D.A. Henderson: acting globally, thinking locally

They had said that it couldn't be done-the worldwide eradication of smallpox. To hear D.A. Henderson tell it, the job of leading the World Health Organization's initiative to conquer the disease in the 1960s and 1970s rather fell into his lap. In fact, he describes each of the posts that he has held with great modesty, beginning with his military service at the Centers for Disease Control and Prevention all the way through his assignments as Dean of Public Health at Johns Hopkins, Associate Director of the Office of Science and Technology Policy in the Executive Office of the President, and more recently as Director of the Office of Public Health Preparedness under Secretary Thompson at the Department of Health and Human Services. Confronted with enormous challenges in terms of public health initiatives, Henderson describes each assignment as a matter of communicating with the people he works with and the people that he serves, and drawing on their insights to devise strategies for accomplishing the task at hand. With bioterrorism posing one of the major public health concerns to face the United States and the world, it's gratifying to know that someone with Henderson's track record and wide-ranging expertise is paying attention and making sure that medical and government officials are preparing to respond to the threat. Again and again, Henderson appears to have the knack for showing up in the right place at the right time with just the right idea.     

The prevention and eradication of smallpox: a commentary on Sloane (1755) ‘An account of inoculation’

Sir Hans Sloane''s account of inoculation as a means to protect against smallpox followed several earlier articles published in Philosophical Transactions on this procedure. Inoculation (also called ‘variolation’) involved the introduction of small amounts of infectious material from smallpox vesicles into the skin of healthy subjects, with the goal of inducing mild symptoms that would result in protection against the more severe naturally acquired disease. It began to be practised in England in 1721 thanks to the efforts of Lady Mary Wortley Montagu who influenced Sloane to promote its use, including the inoculation of the royal family''s children. When Edward Jenner''s inoculation with the cow pox (‘vaccination’) followed 75 years later as a safer yet equally effective procedure, the scene was set for the eventual control of smallpox epidemics culminating in the worldwide eradication of smallpox in 1977, officially proclaimed by WHO in 1980. Here, we discuss the significance of variolation and vaccination with respect to scientific, public health and ethical controversies concerning these ‘weapons of mass protection’. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.     

Ten years of freedom from smallpox: lessons and experiences. Dedicated to the tenth anniversary of worldwide freedom from smallpox

Many lessons and experiences were learned during the global programme of smallpox eradication, the most important being those which could be generalized and applied to other health programmes. This does not mean imitating or implementing smallpox eradication techniques to other diseases, since each infection requires its own strategy. It is difficult to dissect out the single key element or to equate the various factors responsible for the success, as these always worked together, in combination, depending one on others. For global eradication, the element of essential importance was international cooperation and close coordination of activities between nations. This would be impossible without proper mechanisms dedicated to international cooperation in the field of health, provided by the World Health Organization, which also assured mobilization of world resources for national programmes and application of appropriate techniques across international borders. The established specific, practical and measurable goals, objectives and targets made every programme worker clearly understand what was to be accomplished and to find his own role in achieving these objectives. Operational techniques had to be flexible, modified appropriately from country to country to make them suitable to present epidemiological situations, local administrative and health structures as well as to demographic and geographic patterns. It was the effective system of surveillance and outbreak-containment that ultimately proved to have been the key to eradication. However, application of skillful management, sound epidemiological principles, advanced technology and adequate logistic support contributed significantly to the achievement of the final goal.(ABSTRACT TRUNCATED AT 250 WORDS)     

天花预防接种面临的挑战与DNA痘苗

介绍美国重新启动种痘的动因,LIR、A27L、A33R、B5R基因痘苗建立、修饰的Ankara痘苗和Lister基因缺失痘苗动物保护力、安全试验、临床研究现状及预防天花、人类猴痘的前景。     

Results of the research on the preparation and testing of live oral smallpox vaccine in tablet form]

The authors sum up the results of decade of investigations on the elaboration and trial of live oral smallpox vaccine in tablet form. A conclusion was made that due to mild reactogenic properties, satisfactory immunogenicity and weak allergy producing properties, the mentioned preparation, along with a possibility of express and mass use, can posses future prospects under conditions of final smallpox eradication.     

Unraveling the structure of the variola topoisomerase IB-DNA complex: a possible new twist on smallpox therapy

Smallpox is a serious and highly contagious disease that is caused by the variola virus. It is one of the most severe infectious human diseases known, with mortality rates as high as 30%. A successful worldwide vaccination program led to the eradication of smallpox in 1980. However, the high transmission rate of variola virus, coupled with the deadly nature of smallpox, makes this virus a potentially devastating weapon for bioterrorism. Currently, there is no specific treatment for smallpox. However, a recent article on the structure of a variola topoisomerase IB-DNA complex provides an intriguing starting point for the rational design of drugs with potential activity against smallpox.     

Tenth anniversary of smallpox eradication: Results of epidemiological and virological surveillance and studies in the post-eradication period

In accordance with recommendations of the Global Commission on the certification of smallpox eradication for the 10-year period after the eradication of this infection, all suspected cases of smallpox have been thoroughly checked up, and in none of them the diagnosis of smallpox has been confirmed. The study of monkeypox in humans has revealed that this zoonosis is spread over a wider area than supposed earlier and covers 7 countries of Equatorial Africa, occurring most frequently in Zaire. In about 70% of cases of monkeypox in human the disease is contracted from animals serving as natural virus carriers and in about one-third of such cases, from humans having monkeypox. The infectivity of humans with monkeypox for persons having close contacts with them is somewhat lower (12.3%) than in smallpox when this characteristic varies from 37% to 88%. Monkeypox in humans may take an asymptomatic course. Some species of tropical squirrels serve as natural virus carriers. These investigations have also resulted in essential corrections being made in understanding the ecology of cowpox virus, another orthopoxvirus pathogenic for man. At least 5 species of rodents have proved to be of interest as natural carriers of cowpox virus.     

Vaccine refusal and the endgame: walking the last mile first

As multiple papers within this special issue illustrate, the dynamics of disease eradication are different from disease control. When it comes to disease eradication, ‘the last mile is longest’. For social and ecological reasons such as vaccine refusal, further ending incidence of a disease when it has reached low levels is frequently complex. Issues of non-compliance within a target population often influence the outcome of disease eradication efforts. Past eradication efforts confronted such obstacles towards the tail end of the campaign, when disease incidence was lowest. This article provides a comparison of non-compliance within polio, measles and smallpox campaigns, demonstrating the tendency of vaccine refusal to rise as disease incidence falls. In order to overcome one of the most intractable challenges to eradication, future disease eradication efforts must prioritize vaccine refusal from the start, i.e. ‘walk the last mile first’.     

Percutaneous Vaccination as an Effective Method of Delivery of MVA and MVA-Vectored Vaccines

The robustness of immune responses to an antigen could be dictated by the route of vaccine inoculation. Traditional smallpox vaccines, essentially vaccinia virus strains, that were used in the eradication of smallpox were administered by percutaneous inoculation (skin scarification). The modified vaccinia virus Ankara is licensed as a smallpox vaccine in Europe and Canada and currently undergoing clinical development in the United States. MVA is also being investigated as a vector for the delivery of heterologous genes for prophylactic or therapeutic immunization. Since MVA is replication-deficient, MVA and MVA-vectored vaccines are often inoculated through the intramuscular, intradermal or subcutaneous routes. Vaccine inoculation via the intramuscular, intradermal or subcutaneous routes requires the use of injection needles, and an estimated 10 to 20% of the population of the United States has needle phobia. Following an observation in our laboratory that a replication-deficient recombinant vaccinia virus derived from the New York City Board of Health strain elicited protective immune responses in a mouse model upon inoculation by tail scarification, we investigated whether MVA and MVA recombinants can elicit protective responses following percutaneous administration in mouse models. Our data suggest that MVA administered by percutaneous inoculation, elicited vaccinia-specific antibody responses, and protected mice from lethal vaccinia virus challenge, at levels comparable to or better than subcutaneous or intramuscular inoculation. High titers of specific neutralizing antibodies were elicited in mice inoculated with a recombinant MVA expressing the herpes simplex type 2 glycoprotein D after scarification. Similarly, a recombinant MVA expressing the hemagglutinin of attenuated influenza virus rgA/Viet Nam/1203/2004 (H5N1) elicited protective immune responses when administered at low doses by scarification. Taken together, our data suggest that MVA and MVA-vectored vaccines inoculated by scarification can elicit protective immune responses that are comparable to subcutaneous vaccination, and may allow for antigen sparing when vaccine supply is limited.     

Genome-wide genetic associations with IFNγ response to smallpox vaccine

Smallpox is a deadly and debilitating disease that killed hundreds of millions of people in the past century alone. The use of Vaccinia virus-based smallpox vaccines led to the eradication of smallpox. These vaccines are remarkably effective, inducing the characteristic pustule or "take" at the vaccine site in >97?% of recipients, and inducing a wide spectrum of long-lasting humoral and cellular immune responses. The mechanisms behind inter-individual vaccine-response variability are likely to involve host genetic variation, but have not been fully characterized. We report here the first smallpox vaccine response genome-wide association study of over 1,000 recent recipients of Dryvax(?). The data presented here focus on cellular immune responses as measured by both production of secreted IFNγ and quantitation of IFNγ secreting cells by ELISPOT assay. We identified multiple significant SNP associations in genes (RASA1, ADRA1D, TCF7L1, FAS) that are critical components of signaling pathways that directly control lymphocyte IFNγ production or cytotoxic T cell function. Similarly, we found many associations with SNPs located in genes integral to nerve cell function; findings that, given the complex interplay between the nervous and immune systems, deserve closer examination in follow-up studies.     

U.S. medical countermeasure development since 2001: a long way yet to go

The U.S. government has taken significant steps toward developing and acquiring vaccines, drugs, and other medical countermeasures (MCMs) to protect and treat the population after a biological attack. In contrast to 2001, there is now a procedure for the Department of Health and Human Services (HHS) to develop, license, and stockpile MCMs for civilian use. Another major accomplishment is smallpox preparedness: There is now an adequate supply of vaccine for every person in the U.S., and there is an alternative vaccine meant for immunocompromised people and those with close contact with them. In spite of these and other accomplishments, the U.S. government MCM effort has been criticized by federal advisory committees, National Academy of Sciences reports, a congressional commission, and outside analysts who state that the efforts lack central leadership and accountability and that the pace of progress has been slow. A clear operational strategy for using MCMs, which would guide their development and acquisition, is also lacking. In this article, we review key areas of progress made since 2001 to develop and acquire MCMs, and we summarize what we judge to be the most critical and often mentioned areas where improvements are needed.     

从消灭牛瘟分析全球根除小反刍兽疫的可行性

根除,又称为消灭,是指某传染病的传播永远停止,不再发生。2011年,联合国粮农组织和国际兽疫局联合发布了全球根除牛瘟的消息。这两大国际组织的官方信息预示着,牛瘟病毒,正如天花病毒,将来只能在授权的实验室中保存了。牛瘟根除之后,相关学者不禁把目光投向了下一个目标-小反刍兽疫,因为从病原学和病理学等诸多方面考虑,二者最为相似。本文首先分析了前者根除的主客观因素,然后从正反两方面评述了后者全球性根除的可行性。     

One More Piece in the VACV Ecological Puzzle: Could Peridomestic Rodents Be the Link between Wildlife and Bovine Vaccinia Outbreaks in Brazil?

Background

Despite the fact that smallpox eradication was declared by the World Health Organization (WHO) in 1980, other poxviruses have emerged and re-emerged, with significant public health and economic impacts. Vaccinia virus (VACV), a poxvirus used during the WHO smallpox vaccination campaign, has been involved in zoonotic infections in Brazilian rural areas (Bovine Vaccinia outbreaks – BV), affecting dairy cattle and milkers. Little is known about VACV''s natural hosts and its epidemiological and ecological characteristics. Although VACV was isolated and/or serologically detected in Brazilian wild animals, the link between wildlife and farms has not yet been elucidated.

Methodology/Principal Findings

In this study, we describe for the first time, to our knowledge, the isolation of a VACV (Mariana virus - MARV) from a mouse during a BV outbreak. Genetic data, in association with biological assays, showed that this isolate was the same etiological agent causing exanthematic lesions observed in the cattle and human inhabitants of a particular BV-affected area. Phylogenetic analysis grouped MARV with other VACV isolated during BV outbreaks.

Conclusion/Significance

These data provide new biological and epidemiological information on VACV and lead to an interesting question: could peridomestic rodents be the link between wildlife and BV outbreaks?     

The contribution of vaccination to global health: past,present and future

Vaccination has made an enormous contribution to global health. Two major infections, smallpox and rinderpest, have been eradicated. Global coverage of vaccination against many important infectious diseases of childhood has been enhanced dramatically since the creation of WHO''s Expanded Programme of Immunization in 1974 and of the Global Alliance for Vaccination and Immunization in 2000. Polio has almost been eradicated and success in controlling measles makes this infection another potential target for eradication. Despite these successes, approximately 6.6 million children still die each year and about a half of these deaths are caused by infections, including pneumonia and diarrhoea, which could be prevented by vaccination. Enhanced deployment of recently developed pneumococcal conjugate and rotavirus vaccines should, therefore, result in a further decline in childhood mortality. Development of vaccines against more complex infections, such as malaria, tuberculosis and HIV, has been challenging and achievements so far have been modest. Final success against these infections may require combination vaccinations, each component stimulating a different arm of the immune system. In the longer term, vaccines are likely to be used to prevent or modulate the course of some non-infectious diseases. Progress has already been made with therapeutic cancer vaccines and future potential targets include addiction, diabetes, hypertension and Alzheimer''s disease.     

A rapid detection method for Vaccinia virus, the surrogate for smallpox virus

Prior to the World Health Organization's announcement of total eradication in 1977 [J. Am. Med. Assoc. 281 (1999) 1735], smallpox was a worldwide pathogen. Vaccinations were ceased in 1980 and now with a largely unprotected world population, smallpox is considered the ideal biowarfare agent [Antiviral Res. 57 (2002) 1]. Infection normally occurs after implantation of the virus on the oropharyngeal or respiratory mucosa [J. Am. Med. Assoc. 281 (1999) 2127]. Smallpox virus can be detected from the throats of exposed individuals prior to onset of illness and prior to the infectious stage of the illness. A rapid, sensitive real-time assay to detect Variola virus (smallpox) has been developed using the Vaccinia virus, a surrogate of smallpox, as a target. Cyanine 5 dye-labeled anti-Vaccinia antibody was used in a sandwich immunoassay to produce a fluorescent signal in the presence of the Vaccinia virus. The signal was detected using the Analyte 2000 biosensor (Research International, Monroe, WA). The Analyte 2000 uses a 635 nm laser diode to provide excitation light that is launched into a polystyrene optical waveguide. Fluorescent molecules within the evanescent wave are excited and a portion of their emission energy recouples into the waveguide. A photodiode quantifies the emission light at wavelengths between 670 and 710 nm. The biosensor was able to detect a minimum of 2.5 x 10(5) pfu/ml of Vaccinia virus in seeded throat culture swab specimens.     

Vacated niches,competitive release and the community ecology of pathogen eradication

A recurring theme in the epidemiological literature on disease eradication is that each pathogen occupies an ecological niche, and eradication of one pathogen leaves a vacant niche that favours the emergence of new pathogens to replace it. However, eminent figures have rejected this view unequivocally, stating that there is no basis to fear pathogen replacement and even that pathogen niches do not exist. After exploring the roots of this controversy, I propose resolutions to disputed issues by drawing on broader ecological theory, and advance a new consensus based on robust mechanistic principles. I argue that pathogen eradication (and cessation of vaccination) leads to a ‘vacated niche’, which could be re-invaded by the original pathogen if introduced. Consequences for other pathogens will vary, with the crucial mechanisms being competitive release, whereby the decline of one species allows its competitors to perform better, and evolutionary adaptation. Hence, eradication can cause a quantitative rise in the incidence of another infection, but whether this leads to emergence as an endemic pathogen depends on additional factors. I focus on the case study of human monkeypox and its rise following smallpox eradication, but also survey how these ideas apply to other pathogens and discuss implications for eradication policy.     

Smallpox and its control in Canada

Edward Jenner''s first treatise in 1798 described how he used cowpox material to provide immunity to the related smallpox virus. He sent this treatise and some cowpox material to his classmate John Clinch in Trinity, Nfld., who gave the first smallpox vaccinations in North America. Dissemination of the new technique, despite violent criticism, was rapid throughout Europe and the United States. Within a few years of its discovery, vaccination was instrumental in controlling smallpox epidemics among aboriginal people at remote trading posts of the Hudson''s Bay Company. Arm-to-arm transfer at 8-day intervals was common through most of the 19th century. Vaccination and quarantine eliminated endemic smallpox throughout Canada by 1946. The last case, in Toronto in 1962, came from Brazil.