pandemic h1n1 influenza:pandemic h1n1 influenza: what … · canadian recommendation that seasonal...
TRANSCRIPT
Pandemic H1N1 Influenza:Pandemic H1N1 Influenza:What Have We Learned
i B iti h C l bi ?in British Columbia?
David M. PatrickBCCDC and University of British ColumbiaBCCDC and University of British Columbia
What is Pandemic H1N1 I fl Vi ( H1N1)?Influenza Virus (pH1N1)?
An influenza A H1N1 virusRe-assortment of genes
from human, swine, and i i flavian influenza
Similar viruses have been transmitted sporadicallytransmitted sporadically from swine to human in isolated casesH1N1 diff b h ipH1N1 differs by having
adapted for person-to-person transmissionp
NEJM (Trifonov V et al. Geographic dependence, surveillance, and origins of the 2009 influenza A (H1N1) virus. N Engl J Med 2009 May 27 [Epub ahead of print].
Geographic Differencesg p
First wave larger in gOntario, Quebec and Manitoba
R t iti iRemote communities in Manitoba had high morbidity (Winnipeg ICU at capacity)
Fall second wave started earlier and stronger inearlier and stronger in British Columbia
First Nations in BC
No obvious increase risk as observed elsewhereNo obvious increase risk as observed elsewhereRemote communities:Forward placement of antiviralsForward placement of antiviralsPriority for VaccineRapid test deploymentLuck?
Groups at Higher Risk of S i IllSerious Illness
People 65 yearsPeople 65 years Children, i ll l
Children, i ll l PregnantPregnantPeople 65 years
and olderPeople 65 years
and older especially less than 3 years
especially less than 3 years
Pregnant women
Pregnant women5
People with chronic medical
People with chronic medical
Residents of nursing homes Residents of
nursing homes chronic medical conditions
chronic medical conditions
gand chronic care
facilities
gand chronic care
facilities
NACI (http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08vol34/acs-3/index-eng.php) 14 May 09.
Laboratoryy
Lab adapted its own method to confirm first casesLab adapted its own method to confirm first cases (sequencing matrix gene)
First wave pushed lab to brink on utilizationpLater moved to RT PCRNew equipment brought in during the springNew equipment brought in during the spring
and summerWinter volume very high but TAT remained goodte o u e e y g but e a ed goodMajor cost was delay in typing of other viruses
Proliferation of Guidelines
SurveillanceSurveillancePublic Health ManagementClinical PracticeClinical PracticeInfection ControlAntiviralsAntiviralsImmunizationConsensus may come late in a federationConsensus may come late in a federation
Limiting Spread in H lth CHealth Care
HealthLink BC at 8-1-1 to reach a nurse 24/7HealthLink BC at 8 1 1 to reach a nurse 24/7 Billing code for pH1N1 telephone adviceThe N95 debacle – McIntyre et alThe N95 debacle McIntyre et al
VS.
Mark Loeb et al. Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Carefor Preventing Influenza Among Health Care Workers A Randomized Trial JAMA. 2009;302(17):1865-1871. ; ( )
BC Gov’t (http://www.gov.bc.ca/govt/swine_flu.html) 15 May 09
Antivirals
Large stockpiles built largely due to H5N1Large stockpiles built largely due to H5N1> 10 M doses (1 M treatment courses) in BC10% Released to Pharmacies Oct 110% Released to Pharmacies Oct 1 Tracked using BC PharmanetOnly high risk or severe casesOnly high risk or severe casesNot for prophylaxisAbout 16% of stockpile distributed and 14%About 16% of stockpile distributed and 14%
prescribed
Immunization Early Issuesy
Canada’s Pandemic Plan Called for use of adjuvanted vaccine (context of H5N1)
Some controversy over the failure to revisit the dj d i iadjuvant decision
One domestic manufacturer secured by contractA l h ti d ti lAs elsewhere, antigen production an early
challenge improved by better seed strainsCombination of production regulation and safetyCombination of production, regulation and safety
testing meant product not into people before Oct 26 (about 6-8 weeks too late to have optimal
ff )effect)
Seasonal Flu VaccineSeasonal Flu Vaccine
No protection against novel virus.p g6 Canadian studies (and one US armed services
study) have shown an association between lab confirmed pH1N1 and prior receipt of seasonalconfirmed pH1N1 and prior receipt of seasonal influenza vaccine in the previous 1-2 years. (OR~2)
Consequence? qCanadian recommendation that Seasonal influenza
vaccine should be given concurrently or after pH1N1 vaccine in those < 65 years of agevaccine in those < 65 years of age
pH1N1 dominating the circulating strains also played a key role in this approach
H1N1 Influenza in US Military Beneficiaries • CID 2009:49 (15 December) • 1801
Coping with Short Supplyp g pp y
Early supplies were shortEarly supplies were shortFirst few weeks was focused only on those at high
riskNo important private supply as other
manufacturers did not enter market.
At This Stageg
Between 1.5 and 2 M immunizedBetween 1.5 and 2 M immunizedSerious adverse events < 1/100,000 dosesMostly allergic reactionsMostly allergic reactionsNo GBS
Rapid Response Researchp p
Sero-epidemiology (MSFHR) Sero epidemiology (MSFHR) Initial community outbreak study
Vaccine effectiveness assessment Vaccine effectiveness assessment Scale up for real time genomics
Informatic improvements Informatic improvements Immunization evaluation
Mathematical Modelling Mathematical Modelling
Roles for Math Modelingg
Ro from Mexican and Canadian time series ~ 1.5Ro from Mexican and Canadian time series 1.5Herd Immunity Threshold 1-1/Ro Only 33%Only 33%
Lessons in K l d T l tiKnowledge Translation
It’s tough to get media to understand revised riskIt s tough to get media to understand revised risk assessment.
Guideline modification and approval has to ppbecome more timely.
One stop shopping is important (websites).p pp g p ( )Weekly briefings set the right tone.
Lessons in Immunization
Full review of production model needed.Full review of production model needed.Adjuvant not associated with additional excess
risk.Public opinion changes when people die.Worth comparing with US experience with multipleWorth comparing with US experience with multiple
manufacturers.
Lessons in Clinical Care
Antivirals can play a role in mitigating morbidity butAntivirals can play a role in mitigating morbidity but risk of resistance is real. Need to study this post-hoc.
Administrative data can be used in real time to track utilization.
Major stress was on Intensive Care Units –very little surge capacity.
Acknowledgementsg
Greg Deans, PGY4 Infectious DiseasesGreg Deans, PGY4 Infectious DiseasesBonnie Henry and BCCDC Emergency
ManagementgDanuta Skowronski and BCCDC Influenza TeamMonika Naus and BCCDC Immunization TeamMonika Naus and BCCDC Immunization TeamBabak Pourbohloul and Math Modelling Team