Vaccination and its adverse effects: real or perceived. Society should think about means of linking exposure to potential long term effect

Hepatitis B Vaccine and Multiple Sclerosis: Cause or Coincidence

Multiple sclerosis (MS) is an autoimmune disease in which the body’s immune system destroys myelin causing disruption of signals from the brain to the rest of the body. MS can be triggered by a variety of reasons. In this study, we present the case of a patient who developed neurological symptoms immediately (one day) after receiving the hepatitis B vaccine. The temporality of symptoms makes us question whether there is an association between the hepatitis B vaccine and MS. We would like to emphasize the importance of considering MS as a side effect of the hepatitis B vaccine and adding MS to the differential diagnosis of a patient who presents with neurological symptoms after receiving the hepatitis B vaccine.

The Individual Perspective: Did This Vaccine Harm this Person?

With the rapid pace of immunologic research, it is more important than ever for readers to understand rational immunodiagnosis, immunoprophylaxis, and immunotherapy. This column is intended to help you carry out proper immuno-logic drug use in your practice.

Are Vaccines Safe? Risk Communication Applied to Vaccination

With the rapid pace of immunologic research, it is more important than ever for readers to understand rational immunodiagnosis, immunopro-phylaxis, and immunotherapy. This column is intended to help you ensure proper immunologic drug use in your practice.

What can be done to make vaccines more trendy?

Incredibly, vaccines currently capture only about 2% of the world's pharmaceutical market, despite the fact that they can be credited with saving more lives and preventing more suffering and disability than any other form of medical activity, with the possible exception of the provision of clean water.

Safety of hepatitis B vaccines

Although concerns about vaccine safety have increased, true adverse reactions associated with hepatitis B vaccines are few, apart from minor symptoms at the site of injection and occasionally systemic reactions. There is no evidence of an association with hepatitis B vaccination and Sudden Infant Death Syndrome, Multiple Sclerosis and the Chronic Fatigue Syndrome. Hepatitis B vaccines are safe and essential for the prevention of this important and common infection.

"Wait and see" vaccinating behaviour during a pandemic: a game theoretic analysis

During the 2009 H1N1 pandemic, many individuals did not seek vaccination immediately but rather decided to "wait and see" until further information was available on vaccination costs. This behaviour implies two sources of strategic interaction: as more individuals become vaccinated, both the perceived vaccination cost and the probability that susceptible individuals become infected decline. Here we analyze the outcome of these two strategic interactions by combining game theory with a disease transmission model during an outbreak of a novel influenza strain. The model exhibits a "wait and see" Nash equilibrium strategy, with vaccine delayers relying on herd immunity and vaccine safety information generated by early vaccinators. This strategic behaviour causes the timing of the epidemic peak to be strongly conserved across a broad range of plausible transmission rates, in contrast to models without such adaptive behaviour. The model exhibits not only feedback mechanisms but also a feed-forward mechanism: a high initial perceived vaccination cost perpetuates high perceived vaccine costs (and lower vaccine coverage) throughout the remainder of the outbreak. This suggests that any effect of risk communication at the start of a pandemic outbreak will be amplified compared to the same amount of risk communication effort distributed throughout the outbreak.

Protective efficacy, immunotherapeutic potential, and safety of hepatitis B vaccines

Hepatitis B vaccines are highly effective and safe and have been incorporated into national immunization programs in over 150 countries. The major humoral immune response is to the common a determinant of the surface antigen protein of the virus. Approximately 5-10% of healthy immunocompetent subjects do not mount an antibody response (anti-HBs). Non-response is associated with different HLA-DR alleles and impaired Th cell response, among other factors such as route of injection, age, gender, body mass, and other factors. Important hepatitis B surface antigen variants have also been identified, which may have a potential impact on immunization and routine screening of blood, blood products and tissues, and organs for transplantation. Strategies for hepatitis B immunization are reviewed. Over 1,000 million doses of hepatitis B vaccine have been used with an outstanding record of safety. There is no evidence of an association between hepatitis B vaccines and the sudden infant death syndrome, chronic fatigue syndrome, and multiple sclerosis (MS). Several studies are in progress on treatment of chronic hepatitis B infection by immunization with multiple antigenic components, combination of vaccine with antiviral drugs and cytokines, T cell vaccines, DNA vaccines alone or with DNA encoded immunomodulatory cytokines, and direct genetic manipulation of antigen presenting cells.

Smallpox vaccination and risk of allergy and asthma

BACKGROUND

It has been proposed that childhood vaccinations may influence the development of allergy. Atopy and allergic diseases have increased after routine smallpox vaccination was stopped in the 1970s.

OBJECTIVE

We examined whether administration of smallpox vaccination during childhood was associated with a decreased risk of atopy, allergic rhinitis, and asthma.

METHODS

The occurrence of atopy, allergic rhinitis, and asthma was studied in nearly 2000 women participating in a national birth cohort study. Detailed information on smallpox vaccination was available from school health records. Atopic status was assessed serologically by a specific response to 11 common inhalant allergens by using serum samples obtained from the women during the period 1997 to 2001. Information on allergic rhinitis and asthma was available from telephone interviews.

RESULTS

We found no association between having been vaccinated against smallpox in childhood and risk of atopy or allergic rhinitis. Smallpox vaccination was associated with a slightly decreased risk of asthma. There was no association between age at smallpox vaccination and risk of atopy, allergic rhinitis, or asthma. Adjusting for birth cohort, sibship size, age of the woman's mother at birth, and social class in childhood did not change these results.

CONCLUSION

Our findings do not suggest that childhood vaccination against smallpox, even if given early in life, influences the development of atopy or allergic rhinitis. The association with asthma should be interpreted with caution and needs further study.

International patterns of the prevalence of pediatric asthma the ISAAC program

Like so much research, the findings from the ISAAC program have raised more questions than they have answered. Despite their limitations, the ISAAC findings provide the basis for further studies to investigate factors that potentially contribute to these international patterns and may lead to novel public health and pharmacologic intervention strategies that reduce the prevalence and severity of asthma worldwide.

Immunization and symptoms of atopic disease in children: results from the International Study of Asthma and Allergies in Childhood

OBJECTIVES

This study tested the hypothesis that immunization is related to the prevalence of atopic disease in childhood.

METHODS

We used data from the International Study of Asthma and Allergies in Childhood to perform an ecologic analysis of national and local immunization rates for tuberculosis, diphtheria and tetanus toxoids and pertussis (DTP), and measles and prevalence of atopic disease symptoms (asthma, allergic rhinoconjunctivitis, and atopic eczema).

RESULTS

In 13- to 14-year-old children, there were significant negative associations with local birth-year immunization rates for DTP and measles but none with rates for tuberculosis. No associations were found in 6- to 7-year-old children. No associations with national immunization rates were found.

CONCLUSIONS

International variations in childhood atopic diseases are unlikely to be explained by variations in immunization.

Comparing benefits and risks of immunization

BACKGROUND

This paper uses a straightforward method of quantifying the benefits and risks of immunization, illustrated by universal immunization programs in British Columbia against invasive Haemophilus influenzae type b disease (Hib), measles, rubella, and paralytic poliomyelitis.

METHODS

Data were extracted from provincial communicable disease and vaccine adverse event surveillance systems. Average disease incidence was compared before and after implementing universal immunization programs. Estimates of prevented deaths and serious disease complications were calculated and compared with expected numbers of serious vaccine-associated adverse events (VAAEs).

RESULTS

Average incidence of reported cases decreased 90 to 100% over a 5-year period after implementing universal programs. These benefits were sustained or strengthened over time. Rates of reported serious VAAEs were low.

DISCUSSION

The remarkable success of immunization has created a paradox. Despite a low absolute risk of serious VAAEs, the relative risk of some VAAEs can exceed risk of disease in the province.

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.

Adverse events and vaccination-the lack of power and predictability of infrequent events in pre-licensure study

The recent setback in the development of a safe and effective rotavirus vaccine illustrates an important problem regarding prelicensure testing and its ability to identify rare vaccine-related adverse effects. It is our contention that the possibility of a rare but serious vaccine adverse effect is difficult to detect in prelicensure testing. In this paper, we review the history regarding the testing and eventual studies that led to the permanent withdrawal of that vaccine. The post-licensure discovery of a serious adverse event associated with the rotavirus vaccine is not unique among vaccines, but represents a recurrent phenomenon that in fact is mathematically predictable. Prelicensure studies examine thousands of subjects and not hundreds of thousands. A sample size of 10,000 subjects may provide excellent estimates of efficacy, but cannot provide an adequate denominator to rule out rare adverse events. It lacks the power. Just as with the rotavirus vaccine, only after hundreds of thousands of doses of vaccines are distributed, will such rare events appear often enough to permit detection. For that reason, we must depend upon the modern post-licensure surveillance programs that we already have in place.

Vaccine safety: risk communication--a global perspective

The complexity of risks connected with both vaccine-preventable diseases as well as with immunization will be discussed and used as the basis for conclusions: -what should be done to avoid damage to current and future immunization programs and -how to improve risk communication. The need for more complete data on true, perceived and unknown immunization risks necessitates strengthening our research capabilities as well as surveillance and vaccine safety programs, and to critically examine the factors influencing public sentiments, taking into account that public perceptions of risk vary depending on the characteristics of risk. A concerted effort is needed to improve benefit and risk communication at all levels. The medical community should play a key role for improved communication.

Serious adverse events after measles-mumps-rubella vaccination during a fourteen-year prospective follow-up

BACKGROUND

Several disorders have been attributed to measles-mumps-rubella (MMR) vaccination during the past decade. The aim of this prospective follow-up study was to identify serious adverse events causally related to MMR vaccination.

METHODS

When the MMR vaccination program was launched in Finland in 1982, a countrywide surveillance system was set up to detect serious adverse events associated with MMR. To obtain detailed case histories vaccinees' clinical charts were reviewed. Serum samples were analyzed to trace concurrent infections.

SETTING

All hospitals and health centers in Finland from 1982 through 1996.

RESULTS

Immunization of 1.8 million individuals and consumption of almost 3 million vaccine doses by the end of 1996 gave rise to 173 potentially serious reactions claimed to have been caused by MMR vaccination. In all, 77 neurologic, 73 allergic and 22 miscellaneous reactions and 1 death were reported, febrile seizure being the most common event. However, 45% of these events proved to be probably caused or contributed by some other factor, giving an incidence of serious adverse events with possible or indeterminate causal relation with MMR vaccination of 5.3 per 100,000 vaccinees or 3.2 per 100,000 vaccine doses.

CONCLUSIONS

Causality between immunization and a subsequent untoward event cannot be estimated solely on the basis of a temporal relation. Comprehensive analysis of the reported adverse reactions established that serious events causally related to MMR vaccine are rare and greatly outweighed by the risks of natural MMR diseases.

Mothers as active partners in the prevention of childhood diseases: maternal factors related to immunization status of preschool children in Italy

BACKGROUND

We examined how maternal socio-demographic factors, together with mother's education, knowledge, and perception of immunizations, can affect the uptake of optional vaccinations of preschool children in Italy.

METHODS

Interviews of Italian mothers were performed using a structured questionnaire administered by trained interviewers with no specific medical competence.

RESULTS

A convenience sample of 1,035 mothers were interviewed. Fifty-nine percent of the respondents reported to have had their child immunized with the MMR vaccine and 54% reported to have had their child immunized against pertussis. In logistic regression analysis, three variables were significantly associated with both the immunization outcomes: mother's positive attitude toward immunization (OR = 1.69; IC 1.13-2.52 for pertussis; OR = 1.86, IC 1. 17-2.96 for MMR); mothers' residency in the North of the country (OR = 1.74; IC 1.32-2.30 for pertussis; OR = 1.63, IC 1.18-2.24 for MMR); and mother's receipt of satisfactory information on immunization (OR = 1.67; IC 1.15-2.21 for pertussis; OR = 2.25, IC 1. 47-3.43 for MMR). An immunization performed in recent years (after 1994), probably following the widespread use of acellular vaccine, was the most significant predictor for pertussis immunization (OR = 3.21; IC 2.43-4.24).

CONCLUSIONS

The findings suggest that mothers' attitudes, educational level, and socio-demographic characteristics, as well as socio-economic factors and local health policies, can influence children's immunization uptake. Health promotion, based on a partnership between parents and health professionals, should become a priority in Italian vaccination policies.

Do vaccines make best use of available resources? (in other words are they cost-effective?)

Vaccines are the most popular preventive intervention world-wide and are socially useful interventions. As with all social programmes, the effects of vaccines must be carefully assessed. Their economic significance lies partly in the burden of disease that can be avoided and partly in the competition for resources between vaccines and other interventions. Classic methods of economic evaluation depend on the evaluation of effectiveness and safety of each vaccine being evaluated and can indicate whether vaccination represent a good return for investment, especially if the wider social perspective is taken into account. The use of economic logic can also be applied to prioritize research into vaccines, both on the basis of ability of the target population to benefit and of the availability of good quality evidence.

Association between type 1 diabetes and Haemophilus influenzae type b vaccination: birth cohort study

OBJECTIVES

To determine the effect of Haemophilus influenzae type b vaccination and its timing on the risk of type 1 diabetes in Finnish children.

DESIGN

Cumulative incidence and relative risk of type 1 diabetes was compared among three birth cohorts of Finnish children: those born during the 24 months before the H influenzae type b vaccination trial, those in the trial cohort who were vaccinated at 3 months of age and later with a booster vaccine, and those in the trial cohort who were vaccinated at 24 months of age only. The probability of type 1 diabetes was estimated using regression analysis assuming that there were no losses to 10 year follow up and no competing risks.

SETTING

Finland (total population 5 million and annual birth rate 1.3%).

SUBJECTS

128 936 children born from 1 October 1983 to 1 September 1985, and 116 352 children born from 1 October 1985 to 31 August 1987.

MAIN OUTCOME MEASURES

Probability of type 1 diabetes among children vaccinated with H influenzae type b and non-vaccinated children.

RESULTS

No statistically significant difference was found at any time during the 10 year follow up in the risk of type 1 diabetes between the children born before the vaccination period and those vaccinated at the age of 24 months only (relative risk 1.01). The difference in the risk between the cohort vaccinated first at the age of 3 months and the cohort vaccinated at the age of 24 months only was not statistically significant either (1.06).

CONCLUSION

It is unlikely that H influenzae type b vaccination or its timing cause type 1 diabetes in children.

Development and clinical application of new polyvalent combined paediatric vaccines

The availability of combined vaccines containing protective antigens against the majority of (ideally all) diseases for which universal immunization is recommended in infancy would simplify the implementation, increase the acceptance, reduce the global cost of immunization programmes and improve disease control, while offering the possibility of disease elimination or even pathogen eradication. The desirability of combined vaccines is further enhanced, and made more urgent, because of the increasing number of diseases that can be prevented by vaccination. The complicated logistics of administering different vaccines that each require several inoculations is a significant barrier to successful immunization of a population. Furthermore, interest in immunization is continuously gaining momentum since it is now generally recognised that vaccines are among the safest and most cost-effective medical interventions for infectious diseases that continue, in spite of the widespread use of efficacious antimicrobial drugs, to be an important cause of morbidity and mortality. This burden is likely to increase due to the development of antimicrobial resistance. Basic research on new vaccines or improvement of existing ones such as the use of new technologies may be carried out in academic or other non-industrial laboratories but development work, including the necessary extensive clinical testing, that lead to products that can be approved for routine use is usually co-ordinated and financed by commercial companies. The decision to develop any particular combined vaccine will therefore be influenced not only by its medical desirability and technical feasibility but also the potential financial returns that the required investments in time and resources may bring to the company. All major vaccine manufacturers are currently working, either alone or through strategic alliances, towards developing more polyvalent vaccines by adding antigens such as inactivated polio virus, conjugated Haemophilus influenzae type b polysaccharide and hepatitis B surface antigen to the diphtheria-tetanus-pertussis vaccine either in its 'classical' (whole-cell) or more purified (acellular) formulations. Experience is showing that the development of combined vaccines involves much more than the simple mixing of existing antigens. Possible incompatibilities or mutual interferences between the antigens themselves, or between excipients, preservatives, adjuvants, residual contaminants, stabilisers and suspending fluids make it mandatory that each formulation be thoroughly tested for quality, stability, efficacy and safety. Furthermore the ability to produce and control it consistently must be established before it can be licensed for commercial use. The progress being made in this field is reviewed.