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Smallpox Vaccine: Overview for Health Care Response Teams

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. To briefly review smallpox disease

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Smallpox Vaccine: Overview for Health Care Response Teams

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  1. 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

  2. Objectives • 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

  3. Taxonomy • Family: Poxviridae • Genus: Orthopoxviruses • Smallpox (variola) • Cowpox • Monkeypox • Vaccinia 93% DNA Homology

  4. Smallpox • Caused by Variola virus • Unique to humans • Person-to-person spread • usually via close contact - droplets • contaminated materials (uncommon) • aerosolized droplet nuclei spread (rare) • 30% case-fatality rate on average

  5. Smallpox: Clinical Features • 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)

  6. Smallpox - Treatment • Treatment • Supportive care • No treatment proven effective • Experimental treatment with antivirals, e.g., Cidofovir • Prevention/Prophylaxis • Vaccination - protective if given within 3 days of exposure

  7. Smallpox:Why the Concern Now? • 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

  8. 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

  9. Smallpox Vaccine • 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

  10. Vaccinia Vaccine • “Dryvax” (Wyeth Laboratories) • Contains NY City Board of Health strain • 2.7 million doses licensed (phase 1)* • Enough vaccine “to vaccinate every single person in the country in an emergency”* *December 2002

  11. 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

  12. Mack, J. Inf Dis, 1972

  13. Vaccine Efficacy:Post Exposure • Generally prevents smallpox, or significantly decreases severity, if given within 3 days of exposure • Vaccination 4 to 7 days post-exposurestill offered protection to many people, but significantly less than vaccination before 4 days

  14. Vaccine Efficacy:Post Exposure Smallpox AR % 29.5 47.6 75.0 96.3 1.9 21.8 (Madras) (Pakistan) (Pakistan) Postexp vacc Never vacc Vacc <10 days Never vacc Vacc <7 days Never vacc

  15. Duration of Immunity • 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.

  16. Smallpox Vaccine Indications:Non-Emergency • Current Indications: • Laboratory workers who handle cultures or animals infected with non-highly attenuated vaccinia or other Orthopoxviruses • 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

  17. Smallpox Vaccine Indications: Emergency Situations • 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 • Mass Vaccination of entire populations?

  18. Contraindications:Non-Emergency Situations • 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

  19. Contraindications:Immunodeficiency • Conditions causing immunodeficiency: • HIV, leukemia, lymphoma, other cancers, agammaglobulinemia, certain autoimmune disorders (e.g., SLE), other immune disorders • Treatments causing immunodeficiency: • Chemotherapy, radiation treatment, antimetabolites, alkyltating agents, organ transplant meds, high-dose corticosteroids • Immunomodulatory medications? Unknown

  20. Contraindications: Eczema/Atopic Dermatitis • Eczema: a red, itchy rash that lasts at least two weeks and then comes and goes • 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

  21. Contraindications:Emergency Situations • Exposed persons – no contraindications • Unexposed persons – generally same as non-emergency situations w/ some modifications, depending on situation

  22. Vaccine Administration • Surgical needle • Vaccinostyle • Rotary lancet • Jet injector • Bifurcated needle* *Only administration technique currently in use.

  23. Vaccination Technique

  24. Vaccination Site Care • 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 • Avoid salves and ointments • Avoid touching/scratching site and picking scab

  25. Post-Vaccination Follow-up • 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

  26. Clinical Response to Vaccination* Sign/symptom Papule Vesicle Pustule Maximum erythema Scab Scab separation Time after Vacc 3 days 5-6 days 7-11 days 8-12 days 14 days 21 days *typical response in a nonimmune person

  27. Clinical Response to Vaccination • Major (primary) reaction • Indicates viral replication has occurred and vaccination was successful • No reaction or equivocal reaction • No immunity and vaccination must be repeated

  28. Major Reaction*(6-8 days after vaccination) • Primary vaccination • Vesicular or pustular lesion • Area of definite palpable induration surrounding a central crust or ulcer • Revaccination • Less pronounced and more rapid progression • Pustular lesion or induration surrounding a central crust or ulcer *WHO Expert Committee on Smallpox, 1964

  29. Primary Revaccination Day 3

  30. Primary Revaccination Day 7

  31. Primary Revaccination Day 10

  32. Revaccination Primary Day 14

  33. Normal Variants:Satellite Lesions

  34. Normal Variants:Cellulitis & Lymphangitis

  35. Smallpox Vaccination:Normal Side Effects • 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

  36. Smallpox Vaccination:Adverse Events • 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

  37. 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.

  38. Accidental Inoculation

  39. Generalized Vaccinia Generalized vaccinia in an apparently normal child. Recovered without sequelae. Photo courtesy of John M. Leedom, M.D.

  40. Generalized Vaccinia

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