Changing the default to promote influenza vaccination among health care workers

BackgroundThe prevention of health care acquired infections is an important objective for patient safety and infection control in all health care settings. Influenza vaccination uptake among health care workers (HCWs) is the most effective method to prevent transmission to patients, but vaccination coverage rates are low among HCWs. Several educational campaigns have been developed to increase the influenza vaccination coverage rates of HCWs, but showed only small effects. The aim of this study was to test an opt-out strategy in promoting uptake among HCWs in a tertiary care center for patients with complex chronic organ failure.MethodsHCWs were randomly assigned to one of two conditions. In the opt-out condition (N = 61), participants received an e-mail with a pre-scheduled appointment for influenza vaccination, which could be changed or canceled. In the opt-in condition (N = 61), participants received an e-mail explaining that they had to schedule an appointment if they wanted to get vaccinated.ResultsThe findings show no statistically detectable effect of condition on being vaccinated against influenza. However, HCWs in the opt-out condition were more likely to have an appointment for influenza vaccination, which in turn increased the probability of getting vaccinated.ConclusionTo change the default to promote influenza vaccination among HCWs might be an easy and cost-effective alternative to the complex vaccination campaigns that have been proposed in recent years.     

Modelling alternative strategies for delivering hepatitis B vaccine in prisons: the impact on the vaccination coverage of the injecting drug user population

Since 2001 hepatitis B vaccination has been offered to prisoners on reception into prisons in England and Wales. However, short campaigns of vaccinating the entire population of individual prisons have achieved high vaccination coverage for limited periods, suggesting that short campaigns may be a preferable way of vaccinating prisoners. A model is used that describes the flow of prisoners through prisons stratified by injecting status to compare a range of vaccination scenarios that describe vaccination on prison reception or via regular short campaigns. Model results suggest that vaccinating on prison reception can capture a greater proportion of the injecting drug user (IDU) population than the comparable campaign scenarios (63% vs. 55.6% respectively). Vaccination on prison reception is also more efficient at capturing IDUs for vaccination than vaccination via a campaign, although vaccination via campaigns may have a role with some infections for overall control.     

The effect of mass vaccination campaigns against polio on the utilization of routine immunization services: A regression discontinuity design

BackgroundIn most low and middle-income countries (LMIC), vaccines are primarily distributed by routine immunization services (RI) at health facilities. Additional opportunities for vaccination are also provided through mass vaccination campaigns, conducted periodically as part of disease-specific initiatives. It is unclear whether these campaigns are detrimental to RI services, or wether they may stimulate the utilization of RI.MethodsUnobserved confounders and reverse causality have limited existing evaluations of the effects of mass vaccination campaigns on RI services. We explored the use of a regression discontinuity design (RDD) to measure these effects more precisely. This is a quasi-experimental method, which exploits random variations in birth dates to identify the causal effects of vaccination campaigns. We applied RDD to survey data on a nationwide vaccination campaign against Polio conducted in Bangladesh.ResultsWe compared systematically the children born immediately before vs. after the vaccination campaign. These two groups had similar background characteristics, but differed by their exposure to the vaccination campaign. Contrary to previous studies, exposure to the campaign had positive effects on RI utilization. Children exposed to the campaign received between 0.296 and 0.469 additional doses of DPT vaccine by age 4 months than unexposed children.ConclusionsRDD constitutes a promising tool to assess the effects of mass vaccination campaigns on RI services. It could be tested in additional settings, using larger and more precise datasets. It could also be extended to measure the effects of other disease-specific interventions on the functioning of health systems, in particular those that occur at a discrete point in time and/or include age-related eligibility criteria.     

Potential impact of dengue vaccination: Insights from two large-scale phase III trials with a tetravalent dengue vaccine

BackgroundA tetravalent dengue vaccine demonstrated its protective efficacy in two phase III efficacy studies. Results from these studies were used to derive vaccination impact in the five Asian (Indonesia, Malaysia, Philippines, Thailand, Vietnam) and the five Latin American countries (Brazil, Colombia, Honduras, Mexico and Puerto Rico) participating in these trials.MethodsVaccination impact was investigated with an age-structured, host-vector, serotype-specific compartmental model. Parameters related to vaccine efficacy and levels of dengue transmission were estimated using data collected during the phase III efficacy studies. Several vaccination programs, including routine vaccination at different ages with and without large catch-up campaigns, were investigated.ResultsAll vaccination programs explored translated into significant reductions in dengue cases at the population level over the first 10 years following vaccine introduction and beyond. The most efficient age for vaccination varied according to transmission intensity and 9 years was close to the most efficient age across all settings. The combination of routine vaccination and large catch-up campaigns was found to enable a rapid reduction of dengue burden after vaccine introduction.ConclusionOur analysis suggests that dengue vaccination can significantly reduce the public health impact of dengue in countries where the disease is endemic.     

Canine rabies vaccination and domestic dog population characteristics in the developing world: a systematic review

Background

Human rabies remains a significant problem in many developing countries, where canine rabies is the most common means of transmission. Although vaccination of dogs has been shown to be the most effective method of prevention in humans, dog vaccination is often lacking.

Methods

This systematic review examined dog rabies vaccination coverage achieved following mass vaccination campaigns and dog ecology/management factors relevant to rabies control in the developing world. We searched a variety of electronic databases for published articles pertaining to dog rabies vaccination or dog ecology where data were collected utilizing a household cluster survey. We reviewed studies published between January 1, 1980 and present and identified 29 articles for inclusion.

Results

We found the majority of vaccination campaigns were able to achieve the WHO recommended vaccination coverage of ≥70% and calculated weighted mean post-campaign vaccination coverage of 76.5% in urban areas and 73.7% in rural areas. However, we found an absence of studies related to dog vaccination/dog ecology from countries with the greatest burden of rabies such as India, China, and Pakistan. In addition, the majority of dogs in the developing world are very young and short-lived, reducing the effectiveness of vaccination campaigns.

Conclusions

Future studies on canine ecology should be undertaken in countries with high endemic canine rabies. New methods for improving the longevity of dogs and reducing high dog population turnover need to be investigated. Programs which encourage good dog management and promote responsible pet ownership are essential to eliminating canine and human rabies.     

Factors Associated with Missed Vaccination during Mass Immunization Campaigns

Achieving a high percentage of vaccination coverage with polio vaccine, while necessary, is not sufficient to eliminate or eradicate polio. The existence of pockets of under-vaccinated children has allowed outbreaks of polio in countries that have achieved high levels of vaccination coverage and in countries with no cases for many years. In a literature review, 35 articles were identified that described factors associated with missed vaccination in mass immunization campaigns. An annotated bibliography was developed for each article; these were then coded using the AnSWR program, and codes were organized into three larger thematic categories. These thematic areas were: (a) organization and implementation of mass campaigns; (b) population characteristics; and (c) knowledge and practices of caretakers. If these factors were geographically clustered, it was suspected that these clusters might have higher likelihood of becoming pockets of unvaccinated children. Immunization programme managers can target resources to identify if such clusters exist. If so, they can then ensure supervision of vaccination efforts in those sites and take further action, if indicated, to prevent or mitigate pockets of unvaccinated children.Key words: Child health, Evaluation studies, Immunization, Polio, Polio vaccine, Review literature, Vaccine     

Cost-effectiveness of sub-national geographically targeted vaccination programs: A systematic review

Immunization is an essential component of national health plans. However, the growing number of new vaccine introductions, vaccination campaigns and increasing administrative costs create logistic and financial challenges, especially in resource-limited settings. Sub-national geographic targeting of vaccination programs is a potential strategy for governments to reduce the impact of infectious disease outbreaks while optimizing resource allocation and reducing costs, promoting sustainability of critically important national immunization plans. We conducted a systematic review of peer-reviewed literature to identify studies that investigated the cost-effectiveness of geographically targeted sub-national vaccination programs, either through routine immunization or supplementary immunization activities. A total of 16 studies were included in our review, covering nine diseases of interest: cholera, dengue, enterotoxigenic Escherichia coli (ETEC), hepatitis A, Japanese encephalitis, measles, rotavirus, Shigella and typhoid fever. All studies modelled cost-effectiveness of geographically targeted vaccination. Despite the variation in study design, disease focus and country context, studies generally found that in countries where a heterogenous burden of disease exists, sub-national geographic targeting of vaccination programs in areas of high disease burden was more cost-effective than a non-targeted strategy. Sensitivity analysis revealed that cost-effectiveness was most sensitive to variations in vaccine price, vaccine efficacy, mortality rate, administrative and operational costs, discount rate, and treatment costs. This systematic review identified several key characteristics related to geographic targeting of vaccination, including the vaccination strategy used, variations in modelling parameters and their impact on cost-effectiveness. Additional research and guidance is needed to support the appropriateness and feasibility of geographically targeted vaccination and to determine what country context would make this a viable complement to routine immunization programs.     

Global economic evaluations of rotavirus vaccines: A systematic review

Introduction: World Health Organization (WHO) recommends Rotavirus vaccines to prevent and control rotavirus infections. Economic evaluations (EE) have been considered to support decision making of national policy. Summarizing global experience of the economic value of rotavirus vaccines is crucial in order to encourage global WHO recommendations for vaccine uptake. Therefore, a systematic review of economic evaluations of rotavirus vaccine was conducted.Methods: We searched Medline, Embase, NHS EED, EconLit, CEA Registry, SciELO, LILACS, CABI-Global Health Database, Popline, World Bank - e-Library, and WHOLIS. Full economic evaluations studies, published from inception to November 2015, evaluating Rotavirus vaccines preventing Rotavirus infections were included. The methods, assumptions, results and conclusions of the included studies were extracted and appraised using WHO guide for standardization of EE of immunization programs.Results: 104 relevant studies were included. The majority of studies were conducted in high-income countries. Cost-utility analysis was mostly reported in many studies using incremental cost-effectiveness ratio per DALY averted or QALY gained. Incremental cost per QALY gained was used in many studies from high-income countries. Mass routine vaccination against rotavirus provided the ICERs ranging from cost-saving to highly cost-effective in comparison to no vaccination among low-income countries. Among middle-income countries, vaccination offered the ICERs ranging from cost-saving to cost-effective. Due to low- or no subsidized price of rotavirus vaccines from external funders, being not cost-effective was reported in some high-income settings.Conclusion: Mass vaccination against rotavirus was generally found to be cost-effective, particularly in low- and middle-income settings according to the external subsidization of vaccine price. On the other hand, it may not be a cost-effective intervention at market price in some high-income settings. This systematic review provides supporting information to health policy-makers and health professionals when considering rotavirus vaccination as a national program.     

Observational study of vaccination in cancer patients: How can vaccine coverage be improved?

BackgroundChemotherapy increases the risk of infections, often severe, and some of them are vaccine-preventable infections. We aimed to assess vaccination coverage and associated factors in oncology and hematology patients.MethodsConsecutive adult patients followed in a French university hospital for hematological malignancy or solid cancer voluntarily completed an anonymous questionnaire in September and October 2016. It included questions on underlying disease, chemotherapy, flu, and pneumococcal vaccination uptakes, and attitudes toward vaccination. Factors associated with vaccination uptake were assessed by multivariate logistic regression.ResultsThe response rate was 41.9% (N = 671) among 1,600 questionnaires distributed; 232 patients had underlying hematological malignancy and 439 had solid cancer. Half of the patients were aged over 65 years. Chemotherapy was ongoing or discontinued for less than one year in 74.7% of patients. In patients aged < 65 years undergoing chemotherapy, flu vaccination rate was 19.9% whereas patients aged > 65 years had coverage of 47%. Pneumococcal vaccine uptake was 7.3%. However, 64.7% of patients were favorable to vaccination. Vaccine uptake was associated with age > 65 years (OR 4.5 [2.9–7.0]), information about vaccination delivered by the family physician (OR 12.9 [5.5–30.1]), follow-up in hematology unit (OR 2.0 [1.3–3.1]), and positive opinion about vaccination (OR 2.0 [1.3–3.1]).ConclusionDespite specific recommendations regarding immunocompromised patients, anti-pneumococcal and flu vaccinations were rarely conducted, even in elderly patients. Targeted information campaigns to family physicians, oncologists, and patients should be implemented to improve vaccine coverage in patients with underlying malignancies.     

Brazilian vaccinia viruses and their origins

Although the World Health Organization (WHO) declared global smallpox eradicated in 1980, concerns over emergent poxvirus infections have increased. Most poxvirus infections are zoonotic; exploring their genetic diversity will illuminate the genetic and evolutionary aspects of poxvirus infections, ecology, and epidemiology. In recent decades, several strains of the orthopoxvirus vaccinia virus (VACV) have been isolated throughout Brazil, including genetically distinct isolates within the same outbreak. To further investigate the diversity and origins of these viruses, we analyzed molecular data from 8 Brazilian VACV isolates and compared several genes involved in virus structure and pathogenicity. Genetic variation among isolates suggests that ancestral Brazilian VACVs existed before the beginning of the WHO smallpox eradication vaccination campaigns and that these viruses continue to circulate.     

Chronic helminth infections impair pneumococcal vaccine responses

Pneumonia is the leading killer of children and disproportionately affects developing countries. Vaccination campaigns against Streptococcus pneumoniae, the leading cause of pneumonia, have recently been launched with a new conjugate vaccine in Africa. Using a mouse model, we assessed the potential role that the high burden of helminth infections in the countries targeted for vaccine might have on vaccine effectiveness. Mice vaccinated with either commercial conjugate or purified polysaccharide vaccines had impaired antibody responses if they were chronically infected with Taenia crassiceps. This translated to increased susceptibility to pneumococcal pneumonia and high mortality compared to helminth-negative vaccinated animals, which were fully protected from disease and death. Antibodies taken from Taenia-infected, vaccinated mice were unable to effectively opsonize S. pneumoniae for killing by alveolar macrophages, and did not protect against pneumococcal challenge when adoptively transferred into naïve animals. These data may have implications for vaccination programs in countries endemic with helminths.     

Negative trends from 2008/9 to 2011/12 seasons in influenza vaccination coverages among high risk subjects and health care workers in Spain

Objectives

We aim to describe influenza vaccination coverage for the Spanish population across four consecutive campaigns (2008/2009 to 2011/2012). The data was analyzed by high risk groups and health care workers (HCWs). Also, coverage trends were analyzed to assess uptake in post-pandemic seasons.

Methods

We used data from two nation-wide representative health surveys namely the 2009/10 European Health Interview Survey for Spain (N = 22,188) and the 2011–12 Spanish National Health Survey (N = 21,007) Influenza vaccination status was self-reported. We analyzed influenza vaccine coverage by age, sex, number of chronic conditions, being a heath care worker (HCWs) and nationality. Time trends for campaigns among high risk groups were estimated by a multivariate logistic regression model.

Results

We analyzed data from 43,072 subjects aged ≥16 years. As a whole, coverage decreased by 3.31% (22.57–19.26%) between the 2008/2009 and 2011/2012 campaigns with a significant decreasing trend (OR 0.92; 95% CI: 0.90–0.94).Coverage in people under 60 years with a chronic disease decreased significantly (OR 0.92: 95% CI: 0.85–0.99) during the analyzed period from 21.02% in 2008/2009 to 17.40% in 2011/2012. Among HCWs, the highest influenza vaccination coverage was achieved in 2009/2010 (31.08%) in the latest campaign coverage has almost halved (17.88%). For the 2011/2012 season and for all age groups the variables associated with a higher probability of having received the influenza vaccine were older age and presence of associated chronic conditions. Among those aged ≥60 years, immigrants had lower uptake (OR 0.60; 95% CI: 0.32–0.99).

Conclusions

Seasonal influenza vaccine uptake rates in the recommended target groups in Spain are unacceptably low and seem to be decreasing in the post pandemic seasons. Further studies are necessary to precisely identify reasons for non-compliance and barriers to influenza vaccination. Meanwhile urgent strategies to improve seasonal vaccination uptake must be discussed and implemented.     

2009-2010 seasonal and pandemic A (H1N1) influenza vaccination among healthcare workers

Influenza vaccination recommendations are traditionally met with low compliance by healthcare workers (HCWs). The aim of this study is to analyze influenza vaccination among HCWs following a vaccination strategy characterized by an increased effort to maximize the hospital vaccination rate. For this, 2009-2010 seasonal and pandemic influenza vaccination rates among 2739 HCWs at a tertiary university hospital were evaluated. The seasonal influenza vaccination rate was 26.7% (48.3% increase vs. 2008-2009, p = 0.0000), and 14.8% in the case of pandemic influenza. HCWs with direct patient contact showed similar seasonal (25.7%) and pandemic (15.4%) influenza vaccination rates compared to the overall rates. Physician vaccination displayed the highest rate, showing significant differences vs. total rate (38.3%, p = 0.0007 for seasonal, and 32.2%, p = 0.0000 for pandemic influenza). The areas in which the vaccination strategy was most active reflected a significant increase (32.6%, p = 0.0056 for seasonal, and 25.2%, p = 0.0000 for pandemic influenza). It therefore appears that more active campaigns might increase influenza vaccination among HCWs.     

Advances in intranasal vaccine delivery: A promising non-invasive route of immunization

The importance of vaccination has been proven particularly significant the last three years, as it is revealed to be the most efficient weapon for the prevention of several infections including SARS-COV-2. Parenteral vaccination is the most applicable method of immunization, for the prevention of systematic and respiratory infections, or central nervous system disorders, involving T and B cells to a whole-body immune response. However, the mucosal vaccines, such as nasal vaccines, can additionally activate the immune cells localized on the mucosal tissue of the upper and lower respiratory tract. This dual stimulation of the immune system, along with their needle-free administration favors the development of novel nasal vaccines to produce long-lasting immunity. In recent years, the nanoparticulate systems have been extensively involved in the formulation of nasal vaccines as polymeric, polysaccharide and lipid ones, as well as in the form of proteosomes, lipopeptides and virosomes. Advanced delivery nanosystems have been designed and evaluated as carriers or adjuvants for nasal vaccination. To this end, several nanoparticulate vaccines are undergone clinical trials as promising candidates for nasal immunization, while nasal vaccines against influenza type A and B and hepatitis B have been approved by health authorities. This comprehensive literature review aims to summarize the critical aspects of these formulations and highlight their potential for the future establishment of nasal vaccination. Both preclinical (in vitro and in vivo) and clinical studies are incorporated, summarized, and critically discussed, as well as the limitations of nasal immunization.     

Analysis of motivations for antiflu vaccination of the Clermont-Ferrand University Hospital staff

Objective

The vaccination of hospital staff decreases patient mortality and disorganization of services due to sick leave. The main aim of our study was to determine the Clermont-Ferrand University hospital (CHU) personnel’s motivations for or against antiflu vaccination to increase the effectiveness of prevention campaigns.

Design

An autoquestionnaire with multiple choices was given to the 7601 CHU staff in May 2005. It documented socioprofessional characteristics, vaccinal status, and reasons for vaccination, nonvaccination, or stopping antiflu vaccination.

Results

The answer rate was 26.5% (2011 autoquestionnaires returned) and representative of the CHU staff. The rate of vaccination in 2004 was 36.35% with a strong correlation between vaccination and former influenza infection (p < 0.001). Five of the six principal reasons for vaccination were altruistic including the first two: avoiding transmission to patients (61.8%) and his family (59.8%). The main reason for stopping was the lack of time. The reasons for nonvaccination were linked to a feeling of invulnerability: conviction of not being at risk, of being too young, or in good health.

Conclusions

The Haute Autorité de santé’s objective of vaccinal coverage against influenza for 75% of the health professionals requires their active compliance. The effectiveness of future campaigns could aim at improving knowledge by insisting particularly on the young age of the risk populations. The lack of time can be compensated by offering on-site vaccination, including at night and by proposing larger schedules for vaccination.     

A successful measles campaign as a model for achieving high uptakes of MMR

The introduction of MMR makes it imperative to improve and maintain high vaccine uptakes. Here we describe an increase in measles uptake following two short campaigns at a year's interval, run by geographically attached health visitors in inner London. The computer controlled immunisation system was used to organise and evaluate the campaigns. They were directed at two groups of children; those due vaccination (eligible prompt participants) and those who had failed to attend previously (eligible late participants). Results are given as cumulative percent uptake for the 1984, 1985 and 1986 birth cohorts. The campaign resulted in an increased vaccine uptake, from 78% to 87%, and contributed to earlier vaccination; these effects were sustained. The reasons for the success are discussed, as similar campaigns could be used to achieve high uptakes of MMR.     

Transmission Potential of Rift Valley Fever Virus over the Course of the 2010 Epidemic in South Africa

A Rift Valley fever (RVF) epidemic affecting animals on domestic livestock farms was reported in South Africa during January–August 2010. The first cases occurred after heavy rainfall, and the virus subsequently spread countrywide. To determine the possible effect of environmental conditions and vaccination on RVF virus transmissibility, we estimated the effective reproduction number (R_e) for the virus over the course of the epidemic by extending the Wallinga and Teunis algorithm with spatial information. R_e reached its highest value in mid-February and fell below unity around mid-March, when vaccination coverage was 7.5%–45.7% and vector-suitable environmental conditions were maintained. The epidemic fade-out likely resulted first from the immunization of animals following natural infection or vaccination. The decline in vector-suitable environmental conditions from April onwards and further vaccination helped maintain R_e below unity. Increased availability of vaccine use data would enable evaluation of the effect of RVF vaccination campaigns.     

Measuring polio immunity to plan immunization activities

The Global Polio Eradication Initiative is closer than ever to achieving a polio-free world. Immunization activities must still be carried out in non-endemic countries to maintain population immunity at levels which will stop poliovirus from spreading if it is re-introduced from still-infected areas. In areas where there is no active transmission of poliovirus, programs must rely on surrogate indicators of population immunity to determine the appropriate immunization activities, typically caregiver-reported vaccination history obtained from non-polio acute flaccid paralysis patients identified through polio surveillance. We used regression models to examine the relationship between polio vaccination campaigns and caregiver-reported polio vaccination history. We find that in many countries, vaccination campaigns have a surprisingly weak impact on these commonly used indicators. We conclude that alternative criteria and data, such as routine immunization indicators from vaccination records or household surveys, should be considered for planning polio vaccination campaigns, and that validation of such surrogate indicators is necessary if they are to be used as the basis for program planning and risk assessment. We recommend that the GPEI and similar organizations consider or continue devoting additional resources to rigorously study population immunity and campaign effectiveness in at-risk countries.     

Safe landing for global polio eradication: a perspective

After over two decades of immense efforts, the global polio eradication initiative may be approaching its final phase. With leadership from WHO, great efforts of national programs and support from its collaborators, combined with the recent use of mono and bivalent oral polio vaccines, success may be at hand. For a “safe landing” of this global program, it is important once more to recall the key role of routine vaccination as the foundation on which mass vaccination campaigns can be successful. Continued effective routine vaccination programs are essential to reduce the ill effects of high population density in formerly endemic countries. Considering the large number of subclinical poliovirus infections, failing to reduce the number of unvaccinated persons per km² could severely impact the final stage of eradication. Here the authors, from their personal perspectives, discuss how the current program will be viewed from 2012 onwards. The authors will highlight the epidemiological importance of circulating vaccine-derived poliovirus, the problem of biosecurity as well as the use of inactivated polio vaccine and how each of these may affect the post eradication era and how research into each of these must continue to ensure success.