Smallpox primary prevention: Difference between revisions

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==Overview==
==Overview==
[[Primary prevention]] of [[smallpox]] consists in the administration of the ''vaccinia [[vaccine]]'', which attenuates or suppresses the manifestations of the disease, if administrated soon after [[infection]] has occurred. In the absence of an [[outbreak]], the [[vaccine]] is only administered to clinical and/or laboratory workers dealing with the [[smallpox virus|virus]] in specialized laboratories. It has several adverse effects, particularly in [[immunosuppressed]] individuals, those with [[heart]] conditions or [[allergies]], for whom its administration must be guided by specific rules.


==Primary Prevention==
==Primary Prevention==
The administration of the [[vaccine]] can attenuate, sometimes prevent, the development of [[smallpox]].<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref> Vaccinia, a group of related viruses different from the remaining [[orthopoxvirus]]es, 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.
The administration of the [[vaccine]] can attenuate, sometimes prevent, the manifestations of [[smallpox]]. The [[vaccine]] is made from a [[virus]] called vaccinia which is a “pox”-type [[virus]] related to [[smallpox]]. The [[vaccine]] does not contain the [[smallpox virus]] and therefore cannot transmit [[smallpox]]. However, it contains the “live” vaccinia [[virus]], not a dead [[virus]] like many others, for which the [[vaccination]] site must be cared for carefully, in order to prevent the [[virus]] from spreading.<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref> The [[vaccine]] is given in the upper arm, using a bifurcated needle, that is dipped into the [[vaccine]] solution. When removed, the needle retains a droplet of the [[vaccine]]. It is used to prick the [[skin]] a number of times in a few seconds. The pricking is not deep, reaching basilar [[epithelium]], but it will cause a sore spot and one or two droplets of [[blood]] will be formed.<ref name=CDC3>{{cite web | title = Emergence preparedness and response | url = http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp }}</ref>


It is important to notice that people who were [[vaccinated]] prior to 1972, in case of revaccination, may experience accelerated [[immune response]].
If the [[vaccination]] is successful, 1 or 2 droplets of [[blood]] will be formed within the site of the [[vaccine]], a few seconds after administration, and a [[cellular]] reaction will then occur. This will lead to the formation of the ''Jennerian pustule'' (1-2 cm), considered to be the ''major reaction''. The ''Jennerian pustule'' is a sign of successful [[vaccination]], which leads to full [[immunity]] in more than 95% of cases, possibly for 5 to 10 years.
 
Below is the progression of the appearance of the local of administrations of the [[vaccine]]: a red and [[itchy]] bump develops at the [[vaccine]] site within 3 to 4 days. During 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]] is formed. The scab then falls off during the third week, leaving a small [[scar]].<ref name=CDC3>{{cite web | title = Emergence preparedness and response | url = http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp }}</ref>
 
[[Image:Smallpox vaccine.jpg|thumb|center|500px|<SMALL><SMALL>''[http://www.bt.cdc.gov/agent/smallpox/smallpox-images/vaxsit5a.htm  Adapted from Centers for Disease Control and Prevention (CDC), Centers for Disease Control and Prevention.]''<ref name="CDC">{{Cite web | title = Centers for Disease Control and Prevention (CDC) | url = http://www.bt.cdc.gov/agent/smallpox/smallpox-images/vaxsit5a.htm}}</ref></SMALL></SMALL>]]
 
People who were [[vaccinated]] prior to 1972, if revaccinated, may experience accelerated [[immune response]].


===Vaccine Generation===
===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.<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref>
Three generations of [[vaccines]] have been developed so far:
 
* ''1st generation'' - a mixture of related [[virus]]es, which differ from the remaining [[orthopoxvirus]]es. Reactions to these generation include:<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref><ref name="pmid13974310">{{cite journal| author=ROBERTS JA| title=Histopathogenesis of mousepox. I. Respiratory infection. | journal=Br J Exp Pathol | year= 1962 | volume= 43 | issue=  | pages= 451-61 | pmid=13974310 | doi= | pmc=PMC2095140 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13974310  }} </ref><ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref>
There generations of vaccines have been developed so far:
:* [[Fever]]
* ''1st generation'' - a mixture of related viruses, which differ from the remaining orthopoxviruses<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref><ref name="pmid13974310">{{cite journal| author=ROBERTS JA| title=Histopathogenesis of mousepox. I. Respiratory infection. | journal=Br J Exp Pathol | year= 1962 | volume= 43 | issue=  | pages= 451-61 | pmid=13974310 | doi= | pmc=PMC2095140 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13974310  }} </ref><ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref>
:* Regional [[swelling]]
:* [[Edema]]
:* [[Headache]]
:* Painful [[lymphadenitis]]


* ''2nd generation'' - individual vaccinia clones, derived from viruses which are genetically similar, to the ones that made the 1st generation vaccine<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid15014500">{{cite journal| author=Earl PL, Americo JL, Wyatt LS, Eller LA, Whitbeck JC, Cohen GH et al.| title=Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox. | journal=Nature | year= 2004 | volume= 428 | issue= 6979 | pages= 182-5 | pmid=15014500 | doi=10.1038/nature02331 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15014500  }} </ref>
* ''2nd generation'' - individual vaccinia clones, derived from [[virus]]es which are genetically similar, to the ones that made the 1st generation vaccine. This generation had a more efficient production of the [[vaccine]].<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid15014500">{{cite journal| author=Earl PL, Americo JL, Wyatt LS, Eller LA, Whitbeck JC, Cohen GH et al.| title=Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox. | journal=Nature | year= 2004 | volume= 428 | issue= 6979 | pages= 182-5 | pmid=15014500 | doi=10.1038/nature02331 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15014500  }} </ref>


* ''3rd generation'' - developed from the attenuated vaccinia strains, after genetic manipulation or multiple passage through non-human tissue<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid15014500">{{cite journal| author=Earl PL, Americo JL, Wyatt LS, Eller LA, Whitbeck JC, Cohen GH et al.| title=Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox. | journal=Nature | year= 2004 | volume= 428 | issue= 6979 | pages= 182-5 | pmid=15014500 | doi=10.1038/nature02331 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15014500  }} </ref><ref name="pmid11395204">{{cite journal| author=Stittelaar KJ, Kuiken T, de Swart RL, van Amerongen G, Vos HW, Niesters HG et al.| title=Safety of modified vaccinia virus Ankara (MVA) in immune-suppressed macaques. | journal=Vaccine | year= 2001 | volume= 19 | issue= 27 | pages= 3700-9 | pmid=11395204 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11395204  }} </ref><ref name="pmid1566575">{{cite journal| author=Tartaglia J, Perkus ME, Taylor J, Norton EK, Audonnet JC, Cox WI et al.| title=NYVAC: a highly attenuated strain of vaccinia virus. | journal=Virology | year= 1992 | volume= 188 | issue= 1 | pages= 217-32 | pmid=1566575 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1566575  }} </ref>
* ''3rd generation'' - developed from the attenuated vaccinia strains, after [[genetic]] manipulation or multiple passage through non-human tissue. Contains [[strains]] not as virulent as previous generations, and therefore safer, mainly because of a delay in replication of the [[virus]].<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid15014500">{{cite journal| author=Earl PL, Americo JL, Wyatt LS, Eller LA, Whitbeck JC, Cohen GH et al.| title=Immunogenicity of a highly attenuated MVA smallpox vaccine and protection against monkeypox. | journal=Nature | year= 2004 | volume= 428 | issue= 6979 | pages= 182-5 | pmid=15014500 | doi=10.1038/nature02331 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15014500  }} </ref><ref name="pmid11395204">{{cite journal| author=Stittelaar KJ, Kuiken T, de Swart RL, van Amerongen G, Vos HW, Niesters HG et al.| title=Safety of modified vaccinia virus Ankara (MVA) in immune-suppressed macaques. | journal=Vaccine | year= 2001 | volume= 19 | issue= 27 | pages= 3700-9 | pmid=11395204 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11395204  }} </ref><ref name="pmid1566575">{{cite journal| author=Tartaglia J, Perkus ME, Taylor J, Norton EK, Audonnet JC, Cox WI et al.| title=NYVAC: a highly attenuated strain of vaccinia virus. | journal=Virology | year= 1992 | volume= 188 | issue= 1 | pages= 217-32 | pmid=1566575 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1566575  }} </ref>


===Vaccine Recommendations===
===Vaccine Recommendations===
 
Since [[smallpox]] was declared 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 [[smallpox virus|virus]] at specialized laboratories.<ref name="BremanHenderson2002">{{cite journal|last1=Breman|first1=Joel G.|last2=Henderson|first2=D.A.|title=Diagnosis and Management of Smallpox|journal=New England Journal of Medicine|volume=346|issue=17|year=2002|pages=1300–1308|issn=0028-4793|doi=10.1056/NEJMra020025}}</ref>


===Vaccine Adverse Events===
===Vaccine Adverse Events===
The following adverse events to the vaccine were reported:
The following adverse events to the [[vaccine]] have been reported:<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name="pmid12824210">{{cite journal| author=Halsell JS, Riddle JR, Atwood JE, Gardner P, Shope R, Poland GA et al.| title=Myopericarditis following smallpox vaccination among vaccinia-naive US military personnel. | journal=JAMA | year= 2003 | volume= 289 | issue= 24 | pages= 3283-9 | pmid=12824210 | doi=10.1001/jama.289.24.3283 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12824210  }} </ref><ref name="Arness2004">{{cite journal|last1=Arness|first1=M. K.|title=Myopericarditis following Smallpox Vaccination|journal=American Journal of Epidemiology|volume=160|issue=7|year=2004|pages=642–651|issn=0002-9262|doi=10.1093/aje/kwh269}}</ref><ref name="pmid14585633">{{cite journal| author=Chen RT, Lane JM| title=Myocarditis: the unexpected return of smallpox vaccine adverse events. | journal=Lancet | year= 2003 | volume= 362 | issue= 9393 | pages= 1345-6 | pmid=14585633 | doi=10.1016/S0140-6736(03)14674-0 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=14585633  }} </ref>
* Fetal vaccinia
* Fetal vaccinia
* Progressive vaccinia
* Progressive vaccinia
* Generalized vaccinia
* Generalized vaccinia
* Non-specific rashes
* Non-specific [[rashes]]
* Eczema vaccinatum
* [[Eczema vaccinatum]]
* Encephalitis
* [[Encephalitis]]
* [[Myopericarditis]]


===Vaccine Contraindications===
===Vaccine Contraindications===
 
In the absence of reintroduction of [[smallpox]], [[vaccination]] is contraindicated in the following:<ref name="MooreSeward2006">{{cite journal|last1=Moore|first1=Zack S|last2=Seward|first2=Jane F|last3=Lane|first3=J Michael|title=Smallpox|journal=The Lancet|volume=367|issue=9508|year=2006|pages=425–435|issn=01406736|doi=10.1016/S0140-6736(06)68143-9}}</ref><ref name=CDC2>{{cite web | title = Recommendations for Using Smallpox Vaccine in a Pre-Event Vaccination Program
 
| url = http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5207a1.htm }}</ref>
 
* Patients with [[allergy]] to [[vaccine]] components
 
* History of [[atopic dermatitis]]
 
* History of exfoliative [[skin]] disorders
 
* [[Inflammatory]] eye disorders
 
* [[Immunosuppressed]] patients
====Length of Protection====
* [[Heart disease]]
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.
* [[Pregnancy]]
 
* Disease cases in the family
====Receiving the Vaccine====
* Children <1 year
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]].
* [[Breastfeeding]]
 
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.
 
[[Image:Smallpox vaccine.jpg]]


====Post-Vaccination====
====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.
After [[vaccination]] it is important to follow instructions for the care of the [[vaccine]] site. Because the [[virus]] is alive, it can spread to other parts of the body, or to other people. The [[vaccinia virus]] may cause:<ref name=CDC3>{{cite web | title = Emergence preparedness and response | url = http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp }}</ref>
* [[Rash]]
* [[Fever]]
* [[Headache]]
* [[Body]] pain
Elderly and pregnant women are prone to severe [[complications]] following the [[vaccinia virus]] vaccine.


====Vaccine Benefit====
====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.
[[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 the disease or may modify its severity.<ref name=CDC3>{{cite web | title = Emergence preparedness and response | url = http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp }}</ref>
 
====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===
===Vaccine===
The algorithm below demonstrates the action protocol in the presence of a patient who appears to show an adverse reaction to the [[smallpox]] vaccine.<ref name=CDC3>{{cite web | title = Emergence preparedness and response | url = http://www.bt.cdc.gov/agent/smallpox/vaccination/facts.asp }}</ref>


The chart below describes a patient that appears to show an adverse reaction to the smallpox vaccine and the protocol involved with it.
[[Image:Smallpox lab vaccine.jpg|thumb|center|800px|<SMALL><SMALL>''[http://emergency.cdc.gov/agent/smallpox/diagnosis/pdf/poxalgorithm5-2-14.pdf  Adapted from Laboratory Response Network (LRN [CDC]), Laboratory Response Network.]''<ref name="LRN(CDC)">{{Cite web | title = Public Health Image Library (PHIL), Centers for Disease Control and Prevention | url = http://emergency.cdc.gov/agent/smallpox/diagnosis/pdf/poxalgorithm5-2-14.pdf}}</ref></SMALL></SMALL>]]
 
[[Image:Smallpox lab vaccine.jpg]]


==References==
==References==
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[[Category:Disease]]
[[Category:Disease]]
[[Category:Infectious disease]]
 
[[Category:Pediatrics]]
[[Category:Pediatrics]]
[[Category:Smallpox]]
[[Category:Smallpox]]

Latest revision as of 19:05, 18 September 2017

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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 of smallpox consists in the administration of the vaccinia vaccine, which attenuates or suppresses the manifestations of the disease, if administrated soon after infection has occurred. In the absence of an outbreak, the vaccine is only administered to clinical and/or laboratory workers dealing with the virus in specialized laboratories. It has several adverse effects, particularly in immunosuppressed individuals, those with heart conditions or allergies, for whom its administration must be guided by specific rules.

Primary Prevention

The administration of the vaccine can attenuate, sometimes prevent, the manifestations of smallpox. The vaccine is made from a virus called vaccinia which is a “pox”-type virus related to smallpox. The vaccine does not contain the smallpox virus and therefore cannot transmit smallpox. However, it contains the “live” vaccinia virus, not a dead virus like many others, for which the vaccination site must be cared for carefully, in order to prevent the virus from spreading.[1] The vaccine is given in the upper arm, using a bifurcated needle, that is dipped into the vaccine solution. When removed, the needle retains a droplet of the vaccine. It is used to prick the skin a number of times in a few seconds. The pricking is not deep, reaching basilar epithelium, but it will cause a sore spot and one or two droplets of blood will be formed.[2]

If the vaccination is successful, 1 or 2 droplets of blood will be formed within the site of the vaccine, a few seconds after administration, and a cellular reaction will then occur. This will lead to the formation of the Jennerian pustule (1-2 cm), considered to be the major reaction. The Jennerian pustule is a sign of successful vaccination, which leads to full immunity in more than 95% of cases, possibly for 5 to 10 years.

Below is the progression of the appearance of the local of administrations of the vaccine: a red and itchy bump develops at the vaccine site within 3 to 4 days. During 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 is formed. The scab then falls off during the third week, leaving a small scar.[2]

Adapted from Centers for Disease Control and Prevention (CDC), Centers for Disease Control and Prevention.[3]

People who were vaccinated prior to 1972, if revaccinated, may experience accelerated immune response.

Vaccine Generation

Three generations of vaccines have been developed so far:

  • 2nd generation - individual vaccinia clones, derived from viruses which are genetically similar, to the ones that made the 1st generation vaccine. This generation had a more efficient production of the vaccine.[5][6]
  • 3rd generation - developed from the attenuated vaccinia strains, after genetic manipulation or multiple passage through non-human tissue. Contains strains not as virulent as previous generations, and therefore safer, mainly because of a delay in replication of the virus.[5][6][7][8]

Vaccine Recommendations

Since smallpox was declared 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]

Vaccine Adverse Events

The following adverse events to the vaccine have been reported:[5][9][10][11]

Vaccine Contraindications

In the absence of reintroduction of smallpox, vaccination is contraindicated in the following:[5][12]

Post-Vaccination

After vaccination it is important to follow instructions for the care of the vaccine site. Because the virus is alive, it can spread to other parts of the body, or to other people. The vaccinia virus may cause:[2]

Elderly and pregnant women are prone to severe complications following the vaccinia virus vaccine.

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 the disease or may modify its severity.[2]

Vaccine

The algorithm below demonstrates the action protocol in the presence of a patient who appears to show an adverse reaction to the smallpox vaccine.[2]

Adapted from Laboratory Response Network (LRN [CDC), Laboratory Response Network.][13]

References

  1. ↑ 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.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 "Emergence preparedness and response".
  3. ↑ "Centers for Disease Control and Prevention (CDC)".
  4. ↑ ROBERTS JA (1962). "Histopathogenesis of mousepox. I. Respiratory infection". Br J Exp Pathol. 43: 451–61. PMC 2095140. PMID 13974310.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 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.
  6. ↑ 6.0 6.1 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.
  7. ↑ 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.
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ Arness, M. K. (2004). "Myopericarditis following Smallpox Vaccination". American Journal of Epidemiology. 160 (7): 642–651. doi:10.1093/aje/kwh269. ISSN 0002-9262.
  11. ↑ 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.
  12. ↑ "Recommendations for Using Smallpox Vaccine in a Pre-Event Vaccination Program".
  13. ↑ "Public Health Image Library (PHIL), Centers for Disease Control and Prevention" (PDF).

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