Vaccine refusal, mandatory immunization, and the risks of vaccine-preventable diseases

Vaccines are among the most effective prevention tools available to clinicians. However, the success of an immunization program depends on high rates of acceptance and coverage. There is evidence of an increase in vaccine refusal in the United States and of geographic clustering of refusals that results in outbreaks. Children with exemptions from school immunization requirements (a measure of vaccine refusal) are at increased risk for measles and pertussis and can infect others who are too young to be vaccinated, cannot be vaccinated for medical reasons, or were vaccinated but did not have a sufficient immunologic response. Clinicians can play a crucial role in parental decision making. Health care providers are cited as the most frequent source of immunization information by parents, including parents of unvaccinated children. Although some clinicians have discontinued or have considered discontinuing their provider relationship with patients who refuse vaccines, the American Academy of Pediatrics Committee on Bioethics advises against this and recommends that clinicians address vaccine refusal by respectfully listening to parental concerns and discussing the risks of nonvaccination.

Tick-borne encephalitis

Tick-borne encephalitis (TBE) is one of the most dangerous human infections occurring in Europe and many parts of Asia. The etiological agent Tick-borne encephalitis virus (TBEV), is a member of the virus genus Flavivirus, of the family Flaviviridae. TBEV is believed to cause at least 11,000 human cases of encephalitis in Russia and about 3000 cases in the rest of Europe annually. Related viruses within the same group, Louping ill virus (LIV), Langat virus (LGTV) and Powassan virus (POWV), also cause human encephalitis but rarely on an epidemic scale. Three other viruses within the same group, Omsk hemorrhagic fever virus (OHFV), Kyasanur Forest disease virus (KFDV) and Alkhurma virus (ALKV), are closely related to the TBEV complex viruses and tend to cause fatal hemorrhagic fevers rather than encephalitis. This review describes the clinical manifestations associated with TBEV infections, the main molecular-biological properties of these viruses, and the different factors that define the incidence and severity of disease. The role of ticks and their local hosts in the emergence of new virus variants with different pathogenic characteristics is also discussed. This review also contains a brief history of vaccination against TBE including trials with live attenuated vaccine and modern tendencies in developing of vaccine virus strains.

Vaccines: past, present and future

The vaccines developed over the first two hundred years since Jenner's lifetime have accomplished striking reductions of infection and disease wherever applied. Pasteur's early approaches to vaccine development, attenuation and inactivation, are even now the two poles of vaccine technology. Today, purification of microbial elements, genetic engineering and improved knowledge of immune protection allow direct creation of attenuated mutants, expression of vaccine proteins in live vectors, purification and even synthesis of microbial antigens, and induction of a variety of immune responses through manipulation of DNA, RNA, proteins and polysaccharides. Both noninfectious and infectious diseases are now within the realm of vaccinology. The profusion of new vaccines enables new populations to be targeted for vaccination, and requires the development of routes of administration additional to injection. With all this come new problems in the production, regulation and distribution of vaccines.

From empiricism to rational design: a personal perspective of the evolution of vaccine development

Vaccination, which is the most effective medical intervention that has ever been introduced, originated from the observation that individuals who survived a plague or smallpox would not get the disease twice. To mimic the protective effects of natural infection, Jenner - and later Pasteur - inoculated individuals with attenuated or killed disease-causing agents. This empirical approach inspired a century of vaccine development and the effective prophylaxis of many infectious diseases. From the 1980s, several waves of new technologies have enabled the development of novel vaccines that would not have been possible using the empirical approach. The technological revolution in the field of vaccination is now continuing, and it is delivering novel and safer vaccines. In this Timeline article, we provide our views on the transition from empiricism to rational vaccine design.

Compulsory vaccination and conscientious or philosophical exemptions: past, present, and future

Compulsory vaccination has contributed to the success of immunisation programmes in the USA and Australia, yet the benefits from compulsory vaccination are not universally recognised. Some people--experts and the public alike--believe that the benefits of compulsory vaccination are outweighed by the associated ethical problems. A review of vaccination legislation in the UK, Australia, and the USA raises four main points. First, compulsory vaccination may be effective in preventing disease outbreaks, reaching and sustaining high immunisation coverage rates, and expediting the introduction of new vaccines. Second, to be effective, compulsory programmes must have a reliable supply of safe and effective vaccines and most people must be willing to be vaccinated. Third, allowance of exemptions to compulsory vaccination may limit public backlash. Finally, compulsory vaccination may increase the burden on governments to ensure the safety of vaccines. Nevertheless, although compulsory immunisation can be very effective, it might not be acceptable in some countries where high coverage has been achieved through other approaches or efforts, such as in Sweden, Norway, Denmark, the Netherlands, and the UK. These factors should be considered when compulsory vaccinations are being introduced or immunisation laws refined. Lessons learned from compulsory vaccination could be useful to other public-health programmes.

Impact of vaccination on the spatial correlation and persistence of measles dynamics

The onset of measles vaccination in England and Wales in 1968 coincided with a marked drop in the temporal correlation of epidemic patterns between major cities. We analyze a variety of hypotheses for the mechanisms driving this change. Straightforward stochastic models suggest that the interaction between a lowered susceptible population (and hence increased demographic noise) and nonlinear dynamics is sufficient to cause the observed drop in correlation. The decorrelation of epidemics could potentially lessen the chance of global extinction and so inhibit attempts at measles eradication.

Yellow Fever Virus: Knowledge Gaps Impeding the Fight Against an Old Foe

Yellow fever (YF) was one of the most dangerous infectious diseases of the 18th and 19th centuries, resulting in mass casualties in Africa and the Americas. The etiologic agent is yellow fever virus (YFV), and its live-attenuated form, YFV-17D, remains one of the most potent vaccines ever developed. During the first half of the 20th century, vaccination combined with mosquito control eradicated YFV transmission in urban areas. However, the recent 2016-2018 outbreaks in areas with historically low or no YFV activity have raised serious concerns for an estimated 400-500 million unvaccinated people who now live in at-risk areas. Once a forgotten disease, we highlight here that YF still represents a very real threat to human health and economies. As many gaps remain in our understanding of how YFV interacts with the human host and causes disease, there is an urgent need to address these knowledge gaps and propel YFV research forward.

Vaccinology: past achievements, present roadblocks and future promises

Of all the branches of modern medicine, vaccinology can claim to be the one that has contributed most to the relief of human misery and the spectacular increase in life expectancy in the last two centuries. It is the only science that has eradicated an infectious disease-smallpox-responsible for 8-20% of all deaths in several European countries in the 18th century. Other disabling and lethal diseases, like poliomyelitis and measles, are targeted for eradication. Currently, it is estimated that immunization saves the lives of 3 million children a year but 2 million more lives could be saved by existing vaccines. The success of vaccines in controlling and eliminating diseases has, paradoxically, been the cause of a revival of the anti-vaccination movement which in the absence, in developed countries, of many erstwhile common infectious diseases such as diphtheria, tetanus, polio, pertussis, measles, rubella and mumps has come to believe that vaccination is not only no longer necessary but is even dangerous. This is because it accepts, as "reactions", any untoward health event that occurs after administration of a vaccine. Most vaccine "reactions", therefore, appear to be more frequent than vaccine-preventable diseases. Public Health Authorities, aware of the great value of vaccines to society, are facing an uphill battle to get them accepted by a growing proportion of so-called educated minorities, thus endangering disease elimination. Other developments, in the last two decades, that have hampered vaccine usage have been the exploding costs of research, development and manufacture of new vaccines and the emphasis still placed on therapy in preference to prevention in medicine. This has led to the erroneous perception that vaccines are expensive although they are, in most cases, more cost-effective than the popular wait-see-treat approach. A favorable trend for vaccinology has been fueled by recent major breakthroughs in the sciences of immunology, molecular biology, genomics, proteomics, physico-chemistry and computers that promise a bright future for prevention, not only of acute infectious diseases, but also treatment of conditions like chronic infections, allergy, auto-immune diseases and cancer where some malfunctioning of the immune system is thought to play a part. Vaccines are being made more user-friendly by the development of combined vaccines and less painful and invasive inoculation techniques than the traditional syringe and needle. Recent new initiatives, like the Global Alliance on Vaccines and Immunization (GAVI),which are gathering new sources of funding for vaccination, should be beneficial for vaccinology.

A history of fish vaccination: science-based disease prevention in aquaculture

Disease prevention and control are crucial in order to maintain a sustainable aquaculture, both economically and environmentally. Prophylactic measures based on stimulation of the immune system of the fish have been an effective measure for achieving this goal. Immunoprophylaxis has become an important part in the successful development of the fish-farming industry. The first vaccine for aquaculture, a vaccine for prevention of yersiniosis in salmonid fish, was licensed in USA in 1976. Since then the use of vaccines has expanded to new countries and new species simultaneous with the growth of the aquaculture industry. This paper gives an overview of the achievements in fish vaccinology with particular emphasis on immunoprophylaxis as a practical tool for a successful development of bioproduction of aquatic animals.

Smallpox: the triumph over the most terrible of the ministers of death

More than 200 years ago, Edward Jenner performed an experiment that laid the foundation for the eradication of smallpox and transformed humankind's fight against disease. Smallpox afflicted humankind as no other disease had don; its persistence and diffusion were without parallel. The disease brought down at least three empires. Generations watched helplessly as their children succumbed to the disease or were disfigured or blinded by it. Attempts were made to contain smallpox by isolating its sufferers and, later, by using variolation with varying degrees of success. However, the definitive solution was not found until Jenner's work was done at the end of the 18th century. Milkmaids who had developed cowpox from contact with cow udders informed Jenner that they were protected from the human form of the disease; he listened to their folk wisdom and raised it to the status of scientific fact. Jenner did not discover vaccination, but he was the first to demonstrate that this technique offered a reliable defense against smallpox. It was also a reliable defense against other illnesses, such as poliomyelitis, measles, and neonatal tetanus, although this was not known in Jenner's lifetime.

Smallpox: anything to declare?

Smallpox was eradicated in 1977, but it remains a concern owing to the potential use of the causative agent variola virus in bioterrorism. This article provides an overview of the World Health Organization's spectacular success in achieving the eradication of smallpox. It discusses how variola virus could potentially re-emerge and how prepared we are to counter such a re-emergence. Finally, the potential threat from other orthopoxviruses that exist naturally or that have been genetically engineered is considered. In the words of Rep. Christopher Shay, 'Better to be scared by the improbable possibility than to be unprepared for the catastrophic reality'.

Theoretical and methodological aspects of BCG vaccine from the discovery of Calmette and Guérin to molecular biology. A review

The BCG vaccine has been used to prevent tuberculosis since 1921 and applied for immunostimulation in neoplasia since the 1960s. Both the preventive and immunostimulation effects have been evaluated and communicated with contradictory, positive and negative conclusions. For an objective evaluation and interpretation of the protective efficacy, effectiveness and efficiency of the BCG vaccination it must be considered that: (1) several BCG substrains have been developed in manufacturing laboratories that differ in the residual virulence which determines immunogenicity and reactogenicity; (2) various liquid and freeze-dried BCG vaccine production methods are used, resulting in different BCG viable units per dose; (3) quantitative bioassay methods are not yet being used for statistical quality control of the vaccine; (4) BCG products are applied in various demographical, epidemiological and socioeconomic conditions with different vaccination policies; (5) inadequate biostatistical models are often used to analyse efficacy, effectiveness and adverse reactions. The same conditions influence the precise evaluation of BCG immunostimulation in neoplasia. Recombinant DNA technology will modify production methods, and explain at the molecular level the mechanism of the protective effects BCG confers in tuberculosis and immunostimulation in neoplasia. High level laboratory techniques and biostatistical methods, based on probability logic and inductive inference, ensure appropriate experimental designs and the exact analysis of laboratory data and the results of vaccination policies. They will lead to the evaluation of the protective effect of BCG in order to reduce the BCG contradictions.

'They might as well brand us': working-class resistance to compulsory vaccination in Victorian England

From its origins in resistance to the 1853 Compulsory Vaccination Act, the Victorian anti-vaccination movement successfully challenged the public health policies of an increasingly interventionist state. Anti-vaccinationists were not only middle-class reformers, but were also drawn from a politically active working class. These campaigners saw compulsory vaccination as an extreme example of class legislation, for its policy and administration implicitly targeted working-class infants and inflicted multiple penalties on a public who considered themselves 'conscientious objectors'. Anti-vaccinationism was quickly absorbed into English working-class culture. Indeed, it helped to reorganize working-class identities around the site of the vulnerable body thereby absorbing many people into a working class who interpreted the violation of their bodies as a form of political tyranny. Participation in this movement was, however, also an exclusive exercise for anti-vaccinators, as respectable working-class citizens distinguished themselves from members of the 'undeserving' classes. This paper explores the class nature of the Vaccination Acts, their relationship to the New Poor Law, and the political implications of their administration. It also imbeds anti-vaccinationism firmly within working-class culture, illustrating the campaign's relationship to popular protest and entertainment, and this legislation's impact upon working-class bodies.

The myth of the medical breakthrough: smallpox, vaccination, and Jenner reconsidered

A discussion of the particulars leading to the eradication of smallpox is pertinent to both investigators and the public as the clamor for more "breakthroughs" intensifies. The rational allocation of biomedical research funds is increasingly threatened by disease-advocacy groups and congressional earmarking. An overly simplistic view of how advances truly occur promises only to stunt the growth of researchers and research areas not capable of immediate great breakthroughs. The authors review the contributions of Jenner and his countless predecessors to give a more accurate account of how "overnight medical breakthroughs" truly occur-through years of work conducted by many people, often across several continents. In the public eye, few achievements are regarded with such excitement and awe as the medical breakthrough. Developments such as the discovery of penicillin and the eradication of polio and smallpox have each become a great story built around a singular hero. Edward Jenner, for example, is credited with discovering a means of safely conferring immunity to smallpox. The success of vaccination and subsequent eradication of this disease elevated Jenner to a status in medical history that is rivaled by few. However, the story of the eradication of smallpox does not start or end with the work of Jenner. Men such as Benjamin Jesty and Reverend Cotton Mather as well as unnamed physicians from tenth century China to eighteenth century Turkey also made critical contributions to the crowning achievement. Inoculation to prevent smallpox was commonplace in Europe for generations prior to Jenner's work. Jenner himself was inoculated as a child. In fact, vaccination with cowpox matter was documented in England over 20 years prior to Jenner's work. The authors' review of primary and secondary sources indicates that although Jenner's contribution was significant, it was only one of many. It is extremely rare that a single individual or experiment generates a quantum leap in understanding; this "lone genius" paradigm is potentially injurious to the research process. Wildly unrealistic expectations can only yield unsuccessful scientific investigation, but small steps by investigators supported by an informed public can build toward a giant leap, as the story of smallpox eradication clearly demonstrates.

BCG Moreau Rio de Janeiro: an oral vaccine against tuberculosis - review

The vaccine Bacillus of Calmette Guérin (BCG) was originally developed in France as an oral vaccine against tuberculosis. The oral use of this vaccine was replaced by the parenteral route in almost all countries after the Lubeck disaster. In contrast, Brazil retained the oral delivery of the vaccine until the mid-seventies when it was replaced by the intradermal route. This change in route of delivery was mainly secondary to pressure by medical practitioners based on the poor responses of oral immunized subjects to purified protein derivative (PPD) skin tests. Even after the change of route of delivery, Ataulpho de Paiva Foundation continued making the oral vaccine. Currently, BCG Moreau has been described as one of the most immunogenic and with fewer side effects than other BCGs. The genomics, proteomics and vaccine trials for oral BCG Moreau Rio de Janeiro are currently under investigation. In this review, we intend to describe the history of BCG Moreau Rio de Janeiro in Brazil.

Crisis in infectious diseases: time for a new paradigm?

Current practices in the treatment of infectious diseases are the result of two fundamental changes in antimicrobial therapy that occurred in the mid-20th century: the transition from pathogen-specific therapy to non-pathogen-specific therapy and the shift toward emphasis on antiinfective strategies that target microbial pathogens over those that enhance host immunity. The alarming rise in antimicrobial-resistant strains, the increasing frequency of serious infections in immunocompromised patients, and the paucity of new types of antibiotics suggest the need for reevaluation of the manner in which infections are treated. In the short term, the situation may be addressed-at least in part-by increased emphasis on improved diagnosis and, when possible, the use of specific or narrow-spectrum treatments. In the long term, a return to pathogen-specific therapy, possibly in combination with adjunctive immunotherapy, may be an attractive and desirable option provided that significant advances are made in diagnostic microbiology and drug discovery.