Pediatric influenza immunization: should healthy children be vaccinated?

Influenza vaccination coverage and related factors among Spanish children

OBJECTIVES

To ascertain anti-influenza vaccination coverage and factors associated with anti-influenza vaccination among Spanish children.

METHODS

We analyzed 6464 children (age under 16 years) included in the Spanish National Health Survey (ENS) for 2003. As a dependent variable, we used the reply ("yes" or "no") to the question: Was your child vaccinated against influenza during the last campaign? We calculated anti-influenza vaccine coverage for the whole population and depending on whether or not the vaccine is recommended due to the fact that the children present an associated chronic condition. We analyzed the influence of sociodemographic variables on vaccination.

RESULTS

Vaccination coverage in the Spanish infant population was 5.1%, in children with associated conditions it was 17.5%, and 4.4% in healthy children. The only factor significantly associated with anti-influenza vaccination in children with associated conditions was household income: those from homes with a higher level of income were more likely to be vaccinated (OR=4.26). In children for whom vaccination is not recommended, the probability of being vaccinated against influenza is greater in those whose parents had a lower educational level (OR=2.22).

CONCLUSIONS

Anti-influenza vaccination coverage in the Spanish infant population is very low. There seem to be socio-economic inequalities for receiving this vaccine in Spanish children.

Implementation of universal influenza immunization recommendations for healthy young children: results of a randomized, controlled trial with registry-based recall

BACKGROUND

An Advisory Committee on Immunization Practices policy of encouraging influenza vaccination for healthy 6- to 23-month-old children was in effect during the 2003-2004 influenza season, which was unusually severe in Colorado. We collaborated with 5 pediatric practices to attempt universal influenza immunization in this age group.

OBJECTIVES

The objectives were (1) to assess the maximal influenza immunization rates that could be achieved for healthy young children in private practice settings, (2) to evaluate the efficacy of registry-based reminder/recall for influenza vaccination, and (3) to describe methods used by private practices to implement the recommendations.

METHODS

The study was conducted in 5 private pediatric practices in Denver, Colorado, with a common billing system and immunization registry. Although recommendations by the Advisory Committee on Immunization Practices included children who were 6 to 23 months of age at any point during the influenza season, our practices chose not to recall children 22 to 23 months of age, because they would have become >24 months of age during the study period. Therefore, our study population consisted of all healthy children 6 to 21 months of age from the 5 practices (N = 5193), who were randomized to intervention groups (n = 2595) that received up to 3 reminder/recall letters or to control groups (n = 2598) that received usual care. The primary outcome was receipt of >or=1 influenza immunization, as noted either in the immunization registry or in billing data.

RESULTS

Immunization rates for >or=1 dose of influenza vaccine for the intervention groups in the 5 practices were 75.9%, 75.4%, 68.1%, 55.6%, and 44.3% at the end of the season. Overall, 62.4% of children in the intervention groups and 58.0% of children in the control groups were immunized (4.4% absolute difference), with absolute differences, compared with control values, ranging from 1.0% to 9.1% according to practice. However, before intensive media coverage of the influenza outbreak began (November 15, 2003), absolute differences, compared with control values, ranged from 5.1% to 15.3% and were 9.6% overall. Before November 15, significant effects of recall were seen for children in the intervention groups, in both the 12- to 21-month age category (10.4% increase over control) and the 6- to 11-month category (8.1% increase over control); at the end of the season, however, significant effects of recall were seen only for the older age group (6.2% increase over control). The rates of receipt of 2 vaccine doses >or=1 month apart for eligible children ranged from 21% to 48% among the practices. Four of the 5 practices held influenza immunization clinics during office hours, evenings, or weekends, and these clinics achieved higher coverage rates.

CONCLUSIONS

These results demonstrated that, in an epidemic influenza year, private practices were able to immunize the majority of 6- to 21-month-old children in a timely manner. Although media coverage regarding the epidemic blunted the effect of registry-based recall, recall was effective in increasing rates early in the epidemic, especially for children between 1 and 2 years of age. The practices that achieved the highest immunization rates were proactive in planning influenza clinics to handle the extra volume of immunizations required.

Prevalence and characteristics of children at increased risk for complications from influenza, United States, 2000

OBJECTIVES

Annual influenza vaccination is recommended for children at high risk of complications from influenza due to underlying medical conditions, but few children are vaccinated. Vaccination also is encouraged for all children aged 6 to 23 months when feasible. This study describes the prevalence and characteristics of at-risk children nationwide.

STUDY DESIGN

A descriptive analysis of the 2000 National Health Interview Survey (NHIS) was conducted among children in the United States aged 6 months through 17 years with identified high-risk conditions, and among all children aged 6 to 23 months.

RESULTS

Approximately 5.2 to 10.0 million children aged 6 months through 17 years (7.4%-14.2%) had high-risk conditions indicated for influenza vaccination. Asthma accounted for the majority of conditions. An estimated 7.7 million children would be aged 6 to 23 months during influenza season. Most young children and older children at high-risk have access to and frequently utilize healthcare services.

CONCLUSIONS

Existing doctor visits are important opportunities for vaccinating children with high-risk conditions, or for those aged 6 to 23 months. Additional efforts are needed to implement and evaluate efficient strategies for annual influenza vaccination of children aged 6 to 23 months and for older children with medical indications.

Potential burden of universal influenza vaccination of young children on visits to primary care practices

OBJECTIVE

To estimate the additional number of visits to primary care practices that would be required to deliver universal influenza vaccination to 6- to 23-month-old children.

METHODS

Children who were covered by commercial and Medicaid managed care plans (70% of children in the region; >8000 children in each of 3 consecutive influenza seasons) in the 6-county region surrounding and including Rochester, New York, were studied. An analysis was conducted of insurance claims for visits (well-child care [WCC]; all other visits) to primary care practices during 3 consecutive influenza vaccination seasons (1998-2001). We determined the proportion of children who made 1 or 2 visits during the potential influenza vaccination period, simulating several possible lengths of time available for influenza vaccination (2, 3, 4, or 5 months). We measured the proportion of children who were vaccinated during each influenza vaccination period. The added visit burden was defined as the number of additional visits that would be required to vaccinate all children, simulating 2 scenarios: 1) administering influenza vaccination only during WCC visits and 2) considering all visits as opportunities for influenza vaccination.

RESULTS

Results were similar for each influenza season. Considering a 3-month influenza vaccination window and assuming that no opportunities were missed, if only WCC visits were used for influenza vaccination, then 74% of 6- to 23-month-olds would require at least 1 additional visit for vaccination--39% would require 1 additional visit and 35% would require 2 additional visits. If all visits to the practice were used for influenza vaccination during the 3-month window, then 46% would require at least 1 additional visit--34% would require 1 additional visit and 12% would require 2 additional visits. Longer vaccination periods would require fewer additional visits; eg, if a 4-month period were available, then 54% of children would require 1 or 2 additional visits if only WCC visits were used and 29% would require 1 or 2 additional visits if all visits were used for influenza vaccinations. Younger children (eg, 6- to 11-month-olds) would require fewer additional visits than older children (12- to 23-month-olds) because younger children already have more visits to primary care practices.

CONCLUSIONS

Implementation of universal influenza vaccination will result in a substantial increased burden to primary care practices in terms of additional visits for influenza vaccination. Practice-level strategies to minimize the additional burden include 1) using all visits (not just WCC visits) as opportunities for vaccination, 2) providing influenza vaccination for the maximum possible time period by starting to vaccinate as early as possible and continuing to vaccinate as late as possible, and 3) implementing short and efficient vaccination-only visits to accommodate the many additional visits to the practice.