DTIC ADA510381: Novel Influenza A (H1N1) Outbreak at the U.S. Air Force Academy: Epidemiology and Viral Shedding Duration (American Journal of Preventive Medicine, Volume 20, Number 10, 2009)

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ARTICLE IN PRESS
Novel Influenza A (H1N1) Outbreak at the U.S. Air
Force Academy
Epidemiology and Viral Shedding Duration
Catherine Takacs Witkop, MD, MPH, Mark R. Duffy, DVM, MPH, Elizabeth A. Macias, PhD,
Thomas F. Gibbons, PhD, James D. Escobar, MPH, Kristen N. Burwell, MPH, Kenneth K. Knight, MD, MPH
Background: TheU.S.AirForceAcademyisanundergraduateinstitutionthateducatesandtrainscadets
for military service. Following the arrival of 1376 basic cadet trainees in June 2009,
surveillance revealed an increase in cadets presenting with respiratory illness. Specimens
fromillcadetstestedpositivefornovelinfluenzaA(H1N1[nH1N1])–specificribonucleic
acid (RNA) by real-time reverse transcriptase–polymerase chain reaction.
Purpose: Theoutbreakepidemiology,controlmeasures,andnH1N1sheddingdurationaredescribed.
Methods: Case patients were identified through retrospective and prospective surveillance. Symp-
toms, signs, and illness duration were documented. Nasal-wash specimens were tested for
nH1N1-specificRNA.Serialsamplesfromasubsetof53patientswereassessedforpresence
of viable virus by viral culture.
Results: A total of 134 confirmed and 33 suspected cases of nH1N1 infection were identified with
onset date June 25–July 24, 2009. Median age of case patients was 18 years (range, 17–24
years). Fever, cough, and sore throat were the most commonly reported symptoms. The
incidence rate among basic cadet trainees during the outbreak period was 11%. Twenty-
nine percent (31/106) of samples from patients with temperature (cid:1)100°F and 19%
(11/58) of samples from patients reporting no symptoms for (cid:1)24 hours contained viable
nH1N1 virus. Of 29 samples obtained 7 days from illness onset, seven (24%) contained
viable nH1N1 virus.
Conclusions: In the nH1N1 outbreak under study, the number of cases peaked 48 hours after a social
eventandrapidlydeclinedthereafter.Almostonequarterofsamplesobtained7daysfrom
illness onset contained viable nH1N1 virus. These data may be useful for future investiga-
tions and in scenario planning.
(Am J Prev Med 2009;xx(x):xx) Published by Elsevier Inc. on behalf of American Journal of
PreventiveMedicine
Background 6monthsorlongertoestablishworldwidedistribution;
however,thenH1N1virusstrainestablishedworldwide
In April 2009, Department of Defense–affiliated labo-
distribution within 6 weeks.2 On June 11, 2009, the
ratories in San Diego and San Antonio recovered
WHO3 raised the influenza pandemic alert status to
unsubtypeable influenza A virus from patient samples.
Level 6 in response to established global human-to-
The viral specimens were transported to the CDC
human transmission. By July 2009, more than 40,000
influenza laboratory, where both viral samples were
nH1N1 cases had been confirmed, and 263 deaths in
determined to be a novel influenza A virus of swine the U.S. were attributed to the nH1N1 virus.4
origin (nH1N1), consistent with virus isolated from
Characterizingvirus–hostinteractionsandtheepide-
patients in a Mexico influenza outbreak that began in
miology of nH1N1 is important in both assumptions
March2009.1Previousnovelinfluenzastrainsrequired madeduringplanningandindefiningeffectivecontrol
measures. Studies5,6 of seasonal influenza suggest that
viral shedding occurs for as long as 7 days after symp-
From the U.S Air Force Academy (Witkop, Knight), Colorado tom onset. No similar studies on shedding of nH1N1
Springs, Colorado; and the U.S. Air Force School of Aerospace have been published.7 In addition, there are no
Medicine Epidemiology Consult Service (Duffy, Macias, Gibbons,
Escobar,Burwell),BrooksCityBase,Texas published studies of the epidemiology of nH1N1
Addresscorrespondenceandreprintrequeststo:CatherineTakacs infection among military training populations or
Witkop, MD, MPH, 10 AMDS/SGPF, 2355 Faculty Drive, Room
institutionsofhighereducation.Withthe2009influ-
2N286,U.S.AirForceAcademy,ColoradoSpringsCO80840.E-mail:
[email protected]. enza season upon us, characterization of the epide-
AmJPrevMed2009;xx(x) 0749-3797/09/$–seefrontmatter 1
PublishedbyElsevierInc.onbehalfofAmericanJournalofPreventiveMedicine doi:10.1016/j.amepre.2009.10.005
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1. REPORT DATE 3. DATES COVERED
2009 2. REPORT TYPE 00-00-2009 to 00-00-2009
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Novel Influenza A (H1N1) Outbreak at the U.S. Air Force Academy.
5b. GRANT NUMBER
Epidemiology and Viral Shedding Duration
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
U.S. Air Force Academy,10 AMDS/SGPF,2355 Faculty Drive,Colorado REPORT NUMBER
Springs,CO,80840
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ARTICLE IN PRESS
miology and duration of shedding for the nH1N1 On July 10, the USAFSAM epidemiology laboratory re-
virus is critical. portedthatofthefirst18nasalwashestestedforthepresence
In July 2009, the U.S. Air Force Academy (USAFA) of nH1N1 by rRT-PCR, 15 (83%) yielded positive results. By
thistime,88BCTswerealreadyintheseparateddormarea.
experienced an outbreak of nH1N1 illness. An investi-
gationwasinitiatedto(1)describetheoutbreakepide-
Case Definition and Finding
miology,(2)defineandimplementcontrolmeasuresto
limit transmission, and (3) determine the duration of A confirmed nH1N1 case patient was defined as a BCT, a
viral shedding from patients in the outbreak. cadet involved with BCT training, or a preparatory (prep)
school student with symptom onset from June 25 to July 24,
2009, who had a nasal-wash specimen with nH1N1 virus
Methods
identified by rRT-PCR. A suspected case patient also be-
longed to the groups mentioned above and presented with
Setting
respiratorycomplaintonsetfromJune25toJuly24,2009;had
TheUSAFA,locatedwestofColoradoSpringsCOisa4-year a highest recorded temperature of (cid:1)100.5°F; and had no
academicundergraduateinstitutionthateducatesandtrains nasalwashobtained.
cadets for active-duty military service as officers. Incoming Electronicmedicalrecordswerereviewedtoretrospectively
studentsareknownasbasiccadettrainees(BCTs)duringthe identifycaseswithdatesofonsetbetweenJune25andJuly6.
summer prior to the commencement of the first academic Case patients presenting for medical care starting on July 6
year.BCTsareorganizedintosquadronsof135–140individ- through July 24 were prospectively identified. Demographic
uals.OnJune25,atotalof1376BCTsarrivedattheUSAFA and clinical data from confirmed and suspect patients were
tobegina6-weekmilitarytrainingprogram.OnJuly6,active obtained from electronic medical records and from a stan-
surveillanceofdiagnosticcodesforrespiratoryillnessesdem- dard influenza surveillance questionnaire. The 10th Medi-
onstrated an increase in the number of visits for respiratory cal Group pharmacy supplied information related to oselta-
complaintsthatsurpassedlevelsfromthetwopreviousyears. mivirprescription.
By July 7, two cadets evaluated at outside facilities were
identifiedaspositiveforinfluenzaAbyrapidantigentest. Additional Outbreak Control Measures
Becauseofastrongsuspicionthattheresponsibleviruswas
Patients were prescribed oseltamivir at the treating physi-
nH1N1, identification, treatment, and containment efforts
cian’sdiscretion,butweregenerallygiven75mgofoseltami-
werebegunimmediately.Moreover,theUSAFAdoesnotuse
virtwotimesdailyfor5daysifthepatientsindicatedonsetof
rapidantigentestingbecauseofitsmodestsensitivity.Instead,
symptoms no more than 72 hours prior to presentation.
nasal-washspecimenswerecollectedfrompatientswithinflu-
Upper-class cadets ensured meal delivery to patient rooms.
enza like illness (ILI) by saline wash (2–4 mL) of the
Healthcare providers made daily rounds of the separated
nasopharynxrepeatedthrougheachnostril.8ILIwasinitially
dormandapprovedreleasetotheBCTpopulationwhena
definedashavinganoraltemperature(cid:1)100.5°Fandrespira-
cadethadreachedtheendofthe7-dayexclusionperiodand
tory symptoms. Specimens were transported to the U.S. Air hadbeenasymptomaticfor(cid:1)24hours.
ForceSchoolofAerospaceMedicine(USAFSAM)epidemiol- Healthcare providers and staff caring for patients with
ogylaboratory,BrooksCityBaseTX(nearSanAntonio),and respiratory illness were offered oseltamivir prophylaxis and
tested for the presence of nH1N1-specific ribonucleic acid advisedtowearaprotectivemaskwhileinthesameroomas
(RNA) by real-time reverse transcriptase–polymerase chain thepatientexhibitingrespiratorysymptoms.Healthcarepro-
reaction(rRT-PCR).1Allspecimensweretestedforinfluenza viders and technicians were fitted for and provided N95
A;influenzaB;respiratorysyncytialvirus;parainfluenza1,2, masks.Technicianscollectingnasal-washsamplesworeamask,a
and3;andadenovirus.However,onlynH1N1wasidentified gown,gloves,andeyeprotection.
duringtheoutbreakperiod. Screening events were conducted during the outbreak
Beginning on July 7, all cadets meeting the ILI case period.OnJuly13,BCTsmarchedtoalocation3milesnorth
definition were sent to a separate dorm area to convalesce ofthemaincampustoparticipatein12daysoffield-training
untiltheywere7daysfromsymptomonsetandweresymptom activities.BCTshadtheirtemperaturemeasuredwithapaper
free for 24 hours. On July 10, an additional dorm area was oral thermometer (Tempadot) approximately 1 hour after
designated for those presenting with similar respiratory arrival, and those with a temperature (cid:1)99.6°F were referred
complaints but with a temperature of 99.0°F to 100.4°F. forphysicianevaluation.OnJuly15,acohortof239students
Patients in this group also remained isolated for 7 days and arrivedattheUSAFAtostarta1-yearprepschoolcourse.The
until 24 hours after symptom resolution, but they were prepschoolstudentswerescreenedfortemperature(cid:1)99.6°F
separated from those with temperatures (cid:1)100.5°F. The sep- on arrival and were screened again on July 19. Students
aration of this group, in addition to preventing potential meetingthescreeningcriteriawerereferredtoaphysicianfor
transmission, allowed characterization of the spectrum of evaluation.
disease. Interim analysis of data revealed that approximately ThethirdscreeningeventoccurredonAugust1afterthe
50% of individuals with highest recorded temperatures be- remainderofthestudentbody((cid:2)3000cadets)returnedto
tween 100.0°F and 100.4°F were positive for nH1N1, with a campus. Upon arriving on campus, each cadet completed a
lower incidence of positive nH1N1 results in those with screeningquestionnaire(Doyoufeellikeyouhaveafeverorhave
temperatures(cid:1)100.0°F.Thesefindingsledtoachangeinthe youhadafeverinthepast5days?andDoyouhaveacoughorsore
criterionforisolationinthesecondareatohavingatemper- throat?). A cadet answering yes to both questions required
atureintherangeof100.0°Fto100.4°F. immediateevaluationbyaprovider.Allcadetsweregivenan
2 AmericanJournalofPreventiveMedicine,Volumexx,Numberx www.ajpm-online.net
ARTICLE IN PRESS
40 descriptiveresults,categor-
icalvariablesweregivenas
proportions and continu-
35
ous variables were de-
scribed by the median or
30
meanandrange.
s
e
s
ca 25
nt Results
e
d
nci 20 Social mixing event Descriptive
of i
er Epidemiology
mb 15
Nu There were 134 con-
10 firmed and 33 suspected
nH1N1casesidentified
5 foratotalof167incident
cases.Onsetdatesranged
0 from June 26 to July 24,
6/256/266/276/286/296/307/1 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/97/107/117/127/137/147/157/167/177/187/197/207/217/227/237/24 2009.Casecountspeaked
onJuly6,with37casepa-
Day of onset of illness
tients reporting symptom
Confirmed cases (n=134) Suspect cases (n=33) onset, and the counts
declined over the re-
Figure 1. Confirmed (rRT-PCR positive) and suspect (respiratory complaint, temperature
(cid:1)100.5°F, and no specimen obtained) cases of novel influenza A (H1N1) virus infection at the mainderoftheoutbreak
U.S.AirForceAcademy,bydateofillnessonset,fromJune25throughJuly24,2009 period (Figure 1). The
peak occurred approxi-
education sheet on H1N1 that listed recommendations on mately 48 hours after a 4th of July event where (cid:2)1300
whentoseekcare. BCTs socialized with members of other squadrons.
Publichealthpersonnelinitiatedanintenseinfectioncon- Among the 134 confirmed cases, 115 (86%) were BCTs;
trol and education campaign within the first 24 hours of
ten (7%) were prep school students; and nine (7%) were
detecting the outbreak. Mass briefings were conducted on
upper-classcadets.
proper cough and hand hygiene, and educational materials
Of the 115 confirmed cases among BCTs, 20% (23)
wereprovidedforthebasenewspaper,incomingupper-class
werewomencomparedto21%womeninthetotalBCT
cadets, and parents of cadets. Cadets and USAFA personnel
population. The median age of case patients among
also received e-mails detailing the current situation and
recommendationsforpreventionoftransmission.Handsani- BCTs was 18 years (range 17–24 years), consistent with
tizerswereplacedthroughoutthedormsandattheentrances themedianageofBCTs.Themostfrequentlyreported
tothediningfacility. signsandsymptomsincludedcough,chills,sorethroat,
headache,andfatigue(Table1).Among86confirmed
Duration of nH1N1 Shedding
Patientstransferredtotheseparatedormwererequestedto
provideanasal-washsampleapproximatelyevery48to72hours
Table1. Clinicalcharacteristicsof86patientswith
until release. Samples were collected by medical technicians
completeclinicalinformationandconfirmednH1N1
according to standard protocol,8 and specimens were shipped
infection
onicethefollowingdaytotheUSAFSAMepidemiologylabora-
Signorsymptom No.ofpatients(%)
tory.Temperatureandpresenceorabsenceofsymptomswere
documentedforeachcadetateverysamplecollection,andthe Documentedfever(cid:1)100°F 81(94)
date of symptom resolution was noted for each cadet. To Cough 80(93)
determinepresenceofviablevirus,specimenswereinoculated Fatigue 74(86)
onto primary monkey kidney cells.9 Shell vials were stained at Sorethroat 74(86)
Headache 72(84)
24–48 hours for respiratory viruses, including influenza A.
Chills 70(81)
Tubes were incubated at 35°C for 10 days and assessed for
Bodyache 54(63)
cytopathic effect followed by immunofluorescent staining for
Rhinorrhea 41(49)
influenzaA.Culturesnegativeat10daysweretestedbyhemad-
Sinuscongestion 38(44)
sorption to rule out influenza virus growth. Viable virus shed- Chestpain 25(29)
dingwasdefinedasculture-positiveresultsatanytime(24–48- Stiffness 24(28)
hourshellvialor10-daytissueculture). Dyspnea 22(25)
Diarrhea 8(9)
Statistical Analysis
Vomiting 8(9)
Conjunctivitis 6(7)
Data were accumulated in a spreadsheet program and ana-
Earache 6(7)
lyzed using SPSS, version 14.0, and Epi Info 3.3.2. For
Month2009 AmJPrevMed2009;xx(x) 3
ARTICLE IN PRESS
Among 29 samples obtained 7 days from symptom
Table2. Outbreakperiodincidence(attackrate)of
nH1N1infectionbysquadronamongbasiccadettrainees onset, seven (24%) contained viable nH1N1 virus (Ta-
Confirmedaand Squadron Attackrate ble3).Among106samplesobtainedfrompatientswith
Squadron suspectedcases population (per100) atemperature(cid:1)100°Fatthetimeofsamplecollection,
31(29%)containedviablenH1N1virus,and11(19%)
A 10 132 7.6
of 58 samples obtained from patients who had been
B 24 134 17.9
C 9 133 6.8 symptom free for (cid:1)24 hours at the time of collection
D 16 131 12.2 contained viable nH1N1 virus.
E 10 138 7.2
F 18 137 13.1
G 20 130 15.3 Conclusion
H 14 138 10.1
I 15 136 11.0 OnJune25,anincomingclassofBCTsreportedtothe
J 12 137 8.8 USAFA originating from all 50 states and 11 foreign
Total 148 1346 11.0 countries. In July, the BCT class experienced a novel
aReal-timereversetranscriptase–polymerasechainreactionpositive H1N1 outbreak representing one of the largest recog-
nized nH1N1 clusters at a U.S. college to date. The
outbreak period incidence rate (attack rate) of con-
patientswithcompleteclinicalinformation,thehighest firmed and suspected cases among the BCT class was
recorded temperature for each patient ranged from 11/100 BCTs.
98.4°F to 104.6°F, with a mean of 101.3°F. Among a No deaths or hospitalizations were associated with
groupof53BCTswithconfirmednH1N1infectionand thisoutbreak.BCTsundergoextensivemedicalscreen-
forwhomdateofsymptomresolutionwasrecorded,the ingpriortoacceptancetotheUSAFA(e.g.,asthmaisa
mean duration of symptoms was 5.6 days (range, 1–12 disqualifying medical condition). Therefore, mild dis-
days). Disease severity was moderate to mild, and no ease severity and lack of adverse outcomes during this
deaths or hospitalizations were attributed to nH1N1 outbreak may be attributable to the stringent physical
duringtheoutbreakperiod.Amongthese53BCTs,40 requirements for acceptance at the USAFA. The mean
received oseltamivir treatment, and their mean dura- duration of illness, however, was greater than 5 days,
tion of illness was 5.8 days (95% CI(cid:3)4.9, 6.7 days; andasmallsubsetofcadetswassubsequentlydiagnosed
range,1–12days)comparedtoameanof5.0days(95% with bronchitis and pneumonia. Furthermore, college
CI(cid:3)4.0,6.0days;range3–8days;p(cid:3)0.36)inthe13who student populations with more heterogeneous health
did not receive oseltamivir treatment. The primary conditions could experience more severe disease, in-
difference between these two groups was that they cludingpossiblemortalityinthosewithmajorunderly-
presentedeitherinthefirst48hoursoftheirsymptoms ing medical conditions.
or later than that.
Outbreak period incidence rates (attack rates) for Table3. Proportionofnasal-washsampleswithviable
confirmedandsuspectedcasesamongthetentraining nH1N1bytemperature,symptoms,anddaysfromsymptom
onset
squadrons ranged from 6.8/100 BCTs to 17.9/100
BCTs (Table 2). The overall attack rate for confirmed Proportion
Samples Culture culture
and suspected cases among BCTs was 11.0/100 BCTs.
collected positive positive
(n) (n) (%)
Outbreak Control Measures
Temperature(cid:1)100°F 53 46 87
A total of 228 cadets (213 BCTs) were placed in Temperature(cid:1)100°F 106 31 29
separateddormareasduringtheoutbreakperiod.The (cid:1)24hourssymptomfree 101 61 60
orsymptomatic
July 15 screening of approximately 1250 BCTs who
(cid:1)24hourssymptomfree 58 11 19
completed the march to field training resulted in
Dayfromsymptomonset
referralofeight((cid:1)1%)BCTstoaphysicianforfurther (includingdayof
evaluation; four were diagnosed with ILI and sent to symptomonset)
theseparatedorm.Therewerenoconfirmedorsuspect 1st(dayofsymptom 7 6 86
onset)
cases among healthcare personnel.
2nd 21 20 95
3rd 23 20 87
Duration of nH1N1 Shedding 4th 10 7 70
5th 22 9 41
A total of 159 serial nasal-wash specimens were col-
6th 11 4 36
lected from 53 cadets. The proportion of samples 7th 29 7 24
containing viable nH1N1 virus was highest in those 8th 16 2 13
obtained on Days 1–3 from symptom onset and de- 9th 13 1 8
10th–14th 20 0 0
clined with each proceeding day, beginning on Day 2.
4 AmericanJournalofPreventiveMedicine,Volumexx,Numberx www.ajpm-online.net
ARTICLE IN PRESS
Individuals experiencing nH1N1 disease may shed treatmentselectionbiasmayhaveplayedaroleinthe
virus up to 24 hours prior to onset of symptoms10; small difference that was seen.
therefore, it is possible that nH1N1 was introduced by TheUSAFAoutbreakprovidedauniqueopportunity
one or more BCTs or trainers before being aware of togainvaluableinformationaboutthenaturalbehavior
illness themselves. A retrospective records review iden- of the nH1N1 virus. Findings from serial nasal washes
tifiedlowlevelsofpatientspresentingwithILIinBCTs indicatedviablevirussheddingonDay7fromsymptom
prior to a 4th of July event where BCTs socialized with onset among approximately one quarter of confirmed
members of other squadrons. On July 6, cadet clinic cases. Furthermore, being afebrile and asymptomatic
personnel recognized an increase in BCTs presenting did not guarantee that the patient was no longer
for medical care. The number of BCTs presenting for sheddingviablenH1N1virus;infact,19%ofthosewho
careincreasedduringthenext2daysandpeakedwhen
reported being symptom free for more than 24 hours
130presentedwithcomplaintsofrespiratorysymptoms
were still found to shed viable virus. Quantitative anal-
on July 8. A surveillance system that used coding data
ysesof culture results obtained in this study were felt
was in place at the USAFA; this system can compare
to be inappropriate because of the potential for
daily visits for respiratory illnesses with historical data
variability in specimen-collection techniques among
from the previous 2 years. Such surveillance, if not
staff, in specimen-handling procedures, and in transit
already in place at colleges and universities, can be a
times to the diagnostic laboratory. The lack of quanti-
useful tool for early detection of an outbreak.
tative analyses is a limitation of this study. Detection of
The outbreak, as defined by date of symptom onset,
virusbyculturemaynotnecessarilyindicatethattrans-
peaked on July 6, when 37 confirmed and suspect case
mission is still possible. Recommended avenues for
patients reported onset. Onset date counts of con-
future investigation include detailed quantitative anal-
firmed and suspect cases declined during the next 14
yses of viral titer during the follow-up period and the
days.Theoutbreakwaslikelypropagatedbythemixing
identification of specific symptoms associated with via-
eventonJuly4.Theintervalbetweenthemixingevent
ble viral shedding and viral titer.
and peak reported symptom onset is consistent with
Novel H1N1 is now endemic in all 50 U.S. states.
reported incubation periods for nH1N1, ranging from
1 to 5 days.10 In addition, all ten BCT squadrons University- and college-based outbreaks of H1N1 have
alreadyoccurredandmorecanbeexpectedasstudents
experienced nH1N1 transmission in a short time pe-
gather from diverse geographic areas, reside in dorm
riod, suggesting that the outbreak was initially propa-
settings, and attend mass gatherings such as football
gated by a single event.
games,peprallies,andstudentassemblies.Thecombi-
The rapid peak of the outbreak and subsequent
decline indicate the effectiveness of response and mit- nation of aggressive separation of ill BCTs, public
igationeffortsenactedimmediatelyonoutbreakrecog- health education, and prompt implementation of
nition. Communication was critical during the out- healthcareinfectioncontrolpracticeslimitedthedura-
break.Timelyriskcommunicationallowedforisolation tion and scope of the nH1N1 infection at the USAFA.
of sick BCTs within 24 hours of identification of the Comprehensive plans and rapid implementation are
first suspected cases. critical. Isolation procedures implemented at the US-
Otherinterventionsthatpotentiallycontributedto AFA may not be practical in other university settings;
the relatively rapid containment of this large out- however,preparednessplanning,publichealtheducation
break included a public health campaign that began activities, and healthcare infection control practices im-
within 48 hours of the first suspected cases. This plementedattheUSAFAcanbeadoptedinotheruniver-
effort involved e-mails to students, staff, and other sitysettings.
military personnel and publication of an article in
the base newspaper to educate the population about We would like to thank the members of the USAFSAM
nH1N1 and how to reduce transmission. It also EpidemiologyLabandConsultServicesandthe10thMedical
included increased distribution of hand sanitizers to Group for their outstanding support in this investigation.
students and placement of hand sanitizers through- SpecificallywewouldliketothankCol(Dr.)PaulSjoberg,Lt
out the dorms and the dining facility. Real-time use Col(Dr.)VictorMacIntosh,GennyMaupin,andAliciaGuer-
ofdatafromthispopulationtomakeinterimchanges rero from the Epidemiology Consult Service and Madison
to the screening and management of the cadet Greenandprovidersandmedicaltechniciansfromthe10th
population probably contributed to containment as Medical Group. We would also like to thank Dr. Gregory
Polandforhisreviewofanearlierversionofthemanuscript.
well. Infection control among healthcare workers
The views expressed are those of the authors and do not
also potentially limited virus transmission and fur-
necessarily represent the views of the U.S. Air Force or the
ther spread as no nH1N1 transmission was recog-
U.S.DepartmentofDefense.
nized among them. There was no significant differ-
No financial disclosures were reported by the authors of
enceindurationofillnessbetweenthosetreatedand
thispaper.
those not treated with oseltamivir; furthermore,
Month2009 AmJPrevMed2009;xx(x) 5
ARTICLE IN PRESS
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