Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old

Parental Acceptance, Parental Hesitancy, and Uptake of Seasonal Influenza Vaccination among Children Aged 6-59 Months: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis summarises the literature on parental acceptance, parental hesitancy, uptake, and the associated factors of seasonal influenza vaccination (SIV) among children aged 6-59 months. Studies were sourced from the following platforms: PubMed, Web of Science, MEDLINE, and EMBASE databases. A random-effects model was used to evaluate the prevalence and 95% confidence intervals (CI) of parental acceptance, parental hesitancy, and SIV uptake in the last flu season and lifetime among children. A total of 36 studies were included for analysis. The overall prevalence was 64% for parental acceptance (95% CI: 51-75%), 34% for parental hesitancy (95% CI: 22-48%), 41% for SIV uptake in the last flu season (95% CI: 33-50%), and 46% for SIV uptake in a lifetime (95% CI: 20-74%). Associated factors of parental acceptance/hesitancy and uptake included the age of the children or parents, parental education level, household income level, ethnicity, and other modifiable factors, including perceived benefits, perceived barriers, perceived severity, perceived susceptibility, and cues to action related to SIV. Meta-regression analyses revealed regional differences in parental acceptance (Americas: 79% vs. Asia: 60%). The results provided implications informing us of the development of intervention programs targeting parents to improve SIV coverage among young children.

Timeliness of routine childhood vaccination in 103 low-and middle-income countries, 1978-2021: A scoping review to map measurement and methodological gaps

Empiric studies exploring the timeliness of routine vaccination in low-and middle-income countries (LMICs) have gained momentum in the last decade. Nevertheless, there is emerging evidence suggesting that these studies have key measurement and methodological gaps that limit their comparability and utility. Hence, there is a need to identify, and document these gaps which could inform the design, conduct, and reporting of future research on the timeliness of vaccination. We synthesised the literature to determine the methodological and measurement gaps in the assessment of vaccination timeliness in LMICs. We searched five electronic databases for peer-reviewed articles in English and French that evaluated vaccination timeliness in LMICs, and were published between 01 January 1978, and 01 July 2021. Two reviewers independently screened titles and abstracts and reviewed full texts of relevant articles, following the guidance framework for scoping reviews by the Joanna Briggs Institute. From the 4263 titles identified, we included 224 articles from 103 countries. China (40), India (27), and Kenya (23) had the highest number of publications respectively. Of the three domains of timeliness, the most studied domain was 'delayed vaccination' [99.5% (223/224)], followed by 'early vaccination' [21.9% (49/224)], and 'untimely interval vaccination' [9% (20/224)]. Definitions for early (seven different definitions), untimely interval (four different definitions), and delayed vaccination (19 different definitions) varied across the studies. Most studies [72.3% (166/224)] operationalised vaccination timeliness as a categorical variable, compared to only 9.8% (22/224) of studies that operationalised timeliness as continuous variables. A large proportion of studies [47.8% (107/224)] excluded the data of children with no written vaccination records irrespective of caregivers' recall of their vaccination status. Our findings show that studies on vaccination timeliness in LMICs has measurement and methodological gaps. We recommend the development and implement of guidelines for measuring and reporting vaccination timeliness to bridge these gaps.

Knowledge, attitude and practice of influenza vaccination among Lebanese parents: A cross-sectional survey from a developing country

Background

A growing number of parents refuse vaccination due to concerns about side effects. Influenza vaccine is no exception and remains one of the most controversial vaccines. Data regarding influenza vaccine uptake and parental knowledge, attitude and practice towards vaccination in the Lebanese population is lacking. The aim of this study was to assess the rate of vaccination refusal and potential associated factors among Lebanese parents of school-aged children, in general and with a focus on influenza vaccine.

Methods

A parent questionnaire was distributed in randomly selected 2 public and 2 private schools from the greater Beirut area during the school year 2017–2018. Questionnaires covered knowledge, attitude (including themes of efficacy, hesitancy and trust), and practice of vaccination in general and influenza vaccine in particular.

Results

The response rate was 76.5% (306/400). Overall, 29.4% parents reported vaccinating their children against influenza (62.2% in private and 37.7% in public schools). Younger age, paternal employment and higher household income were associated with higher vaccination rates (p = 0.01, 0.02 and <0.0001 respectively). Lack of vaccine recommendation by the physician was the most common reason for not taking it (47%). Parents who accepted influenza vaccination had higher scores in efficacy, hesitancy and trust and were more compliant with other vaccinations.

Conclusion

One third of parents of school aged children in the greater Beirut area vaccinate their children against influenza. This rate is likely lower in rural remote areas. Physician’s recommendation is the single most important predictor of such vaccination. Future studies tackling physicians’ attitude and practice are needed to help improve influenza vaccination rates in the Lebanese population.

Vaccine hesitancy in Argentina: Validation of WHO scale for parents

BACKGROUND

The WHO SAGE Working Group on Vaccine Hesitancy developed the Vaccine Hesitancy Scale (VHS) to identify and compare hesitancy in different global settings. The objectives of the study were to describe and analyze vaccine hesitancy and to validate the VHS in a group of parents in Buenos Aires city, Argentina.

METHODS

A cross-sectional survey was conducted in parents of 1-3 and 12-15 year-old children at three health centres in Buenos Aires City, between June 2018 and May 2019. Sociodemographic data were collected together with history of refusal and/or delay in children's vaccination (defined as hesitancy). The 10-item VHS using 5-point Likert-scale (higher scores indicating lower hesitancy) was administered and children's immunization record cards were verified. Link between hesitancy and socio-demographic variables, and hesitancy and vaccination status was analyzed for five specific vaccines. Cronbach's α was used to determine internal consistency reliability and factor analysis to confirm survey subdomains. Simple and multiple regression analysis was used to examine associations between VHS scores and hesitancy, and VHS scores and vaccination status.

RESULTS

Six hundred parents were surveyed and 469 immunization cards verified; 11.5% (n = 69) parents were hesitant. High maternal educational level showed significant association with hesitancy (OR 2.66 95% CI: 1.20-5.9) in the adjusted model. Hesitancy was significantly associated with incomplete MMR vaccination in children (OR 4.43 95% CI: 1.08-8.20) and HPV vaccination in adolescents (OR 3.75 95% CI: 1.54-9.12). Cronbach's α was 0.66 and factor analysis identified three underlying constructs: "Benefits", "Harms" and "Confidence in healthcare system". High scores in VHS were associated with lack of hesitancy (OR 1.2 95% CI: 1.13-1.27) and complete vaccination status (OR 1.07 95% CI: 1.02-1.12).

CONCLUSIONS

Hesitancy was associated with high maternal educational level, and incomplete MMR and HPV immunization status in children and adolescents. VHS was a reliable and valid tool in this population.

Resources for assessing parents' vaccine hesitancy: a systematic review of the literature

The concept of Vaccine Hesitancy has begun to appear in the scientific landscape, referring to the reluctance of a growing proportion of people to accept the vaccination offer. A variety of factors were identified as being associated with vaccine hesitancy but there was no universal algorithm and currently there aren’t any established metrics to assess either the presence or impact of vaccine hesitancy. The aim of this study was to systematically review the published questionnaires evaluating parental vaccine hesitancy, to highlight the differences among these surveys and offer a general overview on this matter. This study offers a deeper perspective on the available questionnaires, helping future researches to identify the most suitable one according to their own aim and study setting.

Missed Opportunities for Influenza Vaccination Among Hospitalized Children With Influenza at a Tertiary Care Facility

OBJECTIVES

To identify the extent and characteristics of missed opportunities for influenza vaccination among children hospitalized with influenza at a tertiary children's hospital.

METHODS

We conducted a retrospective cohort study of hospitalized patients with polymerase chain reaction-confirmed influenza admitted to Children's Hospital Colorado from 2010 to 2014. We reviewed medical records for vaccination status and previous visits. The primary outcome was the proportion of underimmunized patients hospitalized with influenza with at least 1 missed opportunity visit (visit before influenza diagnosis in which an eligible patient did not receive the influenza vaccine). The relationship between sociodemographic characteristics and the primary outcome were examined using χ(2) tests and nonparametric tests, and variables with P < .2 were entered into a multivariate logistic regression model.

RESULTS

Among 322 patients hospitalized with influenza, 199 (61%) were undervaccinated; 83 of 199 (42%) had at least 1 missed opportunity for influenza vaccination. Multivariate analysis demonstrated that high-risk status (adjusted odds ratio 6.9, 95% confidence interval 3.8-12.4) was associated with increased odds of having a missed opportunity visit. Most missed opportunity visits were to subspecialty clinics (42%), and most visits (71%) occurred from September to November.

CONCLUSIONS

More than 40% of hospitalizations for influenza in children are associated with at least 1 missed opportunity visit at a tertiary center. Our findings highlight the potential role of tertiary care institutions in increasing influenza vaccination rates among children.

Epidemiology and prevention of influenza in children in Argentina and Brazil

A group of influenza experts from Argentina and Brazil got together to discuss the burden of influenza in children, review current vaccine coverage rates in both countries, analyze vaccine effectiveness, and discuss strategies to improve prevention. Active surveillance of respiratory viruses is carried out nationwide in both countries. Years 2014 and 2015 were mild influenza seasons; influenza virus type A/H3N2 prevailed, whereas type B represented less than 30% of isolates. Trivalent inactivated influenza vaccine is included in National Immunization Programs for 1) children 6 months to 2 years old in Argentina; 2) children 6 months to 5 years old in Brazil; and 3) all high-risk individuals. Coverage rates in both countries were about 80% (albeit lower for the second dose). Experts from both countries proposed the following strategies to improve prevention: 1) increase surveillance; 2) assess effectiveness and long-term safety of influenza vaccines; 3) reinforce vaccination programs in order to increase coverage rates; and 4)consider introducing more effective vaccines, such as adjuvanted trivalent vaccines. In Argentina, estimating casefatality rates was also recommended. Other proposed actions included enhancing education of health professionals and the lay community, and better use of communication resources to raise awareness of the burden of influenza and promote vaccine uptake.