Children's perceptions of influenza illness and preferences for influenza vaccine

Characterizing Children's Intuitive Theories of Disease: The Case of Flu

To advance the study of children's knowledge and understanding of disease, we devised a methodology for assessing key features of intuitive theories laid out by Wellman and Gelman (1998). We then assessed a disease-relevant biological ontology, causal propositions involving unobservables, and coherence in explanations of influenza offered by children aged 8 to 13. Use of disease-relevant terms and mention of propositions in a biological theory of flu causality, although not coherence or connectedness of ideas, increased with age. Measures were moderately correlated with one another and with a traditional Piagetian measure of level of disease understanding, each contributing uniquely to the characterization of children's thinking. In multiple regression analyses, scores were highest for older children, Latino/minority children, and children of more educated parents with other factors controlled. Specific gaps in children's intuitive theories are identified to guide theory-based interventions aimed at helping children understand and protect themselves from infectious diseases.

Potential Consequences of Not Using Live Attenuated Influenza Vaccine

INTRODUCTION

Decreased live attenuated influenza vaccine (LAIV) effectiveness in the U.S. prompted the Advisory Committee on Immunization Practices in August 2016 to recommend against this vaccine's use. However, overall influenza uptake increases when LAIV is available and, unlike the U.S., LAIV has retained its effectiveness in other countries. These opposing countercurrents create a dilemma.

METHODS

To examine the potential consequences of the decision to not recommend LAIV, which may result in decreased influenza vaccination coverage in the U.S. population, a Markov decision analysis model was used to examine influenza vaccination options in U.S. children aged 2-8 years. Data were compiled and analyzed in 2016.

RESULTS

Using recently observed low LAIV effectiveness values, fewer influenza cases will occur if LAIV is not used compared with having LAIV as a vaccine option. However, having the option to use LAIV may be favored if LAIV effectiveness returns to prior levels or if the absence of vaccine choice substantially decreases overall vaccine uptake.

CONCLUSIONS

Continued surveillance of LAIV effectiveness and influenza vaccine uptake is warranted, given their importance in influenza vaccination policy decisions.

Does cost-effectiveness of influenza vaccine choice vary across the U.S.? An agent-based modeling study

BACKGROUND

In a prior agent-based modeling study, offering a choice of influenza vaccine type was shown to be cost-effective when the simulated population represented the large, Washington DC metropolitan area. This study calculated the public health impact and cost-effectiveness of the same four strategies: No Choice, Pediatric Choice, Adult Choice, or Choice for Both Age Groups in five United States (U.S.) counties selected to represent extremes in population age distribution.

METHODS

The choice offered was either inactivated influenza vaccine delivered intramuscularly with a needle (IIV-IM) or an age-appropriate needle-sparing vaccine, specifically, the nasal spray (LAIV) or intradermal (IIV-ID) delivery system. Using agent-based modeling, individuals were simulated as they interacted with others, and influenza was tracked as it spread through each population. Influenza vaccination coverage derived from Centers for Disease Control and Prevention (CDC) data, was increased by 6.5% (range 3.25%-11.25%) to reflect the effects of vaccine choice.

RESULTS

Assuming moderate influenza infectivity, the number of averted cases was highest for the Choice for Both Age Groups in all five counties despite differing demographic profiles. In a cost-effectiveness analysis, Choice for Both Age Groups was the dominant strategy. Sensitivity analyses varying influenza infectivity, costs, and degrees of vaccine coverage increase due to choice, supported the base case findings.

CONCLUSION

Offering a choice to receive a needle-sparing influenza vaccine has the potential to significantly reduce influenza disease burden and to be cost saving. Consistent findings across diverse populations confirmed these findings.

Does Choice of Influenza Vaccine Type Change Disease Burden and Cost-Effectiveness in the United States? An Agent-Based Modeling Study

Offering a choice of influenza vaccine type may increase vaccine coverage and reduce disease burden, but it is more costly. This study calculated the public health impact and cost-effectiveness of 4 strategies: no choice, pediatric choice, adult choice, or choice for both age groups. Using agent-based modeling, individuals were simulated as they interacted with others, and influenza was tracked as it spread through a population in Washington, DC. Influenza vaccination coverage derived from data from the Centers for Disease Control and Prevention was increased by 6.5% (range, 3.25%-11.25%), reflecting changes due to vaccine choice. With moderate influenza infectivity, the number of cases averaged 1,117,285 for no choice, 1,083,126 for pediatric choice, 1,009,026 for adult choice, and 975,818 for choice for both age groups. Averted cases increased with increased coverage and were highest for the choice-for-both-age-groups strategy; adult choice also reduced cases in children. In cost-effectiveness analysis, choice for both age groups was dominant when choice increased vaccine coverage by ≥3.25%. Offering a choice of influenza vaccines, with reasonable resultant increases in coverage, decreased influenza cases by >100,000 with a favorable cost-effectiveness profile. Clinical trials testing the predictions made based on these simulation results and deliberation of policies and procedures to facilitate choice should be considered.

Estimates of the Public Health Impact of a Pediatric Vaccination Program Using an Intranasal Tetravalent Live-Attenuated Influenza Vaccine in Belgium

OBJECTIVES

Our objectives were to estimate the public health outcomes of vaccinating Belgian children using an intranasal tetravalent live-attenuated influenza vaccine (QLAIV) combined with current coverage of high-risk/elderly individuals using the trivalent inactivated vaccine.

METHODS

We used a deterministic, age-structured, dynamic model to simulate seasonal influenza transmission in the Belgian population under the current coverage or after extending vaccination with QLAIV to healthy children aged 2-17 years. Differential equations describe demographic changes, exposure to infectious individuals, infection recovery, and immunity dynamics. The basic reproduction number (R 0) was calibrated to the observed number of influenza doctor visits/year. Vaccine efficacy was 80 % (live-attenuated) and 59-68 % (inactivated). The 10-year incidence of symptomatic influenza was calculated with different coverage scenarios (add-on to current coverage).

RESULTS

Model calibration yielded R 0 = 1.1. QLAIV coverage of 75 % of those aged 2-17 years averted 374,000 symptomatic cases/year (57 % of the current number), 244,000 of which were among adults (indirect effect). Vaccinating 75 % of those aged 2-11 years and 50 % of those aged 12-17 years averted 333,200 cases/year (213,000 adult cases/year). Vaccinating only healthy children aged 2-5 years generated direct protection but limited indirect protection, even with 90 % coverage (40,800 averted adult cases/year; -8.4 %). Targeting all children averted twice as many high-risk cases as targeting high-risk children only (8485 vs. 4965/year with 75 % coverage). Sensitivity analyses showed the robustness of results.

CONCLUSIONS

The model highlights the direct and indirect protection benefits when vaccinating healthy children with QLAIV in Belgium. Policies targeting only high-risk individuals or the youngest provide limited herd protection, as school-age children are important influenza vectors in the community.

Improving influenza vaccination in chronically ill children using a tertiary-care based vaccination clinic: Is there a role for the live-attenuated influenza vaccine (LAIV)?

BACKGROUND

Children with underlying medical conditions should receive influenza vaccine (IV) yearly; yet this remains sub-optimal. We aimed to describe our experience with a tertiary-care hospital-based influenza vaccination clinic for this at-risk population.

METHODS

From October to December 2012, 2013, and 2014, we ran an influenza vaccination clinic at the Montreal Children's Hospital, where children with high-risk conditions come for their follow-up. Both injectable IV (IIV) and live-attenuated IV (LAIV) were offered free of charge to patients and their household contacts. Upon vaccination, parents were asked to fill a pre-piloted questionnaire.

RESULTS

We vaccinated a total of 2640 high-risk children and 1912 household members during the three influenza vaccination seasons. In 2012 and 2013, 631 and 630 patients with chronic illnesses were vaccinated, compared to 1379 in 2014. Caregivers preferred LAIV primarily because no needle was involved (49.0%) and because it was perceived as less painful (46.9%). LAIV was administered to 69% (2012), 55% (2013) and 47% (2014) of high-risk children. The main reason for not receiving LAIV was because it was contra-indicated. A small fraction of children previously vaccinated with LAIV who did not present any contraindication to LAIV opted for IIV: 12/101 (11.8%) in 2013 and 16/272 (5.9%) in 2014. In 2014, this was mainly due to a previous negative experience with LAIV (11/16).

CONCLUSION

Having an influenza vaccination clinic on site at a tertiary care hospital, where children come for their scheduled visits, facilitates yearly influenza vaccination in children with chronic illnesses. LAIV is preferred by caregivers and patients, when not contraindicated.

Intranasal Human Growth Hormone (hGH) Induces IGF-1 Levels Comparable With Subcutaneous Injection With Lower Systemic Exposure to hGH in Healthy Volunteers

CONTEXT

The development of an improved, efficacious human GH (hGH) product administered by a noninjectable route of delivery such as the nasal route is highly desirable. We have developed a novel nasal hGH product (CP024) that showed excellent nasal absorption in animal models; however, the translation of these results into the clinical setting is essential because past attempts to develop such formulations by other groups have been unable to induce IGF-1 in man.

OBJECTIVE

The objective of the study was to assess the pharmacokinetics, pharmacodynamics, and tolerability of CP024 compared with a sc hGH injection.

DESIGN

This was a single-center, nonrandomized placebo-controlled, open-label, five-way crossover study in eight healthy volunteers.

SETTING

The study was carried out at a contract research organization, Quotient Bioresearch.

VOLUNTEERS

Eight healthy male volunteers, given an iv infusion of octreotide to suppress the endogenous GH secretion during the study period, participated in the study. No volunteers were withdrawn due to side effects.

MAIN OUTCOME MEASURES

Measurement of hGH and IGF-1 levels and tolerability of the drug product was performed.

RESULTS

No serious adverse events were reported and no subjects withdrawn from study due to the treatment. After the nasal administration of CP024, 3-fold higher hGH blood levels were obtained as compared with hGH nasal control. The relative bioavailability was about 3%. CP024 (given twice daily) induced a significant increase in IGF-1 levels up to 19 hours after administration, with no significant difference to those obtained after the sc injection of hGH.

CONCLUSIONS

The study indicates that CP024 is a promising candidate for an efficacious nasal product for the treatment of GH deficiency due to induction of IGF-1 similar to that after a sc injection, despite the lower plasma hGH concentration obtained. A dose-response study is needed to evaluate the optimal nasal dose.

Procedural and Physical Interventions for Vaccine Injections: Systematic Review of Randomized Controlled Trials and Quasi-Randomized Controlled Trials

BACKGROUND

This systematic review evaluated the effectiveness of physical and procedural interventions for reducing pain and related outcomes during vaccination.

DESIGN/METHODS

Databases were searched using a broad search strategy to identify relevant randomized and quasi-randomized controlled trials. Data were extracted according to procedure phase (preprocedure, acute, recovery, and combinations of these) and pooled using established methods.

RESULTS

A total of 31 studies were included. Acute infant distress was diminished during intramuscular injection without aspiration (n=313): standardized mean difference (SMD) -0.82 (95% confidence interval [CI]: -1.18, -0.46). Injecting the most painful vaccine last during vaccinations reduced acute infant distress (n=196): SMD -0.69 (95% CI: -0.98, -0.4). Simultaneous injections reduced acute infant distress compared with sequential injections (n=172): SMD -0.56 (95% CI: -0.87, -0.25). There was no benefit of simultaneous injections in children. Less infant distress during the acute and recovery phases combined occurred with vastus lateralis (vs. deltoid) injections (n=185): SMD -0.70 (95% CI: -1.00, -0.41). Skin-to-skin contact in neonates (n=736) reduced acute distress: SMD -0.65 (95% CI: -1.05, -0.25). Holding infants reduced acute distress after removal of the data from 1 methodologically diverse study (n=107): SMD -1.25 (95% CI: -2.05, -0.46). Holding after vaccination (n=417) reduced infant distress during the acute and recovery phases combined: SMD -0.65 (95% CI: -1.08, -0.22). Self-reported fear was reduced for children positioned upright (n=107): SMD -0.39 (95% CI: -0.77, -0.01). Non-nutritive sucking (n=186) reduced acute distress in infants: SMD -1.88 (95% CI: -2.57, -1.18). Manual tactile stimulation did not reduce pain across the lifespan. An external vibrating device and cold reduced pain in children (n=145): SMD -1.23 (95% CI: -1.58, -0.87). There was no benefit of warming the vaccine in adults. Muscle tension was beneficial in selected indices of fainting in adolescents and adults.

CONCLUSIONS

Interventions with evidence of benefit in select populations include: no aspiration, injecting most painful vaccine last, simultaneous injections, vastus lateralis injection, positioning interventions, non-nutritive sucking, external vibrating device with cold, and muscle tension.

Focusing on flu: Parent perspectives on school-located immunization programs for influenza vaccine

School-located immunization programs (SLIP) will only be successful if parents consent to their children's participation. It is critical to understand parent perspectives regarding the factors that make them more or less likely to provide that consent. Organizations creating SLIPs will be able to capitalize on the aspects of SLIPs that parents appreciate, and address and correct issues that may give rise to parent concerns. This study involved five focus groups among the parents of school students in a large, urban school district. Findings highlight the broad range of concepts important to parents when considering participation in a SLIP. The safety and trust issues regarding vaccines in general that are so important to parents are also important to parents when considering participation in a SLIP. Effective communication strategies that include assurances regarding tracking of information and the competence and experience of immunizers will be helpful when addressing parents regarding SLIPs. In addition, parents were very cognizant of and positive regarding the public health benefits associated with SLIPs. Further study among larger populations of parents will further refine these ideas and aid in the development of successful influenza vaccine SLIPs that directly address and communicate with parents about the issues most important to them.

Adjuvanted, antigen loaded N-trimethyl chitosan nanoparticles for nasal and intradermal vaccination: adjuvant- and site-dependent immunogenicity in mice

N-trimethyl chitosan (TMC) nanoparticles have been shown to increase the immunogenicity of subunit antigens after nasal and intradermal administration. This work describes a second generation of TMC nanoparticles containing ovalbumin as a model antigen (TMC/OVA nanoparticles) and an immunopotentiator (TMC/OVA/immunopotentiator nanoparticles). The selection of immunopotentiators included Toll-like receptor (TLR) ligands lipopolysaccharide (LPS), PAM(3)CSK(4) (PAM), CpG DNA, the NOD-like receptor 2 ligand muramyl dipeptide (MDP) and the GM1 ganglioside receptor ligand, cholera toxin B subunit (CTB). The TMC/OVA/immunopotentiator nanoparticles were characterised physico-chemically and their immunogenicity was assessed by determining the serum IgG, IgG1, IgG2a titres and secretory IgA levels in nasal washes after intradermal and nasal vaccination in mice. After nasal vaccination, TMC/OVA nanoparticles containing LPS or MDP elicited higher IgG, IgG1 and sIgA levels than non-adjuvanted TMC/OVA particles, whereas nanoparticles containing CTB, PAM or CpG did not. After intradermal vaccination, the TMC/OVA/CpG and TMC/OVA/LPS nanoparticles provoked higher IgG titres than plain TMC/OVA particles. Altogether, our results show that co-encapsulation of an additional immunopotentiator with the antigen into TMC nanoparticles can further improve the immunogenicity of the vaccine. However, the strength and quality of the response depends on the immunopotentiator as well as the route of administration.