Lessons learned concerning vaccine safety

Vaccine Hesitancy in Saudi Arabia: A Cross-Sectional Study

(1) Background: vaccine hesitancy can put the public’s health at risk from vaccine-preventable diseases. This study aimed to address vaccine hesitancy in Saudi Arabia and understand the problem’s magnitude and causes. (2) Methods: this was a descriptive observational study using quantitative and qualitative evaluation methods conducted in Saudi Arabia between December 2020 and February 2021. Public survey forms, exit interviews, and healthcare professional survey forms were used. (3) Results: our study involved 2030 public survey participants, 119 exit interviews of caregivers, and 500 healthcare professionals, demonstrating that vaccine hesitancy was relatively low. Ninety percent of the participants agreed that it was essential for everyone to receive the recommended vaccines with their children (p < 0.001), 92% believed that vaccines are safe for their children (p < 0.001), 91% of the participants agreed to give their new children all the recommended doses (p < 0.001), 86% welcomed mass/school vaccination campaigns (p < 0.001), and 81% were willing to pay for additional vaccines for themselves and their children (p < 0.001). (4) Conclusions: vaccine hesitancy is low in Saudi Arabia, and a positive attitude toward vaccination was detected among most of the participants. Vaccination decision-making is complex and includes emotional, cultural, social, spiritual, and political aspects.

Vaccine confidence in China after the Changsheng vaccine incident: a cross-sectional study

BACKGROUND

China's achievements in immunization are being threatened by a vaccine crisis. This paper aims to investigate vaccine confidence in China after the Changsheng vaccine incident and attempts to identify the factors contributing to it.

METHODS

An online cross-sectional investigation was conducted from 1 to 25 September 2018. Descriptive analysis and logistic regression were performed to examine the associations between socio-demographic factors, cognition and attitudes towards the Changsheng vaccine incident and vaccine confidence.

RESULTS

We included 1115 respondents in the final analysis, and found that approximately 70% (783) of the respondents did not have vaccine confidence. More than half of the respondents (54.53%) were dissatisfied with the government's response measures to the Changsheng vaccine incident. The logistic regression model indicated that vaccine confidence was positively associated with the degree of satisfaction with the government's response measures (OR = 1.621, 95% CI = 1.215-2.163), attitudes towards the risks and benefits of vaccination (OR = 1.501, 95% CI = 1.119-2.013), concerns about vaccine safety (OR = 0.480, 95% CI = 0.317-0.726), and vaccine efficacy (OR = 0.594, 95% CI = 0.394-0.895).

CONCLUSIONS

A majority of the respondents held negative attitudes towards vaccines after the Changsheng vaccine incident. A coordinated effort is required to restore public confidence in vaccines, especially in China, where a nationwide mandatory immunization policy is implemented. To end dissent towards inoculation, a series of actions is crucial and multiple parties should work together to advance efforts and explore the possibility of establishing an open and transparent regulatory system.

Vaccine hesitancy: understanding better to address better

Vaccine hesitancy is an emerging term in the socio-medical literature which describes an approach to vaccine decision making. It recognizes that there is a continuum between full acceptance and outright refusal of some or all vaccines and challenges the previous understanding of individuals or groups, as being either anti-vaccine or pro-vaccine. The behaviours responsible for vaccine hesitancy can be related to confidence, convenience and complacency. The causes of vaccine hesitancy can be described by the epidemiological triad i.e. the complex interaction of environmental- (i.e. external), agent- (i.e. vaccine) and host (or parent)- specific factors. Vaccine hesitancy is a complex and dynamic issue; future vaccination programs need to reflect and address these context-specific factors in both their design and evaluation. Many experts are of the view that it is best to counter vaccine hesitancy at the population level. They believe that it can be done by introducing more transparency into policy decision-making before immunization programs, providing up-to-date information to the public and health providers about the rigorous procedures undertaken before introduction of new vaccines, and through diversified post-marketing surveillance of vaccine-related events.

Vaccine hesitancy: an overview

Despite being recognized as one of the most successful public health measures, vaccination is perceived as unsafe and unnecessary by a growing number of individuals. Lack of confidence in vaccines is now considered a threat to the success of vaccination programs. Vaccine hesitancy is believed to be responsible for decreasing vaccine coverage and an increasing risk of vaccine-preventable disease outbreaks and epidemics. This review provides an overview of the phenomenon of vaccine hesitancy. First, we will characterize vaccine hesitancy and suggest the possible causes of the apparent increase in vaccine hesitancy in the developed world. Then we will look at determinants of individual decision-making about vaccination.

Identification of Candidate Vaccine Antigens In Silico

The identification of immunogenic whole-protein antigens is fundamental to the successful discovery of candidate subunit vaccines and their rapid, effective, and efficient transformation into clinically useful, commercially successful vaccine formulations. In the wider context of the experimental discovery of vaccine antigens, with particular reference to reverse vaccinology, this chapter adumbrates the principal computational approaches currently deployed in the hunt for novel antigens: genome-level prediction of antigens, antigen identification through the use of protein sequence alignment-based approaches, antigen detection through the use of subcellular location prediction, and the use of alignment-independent approaches to antigen discovery. Reference is also made to the recent emergence of various expert systems for protein antigen identification.

The case for a vaccine injury compensation program for Canada

Despite its being deliberated since at least the 1980s, a national vaccine injury compensation program still does not exist in Canada. The omission of such a program stands as a gap in Canadian immunization policy in comparison to many other equivalently developed countries. This article outlines the arguments for a compensation program and the design elements that would be best suited to a program in the Canadian context.

Childhood immunization: when physicians and parents disagree

Persistent fears about the safety and efficacy of vaccines, and whether immunization programs are still needed, have led a significant minority of parents to refuse vaccination. Are parents within their rights when refusing to consent to vaccination? How ought physicians respond? Focusing on routine childhood immunization, we consider the ethical, legal, and clinical issues raised by 3 aspects of parental vaccine refusal: (1) physician counseling; (2) parental decision-making; and (3) continuing the physician-patient relationship despite disagreement. We also suggest initiatives that could increase confidence in immunization programs.

No-fault compensation following adverse events attributed to vaccination: a review of international programmes

Programmes that provide no-fault compensation for an adverse event following vaccination have been implemented in 19 countries worldwide, the first in Germany in 1961 and the most recent in Hungary in 2005. We performed a review of these programmes and determined elements that were common to all of them: administration and funding, eligibility, process and decision-making, standard of proof, elements of compensation and litigation rights. Most programmes were administered by state or national governments except in Finland and Sweden where they are coordinated by pharmaceutical manufacturers. Although funding is usually from Treasury, Taiwan (China) and the United States of America impose a tax on vaccine doses distributed. Decisions on compensation are made using established criteria or assessed on a case-by-case basis, while the standard of proof required is usually less than that required for court cases. Benefits provided by programmes include medical costs, disability pensions and benefits for noneconomic loss and death. Most countries allow claimants to seek legal damages through the courts or a compensation scheme payout but not both. We conclude that a variety of programmes, based on ethical principles, have been successful and financially viable in developed countries throughout the world. We believe there is a strong argument for widespread implementation of these programmes in other developed countries.

Analysis of known bacterial protein vaccine antigens reveals biased physical properties and amino acid composition

Many vaccines have been developed from live attenuated forms of bacterial pathogens or from killed bacterial cells. However, an increased awareness of the potential for transient side-effects following vaccination has prompted an increased emphasis on the use of sub-unit vaccines, rather than those based on whole bacterial cells. The identification of vaccine sub-units is often a lengthy process and bioinformatics approaches have recently been used to identify candidate protein vaccine antigens. Such methods ultimately offer the promise of a more rapid advance towards preclinical studies with vaccines. We have compared the properties of known bacterial vaccine antigens against randomly selected proteins and identified differences in the make-up of these two groups. A computer algorithm that exploits these differences allows the identification of potential vaccine antigen candidates from pathogenic bacteria on the basis of their amino acid composition, a property inherently associated with sub-cellular location.

Parental views on pediatric vaccination: the impact of competing advocacy coalitions

The debate on pediatric vaccination policy has been characterized by the presence of two distinct coalitions: those in favor of current vaccination policies and those expressing concern about these policies. The target of these coalitions is the vaccination decision of parents. To determine their influence, we conducted four focus groups in Toronto, Canada examining parental decision-making concerning pediatric vaccination. Our focus groups consisted of both fathers and mothers and parents who fully vaccinated and those who did not. Using the Advocacy Coalition Framework as an analytic guide, we identified several themes that provided insights into how effective the two coalitions have been in conveying their viewpoints. In general, we identified a variety of levels of belief systems existing amongst parents concerned about vaccination, some more amenable to change than others. We found that the choice to not vaccinate was largely a result of concerns about safety and, to a lesser extent, about lack of effectiveness. These parental views reflected the ability of the coalition concerned about vaccination to challenge parents' trust in traditional public health sources of information. In contrast, the parental decision to vaccinate was due to recognizing the importance of preventing disease and also a consequence of not questioning recommendations from public health and physicians and feeling pressured to because of school policies. Importantly, parents who fully vaccinate appear to have weaker belief systems that are potentially susceptible to change. While current policies appear to be effective in encouraging vaccination, if trust in public health falters, many who currently support vaccination may reevaluate their position. More research needs to be conducted to identify approaches to communicate the risks and benefits of vaccination to parents.

Dynamics of Vaccination Strategies via Projected Dynamical Systems

Previous game theoretical analyses of vaccinating behaviour have underscored the strategic interaction between individuals attempting to maximise their health states, in situations where an individual's health state depends upon the vaccination decisions of others due to the presence of herd immunity. Here, we extend such analyses by applying the theories of variational inequalities (VI) and projected dynamical systems (PDS) to vaccination games. A PDS provides a dynamics that gives the conditions for existence, uniqueness and stability properties of Nash equilibria. In this paper, it is used to analyse the dynamics of vaccinating behaviour in a population consisting of distinct social groups, where each group has different perceptions of vaccine and disease risks. In particular, we study populations with two groups, where the size of one group is strictly larger than the size of the other group (a majority/minority population). We find that a population with a vaccine-inclined majority group and a vaccine-averse minority group exhibits higher average vaccine coverage than the corresponding homogeneous population, when the vaccine is perceived as being risky relative to the disease. Our model also reproduces a feature of real populations: In certain parameter regimes, it is possible to have a majority group adopting high vaccination rates and simultaneously a vaccine-averse minority group adopting low vaccination rates. Moreover, we find that minority groups will tend to exhibit more extreme changes in vaccinating behaviour for a given change in risk perception, in comparison to majority groups. These results emphasise the important role played by social heterogeneity in vaccination behaviour, while also highlighting the valuable role that can be played by PDS and VI in mathematical epidemiology.

Variant Creutzfeldt-Jakob disease and the Canadian blood system after the tainted blood tragedy

The transfusion transmission of hepatitis C and HIV to thousands of Canadian blood recipients was one of this country's largest public health catastrophes. In response to this crisis, and in an effort to prevent such a tragedy from occurring again, the Canadian blood system has undergone substantial reform. Variant Creutzfeldt–Jakob (vCJD) disease was the first infectious threat faced by the blood system since undergoing reform. The response at the time to this risk provides insights into the Canadian blood system's new approach to infectious threats. Our analysis of the decision-making concerning vCJD identifies two dominant themes characterizing the new blood system's approach to safety:(1)

the adoption of a precautionary approach to new risks which involves taking action in advance of definitive evidence, and

(2)

risk aversion amongst policy makers, which has contributed to the adoption of safety measures with comparatively high cost-effectiveness ratios.

Overall the principles governing the new blood system have contributed to the system both providing protection against emerging infectious risks and regaining the confidence of the public and recipients. However, the current set of policy factors will likely contribute to increasingly risk-averse policy making that will contribute to continued increases in the cost of the blood system. The challenge the blood system now faces is to find the appropriate balance between maximizing safety and ensuring the system remains affordable.

Addressing the emergence of pediatric vaccination concerns: recommendations from a Canadian policy analysis

Ever since the advent of pediatric vaccination, individuals have expressed concerns about both its risks and benefits. These concerns have once again resurfaced among some segments of the population and could potentially undermine national vaccination programs. The views of the public, however, must be considered and respected in the formulation of vaccination policy. We have conducted an analysis of the pediatric vaccination "debate" in the Canadian context. We believe that there is common ground between those who support pediatric vaccination and those who are concerned about these programs. Based on our findings, we believe that the goal of public health authorities should be to maintain trust in vaccines by continuing to meet certain reciprocal responsibilities. To do so, we recommend the following: 1) increased investment in adverse event reporting systems; 2) request for proposals for consideration of a no-fault compensation program; 3) developing pre-emptive strategies to deal with potential vaccine risks; 4) further examination of mechanisms to improve communication between physicians and parents concerned about vaccination. All of these approaches would require additional investment in pediatric vaccination. However, such an investment is easy to justify given the benefits offered by pediatric vaccination and the ramifications of failing to maintain confidence in vaccination programs or missing a vaccine-related adverse event.

Imitation dynamics predict vaccinating behaviour

There exists an interplay between vaccine coverage, disease prevalence and the vaccinating behaviour of individuals. Moreover, because of herd immunity, there is also a strategic interaction between individuals when they are deciding whether or not to vaccinate, because the probability that an individual becomes infected depends upon how many other individuals are vaccinated. To understand this potentially complex interplay, a game dynamic model is developed in which individuals adopt strategies according to an imitation dynamic (a learning process), and base vaccination decisions on disease prevalence and perceived risks of vaccines and disease. The model predicts that oscillations in vaccine uptake are more likely in populations where individuals imitate others more readily or where vaccinating behaviour is more sensitive to changes in disease prevalence. Oscillations are also more likely when the perceived risk of vaccines is high. The model reproduces salient features of the time evolution of vaccine uptake and disease prevalence during the whole-cell pertussis vaccine scare in England and Wales during the 1970s. This suggests that using game theoretical models to predict, and even manage, the population dynamics of vaccinating behaviour may be feasible.

Hospitalisations for gastroenteritis: the role of rotavirus

To determine the proportion of hospitalisations for gastroenteritis caused by rotavirus, we tested for rotavirus stool samples of all children under the age of five hospitalised for gastroenteritis between 1 December 1999 and 30 May 2000 in seven community and specialised hospitals in Quebec. Of 944 children hospitalised, 565 (59.9%) were screened for rotavirus and 405 (71.7%) tested positive. From December to April, the proportion of positive results rose from 51.6 to 78.1%. Compared with children whose test results were negative, children who tested positive presented vomiting more frequently upon admission (88.9 versus 60.4%) and needed IV fluids in greater proportion (94.1 versus 78.0%), but spent less time in hospital (2.8 versus 3.3 days). Aside from dehydration, no complications were noted. In Quebec, a large majority of winter and spring hospitalisations for gastroenteritis in children is attributable to rotavirus.

A survey of attitudes towards paediatric vaccinations amongst Canadian naturopathic students

Previous studies have suggested that providers of alternative medicine may harbour anti-vaccination attitudes and that these attitudes may develop at an early stage in their careers. We further explored this question by conducting a survey to determine the attitudes of students of naturopathic medicine, a growing alternative medicine discipline, towards recommended paediatric vaccines. We sampled all 4 years of students at the Canadian College of Naturopathic Medicine (CCNM) and obtained a response rate of 59.4% (312 of 525). We found that only 12.8% (40 of 312) of the respondents would advise full vaccination; however, 74.4% (232 of 312) of the respondents would advise partial vaccination. Importantly, both willingness to advise full vaccination and trust in public health and conventional medicine decreased in students in the later years of the programme. Our findings suggest that public health and conventional medical supporters of vaccination need to identify mechanisms for engaging in discussion with this population of complementary/alternative medical professionals at an early stage in their careers.