Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Smallpox”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2005

Stability of diluted smallpox vaccine under simulated clinical conditions.

CONTEXT: During a mass smallpox immunization campaign, vaccine may be exposed to ambient temperatures for extended periods of time. OBJECTIVE: To determine the viability of undiluted and 5x diluted DryVax smallpox vaccine after cycling vaccine in and out of refrigeration for 2 weeks, as might occur during an immunization campaign. DESIGN: Two vials of Dryvax vaccine were reconstituted as per manufacturer's instructions (1x) and two vials were reconstituted using 5x the recommended diluent (5x). Every 12h over 2 weeks, vials were cycled between refrigeration and room temperature (1x-RT, 5x-RT) or ice bath (1x-cold, 5x-cold). Each vial was sampled in triplicate at time of reconstitution and thereafter at 24 or 48 h intervals. MAIN OUTCOME MEASURES: Viability measured by viral plaque forming units per ml (pfu/ml). RESULTS: All four vaccine vials showed a decline in virus titer over the 2-week period but remained well above 10(7)pfu/ml. Compared with titers on the day of reconstitution (day 0), titers at the end of the study (day 14) had declined by 0.4--0.6l og in all vials (Table 1). Linear regression analysis suggested that decay in viral titer occurred more rapidly in vials exposed to room temperature compared with vials kept on ice and in vaccine diluted 1x compared with vaccine diluted 5x. CONCLUSIONS: After 2 weeks, viability was greater than 10(7)pfu/ml, the titer suggested by Frey et al. as necessary to ensure successful vaccination in more than 97% of vaccinees. When removed from refrigeration, keeping the vaccine on ice lowers the decline in titer.

Drug Stability↗
PubMed2006

A protein-based smallpox vaccine protects mice from vaccinia and ectromelia virus challenges when given as a prime and single boost.

The heightened concern about the intentional release of variola virus has led to the need to develop safer smallpox vaccines. While subunit vaccine strategies are safer than live virus vaccines, subunit vaccines have been hampered by the need for multiple boosts to confer optimal protection. Here we developed a protein-based subunit vaccine strategy that provides rapid protection in mouse models of orthopoxvirus infections after a prime and single boost. Mice vaccinated with vaccinia virus envelope proteins from the mature virus (MV) and extracellular virus (EV) adjuvanted with CpG ODN and alum were protected from lethal intranasal challenge with vaccinia virus and the mouse-specific ectromelia virus. Organs from mice vaccinated with three proteins (A33, B5 and L1) and then sacrificed after challenge contained significantly lower titers of virus when compared to control groups of mice that were not vaccinated or that received sub-optimal formulations of the vaccine. Sera from groups of mice obtained prior to challenge had neutralizing activity against the MV and also inhibited comet formation indicating anti-EV activity. Long-term partial protection was also seen in mice challenged with vaccinia virus 6 months after initial vaccinations. Thus, this work represents a step toward the development of a practical subunit smallpox vaccine.

Adjuvants, Immunologic↗
PubMed2005

Host range, growth property, and virulence of the smallpox vaccine: vaccinia virus Tian Tan strain.

Vaccinia Tian Tan (VTT) was used as a vaccine against smallpox in China for millions of people before 1980, yet the biological characteristics of the virus remain unclear. We have characterized VTT with respect to its host cell range, growth properties in vitro, and virulence in vivo. We found that 11 of the 12 mammalian cell lines studied are permissive to VTT infection whereas one, CHO-K1, is non-permissive. Using electron microscopy and sequence analysis, we found that the restriction of VTT replication in CHO-K1 is at a step before viral maturation probably due to the loss of the V025 gene. Moreover, VTT is significantly less virulent than vaccinia WR but remains neurovirulent in mice and causes significant body weight loss after intranasal inoculation. Our data demonstrate the need for further attenuation of VTT to serve either as a safer smallpox vaccine or as a live vaccine vector for other pathogens.

Animals↗
PubMed2003

Analyzing bioterror response logistics: the case of smallpox.

To evaluate existing and alternative proposals for emergency response to a deliberate smallpox attack, we embed the key operational features of such interventions into a smallpox disease transmission model. We use probabilistic reasoning within an otherwise deterministic epidemic framework to model the 'race to trace', i.e., attempting to trace (via the infector) and vaccinate an infected person while (s)he is still vaccine-sensitive. Our model explicitly incorporates a tracing/vaccination queue, and hence can be used as a capacity planning tool. An approximate analysis of this large (16 ODE) system yields closed-form estimates for the total number of deaths and the maximum queue length. The former estimate delineates the efficacy (i.e., accuracy) and efficiency (i.e., speed) of contact tracing, while the latter estimate reveals how congestion makes the race to trace more difficult to win, thereby causing more deaths. A probabilistic analysis is also used to find an approximate closed-form expression for the total number of deaths under mass vaccination, in terms of both the basic reproductive ratio and the vaccination capacity. We also derive approximate thresholds for initially controlling the epidemic for more general interventions that include imperfect vaccination and quarantine.

Bioterrorism↗
PubMedDate not supplied

Safety and immunogenicity of new cell-cultured smallpox vaccine compared with calf-lymph derived vaccine: a blind, single-centre, randomised controlled trial.

BACKGROUND: US government organisations have identified the need for a new smallpox vaccine to replenish limited stocks of the approved, calf-lymph derived vaccine, the manufacture of which is no longer acceptable. We aimed to compare the safety and immunogenicity of the new cell-cultured smallpox vaccine (CCSV) to that of the calf-lymph derived vaccine (as a positive control) in 350 healthy, adult volunteers. METHODS: We did a randomised controlled study at the University of Kentucky Medical Center. We randomised 150 vaccinia-naive volunteers, aged 18-30 years, and 100 vaccinia-non-naive people, aged 32-65 years, to equivalent doses of either CCSV or test vaccine (2.5x10(5) plaque-forming units) by 15 puncture scarification in double-blind fashion. Immunogenicity was assessed by pock formation (take rate), humoral immune response by plaque-reduction neutralisation titres, and cellular immune response by vaccinia-specific, interferon-gamma T-cell quantification, cytotoxicity, and T-cell proliferation response. A further 100 vaccine-naive individuals, aged 18-30 years, received one of five doses of CCSV (undiluted, diluted 1 in 5, 1 in 10, 1 in 25, and 1 in 50) in single-blind fashion. Routine laboratory assessments, physical examinations, and recording of adverse events were done to assess vaccine safety. The primary endpoints were safety and reactogenicity (take rate) of CCSV. FINDINGS: 349 (99.7%) of 350 volunteers developed pock lesions; one vaccinia-naive individual who received a 1 in 25 dilution of CCSV did not. The rate of adverse events related to vaccine and the extent of humoral and cellular immune responses did not differ between the vaccine groups in vaccinia-naive or non-naive people. CCSV was immunogenic in vaccine-naive volunteers at a dose 50 times lower than that approved for Dryvax. INTERPRETATION: CCSV seems to be a safe and immunogenic alternative to calf-lymph derived vaccine for both vaccinia-naive and non-naive people.

Adolescent↗
PubMed2002

Smallpox vaccination techniques; from knives and forks to needles and pins.

Factors affecting the development of smallpox vaccination techniques are discussed and 11 different techniques for inoculating the vaccine are identified and described. The earliest, the simple cut or scratch, was already widely used for smallpox inoculation (variolation). Later, when it became evident that Jenner's claim of lifelong protection was not being achieved parallel, cross-hatched and rotatory methods which produced more severe reactions were introduced, often at more than one site. These methods were then discontinued and even prohibited in some countries, when improved vaccine quality resulted in excessively-severe reactions with such techniques. They were replaced by improved methods such as multiple pressure and multiple puncture with the bifurcated needle, both of which were used extensively. However, the simple scratch method remained popular until the end of the vaccination era. Although the instruments used are not discussed in detail, representative examples of the wide variety used at various times and for the various techniques are illustrated. Again, the simplest and earliest designs remained in use throughout.

Humans↗
PubMed2004

The cause of the plague of Athens: plague, typhoid, typhus, smallpox, or measles?

The plague of Athens raged for 4 years and resulted in the defeat of Athens. The cause of the plague of Athens continues to be debated. Infectious diseases most often cited as causes of the plague include influenza, epidemic typhus, typhoid fever, bubonic plague, smallpox, and measles. Thucydides provides the only available description of the plague of Athens. Given the nuances of the translation, bubonic plague, smallpox, and measles are the most likely causes of the plague. In my view, measles is the most likely cause of the plague of Athens.

Communicable Diseases↗
PubMed2004

Pulmonary manifestations of other agents: brucella, Q fever, tularemia and smallpox.

Brucella, Q fever, tularemia, and smallpox are all rare infections in the United States but are potential agents of biologic terrorism. The pulmonary manifestations of these infections range from uncommon (brucella and smallpox) to expected (Q fever and tularemia). and all have clinical and radiologic presentations that can be confused with other, more endemic,diseases. Once the release of these agents has been determined, the diagnosis of presenting patients will be straightforward. The onus is on the clinician,however, to be able to recognize the first few, unexpected cases, because early identification will be paramount in helping curb the effect of the outbreak.

Bioterrorism↗
PubMed2003

Forecasting the geographical spread of smallpox cases by air travel.

Instituting air travel restrictions to slow the geographical spread of smallpox cases would have significant consequences and present serious logistical concerns. Public health decision makers must weigh the potential benefits of such restrictions against their negative impact. The goal of this research is to provide a basic analytical framework to explore some of the issues surrounding the use of air travel restrictions as a part of an overall containment strategy. We report preliminary results of a compartmental model for the inter-city spread of smallpox cases resulting from US domestic air travel. Although air traffic can be halted within hours as was shown following the terrorist attacks of 11 September 2001, these results suggest that the consequences of halting domestic air travel may not be outweighed by public health benefits.

Aircraft↗
PubMed2005

Smallpox vaccine-induced antibodies are necessary and sufficient for protection against monkeypox virus.

Vaccination with live vaccinia virus affords long-lasting protection against variola virus, the agent of smallpox. Its mode of protection in humans, however, has not been clearly defined. Here we report that vaccinia-specific B-cell responses are essential for protection of macaques from monkeypox virus, a variola virus ortholog. Antibody-mediated depletion of B cells, but not CD4+ or CD8+ T cells, abrogated vaccine-induced protection from a lethal intravenous challenge with monkeypox virus. In addition, passive transfer of human vaccinia-neutralizing antibodies protected nonimmunized macaques from severe disease. Thus, vaccines able to induce long-lasting protective antibody responses may constitute realistic alternatives to the currently available smallpox vaccine (Dryvax).

Animals↗
PubMed2003

Clonal vaccinia virus grown in cell culture as a new smallpox vaccine.

Although the smallpox virus was eradicated over 20 years ago, its potential release through bioterrorism has generated renewed interest in vaccination. To develop a modern smallpox vaccine, we have adapted vaccinia virus that was derived from the existing Dryvax vaccine for growth in a human diploid cell line. We characterized six cloned and one uncloned vaccine candidates. One clone, designated ACAM1000, was chosen for development based on its comparability to Dryvax when tested in mice, rabbits and monkeys for virulence and immunogenicity. By most measures, ACAM1000 was less virulent than Dryvax. We compared ACAM1000 and Dryvax in a randomized, double-blind human clinical study. The vaccines were equivalent in their ability to produce major cutaneous reactions ('takes') and to induce neutralizing antibody and cell-mediated immunity against vaccinia virus.

Animals↗
PubMed2000

Graves' disease presenting as localized myxoedematous infiltration in a smallpox vaccination scar.

We describe a 54-year-old woman with diffuse myxoedematous infiltration at the site of a smallpox vaccination scar as the presenting symptom of Graves' disease. Associated features included acute ocular symptoms (vascular congestion of the sclera, epiphora and blurred vision) and transient erythema on both shins. However, there were no signs of pretibial myxoedema. A number of neoplastic, inflammatory and systemic diseases may localize to scar tissue in skin, including at smallpox vaccination sites, but this case demonstrates the unusual occurrence of myxoedematous infiltration at such a site and illustrates a most atypical cutaneous presentation of Graves'disease.

Cicatrix↗
PubMed2002

Inverse association between melanoma and previous vaccinations against tuberculosis and smallpox: results of the FEBIM study.

Various forms of immunotherapy utilizing bacille Calmette-Guérin vaccine or vaccinia vaccine have been evaluated in clinical trials on melanoma patients. The effect of the "natural" application of these vaccinations, administered to provide protection against tuberculosis and smallpox, has, however, never been studied in epidemiologic investigations on risk factors for melanoma. In a case-control study comprising 11 institutions in seven countries we recruited 603 incident melanoma cases and 627 population controls frequency matched to the cases with respect to sex, age, and ethnic origin within each center to assess this relationship to obtain insights into the prevention of melanoma. Exposure information, incorporating also detailed ascertainment of potential confounding variables, was obtained in standardized personal interviews at the study subject's home. We found an inverse association between melanoma risk and previous bacille Calmette-Guérin vaccine/vaccinia vaccination depicted by an adjusted odds ratio of 0.44 (95% confidence interval: 0.26-0.72) for those vaccinated against tuberculosis and smallpox compared with subjects without a positive history of either vaccination. A variety of subgroup analyses showing a consistent pattern of results make it unlikely that the observed inverse association is a spurious finding. We conclude that bacille Calmette-Guérin vaccination and vaccinia vaccination may lower melanoma risk. Current immunologic theory of melanoma development provides a sound basis for understanding the biologic plausibility of the findings that have to be confirmed in future studies.

BCG Vaccine↗
PubMed2003

Dermatofibrosarcoma protuberans occurring in a smallpox vaccination scar.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive, rarely metastatic, spindle cell tumor. Trauma has been associated with its development. Since the 1940s, malignant tumors have been described to occur in sites of smallpox vaccination scars. Five cases in the literature document DFSP arising in sites of prior immunizations. We report a case of DFSP occurring in a smallpox vaccination scar and review the available literature.

Aged↗
PubMed2004

Highly attenuated smallpox vaccine protects mice with and without immune deficiencies against pathogenic vaccinia virus challenge.

Modified vaccinia virus Ankara (MVA), developed >30 years ago as a highly attenuated candidate smallpox vaccine, was recloned from a 1974 passage and evaluated for safety and immunogenicity. Replication of MVA is impaired in most mammalian cells, and we found that mice with severe combined immunodeficiency disease remained healthy when inoculated with MVA at 1,000 times the lethal dose of vaccinia virus derived from the licensed Dryvax vaccine seed. In BALB/c mice inoculated intramuscularly with MVA, virus-specific CD8+ T cells and antibodies to purified virions and membrane protein components of the intracellular and extracellular infectious forms of vaccinia virus were induced in a dose-dependent manner. After one or two inoculations of MVA, the T cell numbers and antibody titers equaled or exceeded those induced by percutaneous injection of Dryvax. Antibodies induced by MVA and Dryvax were neutralizing and inhibited virus spread in cultured cells. Furthermore, vaccinated mice were protected against lethal intranasal challenge with a pathogenic vaccinia virus. B cell-deficient mice unable to generate antibodies and beta2-microglobulin-deficient mice unable to express MHC class I molecules for a CD8+ T cell response were also protectively vaccinated by MVA. In contrast, mice with decreased CD4 or MHC class II expression and double-knockout mice deficient in MHC class I- and II-restricted activities were poorly protected or unprotected. This study confirmed the safety of MVA and demonstrated that the overlapping immune responses protected normal and partially immune-deficient animals, an encouraging result for this candidate attenuated smallpox vaccine.

Animals↗
PubMed2002

Emergency response to a smallpox attack: the case for mass vaccination.

In the event of a smallpox bioterrorist attack in a large U.S. city, the interim response policy is to isolate symptomatic cases, trace and vaccinate their contacts, quarantine febrile contacts, but vaccinate more broadly if the outbreak cannot be contained by these measures. We embed this traced vaccination policy in a smallpox disease transmission model to estimate the number of cases and deaths that would result from an attack in a large urban area. Comparing the results to mass vaccination from the moment an attack is recognized, we find that mass vaccination results in both far fewer deaths and much faster epidemic eradication over a wide range of disease and intervention policy parameters, including those believed most likely, and that mass vaccination similarly outperforms the existing policy of starting with traced vaccination and switching to mass vaccination only if required.

Centers for Disease Control and Prevention, U.S.↗
PubMed2002

Identification of vaccinia virus epitope-specific HLA-A*0201-restricted T cells and comparative analysis of smallpox vaccines.

Despite worldwide eradication of naturally occurring variola virus, smallpox remains a potential threat to both civilian and military populations. New, safe smallpox vaccines are being developed, and there is an urgent need for methods to evaluate vaccine efficacy after immunization. Here we report the identification of an immunodominant HLA-A*0201-restricted epitope that is recognized by cytotoxic CD8(+) T cells and conserved among Orthopoxvirus species including variola virus. This finding has permitted analysis and monitoring of epitope-specific T cell responses after immunization and demonstration of the identified T cell specificity in an A*0201-positive human donor. Vaccination of transgenic mice allowed us to compare the immunogenicity of several vaccinia viruses including highly attenuated, replication-deficient modified vaccinia virus Ankara (MVA). MVA vaccines elicited levels of CD8(+) T cell responses that were comparable to those induced by the replication-competent vaccinia virus strains. Finally, we demonstrate that MVA vaccination is fully protective against a lethal respiratory challenge with virulent vaccinia virus strain Western Reserve. Our data provide a basis to rationally estimate immunogenicity of safe, second-generation poxvirus vaccines and suggest that MVA may be a suitable candidate.

Amino Acid Sequence↗
PubMedDate not supplied

Dark Winter and the spring of 1972: deflecting the social lessons of smallpox.

This article examines how the master status of bioterrorism has distracted professional and political attention from the social lessons of smallpox. I illustrate this by comparing an influential bioterrorism simulation known as Dark Winter with the social history surrounding the Yugoslavian smallpox epidemic of 1972. Dark Winter's epidemiological premises were largely based upon what was learned from the Yugoslavian outbreak. Yet, although this epidemic was non-deliberate, the exercise did not attend to the social conditions within which it developed. Most notably, it did not consider that this epidemic was mainly borne by marginalized communities of Kosovan Albanians and that difficulties in controlling it were linked to the relative lack of pre-existing public health infrastructure among these people; instead, the Dark Winter exercise mainly focused upon the proximate determinants of violence and its immediate management. This distraction from the social dynamics of infectious diseases has major implications for the prevention and management of future outbreaks, regardless of whether or not they are deliberately initiated.

Bioterrorism↗