Letters to the Editor

TABLE I. Intent to vaccinate against influenza: Adults with versus

without asthma

Did you get the seasonal flu vaccine last year (in the fall/winter of 2008-

2009)?

No asthma Asthma Overall

Yes, flu shot 36% 54% 39%

Yes, nasal spray flu

vaccine (FluMist)

1% <1% 1%

No 63% 46% 60%

P 5 .0001

Are you planning to get the seasonal flu vaccine this year (in the fall/

winter of 2009-2010)?

No asthma Asthma Overall

Definitely yes or probably

yes (combined)

42% 61% 44%

Not sure 16% 14% 16%

Probably no or definitely

no (combined)

42% 25% 40%

P 5 .0004

Are you planning to get the new H1N1 influenza (‘‘swine flu’’) vaccine this

year (in the fall/winter of 2009-2010) for yourself?

No asthma Asthma Overall

Definitely yes or probably

yes (combined)

33% 44% 35%

Not sure 26% 32% 26%

Probably no or definitely

no (combined)

41% 24% 39%

P 5 .0017

2009 Seasonal and H1N1 influenza vaccinationcompliance in asthmatic children and adults

To the Editor:Seasonal influenza has been associated with increased mor-

bidity and poor outcomes in asthmatic patients, including super-infection with bacterial pneumonia, respiratory compromise, andhospitalization.1-3 Vaccination against seasonal influenza remainsthe most efficient and cost-effective method of management forthe general public and asthmatic subjects.4 Despite campaignsby public health officials to promote seasonal influenza vaccina-tion, there remains significant public reluctance among personsin high-risk groups.5

In 2009, the global rise of novel H1N1 influenza has causedsignificant medical and public health concerns. The World HealthOrganization and Centers for Disease Control and Preventionconsidered addressing pandemic H1N1 vaccination as a majorpriority of world health in an effort to control future outbreaks.Particularly concerning is the morbidity and mortality associatedwith children with chronic respiratory diseases, such as asthma.6

The C. S. Mott Children’s Hospital National Poll on Children’sHealth (NPCH) is designed to measure public opinion, percep-tions and priorities regarding major health care issues and trendsfor US children. The goal of the NPCH is to assess issues in atimely fashion using nationally representative scientific proba-bility sample of US households. Periodic surveys are conductedby using an innovative, rigorous, established, Web-based surveytechnology provided by a private vendor (Knowledge Networks[KN]). KN has established the first online research panel based onprobability sampling that covers both the online and offlinepopulations in the United States. The panel members arerandomly recruited by telephone, and households are providedwith access to the Internet and hardware if needed. The fieldperiod for Web-based surveys is short (3-4 weeks).

NPCH surveys address a wide variety of children’s healthissues, including asthma. In all cases adults are the respondents,and 1 adult is selected per household. The NPCH designoversamples households with parents so that more precise esti-mates can be made of parental opinions. KN calculates initialweights by using national demographic distributions, as per themost recent Current Population Survey. These weights areadjusted to reduce the effects of potential nonresponse andnoncoverage. By using these methods, generalizations can bemade from these survey samples to the national US population ofparents and to the US population of all adults.

Questions focused on previous influenza vaccination in 2008and the likelihood of vaccination for H1N1 and seasonal influenzain 2009-2010. Subgroup analyses were performed on subjectswith a physician’s diagnosis of asthma or who are parents ofchildren with physician-diagnosed asthma. Respondents wereasked whether they had a physician’s diagnosis of asthma basedon spirometric results, wheezing on multiple occasions, ortreatment with long-term controller medications for asthma todetermine whether a respondent or parent of a child had asthma.

Deidentified weighted survey and demographic data werereceived from KN. All analyses were conducted with STATAversion 10 (StataCorp, College Station, Tex). Frequencies foreach survey item were generated and weighted to provide national

166

estimates, and margins of error were calculated for each item. x2

Analyses were used to test for differences among surveyresponses.

The Medical School Institutional Review Board of theUniversity of Michigan approved the NPCH in July 2009.

The survey was fielded from August 13 to 31, 2009. The overallresponse rate was 68% for all households (n 5 2,365) and 62% inthe subset of households with at least 1 child (n 5 1,678). Theprevalence of physician-diagnosed asthma was 15% amongadults and 18% among parents reporting that 1 or more of theirchildren had a physician’s diagnosis of asthma. This is highercompared with other national reported prevalences of 9.3% inchildren and 7.9% in adults in 2006, respectively.3 Descriptors ofsocioeconomic status, race, insurance status, and sex wereobtained but on further analysis did not affect the findings ofthe sample.

Both asthmatic adults and parents of asthmatic children doappear to have higher rates of influenza vaccination and vacci-nation intent for H1N1 than do other subjects (Tables I and II). Inthis most recent NPCH polling for 2008-2009, there is animproved rate of vaccination (>50%), with improved intent tovaccinate for H1H1 influenza in asthmatic subjects and children(>40%) compared with nonasthmatic subjects. Despite signifi-cant vaccination rates in asthmatic adults and children comparedwith their nonasthmatic counterparts, there still remain largeproportions of adults and children who are unlikely to receive

TABLE II. Intent to vaccinate against influenza: Children with

versus without asthma

Did (your child/1 or more of your child[ren]) get the seasonal flu vaccine

last year (in the fall/winter of 2008-2009)?

Yes

Families in which no child in the family has

asthma

41%

Families in which a child in the family has

asthma

63%

P < .0001

Are you planning on having (your child/1 or more of your children) get

seasonal flu vaccine this year (in the fall/winter of 2009-2010)?

No asthma Asthma Overall

Definitely yes or probably yes (combined) 51% 66% 54%

Not sure 20% 17% 19%

Probably no or definitely no (combined) 29% 17% 27%

P 5 .006

Are you planning on having (your child/1 or more of your children) get the

new H1N1 influenza (‘‘swine flu’’) vaccine this year (in the fall/winter of

2009-2010)?

No asthma No asthma Asthma Overall

Definitely yes or Probably yes (combined) 38% 45% 40%

Not sure 30% 35% 31%

Probably no or definitely no (combined) 32% 20% 29%

P 5 .03

TABLE III. Respondent reasons for deferring seasonal influenza

vaccination

Why are you not planning to get the seasonal flu vaccine for yourself this

year?

No asthma Asthma Over all P value

60 52 59 .31 Not worried about getting

seasonal influenza

54 45 53 .26 Can take medications to

treat it

50 39 48 .16 Worried about side effects

of the seasonal flu

vaccine

Numbers shown are percentages selecting this response among adults who are not

planning to get the seasonal flu vaccine (n 5 1,301).

TABLE IV. Respondent reasons for deferring on seasonal

influenza vaccination for their child

Why are you not planning to get the seasonal flu vaccine for your chil-

d(ren) this year?

No asthma Asthma Over all P values

52 64 54 .07 Not worried about getting

seasonal influenza

60 60 60 .96 Can take medications to

treat it

52 47 51 .56 Worried about side effects

of the seasonal flu

vaccine

Numbers shown are percentages selecting this response among parents who do not

plan to get seasonal flu vaccine for their children (n 5 800).

J ALLERGY CLIN IMMUNOL

VOLUME 126, NUMBER 1

LETTERS TO THE EDITOR 167

seasonal, H1N1, or both influenza vaccinations. The reasons forvaccination avoidance are remarkably similar across asthma sta-tus in adults, as well as in parents of asthmatic children (Tables IIIand IV). About half of the respondents in the NPCH noted thatthere was little concern of infection by the viruses, as well as anexpectation that medical treatment is widely available for the con-ditions. These attitudes remained the same across asthma status.About 50% of respondents had concerns about the side effectsof vaccination as a major reason to avoid influenza vaccination.

For more than 40 years, the Advisory Committee on Immuni-zation Practices has recommended seasonal influenza vaccinationfor asthmatic subjects because of their higher risk of medicalcomplications and morbidity.1 The burden of influenza on asth-matic subjects has been well documented from the economic bur-den, medical resource burden, and effect on specific subjects and

their families. Particularly in children, the effect of influenza ill-ness increases health care use and the burden of disease on thechild and his or her family.2-4

The NPCH has identified an increased rate of influenzavaccination in asthmatic adults and children compared with thatseen in the general population. This is a similar finding to theCenters for Disease Control and Prevention report regarding the2004-2005 influenza season.7-9 We suspect that public health ef-forts, continued education, and vaccine access have improved thisrate in the last decade. Although the full burden of H1N1 influ-enza was not yet known at the time this survey was originallyfielded in August 2009, public health authorities were concernedthat H1N1 flu would particularly threaten the well-being of youngpatients with respiratory and cardiac comorbidities.

A significant limitation of this study was that respondents werequeried regarding vaccine intention, and the limited respondentaccess study mechanism does not permit follow-up to confirmwhether respondents were actually vaccinated against eitherseasonal or H1N1 influenza as the influenza season progressed.Furthermore, the respondent sample, despite being weighted toreflect US Census data, has limitations in terms of the ability todraw conclusions regarding the population with other chronicdiseases (ie, the investigators did not oversample based on thepresence of chronic conditions).

For 2009-2010, the looming H1N1 influenza pandemic addedadditional urgency to vaccination of the asthmatic population.Even with improved levels of seasonal influenza vaccinationapproaching the Advisory Committee on Immunization Practi-ces’s Healthy People 2010 goal of 60% vaccination, very fewsubjects were planning on obtaining H1N1 influenza vaccinationdespite the risks of infection. In fact, in the NPCH less than 40%of both asthmatic and nonasthmatic respondents intended toreceive the vaccination. The discrepancies between seasonalinfluenza vaccination and pandemic H1N1 vaccination might bedue principally to lack of education and to concerns about thevaccine because of its rapid development and deployment on theworld stage.

The recent appearance of H1N1 influenza has added to thecomplexity of administering vaccines to the most vulnerablepopulations. Global issues on vaccine development, pandemicspread, and the influence of rapid media sources for laypeople cangreatly influence health perceptions. There are many lessons thatcan be taken from the H1N1 pandemic, particularly in asthmaticsubjects and the general public. Findings in this study about

FIG 1. Seasonal pattern of CRS exacerbation visits (n 5 1217). Each bar

represents 1 week.

J ALLERGY CLIN IMMUNOL

JULY 2010

168 LETTERS TO THE EDITOR

factors influencing subjects’ intent regarding future influenzavaccination might guide education efforts to improve immuniza-tion campaigns for future influenza seasons.

Harvey L. Leo, MDa

Sarah J. Clark, MPHb

Amy T. Butchart, MPHb

Dianne C. Singer, MPHb

Noreen M. Clark, PhDa

Matthew M. Davis, MAPP, MDb

From athe School of Public Health Center for Managing Chronic Disease and bthe

Department of Pediatrics, Child Health Evaluation and Research Unit (CHEAR),

University of Michigan, Ann Arbor, Mich. E-mail: hleo@med.umich.edu.

Disclosure of potential conflict of interest: The authors have declared that they have no

conflict of interest.

REFERENCES

1. Centers for Disease Control and Prevention. Prevention and control of influenza:

recommendations of the Advisory Committee on Immunization Practices.

MMWR Morb Mortal Wkly Rep 2007;56(RR08):1-54.

2. Hassan F, Lewis TC, Davis MM, Gebremariam A, Dombkowski K. Hospital utiliza-

tion and costs among children with influenza, 2003. Am J Prev Med 2009;36:292-6.

3. Miller EK, Griffin MR, Edwards KM, Weinberg GA, Szilagyi PG, Staat MA, et al.

Influenza burden for children with asthma. Pediatrics 2008;121:1-8.

4. Ampofo K, Gesteland PH, Bender J. Epidemiology, complications, and cost of hos-

pitalization in children with laboratory-confirmed influenza infection. Pediatrics

2006;118:2409-17.

5. Dombkowski KJ, Leung SW, Clark SJ. Physician perspectives regarding annual

influenza vaccination among children with asthma. Ambul Pediatr 2008;8:294-9.

6. Jain S, Kamimoto L, Bramley AM, Schmitz AM, Benoit SR, Louie J, et al. Hospi-

talized patients with 2009 H1N1 influenza in the United States, April-June 2009.

N Engl J Med 2009;36:1935-44.

7. Lu PJ, Euler GL, Callahan DB. Influenza vaccination among adults with asthma

findings from the 2007 BRFSS survey. Am J Prev Med 2009;37:109-15.

8. Centers for Disease Control and Prevention. Influenza vaccination coverage among

children with asthma—United States, 2004-05 influenza season. MMWR Morb

Mortal Wkly Rep 2007;56:193-6.

9. Centers for Disease Control and Prevention. Influenza vaccination coverage among

persons with asthma—United States, 2005-06 influenza season. MMWR Morb

Mortal Wkly Rep 2008;57:653-7.

Available online May 24, 2010.

doi:10.1016/j.jaci.2010.03.040

Acute exacerbations of chronic rhinosinusitisoccur in a distinct seasonal pattern

To the Editor:Chronic rhinosinusitis (CRS) is a common and debilitating

problem that involves inflammation of the mucosal surfaceslining the nose and sinuses.1 Triggers leading to CRS disease ex-acerbation are not well characterized. Previous epidemiologicstudies have focused on identification of risk factors for havinga diagnosis of CRS rather than on risk factors that lead to diseaseexacerbation in those with an established CRS diagnosis.2,3 Giventhe insights gained from examining seasonal patterns of asthmaexacerbations (a disease often linked to CRS),4 we performed astudy that examined the seasonal pattern of CRS exacerbationvisits using a unique database that electronically links residentsof a single county in southeastern Minnesota (Olmsted County).

We performed a retrospective cohort study following patientsfor up to 2 years (2003-2004) using existing medical records.Patients were identified by using the Rochester EpidemiologyProject, an electronically linked medical record system thatallows for examination of nearly all health care encounters inOlmsted County, Minnesota. Both sexes and all ages wereincluded. Patients with a diagnosis of specific immune deficiencywere excluded. A CRS exacerbation was defined as any visit with

an International Classification of Diseases–Ninth Revisions(ICD-9) code of 473.xx and at least 1 of the following: aprescription for systemic antibiotics, systemic corticosteroid,plans for a semiurgent surgical intervention, emergency depart-ment or urgent care visit, or a hospitalization for CRS. Eachmedical record was reviewed to ensure subjects met inclusioncriteria and that the prescribed medications were directly linkedwith the diagnosis of CRS. The study was approved by theInstitutional Review Board of the Olmsted Medical Center andMayo Clinic Rochester.

Descriptive statistics were tabulated for subject demographicsand visit frequencies. Seasonality was confirmed by defining 4equal-length calendar seasons and comparing visit frequenciesfor equality across seasons with a x2 test. For graphic displays,visit frequencies were smoothed by using a kernel smootherwith a Parzen kernel and a bandwidth chosen empirically.

One thousand one hundred four patients with a diagnosis of473.xx were screened, and 800 patients had at least 1 visit that metour definition of a CRS exacerbation. Most subjects were female(65.6%) and white (94%). The mean age of the patients was 37years, with 17.8% of the subjects defined as children (<18 yearsold). A total of 1217 CRS exacerbation visits were analyzed. Thenumber of visits per subject over 2003-2004 ranged from 1 to 16,and 607 (75.9%) patients had only 1 CRS exacerbation visit.Primary care provider visits accounted for 55.7% of the visits,whereas allergy (13.7%), otolaryngology (13.1%), and emer-gency department/urgent care (13.1%) accounted for the nearlyall of the remaining visits.

Subjects were approximately twice as likely to present for aCRS exacerbation in winter months compared with spring,summer, or fall (P < .0001, Fig 1). The seasonal pattern of in-creased CRS exacerbation visits in winter was consistent between2003 and 2004. Age and sex did not significantly affect the sea-sonal pattern of CRS exacerbation visits, although in both 2003and 2004, the CRS exacerbation visit frequency of children beganto increase earlier (more in fall than winter) compared with thatseen in adults (Fig 2).

The findings from this study suggest that patients with CRS aremost likely to present for disease exacerbation in the wintermonths in the upper Midwestern United States than in spring,summer, or fall seasons. Using the linked electronic medical