reported for biologicals than for vaccines. Vaccines and biologicals must undergo vigorous assessment before and after licensure to minimise safety concerns. Potential safety concerns should be identified as early as possible during the development for vaccines and biologicals to minimize investment risk. State-of-the art tools and methods to identify safety concerns and biomarkers that are predictive of clinical outcomes are indispensable. For vaccines and adjuvant formulations, systems biology approaches, supported by single-cell microfluidics applied to translational studies between preclinical and clinical studies, could improve reactogenicity and safety predictions. Next-generation animal models for clinical assessment of injection-site reactions with greater relevance for target human population and criteria to define the level of acceptability of local reactogenicity at vaccine injection sites in pre-clinical animal species should be assessed. Advanced in silico machine-learning-based analytics, species-specific cell or tissue expression, receptor occupancy and kinetics and cell-based assays for functional activity are needed to improve pre-clinical safety assessment of biologicals. The in vitro MIMIC® system could be used to compliment preclinical and clinical studies for assessing immune-toxicity, immunogenicity, immuno-inflammatory and mode of action of biologicals and vaccines. Sanofi Pasteur brought together leading experts in this field to review the state-of-the-art at a unique 'Safety Biomarkers Symposium' on 28-29 November 2017. Here we summarise the proceedings of this symposium. This unique scientific meeting confirmed the importance for institutions and industrial organizations to collaborate to develop tools and methods needed for predicting reactogenicity and immune-inflammatory reactions to vaccines and biologicals, and to develop more accuracy, reliability safety biomarkers, to inform decisions on the attrition or advancement of vaccines and biologicals.

Product review of the rotavirus vaccines ROTASIIL, ROTAVAC, and Rotavin-M1

Rotavirus is the leading cause of severe dehydrating gastroenteritis and death due to diarrhea among children under 5, causing over 180,000 under-5 deaths annually. Safe, effective rotavirus vaccines have been available for over a decade and are used in over 98 countries. In addition to the globally available, WHO-prequalified ROTARIX (GSK) and RotaTeq (Merck), several new rotavirus vaccines have attained national licensure - ROTAVAC (Bharat Biotech) and ROTASIIL (Serum Institute of India), licensed and manufactured in India and now WHO-prequalified, and Rotavin-M1 (PolyVac), licensed and manufactured in Vietnam. In this review, we summarize the available clinical trial and post-introduction evidence for these three new orally administered rotavirus vaccines. All three vaccines have demonstrated safety and efficacy against rotavirus diarrhea, although publicly available preclinical data are limited in some cases. This expanding product landscape presents a range of options to optimize immunization programs, and new presentations of each vaccine are currently under development.

Postmarketing Safety of Vaccines Approved by the U.S. Food and Drug Administration : A Cohort Study

BACKGROUND

Vaccines are one of the greatest achievements in public health. Prevalence and clinical significance of emerging postapproval, vaccine-related safety issues have not been systematically studied.

OBJECTIVE

To explore postmarketing safety modifications in U.S. Food and Drug Administration (FDA)-approved vaccine labels.

DESIGN

Retrospective cohort study.

SETTING

United States.

PARTICIPANTS

Initial and subsequent labels of all vaccines that were FDA-approved between 1 January 1996 and 31 December 2015.

MEASUREMENTS

The primary aim was a descriptive analysis of the prevalence and characteristics of postapproval, safety-related label changes. The secondary aim was to describe the distribution of data sources triggering these modifications.

RESULTS

The study cohort comprised 57 FDA-approved vaccines. Initial approval for 53 (93%) of the vaccines was supported by randomized controlled trials, with a median cohort size of 4161 participants (interquartile range, 2204 to 8634 participants). There were 58 postapproval, safety-related label modifications associated with 25 vaccines (49 warnings and precautions, 8 contraindications, and 1 safety-related withdrawal). The initial approval trial characteristics were similar in vaccines with and without postmarketing, safety-related label modifications. The most common safety issue triggering label modifications was expansion of population restrictions (n = 21 [36%]), followed by allergies (n = 13 [22%]). The most common source of safety data was postmarketing surveillance (n = 28 of 58 [48%]).

LIMITATION

The data source of the initial signal triggering safety-related label changes may not necessarily represent all safety data received and processed by the FDA.

CONCLUSION

Over a 20-year period, vaccines were found to be remarkably safe. A large proportion of safety issues were identified through existing postmarketing surveillance programs and were of limited clinical significance. These findings confirm the robustness of the vaccine approval system and postmarketing surveillance.

PRIMARY FUNDING SOURCE

None.

Recommendations and barriers to vaccination in systemic lupus erythematosus

Patients with Systemic Lupus Erythematosus (SLE) pose a unique dilemma pertaining to immunization against common pathogens. SLE patients are usually not immunized with vaccines based on the fear of either precipitating infection in this immunosuppressed patient population (with live vaccines) or aggravating autoimmunity and hence lupus flares (with any vaccines). However, elevated vulnerability to infection makes patients with SLE precisely the population that needs protection from vaccine-preventable diseases. A summary of guidelines from the Centers for Disease Control and Prevention, professional societies, review articles and expert opinions regarding use of individual vaccines applicable to adults with SLE is presented in this review.

Comparative analysis of the immunogenicity of monovalent and multivalent rotavirus immunogens

The strategies for developing rotavirus (RV) vaccines have always been controversial. At present, both the monovalent RV vaccine and the multivalent RV vaccine have displayed excellent safety and efficacy against RV infection and shown cross-reactive immunity, which laid the question whether the multivalent RV vaccine could be replaced by the monovalent RV vaccine. In this study, we focused on comparing the immunogenicity (serum neutralization activity and protection against homotypic and heterotypic RVs’ challenge) of individual standard RV strains (monovalent RV immunogens) and different combinations of them (multivalent RV immunogens). In result, RV immunogens showed general immunogenicity and heterotypic reaction but the multivalent RV immunogens exhibited greater serum neutralization activity and stronger heterotypic reaction than the monovalent RV immunogens (P<0.05). As to the protection, the multivalent RV immunogens also revealed more rapid and stronger protection against homotypic and heterotypic RVs’ challenge than the monovalent RV immunogens. The results demonstrated that both the monovalent and multivalent RV immunogens exhibited high immunogenicity, but the monovalent RV immunogens could not provide enough neutralization antibodies to protect MA104 cells against the infection with heterotypic RV strains and timely protection against homotypic and heterotypic RVs, so the multivalent RV vaccine could not be replaced by the monovalent RV vaccine.

Ethics and Childhood Vaccination Policy in the United States

Childhood immunization involves a balance between parents' autonomy in deciding whether to immunize their children and the benefits to public health from mandating vaccines. Ethical concerns about pediatric vaccination span several public health domains, including those of policymakers, clinicians, and other professionals. In light of ongoing developments and debates, we discuss several key ethical issues concerning childhood immunization in the United States and describe how they affect policy development and clinical practice. We focus on ethical considerations pertaining to herd immunity as a community good, vaccine communication, dismissal of vaccine-refusing families from practice, and vaccine mandates. Clinicians and policymakers need to consider the nature and timing of vaccine-related discussions and invoke deliberative approaches to policy-making.

The UK immunisation schedule: changes to vaccine policy and practice in 2013/14

Vaccination programmes are implemented either as new vaccines become available or evidence about them accumulates, or in response to specific situations. In the United Kingdom, development and implementation of the national immunisation programme is centrally coordinated and funded by the Department of Health on behalf of England, Wales, Scotland and Northern Ireland. A number of significant changes were made to the UK immunisation schedule for 2013/2014. Three new vaccines were introduced: intranasal influenza and oral rotavirus for children and subcutaneous shingles for older adults. To ensure protection against meningococcal C infection into adulthood, there has been a change to the schedule for meningitis C vaccination. The temporary pertussis vaccination programme for pregnant women, set up in response to an increase in the number of cases of pertussis particularly among young babies, has been extended until further notice. Furthermore, in response to large outbreaks of measles in south Wales and other parts of the UK, a national measles, mumps and rubella catch-up campaign specifically targeted at unvaccinated children aged 10-16 years was launched to ensure that all children and young people have received two doses of measles, mumps and rubella vaccine. This review describes the rationale behind these policy changes.

Adjuvants in the Driver's Seat: How Magnitude, Type, Fine Specificity and Longevity of Immune Responses Are Driven by Distinct Classes of Immune Potentiators

The mechanism by which vaccine adjuvants enhance immune responses has historically been considered to be the creation of an antigen depot. From here, the antigen is slowly released and provided to immune cells over an extended period of time. This "depot" was formed by associating the antigen with substances able to persist at the injection site, such as aluminum salts or emulsions. The identification of Pathogen-Associated Molecular Patterns (PAMPs) has greatly advanced our understanding of how adjuvants work beyond the simple concept of extended antigen release and has accelerated the development of novel adjuvants. This review focuses on the mode of action of different adjuvant classes in regards to the stimulation of specific immune cell subsets, the biasing of immune responses towards cellular or humoral immune response, the ability to mediate epitope spreading and the induction of persistent immunological memory. A better understanding of how particular adjuvants mediate their biological effects will eventually allow them to be selected for specific vaccines in a targeted and rational manner.