MASSACHUSETTSDEPARTMENTOFPUBLICHEALTHWEEKLYINFLUENZAUPDATE

May29, 2015

Alldatain thisreport arepreliminary andsubjecttochangeas moreinformationisreceived.

SentinelProviderSurveillance:Influenza‐likeillnessactivity

Week20Activity1(representinggeographicdistribution):Local Week20 ILI Activity2(representingintensityof ILIactivity): 1 (Minimal)

Provider offices across the US reporttheamount ofinfluenza‐likeillness(ILI)theysee in their patientseach week duringregular flu season. These outpatient providers’offices,whichinclude doctors'offices,schoolhealthservices,andcommunity healthcenters, arecalled 'sentinelsites.’ Here wepresent Massachusettssentinelsite data.Please note thatthe datarepresentnotonly confirmedinfluenza cases, butalso those justwithILI, whichmay be causedbyotherviruses.ILI isdefinedasfeverabove 100.01 inadditiontoeithercough orsorethroat. ILIis a marker ofinfluenzaandisused

throughoutthe regularinfluenzaseasonto monitor influenzasince most people arenottested forinfluenza.Figure 1shows that ILI activityremains consistent withexpectedactivityforthistimeofyear.Formoreinformation,see CDC’sinfluenza surveillance website at

1CDCactivityindicator – indicateshow widespreadinfluenzaactivity level isin the state.

2CDC ILI activity indicator – more quantitativeindicatorof the level of ILI activity across the state.

Table 1 below shows a geographicaldistributionof reportedILIin Massachusetts.Table 1 showsthat sentinelsitesintwoof the sevenregions of the stateareexperiencingmildly elevatedILIactivity.

Table1:PercentILIreportedweeklybyMassachusettssentinelsites

RegionalBaseline
%ILI* / 2014‐2015 / 2013‐2014
%ILI / Report.Sites / Totalenroll. / %ILI / Report.Sites / Totalenroll.
Boston / 0.96 / 0.74 / 2 / 6 / 0.74 / 5 / 6
Central / 1.02 / 0.00 / 5 / 10 / 0.42 / 5 / 12
InnerMetroBoston / 0.85 / 0.68 / 8 / 12 / 1.32 / 8 / 13
Northeast / 1.03 / 1.04 / 5 / 9 / 0.76 / 7 / 11
OuterMetroBoston / 1.19 / 0.99 / 2 / 5 / 1.76 / 4 / 5
Southeast / 0.79 / 1.11 / 1 / 4 / 0.26 / 3 / 6
West / 1.53 / 1.22 / 1 / 7 / 0.00 / 3 / 7

*Regionalbaseline % ILIiscalculatedweekly usingreportingproviders’baseline % ILIestimates.

Influenza‐Associated Hospitalizations

In2010, MDPH begantorequestvoluntaryreporting of alllaboratory‐confirmedinfluenzahospitalizationsfromhospitalsinMassachusetts. As many as 50 acute care hospitalsfromacrossthestatereportthese data toMDPH on a weekly basisduringfluseason. The graphbelowshowsthenumberoflaboratory‐confirmedhospitalizations per 1,000licensedbedsrepresentedbyreporting hospitalsfor thecurrentseason and two previousseasons.

Laboratorytestingforinfluenza

Laboratoriesin Massachusettsreportallpositiveinfluenza laboratorytests to MDPH, including viral culture,polymerasechain reaction (PCR) andrapidinfluenza diagnostictests.Because the majorityof casesarenottested, the numberof'confirmed' cases doesnotreflecttheoverallincidence ofinfluenza; however,thisinformationisessential to track thetypesofinfluenza circulating inMassachusetts andcan bea useful indicatorofthe presenceand distributionofinfluenzain the state.Figure 3 illustrates thenumber oflaboratory confirmed cases inMassachusetts byweek,shown along withMassachusettsILI.Table 2 reflects the numberoflaboratory‐confirmedinfluenza casesbyregionandinfluenza type.

Table2:Laboratory‐confirmedInfluenzabyRegion–2014‐2015and2013‐2014InfluenzaSeasons

2014‐2015 / 2013‐2014
A / B / Untyped / A / B / Untyped
Region / Week / YTD / Week / YTD / Week / YTD / Week / YTD / Week / YTD / Week / YTD
Boston / 12 / 2218 / 6 / 604 / 0 / 230 / 13 / 1093 / 23 / 343 / 0 / 7
Central / 0 / 2068 / 5 / 653 / 0 / 188 / 9 / 1044 / 21 / 399 / 0 / 81
InnerMetro Boston / 5 / 3945 / 8 / 891 / 0 / 286 / 16 / 1328 / 27 / 329 / 0 / 6
Northeast / 1 / 6003 / 4 / 1167 / 0 / 449 / 17 / 1654 / 23 / 653 / 3 / 108
OuterMetro Boston / 2 / 3329 / 2 / 802 / 0 / 308 / 7 / 974 / 21 / 219 / 0 / 4
Southeast / 0 / 4812 / 7 / 992 / 4 / 556 / 6 / 1774 / 32 / 448 / 1 / 8
Unknown / 1 / 1248 / 5 / 344 / 0 / 36 / 3 / 515 / 5 / 199 / 0 / 0
West / 0 / 1907 / 2 / 659 / 0 / 87 / 2 / 1290 / 2 / 172 / 0 / 2
Total / 21 / 25,530 / 39 / 6,112 / 4 / 2,140 / 73 / 9,672 / 154 / 2,762 / 4 / 216

TestingattheHintonStateLaboratoryInstitute

As part of a morecomprehensiverespiratorysurveillanceinitiative,MDPH’s Bureau ofLaboratorySciences(MDPH‐BLS)performstestingtoconfirmtypingandsubtypingof circulatinginfluenza viruses followedbytesting ofinfluenza‐negativesamplesfortheevidenceof adenovirus,respiratorysyncytialvirus (RSV)A/B, parainfluenzavirus(PIV)types1‐4 ,coronavirus(HCoV) HKU1,OC43, NL63, 229E, humanmetapneumovirus (HMPV),andrhinovirus/enterovirus (RHV/ENT)usingamultiplexPCRrespiratoryviral panel. Samplesaresubmittedby~60outpatienthealthcareproviders(ILINet) andinclude early influenzapositives, as well asspecimensand isolatesfromclinical hospitaldiagnosticlaboratoriesacrossMassachusetts. Forthe 2014‐2015season,Figure 4 and Tables 3and4 summarizevirologicsurveillance testingconducted byMDPH‐BLSbeginning MMWR week40(week ending October 4, 2014).MDPH‐BLS performsinfluenzasurveillancetesting year round. Forthe 2014‐2015seasonto date, 45 cases ofinfluenza B, four cases ofA/2009H1N1,and 238 casesofA/H3N2 influenza have beenconfirmedin472 casestested.

Figure4:InfluenzapositivetestsreportedtoCDCbyMDPH‐BLS,September28,2014–May23,2015

Table3:WeeklySummaryofMDPH‐BLSInfluenzaSurveillanceTestResults

2014‐2015Season:InfluenzaSurveillance
MA Departmentof Public Health’s Bureau ofLaboratory Sciences(MDPH‐BLS)
MMWR Week:(Specimen Collected) / 2009
H1N1 / seasonal A/H3N2 / B / H3N2v / A
unsub / No. FluPos(%) / Unsat / TotalTested / TotalRec’d
17 (4/26‐ 5/02/2015) / 0 / 0 / 3 / 0 / 0 / 3(75%) / 0 / 4 / 4
18 (5/03‐ 5/09/2015) / 0 / 0 / 4 / 0 / 0 / 4(44%) / 0 / 9 / 9
19 (5/10‐ 5/16/2015) / 1 / 0 / 1 / 0 / 0 / 2(100%) / 0 / 2 / 2
20 (5/17‐ 5/23/2015) / 0 / 0 / 2 / 0 / 0 / 2(100%) / 0 / 2 / 2
Prior 4 wk Total / 1 / 0 / 10 / 0 / 0 / 11(65%) / 0 / 17 / 17
CumulativeSeason total / 4 / 238 / 45 / 0 / 0 / 287(61%) / 29 / 472 / 501

Alldataaresubjecttochangeastestresultsbecomefinalized.The2014‐2015influenzaseasonbeganMMWR40(09/28‐10/04/2014).

Table4:WeeklySummaryofMDPH‐BLSnon‐InfluenzaRespiratorySurveillanceTestResults

2014‐2015Season:InfluenzaLikeIllnessSurveillance
MA Departmentof Public Health’s Bureau ofLaboratory Sciences(MDPH‐BLS)
MMWR Week:(Specimen Collected) / RSV / RHV/ENT / PIV / HMPV / HCV / ADV / # Co‐Infection / No. Pos(%) / Unsat / TotalTested / TotalRec’d
17 (4/26‐ 5/02/2015) / 0 / 0 / 0 / 0 / 0 / 1 / 0 / 1(100%) / 0 / 1 / 1
18 (5/03‐ 5/09/2015) / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0(0%) / 0 / 4 / 4
19 (5/10‐ 5/16/2015) / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0(0%) / 0 / 0 / 0
20 (5/17‐ 5/23/2015) / 0 / 0 / 0 / 0 / 0 / 0 / 0 / 0(0%) / 0 / 0 / 0
Prior 4 wk Total / 0 / 0 / 0 / 0 / 0 / 1 / 0 / 1(20%) / 0 / 5 / 5
CumulativeSeason total / 3 / 23 / 7 / 8 / 13 / 14 / 4 / 64(40%) / 9 / 162 / 171

Alldataaresubjecttochangeastestresultsbecomefinalized.The2014‐2015influenzaseasonbeganMMWR40(09/28‐10/04/2014).

At thestart of the 2014‐2015 season, the first 10 influenza virus isolates and thereafter5 representativeisolatesevery twoweeks will be sentby MDPH‐BLS toa CDCcontract laboratoryperformingNationalInfluenzaVirus Surveillanceto include antigenic characterizationby hemagglutinationinhibition(HI), genetic analysis (sequencing) andsensitivitytoFDA‐approved drugs foridentificationof resistance.Thirteeninfluenza A (H3N2)specimens,one A (2009 H1N1),andnineB have been characterizedfor the 2014‐2015season.The influenza A (2009H1N1), nine B, andfiveof theA (H3N2)specimenswereconsistentwithstrainsinthe2014‐2015seasonal influenzavaccine.EightA (H3N2)specimens showedevidenceofantigenic driftinlaboratory(HI) testingatCDC, suggesting a lowerlikelihoodof protection fromthis year’svaccine.

As samplesare received, MDPH‐BLSwill screenadditional samplesevery twoweeks todetect pointmutationswithin theneuraminidase geneofinfluenza A/H3N2viruses (E119,R292, and N294) and influenza A/2009 H1N1viruses (H275 andI223)to assessresistancetrends. Thisinformationwill bereported locallyand captured nationallyin FluView( were three influenza A/2009 H1N1 isolatesfrom MA during the 2009‐2010seasonwith amutation conferring oseltamivir‐resistance (H275Y)and noneduring the following fourseasons.

Table5:DPH‐BLSInfluenzaAntiviralResistanceScreening:2014‐2015Season

iSamplestestedbypyrosequencingatpositionE119,R292,andN294withintheneuraminidase(NA)gene.

iiSamplestestedbypyrosequencingatpositionH275andI223withintheNAgene.

Additionalinformationon nationalantiviral resistance testingincludingrecommendations forantiviraltreatment andchemoprophylaxisofinfluenzavirus infectioncan be found at