Smallpox primary prevention: Difference between revisions
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===Vaccine Contraindications=== | ===Vaccine Contraindications=== | ||
In the absence of reintroduction of smallpox, vaccination is contraindicated in the following: | |||
* Patients with allergy to vaccine components | |||
* History of atopic dermatitis | |||
* History of exfoliative skin disorders | |||
* Inflammatory eye disorders | |||
* Immunosuppressed patients | |||
* Heart disease | |||
* Pregnancy | |||
* Disease cases in the family | |||
* Children <1 year | |||
* Breastfeeding | |||
Revision as of 23:51, 11 July 2014
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Smallpox Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Smallpox primary prevention On the Web |
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American Roentgen Ray Society Images of Smallpox primary prevention |
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Risk calculators and risk factors for Smallpox primary prevention |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Primary Prevention
The administration of the vaccine can attenuate, sometimes prevent, the development of smallpox.[1] Vaccinia, a group of related viruses different from the remaining orthopoxviruses, is administrated with a bifurcated needle to the basilar epithelium. A cellular reaction will then develop, leading to the formation of the Jennerian pustule (1-2 cm), a major reaction. The Jennerian pustule is a sign of successful vaccination and leads to full immunity in more than 95%, possibly for 5 to 10 years.
It is important to notice that people who were vaccinated prior to 1972, in case of revaccination, may experience accelerated immune response.
Vaccine Generation
Since smallpox was considered eradicated, vaccination is not advised for common citizens. The only people with formal indication for Vaccinia vaccine are the laboratory or clinical individuals who work with the virus at specialized laboratories.[1]
There generations of vaccines have been developed so far:
- 1st generation - a mixture of related viruses, which differ from the remaining orthopoxviruses. Reactions to these generation included:[1][2][3]
- Regional swelling
- Painful lymphadenitis
- 2nd generation - individual vaccinia clones, derived from viruses which are genetically similar, to the ones that made the 1st generation vaccine. More efficient production of the vaccine.[3][4]
- 3rd generation - developed from the attenuated vaccinia strains, after genetic manipulation or multiple passage through non-human tissue. Contain strains not as virulent as previous generations, and therefore safer, mainly because of an delay in replication of the virus.[3][4][5][6]
Vaccine Recommendations
Vaccine Adverse Events
The following adverse events to the vaccine were reported:[3][7][8][9]
- Fetal vaccinia
- Progressive vaccinia
- Generalized vaccinia
- Non-specific rashes
- Eczema vaccinatum
- Encephalitis
- Myopericarditis
Vaccine Contraindications
In the absence of reintroduction of smallpox, vaccination is contraindicated in the following:
- Patients with allergy to vaccine components
- History of atopic dermatitis
- History of exfoliative skin disorders
- Inflammatory eye disorders
- Immunosuppressed patients
- Heart disease
- Pregnancy
- Disease cases in the family
- Children <1 year
- Breastfeeding
Length of Protection
Smallpox vaccination provides high level immunity for 3 to 5 years and decreasing immunity thereafter. If a person is vaccinated again later, immunity lasts even longer. Historically, the vaccine has been effective in preventing smallpox infection in 95% of those vaccinated. In addition, the vaccine was proven to prevent or substantially lessen infection when given within a few days of exposure. It is important to note, however, that at the time when the smallpox vaccine was used to eradicate the disease, testing was not as advanced or precise as it is today, so there may still be things to learn about the vaccine and its effectiveness and length of protection.
Receiving the Vaccine
The smallpox vaccine is not given with a hypodermic needle. It is not a shot as most people have experienced. The vaccine is given using a bifurcated (two-pronged) needle that is dipped into the vaccine solution. When removed, the needle retains a droplet of the vaccine. The needle is used to prick the skin a number of times in a few seconds. The pricking is not deep, but it will cause a sore spot and one or two droplets of blood to form. The vaccine usually is given in the upper arm.
If the vaccination is successful, a red and itchy bump develops at the vaccine site in three or four days. In the first week, the bump becomes a large blister, fills with pus, and begins to drain. During the second week, the blister begins to dry up and a scab forms. The scab falls off in the third week, leaving a small scar. People who are being vaccinated for the first time have a stronger reaction than those who are being revaccinated. The following pictures show the progression of the site where the vaccine is given.
Post-Vaccination
After vaccination, it is important to follow care instructions for the site of the vaccine. Because the virus is live, it can spread to other parts of the body, or to other people. The vaccinia virus (the live virus in the smallpox vaccine) may cause rash, fever, and head and body aches. In certain groups of people, complications from the vaccinia virus can be severe.
Vaccine Benefit
Vaccination within 3 days of exposure will prevent or significantly lessen the severity of smallpox symptoms in the vast majority of people. Vaccination 4 to 7 days after exposure likely offers some protection from disease or may modify the severity of disease.
Safety
The smallpox vaccine is the best protection you can get if you are exposed to the smallpox virus. Anyone directly exposed to smallpox, regardless of health status, would be offered the smallpox vaccine because the risks associated with smallpox disease are far greater than those posed by the vaccine.
There are side effects and risks associated with the smallpox vaccine. Most people experience normal, usually mild reactions that include a sore arm, fever, and body aches. However, other people experience reactions ranging from serious to life-threatening. People most likely to have serious side effects are: people who have had, even once, skin conditions (especially eczema or atopic dermatitis) and people with weakened immune systems, such as those who have received a transplant, are HIV positive, are receiving treatment for cancer, or are currently taking medications (like steroids) that suppress the immune system. In addition, pregnant women should not get the vaccine because of the risk it poses to the fetus. Women who are breastfeeding should not get the vaccine. Children younger than 12 months of age should not get the vaccine. Also, the Advisory Committee on Immunization Practices (ACIP) advises against non-emergency use of smallpox vaccine in children younger than 18 years of age. In addition, those allergic to the vaccine or any of its components should not receive the vaccine. Also, people who have been diagnosed by a doctor as having a heart condition with or without symptoms, including conditions such as previous myocardial infarction (heart attack), angina (chest pain caused by lack of blood flow to the heart), congestive heart failure, and cardiomyopathy (heart muscle becomes inflamed and doesn’t work as well as it should), stroke or transient ischemic attack (a “mini-stroke” that produces stroke-like symptoms but not lasting damage), chest pain or shortness of breath with activity (such as walking up stairs), or other heart conditions being treated by a doctor should not get the vaccine at this time. (Heart disease may be a temporary exclusion and may change as more information is gathered.) Also, individuals who have 3 or more of the following risk factors should not get the vaccine at this time: high blood pressure diagnosed by a doctor; high blood cholesterol diagnosed by a doctor; diabetes or high blood sugar diagnosed by a doctor; a first degree relative (for example, mother, father, brother or sister) with a heart condition before the age of 50; and/or, currently a cigarette smoker. (These may be temporary exclusions and may change as more information is gathered.)
In the past, about 1,000 people for every 1 million people vaccinated for the first time experienced reactions that, while not life-threatening, were serious. These reactions included a toxic or allergic reaction at the site of the vaccination (erythema multiforme), spread of the vaccinia virus to other parts of the body and to other individuals (inadvertent inoculation), and spread of the vaccinia virus to other parts of the body through the blood (generalized vaccinia). These types of reactions may require medical attention. In the past, between 14 and 52 people out of every 1 million people vaccinated for the first time experienced potentially life-threatening reactions to the vaccine. Based on past experience, it is estimated that 1 or 2 people in 1 million who receive the vaccine may die as a result. Careful screening of potential vaccine recipients is essential to ensure that those at increased risk do not receive the vaccine.
Availability
Routine smallpox vaccination among the American public stopped in 1972 after the disease was eradicated in the United States. Until recently, the U.S. government provided the vaccine only to a few hundred scientists and medical professionals working with smallpox and similar viruses in a research setting.
After the events of September and October, 2001, however, the U.S. government took further actions to improve its level of preparedness against terrorism. One of many such measures—designed specifically to prepare for an intentional release of the smallpox virus—included updating and releasing a smallpox response plan. In addition, the U.S. government has enough vaccine to vaccinate every person in the United States in the event of a smallpox emergency.
Vaccine
The chart below describes a patient that appears to show an adverse reaction to the smallpox vaccine and the protocol involved with it.
References
- ↑ 1.0 1.1 1.2 Breman, Joel G.; Henderson, D.A. (2002). "Diagnosis and Management of Smallpox". New England Journal of Medicine. 346 (17): 1300–1308. doi:10.1056/NEJMra020025. ISSN 0028-4793.
- ↑ ROBERTS JA (1962). "Histopathogenesis of mousepox. I. Respiratory infection". Br J Exp Pathol. 43: 451–61. PMC 2095140. PMID 13974310.
- ↑ 3.0 3.1 3.2 3.3 Moore, Zack S; Seward, Jane F; Lane, J Michael (2006). "Smallpox". The Lancet. 367 (9508): 425–435. doi:10.1016/S0140-6736(06)68143-9. ISSN 0140-6736.
- ↑ 4.0 4.1 Earl PL, Americo JL, Wyatt LS, Eller LA, Whitbeck JC, Cohen GH; et al. (2004). "Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox". Nature. 428 (6979): 182–5. doi:10.1038/nature02331. PMID 15014500.
- ↑ Stittelaar KJ, Kuiken T, de Swart RL, van Amerongen G, Vos HW, Niesters HG; et al. (2001). "Safety of modified vaccinia virus Ankara (MVA) in immune-suppressed macaques". Vaccine. 19 (27): 3700–9. PMID 11395204.
- ↑ Tartaglia J, Perkus ME, Taylor J, Norton EK, Audonnet JC, Cox WI; et al. (1992). "NYVAC: a highly attenuated strain of vaccinia virus". Virology. 188 (1): 217–32. PMID 1566575.
- ↑ Halsell JS, Riddle JR, Atwood JE, Gardner P, Shope R, Poland GA; et al. (2003). "Myopericarditis following smallpox vaccination among vaccinia-naive US military personnel". JAMA. 289 (24): 3283–9. doi:10.1001/jama.289.24.3283. PMID 12824210.
- ↑ Arness, M. K. (2004). "Myopericarditis following Smallpox Vaccination". American Journal of Epidemiology. 160 (7): 642–651. doi:10.1093/aje/kwh269. ISSN 0002-9262.
- ↑ Chen RT, Lane JM (2003). "Myocarditis: the unexpected return of smallpox vaccine adverse events". Lancet. 362 (9393): 1345–6. doi:10.1016/S0140-6736(03)14674-0. PMID 14585633.