Vaccine safety: risk communication--a global perspective

Trust in Doctors, Positive Attitudes, and Vaccination Behavior: The Role of Doctor-Patient Communication in H1N1 Vaccination

Although there is a wide variety of scientific evidence that demonstrates the benefits of vaccination on a multitude of diseases, vaccination rates remain low while misperceptions about vaccines are on the rise. The primary objective of the present study is to examine the role of doctor-patient communication and vaccination. We test the impact of doctor-patient communication on trust in doctors' vaccine recommendations as a mediator, to understand the mechanisms leading to positive vaccination attitudes, and ultimately leading to actual H1N1 vaccination behavior. We use data from a nationally representative U.S. sample from one of the Multimedia Audience Research Systems (MARS) data sets collected by Kantar Media. Our results demonstrate the crucial role of doctor-patient communication in building patients' trust in doctors, which in turn positively impact vaccination attitudes and H1N1 vaccination behavior. Unlike other preventive health measures, getting vaccines after a pandemic is a critical decision because these vaccines are previously unknown. Our finding implies that verified communication from the physician's office may be one of the effective strategies during or after a pandemic. Our findings have implications for public health organizations to incorporate effective vaccination communication and could have critical implications for the COVID-19 vaccination.

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.

Adverse Effects on Work and Daily Life Interference among Healthcare Workers after the First and Second ChAdOx1 and BNT162b2 COVID-19 Vaccine Doses

In this study, we assessed the adverse effects and the work and daily life interference associated with each dose of the ChAdOx1 and BNT162b2 COVID-19 vaccines. Questionnaires were distributed to workers after they received both doses; only those who worked the day after receiving the vaccine were included in the analysis. Overall, 368 ChAdOx1-vaccinated and 27 BNT162b2-vaccinated participants were included. Among the ChAdOx1-vaccinated participants, the incidence of adverse effects was significantly lower after the second dose than after the first dose. Among the BNT162b2-vaccinated participants, however, no differences in adverse effects or work and daily life interference were found between the doses. After the first and second dose, the numeric scale score (0–10) for interference with work was 3.9 ± 2.9 and 1.6 ± 1.9 for the ChAdOx1 and 3.2 ± 2.5 and 3.6 ± 3.0 for the BNT162b2 vaccine, respectively. A similar trend was observed for interference with daily life. Factors associated with work and daily life interference in the multivariate model were age, vaccine dose (first or second), and the interaction term of vaccine type and dose. These results could be used to inform the general population of the adverse effects associated with these vaccinations.

Listen to the public and fulfil their information interests - translating vaccine communication research findings into guidance for regulators

Regulatory authorities have a crucial role in communicating about the vaccines they license. In terms of content and timing, their communication to the public is usually driven by data on quality, safety and efficacy. However, concerns over safety and vaccine hesitancy have emerged in some communities in various countries, and this demands a new approach to communication, starting with listening to the public debate. Reviewing communication research findings, coming in particular from the cognitive, decision‐making and media sciences, constitutes one mechanism of listening and has led the European Union (EU) regulatory network to developing guidance about which common concerns and information needs of the public to address through proactive and prepared communication. The guidance has been welcomed by EU and international fora. The current article summarizes the recommendations and shares the underlying research findings, as well as a proof of concept that communication research can be valuable for regulators. It is critical that regulators integrate the communication process with product risk assessment in the framework of pharmacovigilance, to ensure that public concerns are addressed in the assessments and that information about evidence and uncertainty relating to safety is provided to the public and vaccination policy makers in a specific, clear and accurate manner. Additionally, information from regulatory authorities should support healthcare professionals in their communication with patients. Meeting the information interests of the public is the principal prerequisite for informed decisions as well as safe and effective use of vaccines and medicines overall. This is also fundamental for trust in the authorities' commitment to patient and population health.

Contributions and challenges for worldwide vaccine safety: The Global Advisory Committee on Vaccine Safety at 15 years

In 1999, the Global Advisory Committee on Vaccine Safety (GACVS) was established by the World Health Organization (WHO) to provide independent scientific advice on issues relating to the safety of vaccines and immunization. Fifteen years onward, we conducted a multi-faceted review to evaluate the impact, reach and challenges facing GACVS, including the role GACVS plays in informing global, regional and WHO member state vaccine policy. The methods included measures of organizational structure, citation impact, themes approached, and a discussion by previous and current members to evaluate past, present and future challenges. Given the increasing range of data sources and the deployment of many new vaccines, the Committee is facing the complex task of identifying the best available evidence for recommendations on vaccine safety. To help meet the increased demand for public transparency in decision making, GACVS-structured methodology for evidence-based decisions is evolving. GACVS also promotes best practices and capacity building for timely and accurate risk assessment; risk communications; outreach to help countries maintain and, if needed, rebuild public trust in vaccines; and advocacy for bridging the major gaps in vaccine safety capacity globally.

Proteção individual versus proteção coletiva: análise bioética do programa nacional de vacinação infantil em massa

A vacinação é considerada como uma das políticas de saúde pública mais efetivas e de menor custo-benefício, utilizada no controle e na prevenção de doenças. Mas é também considerada uma das técnicas biomédicas mais polêmicas e controversas, o que torna difícil evitar uma abordagem ética, principalmente quando a vacinação é utilizada de forma compulsória em toda a população. Com efeito, visto que as vacinas não são totalmente seguras e eficazes, há um conflito ético entre o interesse individual e o coletivo, pois as crianças carregam de fato o ônus da vacinação em benefício da saúde pública quando são acometidas com reações adversas graves e que ficam alheias aos cuidados que deveriam ser oferecidos pelo Poder Público. O objetivo deste artigo foi demonstrar que as ferramentas da bioética são relevantes nesta discussão para analisar e compreender criticamente estes conflitos, fornecendo argumentos cogentes para orientar a elaboração de biopolíticas que considerem não apenas, com rigor, a prevenção, mas, também, a responsabilidade solidária de todos como fundamento para uma proteção que seja tanto individual como coletiva.

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.

The blame frame: media attribution of culpability about the MMR-autism vaccination scare

Scholars have examined how news media frame events, including responsibility for causing and fixing problems, and how these frames inform public judgment. This study analyzed 281 newspaper articles about a controversial medical study linking the measles, mumps, and rubella (MMR) vaccination with autism. Given criticism of the study and its potential negative impact on vaccination rates across multiple countries, the current study examined actors to whom news media attributed blame for the MMR-vaccine association, sources used to support those attributions, and what solutions (e.g., mobilizing information), if any, were offered. This study provides unique insight by examining the evolution of these attributions over the lifetime of the controversy. Findings emphasize how news media may attribute blame in health risk communication and how that ascription plays a potentially vital role in shaping public behavior. Theoretical and practical implications are discussed.

Publics and vaccinomics: beyond public understanding of science

Vaccines have been among the most effective tools for addressing global public health challenges. With the advent of genomics, novel approaches for vaccine discovery are opening up new opportunities for vaccine development and applications, particularly with the expectation of personalized vaccines and the possibility of addressing a broader range of infectious diseases. In this context, it is useful to reflect on the social contexts of vaccine development as these have been influenced by social, ethical, political challenges. This article discusses the historical context of vaccine controversies and factors that help explain public acceptance and resistance, illustrating that these challenges go well beyond simple public misunderstandings. The broader vaccine challenges evident along the innovation trajectory, from development to commercialization and implementation include problems in research and development, organizational issues, and legal and regulatory challenges that may collectively contribute to public resistance or confidence. The recent history of genomics provides further lessons that the developing field of vaccinomics can learn from.

Factors affecting intention to receive and self-reported receipt of 2009 pandemic (H1N1) vaccine in Hong Kong: a longitudinal study

Background

Vaccination was a core component for mitigating the 2009 influenza pandemic (pH1N1). However, a vaccination program's efficacy largely depends on population compliance. We examined general population decision-making for pH1N1 vaccination using a modified Theory of Planned Behaviour (TBP).

Methodology

We conducted a longitudinal study, collecting data before and after the introduction of pH1N1 vaccine in Hong Kong. Structural equation modeling (SEM) tested if a modified TPB had explanatory utility for vaccine uptake among adults.

Principal Findings

Among 896 subjects who completed both the baseline and the follow-up surveys, 7% (67/896) reported being “likely/very likely/certain” to be vaccinated (intent) but two months later only 0.8% (7/896) reported having received pH1N1 vaccination. Perception of low risk from pH1N1 (60%) and concerns regarding adverse effects of the vaccine (37%) were primary justifications for avoiding pH1N1 vaccination. Greater perceived vaccine benefits (β = 0.15), less concerns regarding vaccine side-effects (β = −0.20), greater adherence to social norms of vaccination (β = 0.39), anticipated higher regret if not vaccinated (β = 0.47), perceived higher self-efficacy for vaccination (β = 0.12) and history of seasonal influenza vaccination (β = 0.12) were associated with higher intention to receive the pH1N1 vaccine, which in turn predicted self-reported vaccination uptake (β = 0.30). Social norm (β = 0.70), anticipated regret (β = 0.19) and vaccination intention (β = 0.31) were positively associated with, and accounted for 70% of variance in vaccination planning, which, in turn subsequently predicted self-reported vaccination uptake (β = 0.36) accounting for 36% of variance in reported vaccination behaviour.

Conclusions/Significance

Perceived low risk from pH1N1 and perceived high risk from pH1N1 vaccine inhibited pH1N1 vaccine uptake. Both the TPB and the additional components contributed to intended vaccination uptake but social norms and anticipated regret predominantly associated with vaccination intention and planning. Vaccination planning is a more significant proximal determinant of uptake of pH1N1 vaccine than is intention. Intention alone is an unreliable predictor of future vaccine uptake.

Social and behavioral science in HIV vaccine trials: a gap assessment of the literature

Social and behavioral science research is integral to the conduct of HIV vaccine trials, especially because the vaccine targets an infection laden with sensitive human issues. Although social and behavioral sciences have played a larger role in HIV vaccine clinical trials than other vaccine clinical trials to date, this role should be expanded. Fortunately, related publications, conference coverage and research proposals are on the rise; community engagement is receiving more attention during the earlier stages of product development; and collaboration between HIV vaccine scientists and social and behavioral scientists is being fostered. Greater attention to social and behavioral science issues could not only facilitate accrual, but also improve research efficiency and relevance. In this review, gaps in the literature on social and behavioral science issues in HIV vaccine clinical research, including barriers and facilitators to trial participation, enhancing feasibility of trial success, health systems, policy and monitoring social and behavioral issues, are identified and directions are suggested for filling those gaps. Development of a safe, efficacious and acceptable HIV vaccine will be nurtured by addressing the gaps through interdisciplinary collaborations.

Accidental introduction of viruses into companion animals by commercial vaccines

The use of biologics in veterinary medicine has been of tremendous value in safeguarding our animal populations from debilitating and oftentimes fatal disease. This article reviews the principles of vaccination and the extensive quality control efforts that are incorporated into preparing the vaccines. Examples of adverse events that have occurred in the past and how enhanced vigilance at the level of the veterinarian and the veterinary diagnostic laboratory help to curtail these events are discussed. Emphasis on understanding the ecology of viral infections in dogs and cats is introduced, together with the concepts of the potential role of vaccines in interspecies spread of viruses.

Enhanced protein expression by internal ribosomal entry site-driven mRNA translation as a novel approach for in vitro loading of dendritic cells with antigens

Transfection of dendritic cells (DCs) with messenger RNAs (mRNAs) of tumor-associated antigens (TAAs) is a promising strategy for cancer vaccines. TAA mRNA can be generated by in vitro transcription using DNA encoding the TAA gene as a template. A cap analog is usually added upon in vitro transcription to stabilize mRNA and enhance the efficiency of mRNA translation. However, the inclusion of the cap analog correlates with significantly lower-yield mRNA transcription, potentially leading to an expensive vaccine manufacturing process. To solve this problem, we present a novel approach in which DNA templates are modified with an internal ribosomal entry site (IRES) sequence inserted upstream of the gene of interest to replace the use of the cap analog. The presence of IRES greatly enhanced transcription for the mRNA in vitro compared with the cap analog. Also, higher transgene expression was achieved using luciferase (Luc) mRNA with IRES than using capped Luc mRNA to transfect DCs. Immunization of mice with DCs transfected with IRES-containing mRNA encoding chicken ovalbumin (OVA) induced significant levels of antigen-specific interferon gamma-producing CD8(+) T cells and in vivo killing of antigen-bearing cells. Consistently, mice immunized with IRES-containing OVA mRNA-transfected DCs were protected from pulmonary metastasis of melanoma cells injected intravenously. We suggest that IRES can be used for the production of larger quantities of mRNA and that such IRES-containing mRNAs may be useful for DC-based antitumor immunotherapy.

Addressing parents' concerns about childhood immunizations: a tutorial for primary care providers

BACKGROUND

Despite the dangers of vaccine-preventable infections and efforts by health care professionals to promote immunization, parents' resistance to routine childhood immunizations continues to grow. This phenomenon can give rise to frustration among health care providers, as well as create barriers in providing medical care to children in need. In response, we developed a CD-ROM-based tutorial that (1) explains the nature and origins of parents' concerns, (2) addresses clinical implications of resistance to immunization, (3) explores ethical and professional obligations that physicians have toward children and their parents, and (4) discusses how physicians can effectively address parents' concerns.

OBJECTIVE

Our goals were to evaluate the tutorial's effectiveness in improving physicians' (1) general knowledge about parents' resistance to childhood immunizations, (2) knowledge of adverse effects of immunization, and (3) attitudes toward parents' resistance to childhood immunization.

DESIGN/METHODS

After pretesting, expert review, and revision, the 45-minute Penn State Immunization Project tutorial was pilot tested with pediatric and family medicine residents at 7 training programs in 4 states (Pennsylvania, New York, Maryland, and Iowa). Knowledge and attitudes were assessed by using a 26-item pretest/posttest, the results of which were then analyzed by using standard statistical methods.

RESULTS

A total of 122 residents completed the pretest/posttest. Statistically and clinically significant improvements were seen in residents' general knowledge, knowledge of adverse events, and all 5 attitudinal measures regarding childhood immunizations.

CONCLUSIONS

The tutorial Addressing Parents Concerns About Childhood Immunizations: A Tutorial for Primary Care Providers is effective in improving resident physicians' general knowledge, knowledge of adverse events, and attitudes. As such, this tutorial has the potential to enhance communication between parents and primary care providers and, more generally, improve clinicians' response to the growing resistance toward routine childhood immunizations.

Communication and marketing as tools to cultivate the public's health: a proposed "people and places" framework

Background

Communication and marketing are rapidly becoming recognized as core functions, or core competencies, in the field of public health. Although these disciplines have fostered considerable academic inquiry, a coherent sense of precisely how these disciplines can inform the practice of public health has been slower to emerge.

Discussion

In this article we propose a framework – based on contemporary ecological models of health – to explain how communication and marketing can be used to advance public health objectives. The framework identifies the attributes of people (as individuals, as social networks, and as communities or populations) and places that influence health behaviors and health. Communication, i.e., the provision of information, can be used in a variety of ways to foster beneficial change among both people (e.g., activating social support for smoking cessation among peers) and places (e.g., convincing city officials to ban smoking in public venues). Similarly, marketing, i.e., the development, distribution and promotion of products and services, can be used to foster beneficial change among both people (e.g., by making nicotine replacement therapy more accessible and affordable) and places (e.g., by providing city officials with model anti-tobacco legislation that can be adapted for use in their jurisdiction).

Summary

Public health agencies that use their communication and marketing resources effectively to support people in making healthful decisions and to foster health-promoting environments have considerable opportunity to advance the public's health, even within the constraints of their current resource base.

Vaccine safety perceptions and experience with adverse events following immunization in Kazakhstan and Uzbekistan: A summary of key informant interviews and focus groups

Few studies have examined vaccine safety attitudes in developing countries and countries in economic transition. The objectives of this study were to identify concerns about immunizations and strategies to address these concerns in Kazakhstan and Uzbekistan, two Central Asian countries in economic transition. Qualitative text analysis was conducted on 16 focus groups and 24 key informant interviews to identify discussion themes related to the study objectives. Specific areas of concern included: adverse events following immunizations, vaccine quality, healthcare worker competence, and lack of vaccine information available to parents. Focus group participants also suggested relevant topics and sources for informational materials.

[Benefit-risk assessment of vaccination strategies]

This article summarises the various stages of the risk/benefit assessment of vaccination strategies. Establishing the awaited effectiveness of a vaccination strategy supposes to have an epidemiologic description of the disease to be prevented. The effectiveness of the vaccine strategy will be thus expressed in numbers of cases, hospitalizations or deaths avoided. The effectiveness can be direct, expressed as the reduction of the incidence of the infectious disease in the vaccinated subjects compared to unvaccinated subjects. It can also be indirect, the unvaccinated persons being protected by the suspension in circulation of the pathogenic agent, consecutive to the implementation of the vaccination campaign. The risks of vaccination related to the adverse effects detected during the clinical trials preceding marketing are well quantified, but other risks can occur after marketing: e.g., serious and unexpected adverse effects detected by vaccinovigilance systems, or risk of increase in the age of cases if the vaccination coverage is insufficient. The medico-economic evaluation forms a part of the risks/benefit assessment, by positioning the vaccine strategy comparatively with other interventions for health. Epidemiologic and vaccinovigilance informations must be updated very regularly, which underlines the need for having an operational and reliable real time monitoring system to accompany the vaccination strategies. Lastly, in the context of uncertainty which often accompanies the risks/benefit assessments, it is important that an adapted communication towards the public and the doctors is planned.

Immediate injection pain in infants aged 18 months during vaccination against measles, mumps and rubella with either Priorix® or MMR-II®

The aim of this study was to investigate whether, the vaccine Priorix causes less immediate injection pain than MMR-II in vaccination of infants aged 18-24 months who were offered vaccine against measles, mumps and rubella. The infants were randomised into one of the two vaccine groups (Priorix/MMR-II in a double-blind study. One observer assessed pain, using CHEOPS (Children's Hospital Eastern Ontario Pain scale), and the parent used the Visual Analogue Pain scale (VAS). Pain assessment was made in 295 infants. Mean age was 19.08 months. Mean VAS value was 2.3/5.2 for Priorix and MMR-II, respectively (p<0.001). Mean CHEOPS value was 1.9/6.1 for Priorix and MMR-II, respectively (p<0.001). The study shows that Priorix gives less immediate injection pain than MMR-II.

Confidence in vaccination: a parent model

Although vaccination has been heralded as one of the 10 greatest public health achievements, how parents differ in their views about vaccination is not well understood. A deeper understanding of these attitudes and beliefs may improve the effectiveness of vaccine communications. In this mailed survey of U.S. parents in January 2001 (return response rate 49%), parental confidence in vaccination was very high, although there was significant variation among parents. Using multivariate analyses to group and profile parents, 90% of parents (n=1820) were classified into one of four distinct parent groups: (1) "Vaccine Believer" parents who were convinced of the benefit of vaccination; (2) "Cautious" parents noteworthy for a high emotional investment in their child; (3) "Relaxed" parents characterized by a less involved parenting style and some skepticism about vaccines; and (4) "Unconvinced" parents distinguished by their distrust of vaccinations and vaccination policy. These findings suggest that messages that are customized to parents' attitudes and beliefs may improve their understanding and acceptance of vaccination.

Vaccine safety controversies and the future of vaccination programs

In the years following the hepatitis B vaccination/multiple sclerosis controversy, a number of new issues regarding vaccine safety have been raised, in some cases leading to more debate and confusion. Against this background, an international group of experts was convened to review the current points of view concerning the use of thimerosal as a preservative and its potential risks; the suggested link between thimerosal-containing vaccines and acute lymphoblastic leukemia; the alleged association between aluminum-containing vaccines/macrophagic myofasciitis and general systemic complaints; a possible link between vaccination and autoimmune pathology; and a hypothetical link between measles-mumps-rubella vaccination and autism. At present, there are no data to conclude that childhood vaccines, and in particular hepatitis B vaccine, pose a serious health risk or justify a change in current immunization practice. However, vaccine "scares" continue to have an international impact on immunization coverage. Creating a positive environment for immunization can be achieved by repositioning the value of vaccines and vaccination, supported by evidence-based information. The role of international organizations, the media, and the industry in the implementation of communication strategies was discussed and the impact of litigation issues on vaccination was evaluated. The Viral Hepatitis Prevention Board confirms its commitment to current recommendations for universal and risk group hepatitis B vaccination and further encourages the conduct of vaccine safety studies and the dissemination of their results.

Measles vaccine coverage and factors related to uncompleted vaccination among 18-month-old and 36-month-old children in Kyoto, Japan

BACKGROUND

Due to low vaccine coverage, Japan has not only experienced outbreaks of measles but has also been exporting it overseas. This study aims to survey measles vaccine coverage and the factors uncompleted vaccination among community-living children.

METHODS

Subjects were the parents whose children had undergone either an 18-month or a 36-month checkup publicly provided by Kyoto City during November 2001 to January 2002. An anonymous self-administered questionnaire survey was conducted.

RESULTS

The coverage was 73.2% among the 18-month-old children (n = 2707) and 88.9% among the 36-month-old children (n = 2340), respectively. The following characteristics of mothers were related to uncompleted measles vaccination: aged below 30, working, concerned about the adverse events of the vaccine, and had insufficient knowledge. Similarly, the following characteristics among children were related to uncompleted measles vaccination: not the first-born child, interacting with other children in group settings. The coverage was the lowest among the children whose mothers were concerned about the adverse events of the vaccine without proper knowledge of measles and its vaccination.

CONCLUSION

To increase vaccine coverage among children, parents' awareness about measles and vaccination against it should be promoted, especially for working mothers. Efforts to enhance access to vaccination services and to communicate with parents about changing vaccination schedules are necessary.

Potential use of nanoparticles for transcutaneous vaccine delivery: effect of particle size and charge

The aim of this study was to investigate the effect of size and charge on the permeation of nanoparticles through the skin as the first step in designing a transdermal vaccine delivery system. Fluorescent particles ranging in size and charge were applied to the surface of full thickness pig skin in a diffusion chamber and the receptor fluid was assayed to determine permeation. Fluorescence microscopy was used to visualise the skin after experiments. The results showed that only 50 and 500 nm particles that were negatively charged were able to permeate the skin. This provides evidence of the potential of nanoparticles as delivery vectors for antigens and DNA for the purpose of transdermal vaccination protocols. The results would indicate that negative particles with sufficient charge may be ideal carriers for this purpose.

Vaccine safety

Rates of reported adverse events are remarkably low. VAERS identifies an adverse event rate approximating 11.4 reports per 100,000 vaccine doses. Approximately 15% of these reports represent SAEs, but less than 2% involve death; in most cases, reviews have shown no causal relation between the events and the vaccine. Across the spectrum of vaccines in use (including those directed against influenza and hepatitis B virus), many claims of adverse events regarding vaccines represent typical reactions to vaccinations. These reactions can be thought of as foreign-body reactions and predominate among the inactivated vaccines. In controlled studies, the adverse event rates that occur with vaccination resemble those that occur with placebo injections. Typical reactions associated with live viral and bacterial vaccines, such as MMR and varicella vaccines, may resemble attenuated forms of the disease for which the vaccine is directed. Other claims against vaccines represent chance-coincidence or misunderstood data; further studies of claims have vindicated the overall safety of the vaccines in most cases. Two documented safety concerns with vaccines, however, have demonstrated that vaccines (like other biologics and pharmacologic) can result in harm (eg, rotavirus and OPV vaccines). The denouement with these vaccines indicates the broad postmarketing data collection and evaluation that extends efforts made with prelicensure study to balance the benefits from vaccination with the risk for harm. Overall, measures including prelicensure study and postlicensure surveillance, such as VAERS, the Vaccine Safety Datalink Project, and the Clinical Immunization Safety Assessment Centers, have resulted in an exceptional safety profile for the vaccines in use.

Safety profile of recombinant canarypox HIV vaccines

Attenuated poxviruses have been developed for use as candidate vaccine vectors. ALVAC, a strain of the Avipoxvirus canarypox, has been extensively evaluated as a vector for vaccines against the human immunodeficiency virus type 1 (HIV-1). This report presents the safety and reactogenicity data derived from 11 multicenter, randomized controlled trials of ALVAC-HIV vaccines conducted by the HIV Vaccine Trials Network (HVTN) and its predecessor, the AIDS Vaccine Evaluation Group (AVEG). Five different ALVAC vaccine constructs were tested among 1497 volunteers. Reactogenicity was similar for different ALVAC constructs. Local reactions of any grade to ALVAC vaccines were common. However, fewer than 2% of vaccinees had severe local responses, and less than 1% experienced severe local pain or tenderness. Systemic responses were mild and transient. As combination vaccine regimens are in common use, we also evaluated side effects of ALVAC vectors given in combination with a recombinant subunit protein. No significant differences were noted in the reactogenicity of ALVAC given with or without a recombinant envelope subunit vaccine. Black, non-Hispanic and male recipients of ALVAC-HIV reported less pain following vaccination than White, non-Hispanics and females, respectively. ALVAC-HIV vaccines are well tolerated at tested doses. The reactogenicity profiles are comparable to those reported for existing vaccines licensed for use among adults. Reactogenicity does not appear to be related to the number or type of inserted genes, and did not vary between different ALVAC constructs.

The overall safety profile of currently available vaccines directed against infectious diseases

The vaccines currently used worldwide for the prevention of infectious diseases are quite safe in comparison to most pharmaceutical and biological agents. Vaccine components may contribute to inflammatory, allergic or anaphylactic reactions. Most adverse events are transient and well-tolerated. Transient severe adverse reactions occur at rates of one in one thousand vaccinations; permanent severe adverse reactions occur on the order of one in one million. The most common of the severe adverse reactions are syncope and allergic reactions. Providers can take steps to prevent or ameliorate these reactions by pursuing both prelicensure testing (albeit limited) and postlicensure testing and monitoring. Systems that enhance the detection of safety concerns include national passive and active surveillance as well as regional vaccine registries and provider-based patient education. Since vaccines are used in universal programmes, their safety is paramount to their continued acceptance. Healthcare managers, including administrators of hospitals, clinics, practice groups, health maintenance organisations (HMOs) and managed care plans, can and should support providers in minimising adverse events associated with vaccines by supporting postvaccination observation policies, postlicensure testing and surveillance, vaccine registries and patient education systems.

The challenge of vaccine safety

Vaccines always will involve some risk, and risk always involves some public concern. Although the benefits of routine vaccination greatly outweigh any adverse effects, our consumer society seeks to eliminate all risk. The balance of risk and benefit appears to falter by the very success of preventing disease: in the immediate absence of the disease, the resolve to vaccinate waivers. We cannot expect the public to think in terms of the decision analyst and carefully weigh probability, risk, and benefit in a numerical fashion. In fact, the public's approach toward vaccination is varied and unscientific. Recognizing these challenges, we propose a program of continued vigilance by increasing our scientific base and methodology, improving vaccine safety communication through research and resources, maintaining a tolerance of conscientious objection as a safety valve for mandated routine vaccination in civilians, and calling for more research funding for the development of new vaccines.

The future of vaccines, immunisation concepts and practice

Vaccines have prevented more deaths, disability and suffering than any other medical discovery or intervention. Recent breakthroughs in immunology and genomics offer the prospect of the development of many new prophylactic and therapeutic vaccines not only against infectious diseases but also for use in conditions such as allergy, autoimmunity and carcinogenesis where malfunction of the immune system undoubtedly plays a role. These hopeful perspectives are however dimmed by several counterproductive societal trends that include the spreading-although unjustified-belief that vaccines are not safe and may even be unnecessary, escalating costs of vaccine research, development, production and control that are exacerbated by political pressure on selling prices and expensive lawsuits by 'victims' of vaccination who claim excessive compensation. Negative media coverage of vaccine issues is adversely affecting acceptance of vaccination. In spite of these negative trends, vaccines should have a bright future, because it is increasingly being realised that prevention is not only better than cure but it is often also more cost-effective. A better understanding of the dynamics of microbial transmission in populations is leading to more rational immunisation practices on a global scale that could lead to eradication of several pathogens. Attention is being given to making vaccines more user-friendly through the development of combined vaccines and the introduction of less invasive inoculation techniques.