Smallpox and Vaccinia The Diseases Behind the Policy

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Smallpox and VacciniaThe Diseases Behind the
Policy

• Jeffrey Engel, MD
• NC State Epidemiologist
• General Communicable Disease Control

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Smallpox Eradicated 1977Last Case in US in 1950s
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Smallpox A Clinical Diagnosis
Henderson JAMA 281199921-27
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Smallpox

• History
• Unique human pathogen
• 1157 BC, mummy of Ramses V
• 15th Century called Small pox to differentiate it
  from the Great Pox
• Variola Major
• CFR 30
• Last case in Bangladesh 1975
• Variola Minor
• CFR
• Last case in Somalia 1977

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Smallpox

• Variola
• Family Poxviridae
• Genus Orthopox
• Large DS DNA viruses
• Replicate in cytoplasm
• Other poxviruses
• Vaccinia (origin unknown)
• Cow pox (Jenner vaccine)
• Monkey pox

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Smallpox

• Pathogenesis of serious manifestations is due to
  overwhelming viremia and host response
• Four Clinical Forms
• Ordinary
• Modified (vaccinated)
• Flat (5-10 in children, CFR 50)
• Hemorrhagic (2 in adults, CFR 60)

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Differential Diagnosis

• Smallpox
• severe prodrome
• centrifugal rash
• firm lesions
• slow progression to scabs in 2-3 weeks
• synchronous lesions
• respiratory and fomite spread

• Chickenpox
• mild prodrome
• centripetal rash
• soft lesions
• progresses to scabs in
• lesions in various stages
• respiratory spread

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Smallpox Diagnosis

• Appearance of rash
• Hemorrhagic smallpox may be mistaken for
  meningococcemia or severe acute leukemia
• Viral Detection
• Culture, molecular (PCR), visual (EM)
• Specimen should be obtained by immunized person
  place in vacutainer tube, tape juncture of
  stopper and tube, place in second durable,
  watertight container
• Alert lab
• Rule in Varicella
• Tsanck prep (multinucleated giant cells)
• DFA for varicella

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Reality

• 26 year-old Israeli man presented to Mercy Main
  Hospital ED in Charlotte on November 6 with a
  vesicular rash
• Not ill, afebrile
• arrived US 9 days ago in Newark, NJ
• travel to Disney World
• in Charlotte on business
• ED doc benign rash, IC Nurse what about
  smallpox?
• Mercy Main notifies RST-7 Dr. Steve Keener
• Dr. Keener calls Dr. Engel
• Dr. Engel notifies NCHAN, Dr. Kirkpatrick
  acknowledges
• Patient isolated, digital photos taken, emailed
  to State and CDC

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Reality Aftermath

• ID consult insect bites
• No vesicular fluid for DFA
• State and CDC benign rash
• FBI background check clear
• Patient discharged 4 hours later
• How would your facility have handled this case?

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Smallpox Epidemiology

• Relatively long incubation period (12-14 days)
• Slow person-to-person spread from infectious
  cases, usually
• Cases infectious only during rash, infectivity
  drops sharply after week 1
• Inapparent infections extremely rare, not
  infectious
• Permanent immunity usually follows recovery from
  the disease
• No known effective treatment

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Smallpox Epidemiology

• A focal disease of only moderate communicability
• Infectious cases comprise only a fraction of the
  population of an infected community
• Only a fraction of communities in an infected
  country contain infectious cases at any one time
• The only persons at risk of acquiring smallpox
  are those susceptible individuals in actual
  physical contact with active cases or their
  fomites
• There are no other hosts (reservoir) and there is
  no carrier state
• Hence the strategy Surveillance (find the active
  cases) and Containment (ring vaccination)

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Smallpox Control

• Vaccinate all persons in the identified
  communities, maintain forced isolation for 2
  incubation periods (1 month) after last onset
  date
• nobody gets in without a vaccination
• nobody gets out if they have a rash

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Vaccinia Facts

• An effective immunogen against smallpox
• routinely possible to abort an incubating
  infection in an exposed individual if vaccination
  is given within 4 to 5 days after exposure
• immunity induced in only 7-10 days in persons
  never previously vaccinated
• in fewer days in persons with past vaccination
• under tropical field conditions, 95 of
  vaccinees were completely protected for a minimum
  of 1 year after a single dose

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Vaccinia Ring and Eradication

• Each time an active case is surrounded by a ring
  of freshly immunized people, a potential chain of
  infection is broken
• When ring vaccination is pursued at a faster rate
  than the natural transmission rate, the incidence
  of smallpox declines
• Eradication occurs when the last case is
  surrounded, and the chain of infection is
  interrupted

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The Basics of Smallpox Eradication

• Surveillance to find the cases
• and
• Containment to interrupt transmission

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Rahima Banu ...a 3 year old girl from Kuralia
village, Bhola Island, Bangladesh onset 16 Oct
75 The last natural case of variola major in the
world. photo by Pierre Claquin
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Smallpox Vaccine

• Discontinued in US in 1972
• Waning immunity
• up to 5 years
• 10 years revaccination recommended
• Most vaccinees will get modified disease

CFR ()
Years since vaccination
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Smallpox Transmission

• Droplet Aerosol
• During first several days of rash
• Exposure within 6 feet
• Airborne (Rare)
• Beyond 6 feet
• Indoor air ventilation
• Fomite
• Until scabs fall off

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Hospital Infection Control

• Plan for Scenarios
• Suspect case in ED
• Inpatient admitted with febrile illness
• General ward
• ICU
• Coordination
• Infection Control, Disaster Planning
• Administration, Hospital Board

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Hospital Infection Control

• No plan to designate a NC smallpox hospital in
  the event of a large outbreak
• Be prepared to cohort locally
• Type C unit smallpox cases
• Type X unit unknown febrile illness in a contact
• incubating smallpox
• vaccine reaction
• other cause
• Type R unit asymptomatic contact

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Hospital Infection Control

• Suspect Case in ED
• Know who to call (Hospital IC, LHD, RST, State,
  CDC)
• NC Health Alert Network
• Isolate patient in Airborne and Contact
  Precautions
• negative pressure room, outside exhaust
• N-95, fit-tested respirator mask
• gowns, gloves, and eye protection
• Record names and contact info of those in ED

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Hospital Infection Control

• Suspect Case in ED
• Obtain expert consultation emergently
• Dermatologist, ID
• Obtain digital photos of rash and email to
  authorities
• Rule in varicella with Tzanck and DFA of
  vesicle scraping/fluid (tests should be available
  locally)

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ACIP of CDC, June 2002Recommendation to
DHHSPre-Event Smallpox Vaccination

• Vaccinate those persons, as designated by the
  appropriate bioterrorism and public health
  authorities, who will conduct initial
  investigation and follow-up of initial smallpox
  cases that would necessitate direct patient
  contact, and
• Vaccinate healthcare personnel at risk for
  exposure to the initial smallpox cases that are
  pre-designated to receive these cases.

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SMALLPOX
VACCINATION METHOD
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VACCINATION METHOD
Multiple puncture vaccination Bifurcated needle
(single use) Discard in Biohazard container
Never dip needle into vial more than once
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VACCINATION METHOD
Preferred site is the Deltoid Area on Upper Arm
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VACCINATION METHOD
Step 1
Skin Preparation
NO skin preparation is required!
DO NOT use alcohol under any circumstances Alcohol
will inactivate the vaccine
Soap and water may be used to clean visible dirt
from skin
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VACCINATION METHOD
Step 2
Dip Needle
The needle is dipped once into the vaccine vial
and withdrawn.
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VACCINATION METHOD
Step 3
Rest wrist on arm of patient
Make 15 perpendicular skin insertions within a
5mm area
Use enough force to see a trace of blood at the
site
Discard needle immediately
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VACCINATION METHOD
Step 4
Absorb excess vaccine on gauze pad
Immediately discard gauze in a Biohazard
container
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VACCINATION METHOD
Step 5
Cover Vaccination Site
The site must be covered to prevent spread of
the virus
Use sterile gauze pad and tape Semi permeable
occlusive dressing OK
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VACCINATION METHOD
Step 6
Caution Vaccinee
Contact transmission of the virus is possible DO
NOT rub or scratch the site CAREFULLY discard
bandage WASH hands after handling bandage or site
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VACCINATION METHOD
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EVOLVING PRIMARY VACCINATION
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Risks Complications of Vaccination U.S., 1968
CDC
Henderson D, et al. JAMA 28119992127-2137
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Vaccine Adverse Events
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Contraindications(Pre-Event)

• Allergic to vaccine components
• Pregnant
• Age
• Immunosuppressed including HIV antibody positive
• Eczema or other chronic skin disease

• Liver or kidney disease
• Recent (60 days) vaccination with live attenuated
  virus
• Recent (6 months) blood transfusion
• Household or occupational contact with person
  with risk factors

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Contraindications(Post-Exposure)

• NONE

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Management of AEs

• Vaccinia Immune Globulin (VIG)
• production is being ramped-up
• controlled by CDC, IND status
• Indicated in eczema vaccinatum, progressive
  vaccinia
• Cidofovir
• FDA approved antiviral for CMV disease
• IND status (off-label use) for vaccinia

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Vaccination Issues

• Voluntary
• Manpower issues
• 30 out-of-work from day 7-10 because of
  symptoms stagger vaccination schedule
• Workmans Comp Vs. sick leave
• Liability
• Homeland Security bill signed into law 11/25/02
  by President Bush
• Federal protection if HHS Secretary declares an
  emergency

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Vaccine Infection Control Issues

• Vaccinia is a communicable disease
• Direct contact
• Rare reports of HCW to patient transmission
• HICPAC no furlough necessary
• viral shedding for 19 days
• cover site with gauze and transparent
  semi-permeable dressing and clothing
• reassign for 2 weeks if caring for
  immunosuppressed patients

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Pre-Event Vaccination

• Who Public Health Disease Investigators,
  Healthcare Teams
• What Undiluted Dryvax (relicensed by FDA early
  November)
• When early 2003
• Where LHD, Occupational Health
• Why Political decision