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

Age Distributiong

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

Collateral Damageg

Pigs – Egypt, AlbertaPigs Egypt, AlbertaEconomics

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%

Pourbohloul et al

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

Thank YouThank You

A Q ti ?Any Questions?