A risk-benefit analysis of vaccination

Using protection motivation theory to predict intention to adhere to official MMR vaccination recommendations in Switzerland

Switzerland has not yet reached the measles vaccination coverage of 95 percent that is recommended by the World Health Organization to achieve herd immunity. Within the overall objective of informing effective ways to promote the combined Measles, Mumps, Rubella (MMR) vaccination in Switzerland, the aim of this study was to identify predictors of parents' intention to adhere to official MMR vaccination recommendations. Between October 2012 and January 2013, we surveyed 554 parents of middle school students aged 13 to 15 in Ticino, Switzerland. Guided by Protection Motivation Theory (PMT), the survey covered predictors related to threat and coping appraisal with regards to measles and the MMR vaccine, MMR-related social attitudes and social norms, past experience with the disease and the vaccine, and information sources in the MMR vaccine context. Data were analyzed using Structural Equation Modelling. Among central PMT concepts describing people's threat and coping appraisal, only response (vaccination) efficacy showed to be directly related to parents' intention to adhere to MMR vaccination recommendations (B = .39, p < .001). In addition, social attitudes (B = .38, p < .001) were a direct predictor. Furthermore, social attitudes, social norms, knowing somebody who experienced MMR vaccination side effects, and having sought MMR information from public health institutions, all indirectly predicted parents' intention to adhere to MMR recommendations by activating different threat and coping appraisal mechanisms. To conclude, future communication measures from public health institutions should highlight the altruistic aspect (herd immunity) of the immunization practice as well as present evidence on the high effectiveness of the vaccination in reducing the risk at both the individual and collective levels of getting infected with measles.

Effect of multiple, simultaneous vaccines on polio seroresponse and associated health outcomes

BACKGROUND

Administration of multiple simultaneous vaccines to infants, children, and military recruits is not uncommon. However, little research exists to examine associated serological and health effects, especially in adults.

METHOD

We retrospectively examined 416 paired serum specimens from U.S. military subjects who had received the inactivated polio vaccine (IPV) alone or in combination with either 1 other vaccine (<3 group) or 4 other vaccines (>4 group). Each of the 2 groups was subdivided into 2 subgroups in which Tdap was present or absent.

RESULTS

The >4 group was associated with a higher proportion of polio seroconversions than the <3 group (95% vs. 58%, respectively, p<0.01). Analysis of the <3 subgroup that excluded Tdap vs. the >4 subgroup that excluded Tdap showed no difference between them (p>0.1). However, the >4 subgroup that included Tdap had significantly more seroconversions than either the <3 subgroup that excluded Tdap or the >4 subgroup that excluded Tdap (p<0.01). Overall, at least 98% of subjects were at or above the putative level of seroprotection both pre- and post-vaccination, yet at least 81% of subjects seroconverted. In an analysis of 400 of the subjects in which clinic in- and outpatient encounters were counted over the course of 1 year following vaccinations, there was no significant difference between the 2 groups (p>0.1).

CONCLUSION

A combination of >4 vaccines including IPV appeared to have an immunopotentiation effect on polio seroconversion, and Tdap in particular was a strong candidate for an important role. The dose of IPV we studied in our subjects, who already had a high level of seroprotection, acted as a booster. In addition, there appear to be no negative health consequences from receiving few versus more multiple simultaneous vaccinations.

Vaccine perceptions among Oregon health care providers

Health care providers exert a significant influence on parental pediatric vaccination decisions. We conducted hour-long interviews with traditional and alternative health care providers in which we explored a range of associations between vaccination perceptions and practice. A key finding was that the Health Belief Model constructs of perceived susceptibility to and severity of either an illness or an adverse vaccine event partially explained health care provider (HCP) beliefs about the risks or benefits of vaccination, especially among alternative care providers. Low or high perceived susceptibility to a vaccine-preventable disease (VPD) or of the severity of a given VPD affects whether an HCP will promote or oppose pediatric vaccination recommendations. Beyond these perceptions, health and vaccination beliefs are affected by the contextual factors of personal experience, group norms, immunology beliefs, and beliefs about industry and government. Building powerful affective heuristics might be critical to balancing the forces that defeat good public health practices.

Implementing clinical practice guidelines about health promotion and disease prevention through shared decision making

Clinical practice guidelines aim to improve the health of patients by guiding individual care in clinical settings. Many guidelines specifically about health promotion or primary disease prevention are beginning to support informed patient choice, and suggest that clinicians and patients engage in shared discussions to determine how best to tailor guidelines to individuals. However, guidelines generally do not address how to translate evidence from the population to the individual in clinical practice, or how to engage patients in these discussions. In addition, they often fail to reconcile patients' preferences and social norms with best evidence. Shared decision making (SDM) is one solution to bridge guidelines about health promotion and disease prevention with clinical practice. SDM describes a collaborative process between patients and their clinicians to reach agreement about a health decision involving multiple medically appropriate treatment options. This paper discusses: 1) a brief overview of SDM; 2) the potential role of SDM in facilitating the implementation of prevention-focused practice guidelines for both preference-sensitive and effective care decisions; and 3) avenues for future empirical research to test how best to engage individual patients and clinicians in these complex discussions about prevention guidelines. We suggest that SDM can provide a structure for clinicians to discuss clinical practice guidelines with patients in a way that is evidence-based, patient-centered, and incorporates patients' preferences. In addition to providing a model for communicating about uncertainty at the individual level, SDM can provide a platform for engaging patients in a conversation. This process can help manage patients' and clinicians' expectations about health behaviors. SDM can be used even in situations with strong evidence for benefits at the level of the population, by helping patients and clinicians prioritize behaviors during time-pressured medical encounters. Involving patients in discussions could lead to improved health through better adherence to chosen options, reduced practice variation about preference-sensitive options, and improved care more broadly. However, more research is needed to determine the impact of this approach on outcomes such as morbidity and mortality.

Ethics of vaccination programs

Ethical issues are present at each stage in the vaccine product life cycle, the period extending from the earliest stages of research through the eventual design and implementation of global vaccination programs. Recent developments highlight fundamental principles of vaccine ethics and raise unique issues for ongoing vaccination activities worldwide. These include the 2009-10 H1N1 pandemic influenza vaccination campaign, renewed attention to the potential global eradication of polio, and the ongoing evaluation of vaccine risk controversies, most notably the alleged link between childhood vaccines and autism. These cases present ethical challenges for public health policy-makers, scientists, physicians, and other stakeholders in their efforts to improve the health of individuals, communities, and nations through vaccination.

Origins of injection-site sarcomas in cats: the possible role of chronic inflammation-a review

The etiology of feline injection-site sarcomas remains obscure. Sarcomas and other tumors are known to be associated with viral infections in humans and other animals, including cats. However, the available evidence suggests that this is not the case with feline injection-site sarcomas. These tumors have more in common with sarcomas noted in experimental studies with laboratory animals where foreign materials such as glass, plastics, and metal are the causal agent. Tumors arising with these agents are associated with chronic inflammation at the injection or implantation sites. Similar tumors have been observed, albeit infrequently, at microchip implantation sites, and these also are associated with chronic inflammation. It is suggested that injection-site sarcomas in cats may arise at the administration site as a result of chronic inflammation, possibly provoked by adjuvant materials, with subsequent DNA damage, cellular transformation, and clonal expansion. However, more fundamental research is required to elucidate the mechanisms involved.

Haematological complications in otherwise healthy children hospitalized for varicella

Although varicella is commonly regarded as a mild childhood disease, complications may occur and frequently require hospitalization. The aim of this study was to establish the type and frequency of varicella complications among hospitalized paediatric patients over a 4.5-year period. This analysis included the medical charts of 306 patients admitted to the Infectious Disease Unit, Children Hospital Bambino Gesù, Roma, Italy from 2006 to 2010 for varicella disease. The most common complications were haematological disorders (41.5%) followed by neurological ones (23.5%). Varicella vaccination in childhood immunization program must be increased.

Preclinical and clinical development of plant-made virus-like particle vaccine against avian H5N1 influenza

The recent swine H1N1 influenza outbreak demonstrated that egg-based vaccine manufacturing has an Achille's heel: its inability to provide a large number of doses quickly. Using a novel manufacturing platform based on transient expression of influenza surface glycoproteins in Nicotiana benthamiana, we have recently demonstrated that a candidate Virus-Like Particle (VLP) vaccine can be generated within 3 weeks of release of sequence information. Herein we report that alum-adjuvanted plant-made VLPs containing the hemagglutinin (HA) protein of H5N1 influenza (A/Indonesia/5/05) can induce cross-reactive antibodies in ferrets. Even low doses of this vaccine prevented pathology and reduced viral loads following heterotypic lethal challenge. We further report on safety and immunogenicity from a Phase I clinical study of the plant-made H5 VLP vaccine in healthy adults 18-60 years of age who received 2 doses 21 days apart of 5, 10 or 20 µg of alum-adjuvanted H5 VLP vaccine or placebo (alum). The vaccine was well tolerated at all doses. Adverse events (AE) were mild-to-moderate and self-limited. Pain at the injection site was the most frequent AE, reported in 70% of vaccinated subjects versus 50% of the placebo recipients. No allergic reactions were reported and the plant-made vaccine did not significantly increase the level of naturally occurring serum antibodies to plant-specific sugar moieties. The immunogenicity of the H5 VLP vaccine was evaluated by Hemagglutination-Inhibition (HI), Single Radial Hemolysis (SRH) and MicroNeutralisation (MN). Results from these three assays were highly correlated and showed similar trends across doses. There was a clear dose-response in all measures of immunogenicity and almost 96% of those in the higher dose groups (2 × 10 or 20 µg) mounted detectable MN responses. Evidence of striking cross-protection in ferrets combined with a good safety profile and promising immunogenicity in humans suggest that plant-based VLP vaccines should be further evaluated for use in pre-pandemic or pandemic situations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00984945.