Transcript Smallpox Vaccination - Virginia Department of Health

Smallpox Vaccine:
Overview for Health Care
Response Teams
Thomas G. Franck, MD, MPH
Regional Physician Consultant
Office of Emergency Preparedness & Response
Virginia Department of Health
January 2003
Objectives
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To briefly review smallpox disease
To gain an in depth understanding of
smallpox vaccine, including:
– history of smallpox vaccination
– overview of vaccinia
– indications
– contraindications
– normal response
– complications
Taxonomy
 Family:
Poxviridae
Genus: Orthopoxviruses
Smallpox (variola)
 Cowpox
 Monkeypox
 Vaccinia
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93% DNA Homology
Smallpox
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Caused by Variola virus
Unique to humans
Person-to-person spread
– usually via close contact - droplets
– contaminated materials (uncommon)
– aerosolized droplet nuclei spread (rare)
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30% case-fatality rate on average
Smallpox: Clinical Features
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Incubation: 12-14 days (range 7-17)
Prodrome: lasts 2-4 days
– fever, malaise, headache, backache, vomiting
Eruptive stage (Rash):
– Oral cavity/pharynx  face, hands, forearms
 lower extremities  trunk
– Synchronous progression: maculopapules 
vesicles  pustules  scabs
– Lesions on palms /soles
– Infectious stage (especially 1st week)
Smallpox - Treatment
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Treatment
– Supportive care
– No treatment proven effective
– Experimental treatment with
antivirals, e.g., Cidofovir
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Prevention/Prophylaxis
– Vaccination - protective if given
within 3 days of exposure
Smallpox:
Why the Concern Now?
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Last case in US in 1949
Last naturally acquired case in 1977
Disease declared eliminated by WHO in 1980
Stocks of Variola virus held by U.S. & Russia
Bio Weapons programs in several countries
Recent Intelligence review: 4 countries may
have covert stocks of smallpox virus –
Russia, Iraq, North Korea, and France
Smallpox Vaccine: History
1796: Edward Jenner develops vaccine (cowpox)
1805: Use of cows to produce vaccine
1940s: Freeze-drying of Vaccinia
1965: Licensure of bifurcated needle
1972: Routine vaccination stopped in U.S.
1983: Vaccine removed from civilian market
1990: U.S. Military vaccination stops
Smallpox Vaccine
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Live virus called “Vaccinia”
An orthopoxvirus, genetically distinct from
other orthopoxviruses such as cowpox,
monkeypox, and variola (cause of smallpox)
Origin unknown: May be a virus now
extinct in nature
Vaccinia Vaccine
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“Dryvax” (Wyeth Laboratories)
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Contains NY City Board of Health strain
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2.7 million doses licensed (phase 1)*
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Enough vaccine “to vaccinate every single
person in the country in an emergency”*
*December 2002
Vaccine Efficacy:
Pre-Exposure
 Reduces chance of getting infected
(i.e., decreases secondary attack rate)
 91%-97%
reduction in cases among
case contacts with vaccination scar
 For those infected, reduces fatality
rate and severity of disease
Mack, J. Inf Dis, 1972
Vaccine Efficacy:
Post Exposure
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Generally prevents smallpox, or
significantly decreases severity, if given
within 3 days of exposure
Vaccination 4 to 7 days post-exposure
still offered protection to many people,
but significantly less than vaccination
before 4 days
Vaccine Efficacy:
Post Exposure
(Madras)
Smallpox AR %
Postexp vacc
29.5
Never vacc
47.6
(Pakistan) Vacc <10 days
Never vacc
75.0
96.3
(Pakistan) Vacc <7 days
Never vacc
1.9
21.8
Duration of Immunity
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High level of protection (95-100%) for 3-5 years
following vaccination
Immunity wanes after 5 years, but some
residual protection evident at 10 and even 20+
years
Reduction in disease severity with any history of
vaccination
However, best protection if vaccinated <3-5 yrs
ago; we cannot rely on previous vaccinations to
protect our population and we should consider
the population to lack immunity to smallpox.
Smallpox Vaccine Indications:
Non-Emergency
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Current Indications:
– Laboratory workers who handle cultures or
animals infected with non-highly attenuated
vaccinia or other Orthopoxviruses
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New Recommendations:
– Public health, hospital, and other personnel,
generally 18-65 years of age, who may have
to respond to a smallpox case or outbreak
Smallpox Vaccine Indications:
Emergency Situations
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Ring Vaccination
– Persons exposed to initial release
– Close contact with confirmed or suspected case
– Direct care or transportation of confirmed or
suspected case
– Laboratory personnel
– Persons with risk of contact with infectious
materials from case
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Mass Vaccination of entire populations?
Contraindications:
Non-Emergency Situations
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Eczema/atopic dermatitis (active or history of) or
household contact with eczema/atopic dermatitis
Other active skin conditions (allergic rash, burns, impetigo,
chickenpox, shingles, herpes,psoriasis, severe acne, etc.)
or household contact with acitve skin condition
Immunosuppression or household contact with
immunosuppression
Pregnancy or pregnant household contact
Breastfeeding
Infants (not advised in children < 18)
Severe allergic reaction to prior vaccination or vaccine
component
Contraindications:
Immunodeficiency
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Conditions causing immunodeficiency:
– HIV, leukemia, lymphoma, other cancers,
agammaglobulinemia, certain autoimmune
disorders (e.g., SLE), other immune disorders
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Treatments causing immunodeficiency:
– Chemotherapy, radiation treatment,
antimetabolites, alkyltating agents, organ
transplant meds, high-dose corticosteroids
– Immunomodulatory medications? Unknown
Contraindications:
Eczema/Atopic Dermatitis
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Eczema: a red, itchy rash that lasts at
least two weeks and then comes and
goes
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It is estimated that at least 15 million
people in U.S. have atopic dermatitis
These people are at risk of a serious
complication, eczema vaccinatum
Contraindications:
Emergency Situations
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Exposed persons – no contraindications
Unexposed persons – generally same
as non-emergency situations w/ some
modifications, depending on situation
Vaccine Administration
Surgical needle
 Vaccinostyle
 Rotary lancet
 Jet injector
 Bifurcated needle*
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*Only administration technique currently in use.
Vaccination Technique
Vaccination Site Care
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Remember – live vaccinia virus is present
at site of vaccination until scab falls off on
its own, usually 2-3 weeks.
Dressing
Health care setting: 3 layers of protection –
gauze, semipermeable dressing, shirt
Non-health care setting: 2 layers of protection
– gauze & shirt
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Avoid salves and ointments
Avoid touching/scratching site and picking
scab
Post-Vaccination Follow-up
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Semipermeable dressing: change dressing
at least every 3-5 days and as needed
Gauze dressing secured by tape: change
dressing every 1-3 days and as needed
“Take” evaluation: 7 days after vaccination
(+/- 1 day)
If significant side effects or adverse event,
follow-up with designated health care
provider
Clinical Response to
Vaccination*
Sign/symptom
Time after Vacc
Papule
3 days
Vesicle
5-6 days
Pustule
7-11 days
Maximum erythema
8-12 days
Scab
14 days
Scab separation
21 days
*typical response in a nonimmune person
Clinical Response to
Vaccination
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Major (primary) reaction
– Indicates viral replication has occurred and
vaccination was successful
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No reaction or equivocal reaction
– No immunity and vaccination must be
repeated
Major Reaction*
(6-8 days after vaccination)
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Primary vaccination
– Vesicular or pustular lesion
– Area of definite palpable induration
surrounding a central crust or ulcer
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Revaccination
– Less pronounced and more rapid progression
– Pustular lesion or induration surrounding a
central crust or ulcer
*WHO Expert Committee on Smallpox,
1964
Primary
Revaccination
Day 3
Primary
Revaccination
Day 7
Primary
Revaccination
Day 10
Primary
Revaccination
Day 14
Normal Variants:
Satellite Lesions
Normal Variants:
Cellulitis & Lymphangitis
Smallpox Vaccination:
Normal Side Effects
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Fever: 10% of adults
Localized soreness: 35-47%
Headache/muscle aches: 40-50%
Redness/swelling > 3 inches: 15%
1/3 may feel bad enough to miss
work, school, activity, or have trouble
sleeping
Smallpox Vaccination:
Adverse Events
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Contact transmission: spread vaccinia to others
Inadvertent autoinoculation: spread to other sites
on body
Generalized vaccinia: spread throughout body
Eczema vaccinatum: severe skin reaction
Progressive vaccinia (vaccinia necrosum)
Postvaccinial encephalitis
Death
Accidental Inoculation
Accidental auto-inoculation
of cheek with vaccinia virus,
approximately 5 days old.
Primary take on arm, 10-12
days old. Photo courtesy of
John M. Leedom, MD.
Accidental Inoculation
Generalized Vaccinia
Generalized vaccinia in an apparently normal child. Recovered without
sequelae. Photo courtesy of John M. Leedom, M.D.
Generalized Vaccinia
Eczema Vaccinatum
Eczema Vaccinatum
Progressive Vaccinia
Post-Vaccinial Encephalitis
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Autoimmune process
No predictors of susceptibility
Supportive care; no specific therapy
Vaccinia Immune Globulin is not
effective and is not recommended.
15-25% mortality; and
25% had permanent neurological
sequelae
Vaccinia Keratitis
Vaccine Adverse Events
Complication
Household transmission
Accidental autoinoculation
Generalized vaccinia
Eczema vaccinatum
Progressive vaccinia
Encephalitis
Death
# per million
27
25-530
23-242
10-39
1-1.5
3-12
1-2
Complication Rates of Vaccination
Rates (per million vaccinations)
U.S., 1968 (ten state survey)
Primary
Vaccination
Revaccination
Inadvertent
Autoinoculation
Generalized
Vaccinia
Eczema
Vaccinatum
Progressive
Vaccinia
Postvaccinal
Encephalitis
529
42
242
9
39
3
1.5
3
12
2
Total
1254
108
Complication
VIG:
Vaccinia Immune Globulin
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Indicated:
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Eczema vaccinatum
Progressive vaccinia
Generalized vaccinia (if severe or recurrent)
Accidental implantation (ocular or extensive lesions)
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Accidental implantation (mild instances)
Generalized vaccinia (mild or limited - most instances)
Erythema multiforme
Encephalitis
Not Recommended:
Contraindicated:
– Vaccinia keratitis
Issues for Discussion
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HIV testing
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Pregnancy testing
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Vaccination site care – who, how often?
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Should healthcare provider continue to work?
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Liability & workers’ compensation
“…it now becomes too manifest to
admit of controversy, that the
annihilation of the Small Pox, the
most dreadful scourge of the
human species, must be the final
result of this practice.”
-Edward Jenner, 1801