Vaccinia Vaccine Description/Insert (smallpox)

[Guest guest]

Found the equivalent of the package insert for the Vaccinia Vaccine (used

for smallpox - by the way it really isn't a smallpox vaccine, its a

vaccinia vaccine)

Sheri

" The currently available vaccinia vaccine (i.e., Dryvax) contains trace

amounts of polymyxin B sulfate, streptomycin sulfate, chlortetracycline

hydrochloride, and neomycin sulfate. Persons who experience anaphylactic

reactions (i.e., hives, swelling of the mouth and throat, difficulty

breathing, hypotension, and shock) to any of these antibiotics should not

be vaccinated. Vaccinia vaccine does not contain penicillin. Future

supplies of vaccinia vaccine will be reformulated and might contain other

preservatives or stabilizers. Refer to the manufacturer's package insert

for additional information. "

" Vaccinia vaccine does not contain smallpox (variola) virus. Previously,

the vaccine had been prepared from calf lymph with a seed virus derived

from the New York City Board of Health (NYCBOH) strain of vaccinia virus

and has a minimum concentration of 108 pock-forming units "

http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5010a1.htm

VACCINIA VACCINE

Dryvax,® the vaccinia (smallpox) vaccine currently licensed in the United

States, is a lyophilized, live-virus preparation of infectious vaccinia

virus (Wyeth Laboratories, Inc., Marietta, Pennsylvania). Vaccinia vaccine

does not contain smallpox (variola) virus. Previously, the vaccine had been

prepared from calf lymph with a seed virus derived from the New York City

Board of Health (NYCBOH) strain of vaccinia virus and has a minimum

concentration of 108 pock-forming units (PFU)/ml. Vaccine was administered

by using the multiple-puncture technique with a bifurcated needle. A

reformulated vaccine, produced by using cell-culture techniques, is now

being developed.

Vaccine Efficacy

Neutralizing antibodies induced by vaccinia vaccine are genus-specific and

cross-protective for other Orthopoxviruses (e.g., monkeypox, cowpox, and

variola viruses) (16--18). Although the efficacy of vaccinia vaccine has

never been measured precisely during controlled trials, epidemiologic

studies demonstrate that an increased level of protection against smallpox

persists for <5 years after primary vaccination and substantial but waning

immunity can persist for >10 years (19,20). Antibody levels after

revaccination can remain high longer, conferring a greater period of

immunity than occurs after primary vaccination alone (3,19). Administration

of vaccinia vaccine within the first days after initial exposure to

smallpox virus can reduce symptoms or prevent smallpox disease (2--4).

Although the level of antibody that protects against smallpox infection is

unknown, after percutaneous administration of a standard dose of vaccinia

vaccine, >95% of primary vaccinees (i.e., persons receiving their first

dose of vaccine) will experience neutralizing or hemagglutination

inhibition antibody at a titer of >1:10 (21). Neutralizing antibody titers

of >1:10 persist among 75% of persons for 10 years after receiving second

doses and <30 years after receiving three doses of vaccine (22,23). The

level of antibody required for protection against vaccinia virus infection

is unknown also. However, when lack of local skin response to revaccination

with an appropriately administered and potent vaccine dose is used as an

indication of immunity, <10% of persons with neutralizing titers of >1:10

exhibit a primary-type response at revaccination, compared with >30% of

persons with titers <1:10 (24). Lack of major or primary-type reaction can

indicate the presence of neutralizing antibody levels sufficient to prevent

viral replication, although it can also indicate unsuccessful vaccination

because of improper administration or less potent vaccine.

Recombinant Vaccinia Viruses

Vaccinia virus is the prototype of the genus Orthopoxvirus. It is a

double-stranded DNA (deoxyribonucleic acid) virus that has a broad host

range under experimental conditions but is rarely isolated from animals

outside the laboratory (25,26). Multiple strains of vaccinia virus exist

that have different levels of virulence for humans and animals. For

example, the Temple of Heaven and Copenhagen vaccinia strains are highly

pathogenic among animals, whereas the NYCBOH strain, from which the Wyeth

vaccine strain was derived, had relatively low pathogenicity (3).

Vaccinia virus can be genetically engineered to contain and express foreign

DNA with or without impairing the ability of the virus to replicate. Such

foreign DNA can encode protein antigens that induce protection against one

or more infectious agents. Recombinant vaccinia viruses have been

engineered to express immunizing antigens of herpesvirus, hepatitis B,

rabies, influenza, human immunodeficiency virus (HIV), and other viruses

(27--32).

Recombinant vaccinia viruses have been created from different strains of

vaccinia virus. In the United States, recombinants have been made from a

nonattenuated NYCBOH strain, or a mouse neuroadapted derivative, the WR

strain. Recombinants have also been made by using the Copenhagen and Lister

vaccinia strains, which are more pathogenic among animals than the NYCBOH

strain. Additionally, certain highly attenuated, host-restricted, non- or

poorly replicating poxvirus strains have been developed for use as

substrates in recombinant vaccine development. These strains include the

Orthopoxviruses, modified vaccinia Ankara (MVA) and NYVAC (derived from the

Copenhagen vaccinia strain), and the Avipoxviruses, ALVAC and TROVAC

(derived from canarypox and fowlpox viruses, respectively) (33--36) (Table

1).

Animal studies indicate that recombinants are less pathogenic than the

parent strain of vaccinia virus (37). Laboratory-acquired infections with

nonhighly attenuated vaccinia and recombinant viruses derived from

nonhighly attenuated vaccinia strains have been reported (38--41). However,

highly attenuated poxvirus strains (MVA, NYVAC, ALVAC, and TROVAC) are

unable to replicate (MVA, ALVAC, and TROVAC) or replicate poorly (NYVAC) in

mammalian host cells; therefore, highly attenuated poxvirus strains do not

create productive infections (36).

These highly attenuated strains have also been reported to be avirulent

among normal and immunosuppressed animals (MVA, NYVAC, ALVAC, or TROVAC)

and safe among humans (MVA) (33,35,42,43). Although no formal surveillance

system has been established to monitor laboratory workers, no

laboratory-acquired infections resulting from exposure to these highly

attenuated strains or recombinant vaccines derived from these strains have

been reported in the scientific literature or to CDC. Because of the

biological properties and accumulated attenuation data for NYVAC, ALVAC,

and TROVAC, the Recombinant DNA Advisory Committee of the National

Institutes of Health (NIH) reduced the biosafety level for these viruses to

biosafety level 1 (44). The Occupational Safety and Health Board of NIH no

longer requires vaccinia (smallpox) vaccination for personnel manipulating

MVA or NYVAC in a laboratory where no other vaccinia viruses are being

manipulated (45).

During human trials of recombinant vaccines, physicians, nurses, and other

health-care personnel who provide clinical care to recipients of these

vaccines could be exposed to both vaccinia and recombinant viruses. This

exposure could occur from contact with dressings contaminated with the

virus or through exposure to the vaccine. Although the risk for

transmission of recombinant vaccinia viruses to exposed health-care workers

is unknown, no reports of transmission to health-care personnel from

vaccine recipients have been published. If appropriate infection-control

precautions are observed (46,47), health-care workers are at less risk for

infection than laboratory workers because of the smaller volume and lower

titer of virus in clinical specimens compared with laboratory material.

However, the potential does exist of nonhighly attenuated vaccinia viruses

or recombinant viruses derived from these strains being transmitted to

health-care personnel. Therefore, those workers who have direct contact

with contaminated dressings or other infectious material from volunteers in

clinical studies where such strains are used can be offered vaccination.

Vaccination is not indicated for health-care personnel who are exposed to

clinical materials contaminated with highly attenuated poxvirus strains

used to develop vaccine recombinants.

Laboratory and other health-care personnel who work with highly attenuated

strains of vaccinia virus (e.g., MVA and NYVAC) do not require routine

vaccinia vaccination. Laboratory and other health-care personnel who work

with the Avipoxvirus strains ALVAC and TROVAC also do not require routine

vaccinia vaccination because these viruses do not grow in mammalian cells

and, therefore, do not produce clinical infections among humans. In

addition, antibodies induced by vaccinia vaccine are genus-specific (16)

and would probably not inhibit the expression of genes incorporated into

recombinant vaccines derived from ALVAC and TROVAC. Therefore, vaccination

would provide no theoretical benefit in preventing seroconversion to the

foreign antigen expressed by a recombinant virus if an inadvertent exposure

occurred. Laboratory and other health-care personnel who work with viral

cultures or other infective materials should always observe appropriate

biosafety guidelines and adhere to published infection-control procedures

(46--48).

Routine Nonemergency Vaccine Use

Vaccinia vaccine is recommended for laboratory workers who directly handle

a) cultures or animals contaminated or infected with, nonhighly

attenuated vaccinia virus, recombinant vaccinia viruses derived from

nonhighly attenuated vaccinia strains, or other Orthopoxviruses that infect

humans (e.g., monkeypox, cowpox, vaccinia, and variola). Other health-care

workers (e.g., physicians and nurses) whose contact with nonhighly

attenuated vaccinia viruses is limited to contaminated materials (e.g.,

dressings) but who adhere to appropriate infection control measures are at

lower risk for inadvertent infection than laboratory workers. However,

because a theoretical risk for infection exists, vaccination can be offered

to this group. Vaccination is not recommended for persons who do not

directly handle nonhighly attenuated virus cultures or materials or who do

not work with animals contaminated or infected with these viruses.

Vaccination with vaccinia vaccine results in high seroconversion rates and

only infrequent adverse events (see Side Effects and Adverse Reactions).

Recipients of standard potency vaccinia vaccine (Dryvax) receive controlled

percutaneous doses (approximately 2.5 × 105 PFU [3]) of relatively low

pathogenicity vaccinia virus. The resulting immunity should provide

protection to recipients against infections resulting from uncontrolled,

inadvertent inoculation by unusual routes (e.g., the eye) with a

substantial dose of virus of higher or unknown pathogenicity. In addition,

persons with preexisting immunity to vaccinia might be protected against

seroconversion to the foreign antigen expressed by a recombinant virus if

inadvertently exposed (41). However, persons with preexisting immunity to

vaccinia might not receive the full benefit of recombinant vaccinia

vaccines developed for immunization against other infections (31,49).

Routine Nonemergency Revaccination

According to data regarding the persistence of neutralizing antibody after

vaccination, persons working with nonhighly attenuated vaccinia viruses,

recombinant viruses developed from nonhighly attenuated vaccinia viruses,

or other nonvariola Orthopoxviruses should be revaccinated at least every

10 years (13). To ensure an increased level of protection against more

virulent nonvariola Orthopoxviruses (e.g., monkeypox), empiric

revaccination every 3 years can be considered (17).

Side Effects and Adverse Reactions

Vaccine Recipients

Side Effects and Less Severe Adverse Reactions. In a nonimmune person who

is not immunosuppressed, the expected response to primary vaccination is

the development of a papule at the site of vaccination 2--5 days after

percutaneous administration of vaccinia vaccine. The papule becomes

vesicular, then pustular, and reaches its maximum size in 8--10 days. The

pustule dries and forms a scab, which separates within 14--21 days after

vaccination, leaving a scar (Figure 3). Primary vaccination can produce

swelling and tenderness of regional lymph nodes, beginning 3--10 days after

vaccination and persisting for 2--4 weeks after the skin lesion has healed.

Maximum viral shedding from the vaccination site occurs 4--14 days after

vaccination, but vaccinia can be recovered from the site until the scab

separates from the skin (50).

A fever is also common after the vaccine is administered. Approximately 70%

of children experience >1 days of temperatures >100 F for 4--14 days after

primary vaccination (21), and 15%--20% of children experience temperatures

>102 F. After revaccination, 35% of children experience temperatures >100

F, and 5% experience temperatures of >102 F (24). Fever is less common

among adults after vaccination or revaccination (CDC, unpublished data,

undated).

Inadvertent inoculation at other sites is the most frequent complication of

vaccinia vaccination and accounts for approximately half of all

complications of primary vaccination and revaccination (Tables 2,3).

Inadvertent inoculation usually results from autoinoculation of vaccinia

virus transferred from the site of vaccination. The most common sites

involved are the face, eyelid, nose, mouth, genitalia, and rectum (Figure

4). Most lesions heal without specific therapy, but vaccinia immunoglobulin

(VIG) can be useful for cases of ocular implantation (see Treatment for

Vaccinia Vaccine Complications). However, if vaccinial keratitis is

present, VIG is contraindicated because it might increase corneal scarring

(51).

Erythematous or urticarial rashes can occur approximately 10 days after

primary vaccination and can be confused with generalized vaccinia. However,

the vaccinee is usually afebrile with this reaction, and the rash resolves

spontaneously within 2--4 days. Rarely, bullous erythema multiforme (i.e.,

s- syndrome) occurs (52).

Moderate to Severe Adverse Reactions. Moderate and severe complications of

vaccinia vaccination include eczema vaccinatum, generalized vaccinia,

progressive vaccinia, and postvaccinial encephalitis (Table 2). These

complications are rare but occur >10 times more often among primary

vaccinees than among revaccinees and are more frequent among infants than

among older children and adults (53--55) (Table 3). A study of Israeli

military recruits aged >18 years, who were vaccinated during 1991--1996,

reported rates of the severe complications progressive vaccinia (i.e.,

vaccinia necrosum rate: 0/10,000 vaccinees) and postvaccinial encephalitis

(rate: 0/10,000 vaccinees) similar to those reported in previous studies

(56).

Eczema vaccinatum is a localized or systemic dissemination of vaccinia

virus among persons who have eczema or a history of eczema or other chronic

or exfoliative skin conditions (e.g., atopic dermatitis) (Figure 5).

Usually, illness is mild and self-limited but can be severe or fatal. The

most serious cases among vaccine recipients occur among primary vaccinees

and are independent of the activity of the underlying eczema (57). Severe

cases have been observed also after contact of recently vaccinated persons

with persons who have active eczema or a history of eczema (see Contacts of

Vaccinees) (Figure 6).

Generalized vaccinia is characterized by a vesicular rash of varying extent

that can occur among persons without underlying illnesses (Figure 7). The

rash is generally self-limited and requires minor or no therapy except

among patients whose conditions might be toxic or who have serious

underlying immunosuppressive illnesses (e.g., acquired immunodeficiency

syndrome [AIDS]) (58).

Progressive vaccinia (vaccinia necrosum) is a severe, potentially fatal

illness characterized by progressive necrosis in the area of vaccination,

often with metastatic lesions (Figure 8). It has occurred almost

exclusively among persons with cellular immunodeficiency. The most serious

complication is postvaccinial encephalitis. In the majority of cases, it

affects primary vaccinees aged <1 year or adolescents and adults receiving

a primary vaccination (3). Occurrence of this complication was influenced

by the strain of vaccine virus and was higher in Europe than in the United

States. The principle strain of vaccinia virus used in the United States,

NYCBOH, was associated with the lowest incidence of postvaccinial

encephalitis (3). Approximately 15%--25% of affected vaccinees with this

complication die, and 25% have permanent neurological sequelae (52--54).

Fatal complications caused by vaccinia vaccination are rare, with

approximately 1 death/million primary vaccinations and 0.25 deaths/million

revaccinations (54). Death is most often the result of postvaccinial

encephalitis or progressive vaccinia.

Contacts of Vaccinees

Transmission of vaccinia virus can occur when a recently vaccinated person

has contact with a susceptible person. In a 1968 10-state survey of

complications of vaccinia vaccination, the risk for transmission to

contacts was 27 infections/million total vaccinations; 44% of those contact

cases occurred among children aged <5 years (53). Before the U.S. military

discontinued routine smallpox vaccination in 1990, occurrences of contact

transmission of vaccinia virus from recently vaccinated military recruits

had been reported, including six cases resulting from transmission from one

vaccine recipient (59--61).

Approximately 60% of contact transmissions reported in the 1968 10-state

survey resulted in inadvertent inoculation of otherwise healthy persons.

Approximately 30% of the eczema vaccinatum cases reported in that study

were a result of contact transmission (53). Eczema vaccinatum might be more

severe among contacts than among vaccinated persons, possibly because of

simultaneous multiple inoculations at several sites (54,62). Contact

transmission rarely results in postvaccinial encephalitis or vaccinia

necrosum.

Precautions and Contraindications

Routine Nonemergency Laboratory and Health-Care Worker Contraindications

The following contraindications to vaccination apply to routine

nonemergency use of vaccinia vaccine (see Smallpox Vaccine for Bioterrorism

Preparedness for information regarding precautions and contraindications to

vaccination during a smallpox outbreak emergency) (Table 4). Before

administering vaccinia vaccine, the physician should complete a thorough

patient history to document the absence of vaccination contraindications

among both vaccinees and their household contacts. Efforts should be made

to identify vaccinees and their household contacts who have eczema, a

history of eczema, or immunodeficiencies. Vaccinia vaccine should not be

administered for routine nonemergency indications if these conditions are

present among either recipients or their household contacts.

History or Presence of Eczema or Other Skin Conditions

Because of the increased risk for eczema vaccinatum, vaccinia vaccine

should not be administered to persons with eczema of any degree, those with

a past history of eczema, those whose household contacts have active

eczema, or whose household contacts have a history of eczema. Persons with

other acute, chronic, or exfoliative skin conditions (e.g., atopic

dermatitis, burns, impetigo, or varicella zoster) might also be at higher

risk for eczema vaccinatum and should not be vaccinated until the condition

resolves.

Pregnancy

Live-viral vaccines are contraindicated during pregnancy; therefore,

vaccinia vaccine should not be administered to pregnant women for routine

nonemergency indications. However, vaccinia vaccine is not known to cause

congenital malformations (63). Although <50 cases of fetal vaccinia

infection have been reported, vaccinia virus has been reported to cause

fetal infection on rare occasions, almost always after primary vaccination

of the mother (64). Cases have been reported as recently as 1978 (55,65).

When fetal vaccinia does occur, it usually results in stillbirth or death

of the infant soon after delivery.

Altered Immunocompetence

Replication of vaccinia virus can be enhanced among persons with

immunodeficiency diseases and among those with immunosuppression (e.g., as

occurs with leukemia, lymphoma, generalized malignancy, solid organ

transplantation, cellular or humoral immunity disorders, or therapy with

alkylating agents, antimetabolites, radiation, or high-dose corticosteroid

therapy [i.e., >2 mg/kg body weight or 20 mg/day of prednisone for >2

weeks] [66]). Persons with immunosuppression also include hematopoietic

stem cell transplant recipients who are <24 months posttransplant, and

hematopoietic stem cell transplant recipients who are >24 months

posttransplant but who have graft-versus-host disease or disease relapse.

Persons with such conditions or whose household contacts have such

conditions should not be administered vaccinia vaccine.

Persons Infected with HIV

Risk for severe complications after vaccinia vaccination for persons

infected with HIV is unknown. One case of severe generalized vaccinia has

been reported involving an asymptomatic HIV-infected military recruit after

the administration of multiple vaccines that included vaccinia vaccine

(58). Additionally, a 1991 report indicated that two HIV-infected persons

might have died of a progressive vaccinia-like illness after treatment with

inactivated autologous lymphocytes infected with a recombinant HIV-vaccinia

virus (67). No evidence exists that smallpox vaccination accelerates the

progression of HIV-related disease. However, the degree of

immunosuppression that would place an HIV-infected person at greater risk

for adverse events is unknown. Because of this uncertainty, until

additional information becomes available, not vaccinating persons (under

routine nonemergency conditions) who have HIV infection is advisable.

Infants and Children

Before the eradication of smallpox, vaccinia vaccination was administered

routinely during childhood. However, smallpox vaccination is no longer

indicated for infants or children for routine nonemergency indications.

Persons with Allergies to Vaccine Components

The currently available vaccinia vaccine (i.e., Dryvax) contains trace

amounts of polymyxin B sulfate, streptomycin sulfate, chlortetracycline

hydrochloride, and neomycin sulfate. Persons who experience anaphylactic

reactions (i.e., hives, swelling of the mouth and throat, difficulty

breathing, hypotension, and shock) to any of these antibiotics should not

be vaccinated. Vaccinia vaccine does not contain penicillin. Future

supplies of vaccinia vaccine will be reformulated and might contain other

preservatives or stabilizers. Refer to the manufacturer's package insert

for additional information.

Treatment for Vaccinia Vaccine Complications

Using VIG

The only product currently available for treatment of complications of

vaccinia vaccination is VIG, which is an isotonic sterile solution of the

immunoglobulin fraction of plasma from persons vaccinated with vaccinia

vaccine. It is effective for treatment of eczema vaccinatum and certain

cases of progressive vaccinia; it might be useful also in the treatment of

ocular vaccinia resulting from inadvertent implantation (68,69). However,

VIG is contraindicated for the treatment of vaccinial keratitis (51,54).

VIG is recommended for severe generalized vaccinia if the patient is

extremely ill or has a serious underlying disease. VIG provides no benefit

in the treatment of postvaccinial encephalitis and has no role in the

treatment of smallpox. Current supplies of VIG are limited, and its use

should be reserved for treatment of vaccine complications with serious

clinical manifestations (e.g., eczema vaccinatum, progressive vaccinia,

severe generalized vaccinia, and severe ocular viral implantation) (Table 2).

The recommended dosage of the currently available VIG for treatment of

complications is 0.6 ml/kg of body weight. VIG must be administered

intramuscularly and should be administered as early as possible after the

onset of symptoms. Because therapeutic doses of VIG might be substantial

(e.g., 42 ml for a person weighing 70 kg), the product should be

administered in divided doses over a 24- to 36-hour period. Doses can be

repeated, usually at intervals of 2--3 days, until recovery begins (e.g.,

no new lesions appear). Future reformulations of VIG might require

intravenous administration, and health-care providers should refer to the

manufacturer's package insert for correct dosages and route of

administration. CDC is currently the only source of VIG for civilians (see

Vaccinia Vaccine Availability for contact information).

Other Treatment Options for Vaccinia Vaccine Complications

The Food and Drug Administration has not approved the use of any antiviral

compound for the treatment of vaccinia virus infections or other

Orthopoxvirus infections, including smallpox. Certain antiviral compounds

have been reported to be active against vaccinia virus or other

Orthopoxviruses in vitro and among test animals (70--75). However, the

safety and effectiveness of these compounds for treating vaccinia

vaccination complications or other Orthopoxvirus infections among humans is

unknown. Questions also remain regarding the effective dose and the timing

and length of administration of these antiviral compounds. Insufficient

information exists on which to base recommendations for any antiviral

compound to treat postvaccination complications or Orthopoxvirus

infections, including smallpox. However, additional information could

become available, and health-care providers should consult CDC to obtain

up-dated information regarding treatment options for smallpox vaccination

complications (see Consultation Regarding Complications of Vaccinia Vaccine).

Consultation Regarding Complications of Vaccinia Vaccine

CDC can assist physicians in the diagnosis and management of patients with

suspected complications of vaccinia vaccination. VIG is available when

indicated. Physicians should telephone CDC at (404) 639-3670 during

Mondays--Fridays, except holidays, or (404) 639-3311 during evenings,

weekends, and holidays. Health-care workers are requested to report

complications of vaccinia vaccination to the Vaccine Adverse Event

Reporting System at (800) 822-7967, or to their state or local health

department.

PREVENTING CONTACT TRANSMISSION OF VACCINIA VIRUS

Vaccinia virus can be cultured from the site of primary vaccination

beginning at the time of development of a papule (i.e., 2--5 days after

vaccination) until the scab separates from the skin lesion (i.e., 14--21

days after vaccination). During that time, care must be taken to prevent

spread of the virus to another area of the body or to another person by

inadvertent contact. Thorough hand-hygiene with soap and water or

disinfecting agents should be performed after direct contact with the site

or materials that have come into contact with the site to remove virus from

the hands and prevent accidental inoculation to other areas of the body

(76). In addition, care should be taken to prevent contact of the site or

contaminated materials from the site by unvaccinated persons. The

vaccination site can be left uncovered, or it can be loosely covered with a

porous bandage (e.g., gauze) until the scab has separated on its own to

provide additional barrier protection against inadvertent inoculation. An

occlusive bandage should not be routinely used because maceration of the

site might occur. Bandages used to cover the vaccination site should be

changed frequently (i.e., every 1--2 days) to prevent maceration of the

vaccination site secondary to fluid buildup. Hypoallergenic tape should be

used for persons who experience tape hypersensitivity. The vaccination site

should be kept dry, although normal bathing can continue. No salves or

ointments should be placed on the vaccination site. Contaminated bandages

and, if possible, the vaccination site scab, after it has fallen off,

should be placed in sealed plastic bags before disposal in the trash to

further decrease the potential for inadvertent transmission of the live

virus contained in the materials. Clothing or other cloth materials that

have had contact with the site can be decontaminated with routine

laundering in hot water with bleach (2,4).

Recently vaccinated health-care workers should avoid contact with

unvaccinated patients, particularly those with immunodeficiencies, until

the scab has separated from the skin at the vaccination site. However, if

continued contact with unvaccinated patients is unavoidable, health-care

workers can continue to have contact with patients, including those with

immunodeficiencies, as long as the vaccination site is well-covered and

thorough hand-hygiene is maintained. In this setting, a more occlusive

dressing might be required. Semipermeable polyurethane dressings (e.g.,

Opsite®) are effective barriers to vaccinia and recombinant vaccinia

viruses (31). However, exudates can accumulate beneath the dressing, and

care must be taken to prevent viral contamination when the dressing is

removed. In addition, accumulation of fluid beneath the dressing can

increase the maceration of the vaccination site. Accumulation of exudates

can be decreased by first covering the vaccination site with dry gauze,

then applying the dressing over the gauze. The dressing should also be

changed at least once a day. To date, experience with this type of

containment dressing has been limited to research protocols. The most

critical measure in preventing inadvertent implantation and contact

transmission from vaccinia vaccination is thorough hand-hygiene after

changing the bandage or after any other contact with the vaccination site.

VACCINATION METHOD

The skin over the insertion of the deltoid muscle or the posterior aspect

of the arm over the triceps muscle are the preferred sites for smallpox

vaccination. Alcohol or other chemical agents are not required for skin

preparation for vaccination unless the area is grossly contaminated. If

alcohol is used, the skin must be allowed to dry thoroughly to prevent

inactivation of the vaccine by the alcohol. The multiple-puncture technique

uses a presterilized bifurcated needle that is inserted vertically into the

vaccine vial, causing a droplet of vaccine to adhere between the prongs of

the needle. The droplet contains the recommended dosage of vaccine, and its

presence within the prongs of the bifurcated needle should be confirmed

visually. Holding the bifurcated needle perpendicular to the skin, 15

punctures are rapidly made with strokes vigorous enough to allow a trace of

blood to appear after 15--20 seconds (3). Any remaining vaccine should be

wiped off with dry sterile gauze and the gauze disposed of in a biohazard

waste container.

EVIDENCE OF IMMUNITY AND VACCINATION-RESPONSE INTERPRETATION

Appearance of neutralizing antibodies after vaccination with live vaccinia

virus indicates an active immune response that includes the development of

antibodies to all viral antigens and increased vaccinia-specific

cell-mediated immunity. In a person with normal immune function,

neutralizing antibodies appear approximately 10 days after primary

vaccination and 7 days after revaccination (3). Clinically, persons are

considered fully protected after a successful response is demonstrated at

the site of vaccination.

The vaccination site should be inspected 6--8 days after vaccination and

the response interpreted at that time. Two types of responses have been

defined by the World Health Organization (WHO) Expert Committee on

Smallpox. The responses include a) major reaction, which indicates that

virus replication has taken place and vaccination was successful; or

equivocal reaction, which indicates a possible consequence of immunity

adequate to suppress viral multiplication or allergic reactions to an

inactive vaccine without production of immunity.

Major Reaction

Major (i.e., primary) reaction is defined as a vesicular or pustular lesion

or an area of definite palpable induration or congestion surrounding a

central lesion that might be a crust or an ulcer. The usual progression of

the vaccination site after primary vaccination is as follows:

The inoculation site becomes reddened and pruritic 3--4 days after

vaccination.

A vesicle surrounded by a red areola then forms, which becomes umbilicated

and then pustular by days 7--11 after vaccination.

The pustule begins to dry; the redness subsides; and the lesion becomes

crusted between the second and third week. By the end of approximately the

third week, the scab falls off, leaving a permanent scar that at first is

pink in color but eventually becomes flesh-colored (77).

Skin reactions after revaccination might be less pronounced with more rapid

progression and healing than those after primary vaccinations.

Revaccination is considered successful if a pustular lesion is present or

an area of definite induration or congestion surrounding a central lesion

(i.e., scab or ulcer) is visible upon examination 6--8 days after

revaccination (3).

Equivocal Reaction

Equivocal reaction, including accelerated, modified, vaccinoid, immediate,

early, or immune reactions, are defined as all responses other than major

reactions. If an equivocal reaction is observed, vaccination procedures

should be checked and the vaccination repeated by using vaccine from

another vial or vaccine lot, if available. Difficulty in determining if the

reaction was blunted could be caused by immunity, insufficiently potent

vaccine, or vaccination technique failure. If the repeat vaccination by

using vaccine from another vial or vaccine lot fails to elicit a major

reaction, health- care providers should consult CDC or their state or local

health department before attempting another vaccination.

MISUSE OF VACCINIA VACCINE

Vaccinia vaccine should not be used therapeutically for any reason. No

evidence exists that vaccinia vaccine has any value in treating or

preventing recurrent herpes simplex infection, warts, or any disease other

than those caused by human Orthopoxviruses (78). Misuse of vaccinia vaccine

to treat herpes infections has been associated with severe complications,

including death (54,79,80).

VACCINIA VACCINE AVAILABILITY

CDC is the only source of vaccinia vaccine and VIG for civilians. CDC will

provide vaccinia vaccine to protect laboratory and other health-care

personnel whose occupations place them at risk for exposure to vaccinia and

other closely related Orthopoxviruses, including vaccinia recombinants.

Vaccine should be administered under the supervision of a physician

selected by the institution. Vaccine will be shipped to the responsible

physician. Requests for vaccine and VIG, including the reason for the

request, should be referred to

Centers for Disease Control and Prevention

Drug Services, National Center for Infectious Diseases

Mailstop D-09

Atlanta, GA 30333

Telephone: (404) 639-3670

Facsimile: (404) 639-3717

--------------------------------------------------------

Sheri Nakken, R.N., MA

Vaccination Information & Choice Network, Nevada City CA & UK

$$ Donations to help in the work - accepted by Paypal account

vaccineinfo@...

(go to http://www.paypal.com) or by mail

PO Box 1563 Nevada City CA 95959 530-740-0561 Voicemail in US

http://www.nccn.net/~wwithin/vaccine.htm

ANY INFO OBTAINED HERE NOT TO BE CONSTRUED AS MEDICAL OR LEGAL ADVICE. THE

DECISION TO VACCINATE IS YOURS AND YOURS ALONE.

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