Vaccinia Immune Globulin Research Articles

Prevention of Vaccinia Infection in a Laboratory Worker

Because smallpox may be a weapon, immunization programs have been restarted and research continues with vaccinia (smallpox vaccine). Ocular complications occur in 5 to 9% of those who contract smallpox and in 10 to 20 per million vaccinia recipients through self-inoculation or from contact with vaccinated individuals. Both variola virus (smallpox) and vaccinia virus (smallpox vaccine) are orthopoxviruses that can cause conjunctival and eyelid infections, cornea ulceration, keratitis, iritis, optic neuritis, and loss of vision. Clinicians should maintain a high index of suspicion for smallpox vaccine-associated reactions in vaccinia researchers, the immunized, and their close contacts. A researcher sprayed vaccinia in her eye. Timely irrigation may have prevented a viral infection. The possibility that this individual had self-immunized herself with smallpox vaccine via the conjunctiva and preventive measures are discussed. Greater precautionary measures need to be taken to prevent laboratory accidents. Antiviral ophthalmic medication and vaccinia-immune globulin medication are treatment options.

Antibodies to the A27 Protein of Vaccinia Virus Neutralize and Protect against Infection but Represent a Minor Component of Dryvax Vaccine–Induced Immunity

The smallpox vaccine Dryvax, which consists of replication-competent vaccinia virus, elicits antibodies that play a major role in protection. Several vaccinia proteins generate neutralizing antibodies, but their importance for protection is unknown. We investigated the potency of antibodies to the A27 protein of the mature virion in neutralization and protection experiments and the contributions of A27 antibodies to Dryvax-induced immunity. Using a recombinant A27 protein (rA27), we confirmed that A27 contains neutralizing determinants and that vaccinia immune globulin (VIG) derived from Dryvax recipients contains reactivity to A27. However, VIG neutralization was not significantly reduced when A27 antibodies were removed, and antibodies elicited by an rA27 enhanced the protection conferred by VIG in passive transfer experiments. These findings demonstrate that A27 antibodies do not represent the major fraction of neutralizing activity in VIG and suggest that immunity may be augmented by vaccines and immune globulins that include strong antibody responses to A27.

Genomic sequence and analysis of a vaccinia virus isolate from a patient with a smallpox vaccine-related complication

BackgroundVaccinia virus (VACV)-DUKE was isolated from a lesion on a 54 year old female who presented to a doctor at the Duke University Medical Center. She was diagnosed with progressive vaccinia and treated with vaccinia immune globulin. The availability of the VACV-DUKE genome sequence permits a first time genomic comparison of a VACV isolate associated with a smallpox vaccine complication with the sequence of culture-derived clonal isolates of the Dryvax vaccine.ResultsThis study showed that VACV-DUKE is most similar to VACV-ACAM2000 and CLONE3, two VACV clones isolated from the Dryvax® vaccine stock confirming VACV-DUKE as an isolate from Dryvax®. However, VACV-DUKE is unique because it is, to date, the only Dryvax® clone isolated from a patient experiencing a vaccine-associated complication. The 199,960 bp VACV-DUKE genome encodes 225 open reading frames, including 178 intact genes and 47 gene fragments. Between VACV-DUKE and the other Dryvax® isolates, the major genomic differences are in fragmentation of the ankyrin-like, and kelch-like genes, presence of a full-length Interferon-α/β receptor gene, and the absence of a duplication of 12 ORFs in the inverted terminal repeat. Excluding this region, the DNA sequence of VACV-DUKE differs from the other two Dryvax® isolates by less than 0.4%. DNA sequencing also indicated that there was little heterogeneity in the sample, supporting the hypothesis that virus from an individual lesion is clonal in origin despite the fact that the vaccine is a mixed population.ConclusionVirus in lesions that result from progressive vaccinia following vaccination with Dryvax are likely clonal in origin. The genomic sequence of VACV-DUKE is overall very similar to that of Dryvax® cell culture-derived clonal isolates. Furthermore, with the sequences of multiple clones from Dryvax® we can begin to appreciate the diversity of the viral population in the smallpox vaccine.

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Chimpanzee/human mAbs to vaccinia virus B5 protein neutralize vaccinia and smallpox viruses and protect mice against vaccinia virus

Chimpanzee Fabs against the B5 envelope glycoprotein of vaccinia virus were isolated and converted into complete mAbs with human gamma 1 heavy chain constant regions. The two mAbs (8AH8AL and 8AH7AL) displayed high binding affinities to B5 (Kd of 0.2 and 0.7 nM). The mAb 8AH8AL inhibited the spread of vaccinia virus as well as variola virus (the causative agent of smallpox) in vitro, protected mice from subsequent intranasal challenge with virulent vaccinia virus, protected mice when administered 2 days after challenge, and provided significantly greater protection than that afforded by a previously isolated rat anti-B5 mAb (19C2) or by vaccinia immune globulin. The mAb bound to a conformational epitope between amino acids 20 and 130 of B5. These chimpanzee/human anti-B5 mAbs may be useful in the prevention and treatment of vaccinia virus-induced complications of vaccination against smallpox and may also be effective in the immunoprophylaxis and immunotherapy of smallpox.

Adverse Events Associated With Smallpox Vaccination in the United States, January-October 2003

On January 24, 2003, the US Department of Health and Human Services (DHHS) implemented a preparedness program in which smallpox (vaccinia) vaccine was administered to federal, state, and local volunteers who might be first responders during a bioterrorism event. To describe results from the comprehensive DHHS smallpox vaccine safety monitoring and response system. Descriptive study of adverse event reports from the DHHS smallpox vaccine safety monitoring and response system received between January 24 and October 31, 2003, through the Vaccine Adverse Event Reporting System (VAERS) and the Centers for Disease Control and Prevention. A total of 37,901 volunteers in 55 jurisdictions received at least 1 dose of smallpox vaccine. Number of vaccinations administered and description of adverse events and reporting rates. A total of 38,885 smallpox vaccinations were administered, with a take rate of 92%. VAERS received 822 reports of adverse events following smallpox vaccination (overall reporting rate, 217 per 10,000 vaccinees). A total of 590 adverse events (72%) were reported within 14 days of vaccination. Nonserious adverse events (n = 722) included multiple signs and symptoms of mild and self-limited local reactions. One hundred adverse events (12%) were designated as serious, resulting in 85 hospitalizations, 2 permanent disabilities, 10 life-threatening illnesses, and 3 deaths. Among the serious adverse events, 21 cases were classified as myocarditis and/or pericarditis and 10 as ischemic cardiac events that were not anticipated based on historical data. Two cases of generalized vaccinia and 1 case of postvaccinial encephalitis were detected. No preventable life-threatening adverse reactions, contact transmissions, or adverse reactions that required treatment with vaccinia immune globulin were identified. Serious adverse events were more common among older revaccinees than younger first-time vaccinees. Rigorous smallpox vaccine safety screening, educational programs, and older vaccinees may have contributed to low rates of preventable life-threatening adverse reactions. Other rare, clinically significant, or unexpected cardiac adverse events were detected by timely review of VAERS data and intensive clinical case investigation.

Identification and preliminary characterization of vaccinia virus (Dryvax) antigens recognized by vaccinia immune globulin

Using vaccinia immune globulin (VIG), a high-titer antibody preparation from immunized subjects, we demonstrate that the humoral immune response in humans is directed against numerous antigens in the Dryvax vaccine strain. Western blot and immunoprecipitation analyses revealed highly antigenic proteins associated with both the extracellular enveloped virus and intracellular mature virus forms. The modified vaccinia virus Ankara (MVA), a new generation smallpox vaccine that is attenuated for replication in humans, expresses most, but not all, of the major vaccinia antigens recognized by antibodies in VIG, lacking the highly antigenic protein corresponding to the A-type inclusion body protein. Since new-generation smallpox vaccines such as MVA will require extensive comparison to traditional smallpox vaccines in animal models of immunogenicity and protection, we compared the vaccinia virus antigens recognized by VIG to those recognized by sera from Dryvax and MVA immunized mice. The humoral immune response in immunized mice is qualitatively similar to that in humans.

Biological Activity of an Intravenous Preparation of Human Vaccinia Immune Globulin in Mouse Models of Vaccinia Virus Infection

The biological activity of a new intravenous (i.v.) preparation of human vaccinia immune globulin (VIGIV) was evaluated in two mouse models of vaccinia virus (VV) infection. In a mouse tail lesion model, female CD-1 mice were inoculated i.v. with 7 x 10(4) PFU of VV to produce >10 lesions per tail 8 days later. In a mouse lethality model, female severe combined immunodeficient (SCID) mice were inoculated i.v. with 3 x 10(4) PFU of VV to produce 100% mortality within 45 days. The ability of VIGIV to reduce tail lesion formation in CD-1 mice and mortality in SCID mice was determined by (i) pretreatment of a lethal VV dose with VIGIV prior to i.v. inoculation into SCID mice and (ii) i.v. administration of VIGIV to CD-1 and SCID mice the day before and up to 8 days after VV infection. VIGIV reduced the proportion of CD-1 mice with >10 tail lesions in a dose-related manner when VIGIV was given 1 day before and up to 1 day after VV inoculation. The pretreatment of VV with VIGIV prolonged survival and decreased mortality. VIGIV (100 and 400 mg/kg) prolonged survival when given up to 4 days after VV inoculation, and the 400-mg/kg dose reduced the mortality rate by 80% when given the day before or immediately after VV inoculation. The biological activity of VIGIV was demonstrated in both the immunocompetent and immunocompromised murine models. The timing of treatment relative to VV inoculation appeared to be important for the demonstration of VIGIV's biological activity.

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An investigation of the therapeutic value of vaccinia-immune IgG in a mouse pneumonia model

Vaccinia-immune globulin (VIG) was used to treat severe complications of smallpox vaccination, but its use was controversial because it resolved disease in only some clinical cases. VIG is a pool of hyperimmune sera collected from individuals with a high neutralizing titre against the intracellular mature form (IMV) of vaccinia virus (VACV), but activity against the extracellular enveloped form (EEV) was often not considered. Here, the efficacy of anti-VACV antibodies (Abs) in protecting mice from intranasal infection with the VACV strain Western Reserve (WR) was evaluated. Mice were immunized passively with hyperimmune rabbit Abs (IgG) generated against inactivated IMV or produced following infection by VACV; subsequently, animals were challenged with VACV WR. The results demonstrated that: (i) good protection requires Abs to EEV in addition to IMV; (ii) Abs were effective when given before or up to 4 days after infection; and (iii) protection of mice from VACV WR correlated with a reduction of virus replication in lungs, but not in brain. In agreement with studies conducted before smallpox was eradicated and recent studies using EEV antigens for immunization, this study reiterates the importance of anti-EEV Abs in protecting against orthopoxvirus infection and illustrates the need to evaluate both anti-IMV and anti-EEV neutralizing Abs in VIG.

Pregnancy discovered after smallpox vaccination: Is vaccinia immune globulin appropriate?

Smallpox vaccination just before conception or during pregnancy can result, in rare instances, in fetal vaccinia from viral infection of the fetus. Approximately 50 cases have been documented, despite literally billions of people having been vaccinated. This live viral vaccine has a wider array of rare but serious medical side effects (eg, eczema vaccinatum, progressive vaccinia, encephalitis, myopericarditis) compared with other vaccines that are given currently to the public. In response to recent world events, the Centers for Disease Control and Prevention and the United States Department of Defense established a preoutbreak smallpox vaccination program. Because no actual outbreak has yet occurred, some investigators have proposed prophylactic treatment with vaccinia immune globulin for pregnancies that are exposed to smallpox vaccine to prevent fetal vaccinia. We review the existing medical literature to access the risks of fetal vaccinia in these pregnancies and the controversy regarding the prophylactic use of vaccinia immune globulin.

Ocular complications in the Department of Defense Smallpox Vaccination Program

Objective The purpose of this case series was to present an overview of the nature and frequency of ocular complications in the Department of Defense (DoD) Smallpox Vaccination Program. Design Retrospective, noncomparative case series. Participants The authors retrospectively evaluated data collected on individuals with an ophthalmologic complaint after receiving smallpox vaccination or after contact with a recently immunized individual. The vaccinee and contact cases occurred secondary to inoculations given between December 13, 2002 and May 28, 2003 as part of the DoD Smallpox Vaccination Program. Methods Data were collected primarily from reports to military headquarters or to the Vaccine Adverse Event Reporting System and individual medical records. Main outcome measures The incidence, types, and timing of ocular complications were evaluated. Diagnostic and treatment considerations also were reviewed. Results Between December 13, 2002 and May 28, 2003, 450,293 smallpox vaccinations were given. We identified 16 confirmed or probable cases of ocular vaccinia, with an incidence of 3.6 per 100,000 inoculations. Of these cases, 12 (75%) were seen in the vaccinees, and 4 (25%) in close contacts. Of the 12 self-inoculation cases, 7 (58.3%) were seen in individuals receiving the vaccine for the first time (primary vaccination), and 3 (25.0%) were seen in individuals previously vaccinated (revaccination); the vaccination status in 2 cases was unknown. Clinical manifestations included lid pustules, blepharitis, periorbital cellulitis, conjunctivitis, conjunctival ulcers, conjunctival membranes, limbal pustules, corneal infiltrates, and iritis, with onset of symptoms 3 to 24 days after inoculation or contact. Five of 9 tested cases were culture or polymerase chain reaction positive for vaccinia. Treatment for most cases was topical trifluridine 1% (Viroptic; King Pharmaceuticals, Inc., Bristol, TN). Vaccinia immune globulin was used in 1 case. In all patients, recovery occurred without significant visual sequelae. Conclusions When compared with historical data on the ocular complications of smallpox vaccination, the incidence of ocular complications during the DoD Smallpox Vaccination program has been low. In addition, the severity of disease seems to be less than during other vaccination periods. These findings perhaps are the result of improved screening of vaccinees, prevaccination counseling, postvaccination wound care, and the suggested efficacy of trifluridine in the treatment of ocular vaccinia.

Smallpox containment updated: considerations for the 21st century

Smallpox containment updated: considerations for the 21st century

Smallpox containment updated: considerations for the 21st century

SummaryThe emergence and re-emergence of infectious diseases since the eradication of smallpox has had a direct impact on preparedness for a deliberately-caused smallpox outbreak, should one occur. The emergence of HIV has placed restrictions on the safe and effective use of smallpox vaccines and made the need for vaccinia immune globulin important for outbreak control. At the same time, the threat of international spread of emerging and re-emerging infections has prompted global investments in surveillance and response mechanisms such as the Global Outbreak Alert and Response Network (GOARN), a mechanism that would enhance the world's collaboration in smallpox containment as it did during the recent outbreak of SARS. Though global preparedness for a deliberately-caused smallpox outbreak has increased with the creation of GOARN, it does not replace the need for increased national public health investment to expand surge capacity for the management of patients and their contacts and to strengthen emergency communication networks to ensure effective response.

Clinical efficacy of intramuscular vaccinia immune globulin: a literature review.

Numerous literature reports describe clinical efficacy of intramuscular vaccinia immune globulin (VIG) for complications of smallpox vaccination, prophylaxis of individuals with contraindications to vaccination, and prevention of smallpox among close contacts of patients with smallpox. We reviewed the literature regarding VIG treatment and prophylaxis of smallpox vaccine complications and the use of VIG as a preventative measure for close contacts of patients with smallpox. Data regarding intramuscular administration of VIG for treatment of smallpox vaccine complications occurred in 16 articles, none of which reported formal controlled trials. The indications for treatment include generalized vaccinia, progressive vaccinia, eczema vaccinatum, and certain accidental implantations. Six publications suggest VIG efficacy for prophylaxis of vaccinial superinfection of eczema, burns, chickenpox, immunosuppression, pregnancy, or certain skin conditions. Prophylactic VIG has also been used in healthy military recruits to reduce the incidence of postvaccinial encephalitis. The use of intramuscular administration of VIG to prevent smallpox in contacts of patients with documented cases of smallpox is reported in 4 studies that compare contacts who received intramuscular administration of VIG with those who did not and in 1 observational study, with varying but promising results. Although controlled clinical trials do not exist to support the use of VIG for treatment of vaccinia-related complications or prophylaxis among individuals with contraindications to smallpox vaccination, available data suggest that VIG reduces morbidity and mortality associated with progressive vaccinia (vaccinia necrosum) and eczema vaccinatum. Furthermore, VIG seems to prevent vaccinial superinfection in patients with inflammatory skin diseases or burns, given the low incidence of vaccina-related complications associated with these conditions.

Antibodies against the extracellular enveloped virus B5R protein are mainly responsible for the EEV neutralizing capacity of vaccinia immune globulin

In the event of smallpox bioterrorism, widespread vaccination may be required. Vaccinia immune globulin (VIG) has been used to treat complications from the smallpox vaccine. While the potency of VIG was defined by its ability to neutralize intracellular mature virus, a second form of vaccinia called the extracellular enveloped virus (EEV) is critical for virus spread in the host. The B5R-protein is one of many EEV-specific proteins. Immunoprecipitation and ELISA revealed that VIG recognizes the B5R-protein. An EEV plaque-reduction assay using a recombinant vaccinia that lacks the majority of the extracellular domain of B5R showed that the ability of VIG to neutralize EEV is principally directed at B5R. In addition, absorbing out the anti-B5R antibody present in VIG through the addition of recombinant B5R protein abrogated VIG's ability to significantly neutralize wild-type EEV. This work demonstrates the prominent role of B5R as a target of EEV-neutralizing activity of human antibodies.

Ocular vaccinia following exposure to a smallpox vaccinee

PurposeTo describe the presentation and management of the first identified case of ocular vaccinia infection associated with the current smallpox vaccination program. DesignCase report. MethodsVaccinia virus was isolated by cell culture of a conjunctival swab. Direct staining with fluorescein isothiocyanate-labeled vaccinia antibody and polymerase chain reaction testing confirmed the diagnosis. ResultsIn February 2003, a 26-year-old woman developed right preseptal cellulitis and blepharoconjunctivitis following contact with a vaccinated member of the military. The preseptal cellulitis resolved with antibacterial therapy, and the conjunctival infection was treated successfully with a 14-day course of topical trifluridine and a single dose of intravenous vaccinia immune globulin. ConclusionsTo facilitate rapid diagnosis and appropriate treatment, clinicians must maintain a high index of suspicion for ocular smallpox vaccine-associated adverse reactions in vaccine recipients and their close contacts.

Frequency of revaccination against smallpox.

Recent suggestions to revise guidelines that recommend extending the time for revaccination beyond 10 years may be based on insufficient and conflicting evidence of persistence of immunity (1,2). The evidence that cell-mediated immunity and neutralizing antibody persist after one vaccination is conflicting (2–5). This residual immunity is often low, and its protective activity in vivo is unclear. Similarly, in vivo reports of durable immunity to smallpox (1) were not sufficiently controlled, and short persistence of resistance to dermal challenge with the antigenically related vaccinia virus has been reported (3,6). We confirmed the previous report (5) that the residual antivaccinia virus titers of serum samples from singly vaccinated adults are low (average 32) (Table). The titer of normal commercial immunoglobulin (Ig) (Panglobulin) (11 times concentrated sera) was 150 U/mL, which when calculated to include the 11-fold concentration, confirms the low residual titers. Table Residual vaccinia virus neutralizing titers of serum from vaccinated and unvaccinated persons The titers of the control, unvaccinated persons, averaged 14, raising questions about the importance and specificity of the residual antibody in vaccinated persons. We determined that the persistent neutralizing activity is mainly IgG antibody in serum from both single-vaccinated persons and ordinary commercial IgG, since sequential absorption with protein G beads and anti-IgG beads reduced the titers 80%. However, the neutralizing activity in unvaccinated control serum may not be mainly IgG antibody since neutralizing activity was reduced by an average of 48%, favoring nonspecific inhibitors. Studies of these nonspecific inhibitors and possible cross-immunizing antigens in the environment should be conducted to explain the occurrence of neutralizing activity in serum of unvaccinated persons. To determine whether the low residual titers in sera from single vaccinated persons protected in vivo against a systemic infection, mice were pretreated subcutaneously with 1 mL of either 1) serum from a single-vaccinated study participant containing the low 10 U/mL neutralizing activity (patient A), 2) serum from a single-vaccinated person containing the higher 43 U/mL (patient E), or 3) normal commercial Ig containing 150 U/mL and challenged 24 hours later with one LD100 vaccinia virus, strain IHD-E, intraperitoneally. The 1 mL of serum injected into the mice is estimated to provide its original titer in the mouse. The lowest titer serum (10 U/mL) did not protect the mice against lethal systemic infection, whereas the highest titer serum (43 U/mL) and the commercial Ig (150 U/mL) protected 50% of the mice. Thus, the levels of residual antibody in vaccinated persons are either not protective or only partially protective in mice. Consistent with the reported protection by the higher levels of antibody, vaccinia immune globulin (VIG), which contains 500 neutralizing U/mL, is effective under some conditions (7–10). As a positive control for protection in this animal model, 100 μg of the interferon inducer Poly I:CLC protected 100% of the mice. Undetermined and requiring study is whether active immunity might be protective through an anamnestic response. The animal models of poxvirus infection have been used to evaluate immunity, but no generally established laboratory surrogate exists for immunity to smallpox virus itself. Persistence of effective humoral immunity after a single vaccination and its ability to effectively protect in vivo remain questionable.

Ocular complications of smallpox vaccination

Purpose To describe the ocular complications of smallpox vaccination and to discuss potential therapeutic options. Design Review of pertinent medical literature and recent treatment recommendations of the Centers for Disease Control and Prevention. Results After immunization against smallpox, vaccinia infection of the eyelid, conjunctiva, or ocular surface can result from accidental autoinoculation from a vaccination site before scab formation or from contact with a recently vaccinated individual. While uncommon, corneal involvement can lead to stromal opacification and scarring. Clinical findings of ocular and periocular vaccinia must be differentiated from those produced by other pathogens such as molluscum contagiosum, herpes simplex, varicella zoster, and acanthamoeba infections. Clinical diagnosis can be confirmed by electron microscopy to identify the presence of orthopoxvirus, as well as by virologic culture, polymerase chain reaction, and/or restriction endonuclease analysis of viral isolates. Conclusions While the majority of ocular complications of smallpox vaccination in immunocompetent patients are self-limiting, selective cases may require treatment with trifluridine drops, topical corticosteroids and vaccinia immune globulin (VIG). Vaccinia virus does not appear to be sensitive to acyclovir. Specific treatment recommendations are outlined for the spectrum of ocular manifestations.

Development of a novel vaccinia-neutralization assay based on reporter-gene expression.

In anticipation of large-scale smallpox vaccination, clinical trials of new vaccine candidates with improved safety profiles, and new vaccinia immune globulin (VIG) products, there is an immediate need to develop new assays to measure vaccinia-specific immune responses. The classical assay to measure vaccinia neutralization, the plaque-reduction neutralization test (PRNT), is slow, labor intensive, and difficult to validate and transfer. Here we describe the development of a novel vaccinia-neutralization assay based on the expression of a reporter gene, beta-galactosidase (beta-Gal). Using a previously constructed vaccinia-beta-Gal recombinant virus, vSC56, we developed a neutralization assay that is rapid, sensitive, and reproducible. The readout is automated. We show that the neutralizing titers, ID(50), for several VIG products measured by our assay were similar to those obtained by PRNTs. A new Food and Drug Administration VIG standard was established for distribution to other laboratories. The new assay will serve as an important tool both for preclinical and clinical trials of new smallpox vaccines and for evaluation of therapeutic agents to treat vaccine-associated adverse reactions.