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Military Medicine Dec 2019Smallpox has been eradicated but advances in synthetic biology have increased the risk of its re-emergence. Residual immunity in individuals who were previously...
INTRODUCTION
Smallpox has been eradicated but advances in synthetic biology have increased the risk of its re-emergence. Residual immunity in individuals who were previously vaccinated may mitigate the impact of an outbreak, but there is a high degree of uncertainty about the duration and degree of residual immunity. Both cell-mediated and humoral immunity are thought to be important but the exact mechanisms of protection are unclear. Guidelines usually suggest vaccine-induced immunity wanes to zero after 3-10 years post vaccination, whereas other estimates show long term immunity over decades.
MATERIALS AND METHODS
A systematic review of the literature was conducted to quantify the duration and extent of residual immunity to smallpox after vaccination.
RESULTS
Twenty-nine papers related to quantifying residual immunity to smallpox after vaccination were identified: neutralizing antibody levels were used as immune correlates of protection in 11/16 retrospective cross-sectional studies, 2/3 epidemiological studies, 6/7 prospective vaccine trials and 0/3 modeling studies. Duration of protection of >20 years was consistently shown in the 16 retrospective cross-sectional studies, while the lowest estimated duration of protection was 11.7 years among the modeling studies. Childhood vaccination conferred longer duration of protection than vaccination in adulthood, and multiple vaccinations did not appear to improve immunity.
CONCLUSIONS
Most studies suggest a longer duration of residual immunity (at least 20 years) than assumed in smallpox guidelines. Estimates from modeling studies were less but still greater than the 3-10 years suggested by the WHO Committee on International Quarantine or US CDC guidelines. These recommendations were probably based on observations and studies conducted while smallpox was endemic. The cut-off values for pre-existing antibody levels of >1:20 and >1:32 reported during the period of endemic smallpox circulation may not be relevant to the contemporary population, but have been used as a threshold for identifying people with residual immunity in post-eradication era studies. Of the total antibodies produced in response to smallpox vaccination, neutralizing antibodies have shown to contribute significantly to immunological memory. Although the mechanism of immunological memory and boosting is unclear, revaccination is likely to result in a more robust response. There is a need to improve the evidence base for estimates on residual immunity to better inform planning and preparedness for re-emergent smallpox.
Topics: Humans; Immunity; Smallpox; Smallpox Vaccine
PubMed: 31369103
DOI: 10.1093/milmed/usz181 -
Planta Medica Oct 2020Viruses have a high mutation rate, and, thus, there is a continual emergence of new antiviral-resistant strains. Therefore, it becomes imperative to explore and develop...
Viruses have a high mutation rate, and, thus, there is a continual emergence of new antiviral-resistant strains. Therefore, it becomes imperative to explore and develop new antiviral compounds continually. The search for pharmacological substances of plant origin that are effective against animal viruses, which have a high mortality rate or cause large economic losses, has garnered interest in the last few decades. This systematic review compiles 130 plant species that exhibit antiviral activity on 37 different virus species causing serious diseases in animals. The kind of extract, fraction, or compound exhibiting the antiviral activity and the design of the trial were particularly considered for review. The literature revealed details regarding plant species exhibiting antiviral activities against pathogenic animal virus species of the following families-, and that cause infections, among others, in poultry, cattle, pigs, horses, shrimps, and fish. Overall, 30 plant species exhibited activity against various influenza viruses, most of them causing avian influenza. Furthermore, 30 plant species were noted to be active against Newcastle disease virus. In addition, regarding the pathogens most frequently investigated, this review provides a compilation of 20 plant species active against bovine herpesvirus, 16 against fowlpox virus, 12 against white spot syndrome virus in marine shrimps, and 10 against suide herpesvirus. Nevertheless, some plant extracts, particularly their compounds, are promising candidates for the development of new antiviral remedies, which are urgently required.
Topics: Animal Diseases; Animals; Antiviral Agents; Cattle; Horses; Orthomyxoviridae; Plant Extracts; Plants, Medicinal; Swine; Veterinary Medicine
PubMed: 32777833
DOI: 10.1055/a-1224-6115 -
Journal of Medical Virology Jan 2023The current literature shows increasing concerns about potential seminal transmission of monkeypox virus (MPXV). Accordingly, we aimed to understand better the potential... (Meta-Analysis)
Meta-Analysis
The current literature shows increasing concerns about potential seminal transmission of monkeypox virus (MPXV). Accordingly, we aimed to understand better the potential presence of MPXV in the seminal fluids and others specimens obtained from MPX cases. On June 26, 2022, a systematic search of the literature was conducted to find articles that examine the presence of MPXV in the seminal fluid of confirmed cases. The search was updated once on August 12 and another on October 12, 2022, to include newly published articles. The prevalence of MPXV DNA presence in the seminal fluid and other specimens was pooled in a meta-analysis (from studies with sample size > 5 to reduce overestimation) and results were presented as effect sizes (ES) and their corresponding 95% confidence intervals (CI). Nine articles were included. Only five studies were eligible for a meta-analysis, and the pooled prevalence of MPXV DNA in semen specimens was 72.4% (95% CI: 55.7%-84.5%) among 115 patients. The positive rate of MPXV viral polymerase chain reaction (PCR) was higher among skin samples (89%; 95% CI: 78.2%-94.8%; N = 62; studies = 2), followed by anogenital/rectal samples (74.3%; 95% CI: 60.4%-84.5%; N = 54; studies = 2). On the other hand, the positivity rate was lower in nasopharyngeal (62.4%; 95% CI: 20.4%-91.5%; N = 587; studies = 3), urine (21.1%; 95% CI: 4.3%-61.1%; N = 617; studies = 4), and blood/plasma (14.3%; 95% CI: 11.3%-18.1%; N = 609; studies = 3) samples. Besides, MPXV can be detected in semen early from Day 1 and up to 19 days after symptoms onset. Finally, two articles investigated the infectivity of MPXV particles detected in seminal specimens by testing their replication competence. Culturing MPXV was successful in two out of four patients included in these studies. MPXV is highly prevalent in seminal specimens of MPX cases, further corroborating the role of sexual transmission of the disease. However, further evidence is still needed to shed more light on the replication competence of these particles.
Topics: Humans; Mpox (monkeypox); Monkeypox virus; Semen; Polymerase Chain Reaction; DNA
PubMed: 36271741
DOI: 10.1002/jmv.28250 -
BMC Public Health Jan 2024Mpox is a zoonotic viral disease that emerged in May 2022 and has since shown a high prevalence in non-mpox-endemic areas, resulting in an outbreak that caused more than... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Mpox is a zoonotic viral disease that emerged in May 2022 and has since shown a high prevalence in non-mpox-endemic areas, resulting in an outbreak that caused more than 84,000 cases in 110 countries around the globe. Several vaccines are available to prevent the disease, and multiple studies have been conducted to assess the attitudes of different populations toward receiving the mpox vaccine. This study systematically reviews all the studies conducted on mpox vaccine acceptance/hesitancy among healthcare workers.
METHODS
A systematic literature search was conducted through four electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar, up to March 2023. Studies that described mpox vaccine acceptance/hesitancy among healthcare workers were included, and the data were extracted using a uniform extraction sheet. Following the extraction, the meta-analysis included ten studies with 7322 healthcare workers. Three researchers independently assessed the risk of bias in the included study using the Newcastle-Ottawa Scale (NOS).
RESULTS
Ten studies were included in the review. This review indicates that the prevalence of mpox vaccine acceptance was 58.5%, and the prevalence of mpox vaccine hesitancy was 41.5%. There was a higher prevalence of acceptance in countries located in Asian and African areas compared to those in North America and Europe, estimated at 68% and 44.3%, respectively. Among the studies conducted solely among physicians, there was a high prevalence of mpox vaccine acceptance, at 77.1%, compared to 49% in studies that included all healthcare workers.
CONCLUSION
There is a significant variation in the prevalence of mpox vaccine acceptance among different populations. Further research is needed to identify the factors that contribute to this variation and to develop interventions to increase vaccine acceptance. In addition, it is important to promote research on mpox vaccine acceptance and hesitancy among healthcare workers in countries where data is limited. This research will help policymakers develop effective policies to increase acceptance and reduce the disease burden.
Topics: Humans; Health Personnel; Mpox (monkeypox); Physicians; Smallpox Vaccine; Zoonoses
PubMed: 38166685
DOI: 10.1186/s12889-023-17186-2 -
Viral Immunology May 2024In May 2022, mpox began to spread worldwide, posing a serious threat to human public health. Modified Vaccinia Ankara-Bavaria Nordic (MVA-BN) is a live attenuated... (Meta-Analysis)
Meta-Analysis
In May 2022, mpox began to spread worldwide, posing a serious threat to human public health. Modified Vaccinia Ankara-Bavaria Nordic (MVA-BN) is a live attenuated orthopoxvirus vaccine that has been authorized by the U.S. Food and Drug Administration as the vaccine of choice for the prevention of mpox. In this study, we conducted a meta-analysis of all currently published literature on the efficacy and safety of the MVA-BN vaccine in the real world, showing that the MVA-BN vaccine is effective and safe, with efficacy of up to 75% with a single dose and up to 80% with a two-dose vaccine. Meanwhile, we found that subcutaneous injection has lower local and systemic adverse events than intradermal injection, regardless of single- or two-dose vaccination, and subcutaneous injection is better tolerated in children, the elderly, or people with underlying medical conditions. These results have important reference value for clinical practice.
Topics: Humans; Vaccine Efficacy; Vaccines, Attenuated; Poxviridae Infections; Vaccinia virus; Vaccination; Injections, Subcutaneous; Injections, Intradermal; Viral Vaccines; Orthopoxvirus; Child
PubMed: 38717823
DOI: 10.1089/vim.2023.0147 -
Frontiers in Cellular and Infection... 2023Human monkeypox (mpox) disease is a multicountry outbreak driven by human-human transmission which has resulted in an international public health emergency. However,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Human monkeypox (mpox) disease is a multicountry outbreak driven by human-human transmission which has resulted in an international public health emergency. However, there is limited evidence on the positivity rate of skin lesions for mpox viral DNA. We aim to fill this gap by estimating the pooled positivity rate of skin samples with mpox viral DNA from mpox patients globally.
METHODS
In this systematic review and meta-analysis, seven databases and several preprint servers have been extensively searched until 17 January 2023 according to a prospectively registered protocol (PROSPERO: CRD42023392505). Articles including the positivity rate of skin samples with mpox viral DNA in mpox-confirmed patients were considered eligible. After a quality assessment, a random-effect meta-analysis was used for pooled prevalence. To explore and resolve heterogeneity, we used statistical methods for outlier detection, influence analysis, and sensitivity analysis.
FINDINGS
Among the 331 articles retrieved after deduplication, 14 studies were finally included. The pooled positivity rate of the skin samples was 98.77% (95% CI: 94.74%-99.72%). After the removal of an influential outlier, for heterogeneity dropped from 92.5% to 10.8%. Meta-regression did not reveal any significant moderator.
CONCLUSION/INTERPRETATION
The present findings reinforce that skin lesions act as a reservoir of mpox viral DNA and contribute to a high infectivity risk. This may be a prevailing basis of prompt transmission during the current multicountry outbreak and also needs further investigation. The present imperative outcome may benefit in producing valuable preventive and management procedures in an appropriate health strategy.
Topics: Humans; DNA, Viral; Mpox (monkeypox); Prevalence; Databases, Factual; Disease Outbreaks
PubMed: 37457957
DOI: 10.3389/fcimb.2023.1179885 -
BMC Public Health Dec 2020Previous initiatives have aimed to document the history and legacy of the Smallpox Eradication Program (SEP) and the Global Polio Eradication Initiative (GPEI). In this...
A multi-pronged scoping review approach to understanding the evolving implementation of the Smallpox and Polio eradication programs: what can other Global Health initiatives learn?
BACKGROUND
Previous initiatives have aimed to document the history and legacy of the Smallpox Eradication Program (SEP) and the Global Polio Eradication Initiative (GPEI). In this multi-pronged scoping review, we explored the evolution and learning from SEP and GPEI implementation over time at global and country levels to inform other global health programs.
METHODS
Three related reviews of literature were conducted; we searched for documents on 1) the SEP and 2) GPEI via online database searches and also conducted global and national-level grey literature searches for documents related to the GPEI in seven purposively selected countries under the Synthesis and Translation of Research and Innovations from Polio Eradication (STRIPE) project. We included documents relevant to GPEI implementation. We conducted full text data analysis and captured data on Expert Recommendations for Implementing Change (ERIC) implementation strategies and principles, tools, outcomes, target audiences, and relevance to global health knowledge areas.
RESULTS
200 articles were included in the SEP scoping review, 1885 articles in the GPEI scoping review, and 963 documents in the grey literature review. M&E and engagement strategies were consistently translated from the SEP to GPEI; these evolved into newer approaches under the GPEI. Management strategies including setting up robust record systems also carried forward from SEP to GPEI; however, lessons around the need for operational flexibility in applying these strategies at national and sub-national levels did not. Similarly, strategies and lessons around conducting health systems readiness assessments prior to implementation were not carried forward from SEP to GPEI. Differences in the planning and communication strategies between the two programs included fidelity to implementation blueprints appeared to be higher under SEP, and independent monitoring boards and communication and media strategies were more prominent under GPEI.
CONCLUSIONS
Linear learning did not always occur between SEP and GPEI; several lessons were lost and had to be re-learned. Implementation and adaptation of strategies in global health programs should be well codified, including information on the contextual, time and stakeholders' issues that elicit adaptations. Such description can improve the systematic translation of knowledge, and gains in efficiency and effectiveness of future global health programs.
Topics: Communication; Disease Eradication; Global Health; Health Education; Humans; Immunization Programs; Poliomyelitis; Smallpox
PubMed: 33339517
DOI: 10.1186/s12889-020-09439-1 -
BMC Cardiovascular Disorders Jun 2023Monkeypox is a zoonotic viral infection first reported in May 2022. Monkeypox cases present with prodromal symptoms, rash, and/or systemic complications. This study...
BACKGROUND
Monkeypox is a zoonotic viral infection first reported in May 2022. Monkeypox cases present with prodromal symptoms, rash, and/or systemic complications. This study systematically reviews the monkeypox cases presented with any cardiac complications.
METHODS
A systematic literature search was done to locate papers that discuss any cardiac complications associated with monkeypox; then, data were analyzed qualitatively.
RESULTS
Nine articles, including the 13 cases that reported cardiac complications of the disease, were included in the review. Five cases previously had sex with men, and two cases had unprotected intercourse, which reveals the importance of the sexual route in disease transmission. All cases have a wide spectrum of cardiac complications, such as acute myocarditis, pericarditis, pericardial effusion, and myopericarditis.
CONCLUSION
This study clarifies the potential for cardiac complications in monkeypox cases and provides avenues for future research to determine the underlying mechanism. Also, we found that the cases with pericarditis were treated with colchicine, and those with myocarditis were treated with supportive care or cardioprotective treatment (Bisoprolol and Ramipril). Furthermore, Tecovirimat is used as an antiviral drug for 14 days.
Topics: Male; Humans; Myocarditis; Mpox (monkeypox); Heart; Pericarditis; Pericardial Effusion
PubMed: 37380955
DOI: 10.1186/s12872-023-03351-3