search text   Advanced Search

This Article Abstract Full Text (PDF) P3Rs: Submit a response Alert me when this article is cited Alert me when P3Rs are posted Alert me if a correction is posted Citation Map Services E-mail this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Poehling, K. A. Articles by Edwards, K. M. Search for Related Content PubMed PubMed Citation Articles by Poehling, K. A. Articles by Edwards, K. M. Related Collections Infectious Disease & Immunity Related AAP Red Book topics: Influenza

Predictors of Influenza Virus Vaccination Status in Hospitalized Children

Katherine A. Poehling, MD^*,||, Theodore Speroff, PhD^,,||, Robert S. Dittus, MD, MPH^,||, Marie R. Griffin, MD, MPH^,, Gerald B. Hickson, MD^* and Kathryn M. Edwards, MD^*

^* Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
Preventive Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
^|| Quality Scholars Program, Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee

	ABSTRACT

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Objective. To determine predictors of influenza virus vaccination status in children who are hospitalized during the influenza season.

Methods. A cross-sectional study was conducted among children who were hospitalized with fever between 6 months and 3 years of age or with respiratory symptoms between 6 months and 18 years of age. The 1999 to 2000 influenza vaccination status of hospitalized children and potential factors that influence decisions to vaccinate were obtained from a questionnaire administered to parents/guardians.

Results. Influenza vaccination rates for hospitalized children with and without high-risk medical conditions were 31% and 14%, respectively. For both groups of children, the vaccination status was strongly influenced by recommendations from physicians. More than 70% of children were vaccinated if a physician had recommended the influenza vaccine, whereas only 3% were vaccinated if a physician had not. Lack of awareness that children can receive the influenza vaccine was a commonly cited reason for nonvaccination.

Conclusions. A minority of hospitalized children with high-risk conditions had received the influenza vaccine. However, parents’ recalling that a clinician had recommended the vaccine had a positive impact on the vaccination status of children.

Key Words: influenza • vaccination • hospitalized children

	INTRODUCTION

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Influenza virus causes febrile and respiratory illnesses in 20% to 40% of children each winter.¹ Although pediatric mortality from influenza infections is rare, morbidity is not. Influenza-related morbidity includes hospitalizations for suspected bacterial sepsis in neonates, respiratory illnesses, and rarely encephalitis. For children who are younger than 5 years, annual estimates of influenza-related hospitalization rates are 1 per 1000 children without high-risk conditions and 5 per 1000 children with high-risk conditions.^2,,3

Many hospitalizations of children with high-risk medical conditions are potentially avoidable. The Advisory Committee on Immunization Practices and the American Academy of Pediatrics recommend influenza vaccination for children with high-risk conditions such as asthma and sickle cell anemia. Despite these long-standing recommendations, fewer than 30% of children with high-risk conditions receive the annual influenza vaccine.^4,5,6

Almost all studies that analyze predictors of influenza vaccine acceptance focus on adult populations, particularly the elderly.^7,8,9,10,11 Factors that are predictive of adults’ receiving the influenza vaccine include elderly age, perceived susceptibility to influenza illness, favorable perceptions about the vaccine, a previous vaccination, knowledge of risk factors for influenza infection, clinician recommendation, and chronic medical conditions.^{7,8,9,,11,12,13,14} Two pediatric studies analyzed predictors of influenza vaccinations in children with asthma. The first study found that mothers who worry about their children’s asthma were more likely to have their children vaccinated after a mailed reminder than were mothers who worry about the side effects of the influenza vaccine.¹⁵ The second study used an administrative database, which restricted the study to an evaluation of health care utilization patterns and prescribed treatments for children with asthma in a health maintenance organization. In a study population in which 10% of children with asthma were vaccinated, indicators of moderate to severe asthma predicted influenza vaccination. Of note, 61% of nonvaccinated children with asthma had an outpatient visit with a missed opportunity for vaccination.¹⁶

Reducing the gap between influenza vaccine recommendations and current vaccination status in children requires knowledge about factors that encourage families to vaccinate children. To expand our understanding of the influenza vaccination status in children, we assessed the influenza vaccination status and factors that might influence a family’s decisions in a population of hospitalized children. Special emphasis was placed on understanding the motivation of parents whose children received the vaccine.

	METHODS

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Study Population
All children admitted to Vanderbilt Children’s Hospital between January 10 and February 25, 2000, were eligible for inclusion if they 1) were younger than 3 years and had a history of fever or 2) were younger than 18 years and had any respiratory symptoms. All children with a primary admission diagnosis of an acute respiratory illness characterized by rhinorrhea, sore throat, cough, shortness of breath, or apnea were eligible. Broad inclusion criteria were chosen such that all children hospitalized with symptoms potentially related to influenza infections were eligible. For children with multiple qualifying admissions, only the first was included. Children younger than 6 months were excluded because the vaccine is not recommended for this age group. This effort was part of an ongoing Centers for Disease Control and Prevention surveillance study designed to calculate the burden of respiratory illness in hospitalized children.

Each day, potential subjects were identified by reviewing admission logs to all of the pediatric inpatient services. We reviewed the charts of children with admission diagnoses potentially consistent with febrile or respiratory illnesses to verify that history during this illness. A research team member approached eligible children and their parents within 24 hours of admission. Discharge logs were reviewed to verify that all eligible patients had been identified. The study was reviewed and approved by the Vanderbilt University Institutional Review Board.

Questionnaire
After consent was obtained, we administered a questionnaire to parents. The questionnaire, which had been created and revised after pilot testing, elicited information regarding the child’s routine vaccinations and the 1999 to 2000 influenza vaccination status, factors that might influence the influenza vaccination status, the parent’s reasons for the influenza vaccination status, and the child’s medical history.

Influenza vaccination status was determined by whether the child had received at least 1 dose of influenza vaccine after September 1, 1999. To validate the influenza vaccine history, we asked when the vaccine was given. All parents who stated that their child received the influenza vaccine reported that the first dose was given between September and December, except for 1 child, who received it in January after having received a diagnosis of cystic fibrosis.

Gender and race information was collected from the medical record. All other variables were determined by parental responses to the questionnaire. If parents reported that a physician had recommended the influenza vaccine for their child within the past year, then it was coded as physician recommended. A family member was considered vaccinated if at least 1 person who lived with the child had received the influenza vaccine after September 1, 1999.

To understand the reasons for children’s vaccination status, we asked several questions. All parents were asked whether a physician had recommended the influenza vaccine for their child within the past year. Parents of unvaccinated children were asked, "What were the reasons your child did not get a flu shot this year?" Potential responses included lack of awareness, concern about side effects, inconvenience, or other. Parents of vaccinated children were asked, "What were the reasons your child got a flu shot this year?" Potential responses included protection of an elderly family member, previous influenza-like illness, physician recommendation, or other. Parents could report multiple responses for the child’s vaccination status. Explanations for any response including "other" were documented.

To determine which children had high-risk conditions, parents were asked whether the child had a history of asthma, kidney disease, heart disease, sickle cell anemia, diabetes mellitus, bronchopulmonary dysplasia, or other medical problems. To screen further for high-risk conditions, we ascertained the child’s daily medicines. For parents who reported asthma, we validated the diagnosis with a detailed asthma history and a review of the medical chart. High-risk conditions were restricted to those for which the influenza vaccine is explicitly recommended in the 2000 Red Book.¹⁷ They include 1) asthma or other chronic pulmonary diseases, 2) hemodynamically significant cardiac disease, 3) immunosuppressive disorder or therapy, 4) human immunodeficiency virus infection, 5) sickle cell anemia and other hemoglobinopathies, 6) diseases requiring long-term aspirin therapy, 7) chronic renal dysfunction, and 8) chronic metabolic disease.

Statistical Analysis
The primary outcome, influenza vaccination status in 1999 to 2000, and all variables, except for age, were coded as dichotomous variables. Age was classified as a categorical variable with 3 age groups: 6 months to younger than 18 months, 18 months to younger than 5 years, and 5 years to 18 years. Odds ratios and 95% confidence intervals were calculated by univariate and multivariate logistic regression analyses. Because interactions between age group and physician recommendation, age group and high-risk condition, and high-risk condition and physician recommendation were insignificant, these interactions were excluded from the final analyses. Nine children (5%) whose caregivers reported uncertainty about whether a physician had recommended the influenza vaccine were classified in the "not recommended" category. Because inclusion or exclusion of these 9 children from the analyses did not change the results, they were included in the final analyses. STATA, Version 6.0 (STATA, College Station, TX) was used for all analyses.

	RESULTS

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Of the children who were hospitalized during the study period, the cohort enrolled in the study is depicted in Fig 1. Of 245 eligible children, 26 were identified after 24 hours of admission, 27 declined participation, and 3 had an unknown vaccination status. The remaining 189 children (77%) were enrolled. The study children were more frequently male, predominantly white, and had approximately equal distributions among the 3 age groups (Table 1). Of the study population, 48% had high-risk conditions; the most common were asthma, malignancy, congenital heart disease, and cystic fibrosis (Table 2). Of the 55 children with asthma, 100% used albuterol at home, 26 (47%) used prophylactic medications, and 45 (82%) had taken oral steroids for an asthma exacerbation within the past year.

View larger version (20K): [in this window] [in a new window]   Fig 1. Identification of the study population.

To analyze the importance of each factor adjusting for all the others, we performed a multivariate logistic regression analysis (Table 1). Physician recommendation was the only independent predictor of influenza vaccination. Although increasing age was not significant in the adjusted model, the increasing proportion of children with and without high-risk conditions vaccinated for influenza by age group is shown in Fig 2. In addition, the proportion of parents who recalled that a physician had recommended the vaccine increased by age group.

View larger version (52K): [in this window] [in a new window]   Fig 2. Influenza vaccination by age groups and by high-risk group status.

For the 147 unvaccinated children, 11% of parents recalled that a physician had recommended the influenza vaccine. Many of these parents reported that they did not proceed with vaccination because the child was ill at that visit (n = 8) or because they were concerned about the side effects of the vaccine (n = 12), specifically that the child would get "the flu" from the vaccine itself (n = 7). For all nonvaccinated children, the 3 most common reasons (Table 3) were lack of knowledge about the influenza vaccine for children (29%), lack of physician recommendation (27%), and not thinking or forgetting about it (8%).

	DISCUSSION

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

Although school-aged children, children with high-risk conditions, and children with a vaccinated family member were more likely to receive the influenza vaccine, these factors were not independent predictors of vaccination in the multivariate analysis. Several factors may explain why age and high-risk conditions were not predictors in our study but were in adult studies.^{7,,12,,18,,19} First, physicians in our study were more likely to recommend influenza vaccination for older children with high-risk conditions, which reduced the power to detect age as an independent predictor. Second, physician recommendation was an overwhelming predictor in our model. Third, only 42 children (22%) were vaccinated, so the power to detect factors that may influence the influenza vaccination status was limited.

This study reinforces the importance of physician recommendations in promoting vaccine acceptance. Unfortunately, many parents of children with high-risk conditions did not recall physicians’ having discussed or recommended the influenza vaccine. Our data, like studies in high-risk adults, suggest that physician recommendation is a strong predictor of vaccination acceptance.^{8,,9,,13,,20,,21} We determined physician recommendation by whether the parent of a hospitalized child recalled that a physician had recommended the vaccine. Physicians were not interviewed, nor were charts reviewed, to confirm whether the physician had recommended the vaccine. Because parents of vaccinated children, who may have ruminated about the vaccine’s apparent lack of effectiveness, may remember a physician recommendation more often than parents of nonvaccinated children, recall bias is possible. Although lack of a reported physician recommendation does not necessarily indicate that a physician failed to mention or discuss the influenza vaccine, it does indicate that the message was not received. Hence, clinicians should be able to increase the vaccination rate by improving communication about the influenza vaccine, recommending its use, and confirming that the message was received.

This study has other potential limitations. Selection bias was minimized by enrolling 77% of eligible children and by defining broad inclusion criteria. The inclusion criteria were designed so that all children admitted with potential influenza infections were eligible. Because young children with influenza infections can present with only fever, children who younger than 3 years and were admitted with fever and without respiratory symptoms were eligible.²² Because respiratory symptoms are present in 92% of children with influenza infections, all children with respiratory symptoms were eligible.²³ Although misclassification bias remains possible, other studies of high-risk children in outpatient settings have reported similar vaccination rates.^4,5,6 Because the pneumococcal conjugate vaccine received Food and Drug Administration approval 9 days before the end of the study period and because the 23-valent pneumococcal vaccine is infrequently administered to children, it is unlikely that parents would have confused the pneumococcal and influenza vaccines. Parents who reported safety concerns about the influenza vaccine mentioned getting "the flu" from the vaccine. No parent mentioned a concern about risks associated with any component of the influenza vaccine, such as trace amounts of thiomersal.

Influenza infections may cause more pediatric illnesses and hospitalizations than previously recognized. Estimates of annual influenza-related hospitalization rates for healthy children younger than 2 years are comparable to high-risk groups for whom the vaccine is explicitly recommended.³ Influenza illness also accounts for an estimated 6 to 15 and 10 to 20 outpatient visits annually for healthy and high-risk children younger than 15 years, respectively.^2,,24 Thus, influenza has a significant impact on the health of children.

To reconcile that influenza virus causes many winter illnesses and that few children are vaccinated for influenza, we explored some of the potential reasons. One possibility is that the low vaccination rate among patients with asthma reflects an interpretation that only children on prophylactic medications need the influenza vaccine. The rate of vaccination among patients who have asthma and are taking prophylactic medication (39%) was higher than the rate for patients who have asthma and are not taking prophylactic medications (21%). Another possibility is the complexity of the influenza vaccine recommendations. Of 441 general practices in England, 71% to 82% of practitioners reported always offering the influenza vaccination to high-risk adults, but only 33% to 43% of the same practitioners reported always offering the influenza vaccine to high-risk children.²⁵ Although the influenza vaccine is strongly recommended for children with high-risk conditions and their families,¹⁷ the recommendation of vaccination for everyone who wishes to avoid influenza illness is ambiguous and may be interpreted as "not recommended." Varying dosages and number of doses recommended based on age and on past influenza vaccination status may also contribute to the tendency not to recommend it. Simplifying and clarifying the recommendations may improve uptake.

Another barrier to vaccination is the lack of parental knowledge about the influenza vaccine for children. Public health efforts to vaccinate the elderly have been impressive. The public health initiatives included educational campaigns targeting both health care providers and the elderly and recommending clinic-based standing orders for adults older than 65 years. These initiatives paralleled the increase in the influenza vaccination rate of the elderly to 50% to 67%.^{26,27,28,29,30,31,32}

Health beliefs of the family probably play an important role in determining the influenza vaccination status of children. Having a vaccinated family member increased the likelihood that a child had received the influenza vaccine. This association is consistent with pediatric studies that report that the health beliefs of the family have an impact on the vaccination status of children. For example, Szilagyi et al¹⁵ reported that mothers who are very worried about their child’s asthma are more likely to vaccinate their children for influenza after receiving a mailed reminder. Another study indicated that the health beliefs of a maternal grandmother significantly influence the 2-month and 6-month vaccination status of children in an underserved population.³³ The impact of the health beliefs of the family on the influenza vaccination status of children is an important area of additional exploration.

In this study, three quarters of the reasons cited for failing to vaccinate children can be addressed by improving parent education about influenza. Our data suggest that physicians have the potential to improve influenza vaccination rates by informing families about the vaccine recommendations and by reducing missed opportunities. To increase compliance with the recommendations, clinicians need to understand the reasons that children are not vaccinated. Identifying barriers to vaccination can highlight system issues that are likely to have an impact on the influenza vaccination status.³⁴ In our study, the only high-risk condition for which all of the children were vaccinated was cystic fibrosis (Table 2). The cystic fibrosis clinic attributed its exemplary vaccination rate to a strong consensus statement from the Cystic Fibrosis Foundation and several efforts in the clinic. They include 1) educating children and parents about influenza and its prevention, 2) a computerized registry, and 3) designing the clinic so that it is conducive to administering the influenza vaccine, even for children who come to the clinic without an appointment. As advocates for children, it is time for us to identify and eliminate system barriers that interfere with the health of children.

	CONCLUSION

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Many high-risk children are not receiving the annual influenza vaccine. Because we found that parents’ recalling that a clinician had recommended the vaccine significantly influenced the vaccination status of children, clinicians should consider evaluating the systems they use to recommend the vaccine.

	ACKNOWLEDGMENTS

 
Funding was provided by Cooperative Agreement U50/CCU41398 from the Centers for Disease Control and Prevention, the Quality Scholars Program of the Veterans Affairs Medical Center, and a nonrestricted educational grant from the Pfizer Foundation. This work was presented at the Pediatric Academies Societies on May 1, 2001, in Baltimore, Maryland.

We thank Gay Waddling, Ayesha Khan, Brent Frisbee, and Brian Emerson for assistance in data collection, and Lisa Halburnt for data entry.

	FOOTNOTES

 
Received for publication Apr 16, 2001; Accepted Jul 18, 2001.

Reprint requests to (K.A.P.) Vanderbilt Children’s Hospital, Division of General Pediatrics, D-5028 Medical Center East, Nashville, TN 37232-8555. E-mail: katherine.poehling{at}mcmail.vanderbilt.edu

	REFERENCES

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 

1. Glezen WP. Emerging infections: pandemic influenza. Epidemiol Rev.1996; 18:64–76[Medline]
2. Neuzil KM, Mellen DG, Wright PF, Mitchel EF Jr, Griffin MR. The effect of influenza on hospitalization, outpatient visits and courses of antibiotics in children. N Engl J Med.2000; 342:225–231[Abstract/Full Text]
3. Izurieta HS, Thompson WW, Kramarz P, et al. Influenza and the rates of hospitalization for respiratory disease among infants and young children. N Engl J Med.2000; 342:232–239[Abstract/Full Text]
4. Chung EK, Casey R, Pinto-Martin JA, Pawlowski NA. Routine and influenza vaccination rates in children with asthma. Ann Allergy Asthma Immunol.1998; 80:318–322[Medline]
5. Kramarz P, DeStefano F, Gargiullo PM, et al. Does influenza vaccination exacerbate asthma? Analysis of a large cohort of children with asthma. Vaccine Safety Datalink Team. Arch Fam Med.2000; 9:617–623[Medline]
6. Szilagyi PG, Holl JL, Rodewald LE, et al. Evaluation of New York State’s Child Health Plus: children who have asthma. Pediatrics.2000; 105:719–727[Medline]
7. Honkanen PO, Keistinen T, Kivela SL. Factors associated with influenza vaccination coverage among the elderly: role of health care personnel. Public Health.1996; 110:163–168[Medline]
8. Gianino CA, Corazzini K, Tseng WT, Richardson JP. Factors affecting influenza vaccination among attendees at a senior center. Md Med J.1996; 45:27–32[Medline]
9. Centers for Disease Control. Adult immunization: knowledge, attitudes, and practices—DeKalb and Fulton Counties, Georgia, 1988. MMWR Morb Mortal Wkly Rep.1988; 37:657–661[Medline]
10. Stehr-Green PA, Sprauer MA, Williams WW, Sullivan KM. Predictors of vaccination behavior among persons ages 65 years and older. Am J Public Health.1990; 80:1127–1129[Abstract]
11. Frank JW, Henderson M, McMurray L. Influenza vaccination in the elderly: 1. Determinants of acceptance. Can Med Assoc J.1985; 132:371–375[Medline]
12. Chapman GB, Coups EJ. Predictors of influenza vaccine acceptance among healthy adults. Prev Med.1999; 29:249–262[Medline]
13. Nichol KL, Lofgren RP, Gapinski J. Influenza vaccination. Knowledge, attitudes, and behavior among high-risk outpatients. Arch Intern Med.1992; 152:106–110[Medline]
14. Fiebach NH, Viscoli CM. Patient acceptance of influenza vaccination. Am J Med.1991; 91:393–400[Medline]
15. Szilagyi PG, Rodewald LE, Savageau J, Yoos L, Doane C. Improving influenza vaccination rates in children with asthma: a test of computerized reminder system and an analysis of factors predicting vaccination compliance. Pediatrics.1992; 90:871–875[Abstract]
16. Kramarz P, DeStefano, Gargiullo PM, et al. Influenza vaccination in children with asthma in health maintenance organizations. Vaccine Safety Datalink Team. Vaccine.2000; 18:2228–2294
17. American Academy of Pediatrics. Influenza. In: Pickering LK, ed. 2000 Red Book: Report of the Committee on Infectious Diseases. 25th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2000:351–359
18. Nichol KL, Wuorenma J, von Sternberg T. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Arch Intern Med.1998; 158:1769–1776[Medline]
19. Nichol KL, Margolis KL, Wuorenma J, von Sternberg T. The efficacy and cost effectiveness of vaccination against influenza among elderly persons living in the community. N Engl J Med.1994; 331:778–784[Abstract/Full Text]
20. Nichol KL, MacDonald R, Hauge M. Factors associated with influenza and pneumococcal vaccination behavior among high-risk adults. J Gen Intern Med.1996; 11:673–677[Medline]
21. Ashby-Hughes B, Nickerson N. Provider endorsement: the strongest cue in promoting high-risk adults to receive influenza and pneumococcal immunizations. Clin Excell Nurse Pract.1999; 3:97–104[Medline]
22. Dagan R, Hall CB. Influenza A virus infection imitating bacterial sepsis in early infancy. Pediatr Infect Dis J.1984; 3:218–221
23. Wright PF, Ross KB, Thompson J, Karzon DT. Influenza A infections in young children. Primary natural infection and protective efficacy of live-vaccine-induced or naturally acquired immunity. N Engl J Med.1977; 296:829–834[Abstract]
24. Neuzil KM, Wright PF, Mitchel EF, Griffin MR. The burden of influenza illness in children with asthma and other chronic medical conditions. J Pediatr.2000; 137:856–863[Medline]
25. Booth LV, Coppin R, Dunleavey J, Smith H. Implementing of influenza immunization policy in general practice: 1997 to 1998. Commun Dis Public Health2000; 3:39–42[Medline]
26. Pneumococcal and influenza vaccination levels among adults aged > or = 65 years—United States, 1995. MMWR Morb Mortal Wkly Rep.1997; 46:913–919[Medline]
27. Nichol KL. Ten-year durability and success of an organized program to increase influenza and pneumococcal vaccination rates among high-risk adults. Am J Med.1998; 105:385–392[Medline]
28. Nichol KL, Mendelman PM, Mallon KP, et al. Effectiveness of live, attenuated intranasal influenza virus vaccine in healthy, working adults: a randomized controlled trial. JAMA.1999; 282:137–144[Medline]
29. Nichol KL, Lind A, Margolis KL, et al. The effectiveness of vaccination against influenza in healthy, working adults. N Engl J Med.1995; 333:889–893[Abstract/Full Text]
30. Fedson DS, Wajda A, Nichol JP, Hammond GW, Kaiser DL, Roos LL. Clinical effectiveness of influenza vaccination in Manitoba. JAMA.1993; 270:1956–1961[Medline]
31. Ahmed AE, Nicholson KG, Nguyen-Van-Tam JS. Reduction in mortality associated with influenza vaccine during 1989–1990 epidemic. Lancet.1995; 346:591–595[Medline]
32. Gross PA, Hermogenes AW, Sacks HS, Lau J, Levandowski RA. The efficacy of influenza vaccine in elderly persons. A meta-analysis and review of the literature. Ann Intern Med.1995; 123:518–527[Medline]
33. Bates AS, Fitzgerald JF, Dittus RS, Wolinsky FD. Risk factors for underimmunization in poor urban infants. JAMA.1994; 272:1105–1110[Medline]
34. Berwick DM, Nolan TM. Physicians as leaders in improving health care: a new series in Annals of Internal Medicine. Ann Intern Med.1998; 128:289–292[Medline]

This article has been cited by other articles:

				M. F. Daley, B. L. Beaty, J. Barrow, K. Pearson, L. A. Crane, S. Berman, and A. Kempe Missed Opportunities for Influenza Vaccination in Children With Chronic Medical Conditions Arch Pediatr Adolesc Med, October 1, 2005; 159(10): 986 - 991. [Abstract] [Full Text] [PDF]

				S S S Teo, J S Nguyen-Van-Tam, and R Booy Influenza burden of illness, diagnosis, treatment, and prevention: what is the evidence in children and where are the gaps? Arch. Dis. Child., May 1, 2005; 90(5): 532 - 536. [Abstract] [Full Text] [PDF]

				Childhood Influenza-Vaccination Coverage--United States, 2002-03 Influenza Season JAMA, November 3, 2004; 292(17): 2074 - 2075. [Full Text] [PDF]

				M. J. Friedman and M. W. Attia Clinical Prediction Model for Influenza--Reply Arch Pediatr Adolesc Med, October 1, 2004; 158(10): 1018 - 1018. [Full Text] [PDF]

				Influenza Vaccine: What We Say Matters! Journal Watch Pediatrics and Adolescent Medicine, March 11, 2002; 2002(311): 2 - 2. [Full Text]

This Article Abstract Full Text (PDF) P3Rs: Submit a response Alert me when this article is cited Alert me when P3Rs are posted Alert me if a correction is posted Citation Map Services E-mail this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Poehling, K. A. Articles by Edwards, K. M. Search for Related Content PubMed PubMed Citation Articles by Poehling, K. A. Articles by Edwards, K. M. Related Collections Infectious Disease & Immunity Related AAP Red Book topics: Influenza

	Home | My Pediatrics | Journal Information | Current Issue | Past Issues | Subscriptions & Services | Contact Us Click here for faster international access © 2001 American Academy of Pediatrics. All rights reserved.