Smallpox in the Post-Eradication Era Meyer, Hermann; Ehmann, Rosina; Smith, Geoffrey L
Viruses,
01/2020, Letnik:
12, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Widespread vaccination programmes led to the global eradication of smallpox, which was certified by the World Health Organisation (WHO), and, since 1978, there has been no case of smallpox anywhere ...in the world. However, the viable variola virus (VARV), the causative agent of smallpox, is still kept in two maximum security laboratories in Russia and the USA. Despite the eradication of the disease smallpox, clandestine stocks of VARV may exist. In a rapidly changing world, the impact of an intentional VARV release in the human population would nowadays result in a public health emergency of global concern: vaccination programmes were abolished, the percentage of immunosuppressed individuals in the human population is higher, and an increased intercontinental air travel allows for the rapid viral spread of diseases around the world. The WHO has authorised the temporary retention of VARV to enable essential research for public health benefit to take place. This work aims to develop diagnostic tests, antiviral drugs, and safer vaccines. Advances in synthetic biology have made it possible to produce infectious poxvirus particles from chemicals in vitro so that it is now possible to reconstruct VARV. The status of smallpox in the post-eradication era is reviewed.
A candidate vaccine against smallpox, modified vaccinia Ankara, was studied in 440 participants. MVA elicited immune responses similar to those associated with the established vaccinia-based vaccine ...and attenuated vaccinia replication in a human challenge model.
House on fire Foege, William H
2011., 20110507, 2011, 2011-06-06, Letnik:
21
eBook
A story of courage and risk-taking, House on Fire tells how smallpox, a disease that killed, blinded, and scarred millions over centuries of human history, was completely eradicated in a spectacular ...triumph of medicine and public health. Part autobiography, part mystery, the story is told by a man who was one of the architects of a radical vaccination scheme that became a key strategy in ending the horrible disease when it was finally contained in India. In House on Fire, William H. Foege describes his own experiences in public health and details the remarkable program that involved people from countries around the world in pursuit of a single objective--eliminating smallpox forever. Rich with the details of everyday life, as well as a few adventures, House on Fire gives an intimate sense of what it is like to work on the ground in some of the world's most impoverished countries--and tells what it is like to contribute to programs that really do change the world.
Monkeypox: A Review Singhal, Tanu; Kabra, S. K.; Lodha, Rakesh
Indian journal of pediatrics,
10/2022, Letnik:
89, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Monkeypox is caused by a pox virus closely related to smallpox virus and spreads from animals to humans, and humans to humans following close contact. Prior smallpox vaccination gives partial ...protection against monkeypox. The steady increase in monkeypox cases in Africa over the past few decades were ignored by the global scientific community till this year, when more than 16,000 cases have been reported from nonendemic countries. Monkeypox has recently been labelled as a public health emergency of international concern by the WHO. While most of the current cases are in men who have sex with men, there is the larger threat of the disease spilling into the general population. The disease is characterized by a short febrile illness with lymphadenopathy followed by a rash which spreads centrifugally and passes through phases of macules, papules, vesicles, and pustules. Recovery occurs in most patients within 2–4 wk. Complications are more likely in children, pregnant women, and the immunocompromised. Specific diagnosis is by detection of viral DNA by PCR. Treatment is largely symptomatic. Tecorivimat is a promising antiviral drug. Vaccination with the currently available smallpox vaccines is recommended for high-risk groups, health care workers, and close contacts. Control of the monkeypox outbreak needs a multipronged effort comprising enhanced surveillance, quick diagnosis, isolation of affected people, ring immunization, and adoption of “one health” approach.
We report a case of atypical cowpox virus infection in France in 2016. The patient sought care for thoracic lesions after injury from the sharp end of a metallic guardrail previously stored in the ...ground. We isolated a cowpox virus from the lesions and sequenced its whole genome. The patient reported that he had been previously vaccinated against smallpox. We describe an alternative route of cowpox virus infection and raise questions about the immunological status of smallpox-vaccinated patients for circulating orthopoxviruses.
Background. Human immunodeficiency virus (HIV)—infected persons are at higher risk for serious complications associated with traditional smallpox vaccines. Alternative smallpox vaccines with an ...improved safety profile would address this unmet medical need. Methods. The safety and immunogenicity of modified vaccinia Ankara (MVA) was assessed in 91 HIV-infected adult subjects (CD4 + T-cell counts, ≥350 cells/mm 3 ) and 60 uninfected volunteers. The primary objectives were to evaluate the safety of MVA and immunogenicity in HIV-infected and uninfected subjects. As a measure of the potential efficacy of MVA, the ability to boost the memory response in people previously vaccinated against smallpox was evaluated by the inclusion of vaccinia-experienced HIV-infected and HIV-uninfected subjects. Results. MVA was well tolerated and immunogenic in all subjects. Antibody responses were comparable between uninfected and HIV-infected populations, with only 1 significantly lower total antibody titer at 2 weeks after the second vaccination, while no significant differences were observed for neutralizing antibodies. MVA rapidly boosted the antibody responses in vaccinia-experienced subjects, supporting the efficacy of MVA against variola. Conclusions. MVA is a promising candidate as a safer smallpox vaccine, even for immunocompromised individuals, a group for whom current smallpox vaccines have an unacceptable safety profile. Clinical Trials Registration. NCT00189904.
Monkeypox is an emerging infectious disease for which outbreak frequency and expected outbreak size in human populations have steadily increased.1 The geographic spread of monkeypox cases has ...expanded beyond the forests of central Africa, where cases were initially found, to other parts of the world, where cases have been imported. This transmission pattern is likely due to the worldwide decline in orthopoxvirus immunity, following cessation of smallpox vaccination, once smallpox was declared eradicated in 1980. Monkeypox could therefore emerge as the most important orthopoxvirus infection in humans.2 We use mathematical modelling to argue that, in a population with diminishing herd immunity against orthopoxvirus species, the epidemic potential of monkeypox will continue increasing. Monkeypox is caused by the monkeypox virus, member of the orthopoxvirus genus in the Poxviridae family. This genus includes three other human pathogens: variola virus (causing smallpox), cowpox virus and vaccinia virus. Monkeypox and smallpox yield similar clinical presentations, with monkeypox causing lymphadenopathy, as a distinguishing feature, early in the disease course.2 Smallpox infection leads to long-lasting immunity; repeat attack rates of smallpox are just about 1 in 1000 for 15–20 years.3 Smallpox vaccination with vaccinia, a first-generation vaccine, also yields long-lasting immunity, with an efficacy of 80–95%. The current recommendation for revaccination is every 10 years, although longitudinal studies suggest that protection may last much longer.4 Vaccinia is also known to deliver long-lasting immunity against monkeypox, with 85% efficacy.5 Furthermore, studies of antibody responses to orthopoxvirus species suggest perfect cross-immunity between smallpox and monkeypox.
The re-emergence of smallpox is an increasing and legitimate concern due to advances in synthetic biology. Vaccination programs against smallpox using the vaccinia virus vaccine ceased with the ...eradication of smallpox and, unlike many other countries, Australia did not use mass vaccinations. However, vaccinated migrants contribute to population immunity. Testing for vaccinia antibodies is not routinely performed in Australia, and few opportunities exist to estimate the level of residual population immunity against smallpox. Serological data on population immunity in Australia could inform management plans against a smallpox outbreak. Vaccinia antibodies were measured in 2003 in regular plasmapheresis donors at the Australian Red Cross Blood Service from New South Wales (NSW). The data were analysed to estimate the proportion of Australians in NSW with detectable serological immunity to vaccinia. The primary object of this study was to measure neutralising antibody titres against vaccinia virus. Titre levels in donor samples were determined by plaque reduction assay. To estimate current levels of immunity to smallpox infection, the decline in geometric mean titres (GMT) over time was projected using two values for the antibody levels estimated on the basis of different times since vaccination. The results of this study suggest that there is minimal residual immunity to the vaccinia virus in the Australian population. Although humoral immunity is protective against orthopoxvirus infections, cell-mediated immunity and immunological memory likely also play roles, which are not quantified by antibody levels. These data provide an immunological snapshot of the NSW population, which could inform emergency preparedness planning and outbreak control, especially concerning the stockpiling of vaccinia vaccine.
Global eradication of smallpox was driven by the development of the smallpox vaccine. In this report, light is shed on the origins of the vaccinia virus.
Men who have sex with men and people living with HIV are disproportionately affected in the 2022 multi-country monkeypox epidemic. The smallpox vaccine can induce cross-reactive antibodies against ...the monkeypox virus (MPXV) and reduce the risk of infection. Data on antibodies against MPXV induced by historic smallpox vaccination in people with HIV are scarce. In this observational study, plasma samples were collected from people living with and without HIV in Shenzhen, China. We measured antibodies binding to two representative proteins of vaccinia virus (VACV; A27L and A33R) and homologous proteins of MPXV (A29L and A35R) using an enzyme-linked immunosorbent assay. We compared the levels of these antibodies between people living with and without HIV. Stratified analyses were performed based on the year of birth of 1981 when the smallpox vaccination was stopped in China. Plasma samples from 677 people living with HIV and 746 people without HIV were tested. A consistent pattern was identified among the four antibodies, regardless of HIV status. VACV antigen-reactive and MPXV antigen-reactive antibodies induced by historic smallpox vaccination were detectable in the people born before 1981, and antibody levels reached a nadir during or after 1981. The levels of smallpox vaccine-induced antibodies were comparable between people living with HIV and those without HIV. Our findings suggest that the antibody levels against MPXV decreased in both people living with and without HIV due to the cessation of smallpox vaccination.
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