Smallpox primary prevention

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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

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

Primary Prevention

The administration of the vaccine can attenuate, sometimes prevent, the manifestations of smallpox. 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. The needle 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.

If the vaccination is successful 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.

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 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 is formed. The scab falls off in the third week, leaving a small scar.

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.

Three 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:

• Fever

• 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. More efficient production of the vaccine.

• 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.

Vaccine Adverse Events

The following adverse events to the vaccine were reported:

• 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

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.

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.

Image Gallery

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  Upper arm revealing the site of a newly-administered smallpox vaccination, which had been performed using a “Ped-O-Jet®” jet injector. Notice the wheal type morphology of the vaccination site.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  This was a vaccinial lesion that had manifested itself on the face of a mother who had acquired the virus after her daughter’s smallpox vaccination.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  This image depicts the smallpox vaccination site, which in the case of this recipient, displayed a reaction after a period of seven days.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  This image depicts the right shoulder region of a male patient from a lateral perspective, who’d received a smallpox vaccination, while ill with chickenpox. Note the intense reaction at the vaccination site.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  African Cameroonian boy in the process of receiving his vaccinations during the African Smallpox Eradication and Measles Control Program.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Girl who received a smallpox vaccination in the left upper arm displayed a local complication at the vaccination site, where a chronic superinfection resulted in a granulation tissue reaction. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Child’s arm after having received a smallpox vaccination in the country of Sierra Leone. Note intradermal wheal, which is a raised area at the site where the Ped-o-jet® delivered the smallpox vaccine. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Newborn infant delivered during its 28th week of gestation, to a mother who’d received a primary smallpox vaccination during the 23rd week of her pregnancy. Upon delivery, this infant displayed typical vaccinial skin lesions, and died at 8 days of age. Vaccinia virus was isolated from the placenta. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Right eye of the same 80 year-old female patient who's been accidentally infected by her grandchild, who’d been vaccinated not long before. Note the severe distortion of the palpebral margins due to the typical vaccinial lesion of the outer canthus.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Right eye of a 6 year-old child, who'd been accidentally inoculated with the vaccinia virus, and subsequently developed these severe conjunctival vaccinial lesions. The child had received a primary vaccination, and inadvertently transferred the vaccinial virus to his/her own eye.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  6 year-old boy, who'd been accidentally inoculated with the vaccinia virus, and subsequently developed these vaccinial lesions upon his face. This boy's lesions healed with no residual scarring.

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  Left upper arm of a middle-aged woman who’d received a primary smallpox vaccination, and thereafter, developed local erythema, and a “bull’s eye” surrounding the site. This type of “local involvement is common in older, primary vaccines.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  After having received a smallpox vaccination on the small of his back, a 14 month old infant manifested a non-specific rash in the form of extensive erythematous patches over his entire body, except for relative paring of the soles of his feet.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Accidental vaccinial inoculation of a two year-old boy’s left eye. This boy’s mother had been vaccinated 12 days before his ocular vaccinia became apparent. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  70 year-old female smallpox patient who’d received a smallpox vaccination, and subsequently developed a severe reaction to the vaccine known as “vaccinia necrosum”.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Initial vaccination site. This was a case of progressive vaccinia, also known as vaccinia necrosum, and despite intensive treatment, this patient died, and was found to have a deficiency in her cellular immunity mechanism.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Dorsum of the right hand of a 71 year-old woman revealing a metastatic lesion of vaccinia necrosum, also known as progressive vaccinia. The margins of this lesion display the characteristic of typical confluent vaccinial growth. Despite intensive treatment, this patient died, and was found to have a deficiency in her cellular immunity mechanism.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Female who’d received a smallpox vaccination, and subsequently developed a severe reaction to the vaccine known as “vaccinia necrosum”. This woman was also a chronic lymphocytic leukemia patient. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  7 year-old male patient with microcephaly, and cerebral palsy, subsequently developed progressive vaccinia after having received a smallpox vaccination in his left shoulder. Note the large necrotic area at the vaccination site. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Left arm and shoulder area of child with deficient cellular immunity, who had sustained the ravages of vaccinia necrosum, after having received a smallpox vaccination 4 month earlier. Appearance of the severely-necrotic wound two weeks after having performed a surgical intervention, involving the debridement of necrotic tissues.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Left arm and shoulder area of child with deficient cellular immunity, who had sustained the ravages of vaccinia necrosum, after having received a smallpox vaccination 4 month earlier. Note massive necrosis and destruction of tissue caused by this condition.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Right lower lip and chin region of a 25 year old woman, who had been accidentally infected on her face after her daughter was vaccinated against smallpox.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  22 month-old male with Bruton’s hypogammaglobulinemia accompanied by vaccinia necrosum. Note the large necrotic area at the vaccination site.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Plantar surface of the right foot of a 5 week-old Washington State male patient who after receiving a smallpox vaccination, developed an erythema multiforme reaction. In this particular view, note how the maculopapular rash had spread to his the plantar surface of his right foot. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Left lower extremity of a 5 week-old male patient who after receiving a smallpox vaccination, developed an erythema multiforme reaction. Note how the maculopapular rash had spread to his left, lower extremity.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Right lower extremity of a 5 week-old male patient who after receiving a smallpox vaccination, developed an erythema multiforme reaction. Note how the maculopapular rash had spread to his right thigh and calfAdapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Right chest surface of a 2 year-old female patient who after receiving a smallpox vaccination in her left shoulder region, developed an erythema multiforme reaction. Note maculopapular rash, which had spread to her chest and left upper arm. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  Chest surface of a 2 year-old female patient who after receiving a smallpox vaccination in her left shoulder region, developed an erythema multiforme reaction. Note the maculopapular rash, which had spread to her chest and left upper arm.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  2 year-old female patient who after receiving a smallpox vaccination in her left shoulder region, developed an erythema multiforme reaction. Note left shoulder vaccination site. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  2 year-old Georgian female patient who after receiving a smallpox vaccination, developed an erythema multiforme reaction. Note maculopapular lesions on her chest, arms, and face. Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  6 year-old child, who after having received a smallpox vaccination, sustained what is termed an “accidental implantation” of the newly-introduced vaccinia virus. Note the erythematous blush over his cheeks, and inflamed nasal lesion, as well as the overall lethargic posture all due to this accidental implantation.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.

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  2 year-old child, who after having received a smallpox vaccination, sustained what is termed an “accidental implantation” of the newly-introduced vaccinia virus. Note the erythema and swelling around her left eye due to this accidental implantation of the vaccinial virus.Adapted from Public Health Image Library (PHIL), Centers for Disease Control and Prevention.