Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial (Ebola Ça Suffit!).

BACKGROUND: rVSV-ZEBOV is a recombinant, replication competent vesicular stomatitis virus-based candidate vaccine expressing a surface glycoprotein of Zaire Ebolavirus. We tested the effect of rVSV-ZEBOV in preventing Ebola virus disease in contacts and contacts of contacts of recently confirmed cases in Guinea, west Africa. METHODS: We did an open-label, cluster-randomised ring vaccination trial (Ebola ça Suffit!) in the communities of Conakry and eight surrounding prefectures in the Basse-Guinée region of Guinea, and in Tomkolili and Bombali in Sierra Leone. We assessed the efficacy of a single intramuscular dose of rVSV-ZEBOV (2×107 plaque-forming units administered in the deltoid muscle) in the prevention of laboratory confirmed Ebola virus disease. After confirmation of a case of Ebola virus disease, we definitively enumerated on a list a ring (cluster) of all their contacts and contacts of contacts including named contacts and contacts of contacts who were absent at the time of the trial team visit. The list was archived, then we randomly assigned clusters (1:1) to either immediate vaccination or delayed vaccination (21 days later) of all eligible individuals (eg, those aged ≥18 years and not pregnant, breastfeeding, or severely ill). An independent statistician generated the assignment sequence using block randomisation with randomly varying blocks, stratified by location (urban vs rural) and size of rings (≤20 individuals vs >20 individuals). Ebola response teams and laboratory workers were unaware of assignments. After a recommendation by an independent data and safety monitoring board, randomisation was stopped and immediate vaccination was also offered to children aged 6-17 years and all identified rings. The prespecified primary outcome was a laboratory confirmed case of Ebola virus disease with onset 10 days or more from randomisation. The primary analysis compared the incidence of Ebola virus disease in eligible and vaccinated individuals assigned to immediate vaccination versus eligible contacts and contacts of contacts assigned to delayed vaccination. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201503001057193. FINDINGS: In the randomised part of the trial we identified 4539 contacts and contacts of contacts in 51 clusters randomly assigned to immediate vaccination (of whom 3232 were eligible, 2151 consented, and 2119 were immediately vaccinated) and 4557 contacts and contacts of contacts in 47 clusters randomly assigned to delayed vaccination (of whom 3096 were eligible, 2539 consented, and 2041 were vaccinated 21 days after randomisation). No cases of Ebola virus disease occurred 10 days or more after randomisation among randomly assigned contacts and contacts of contacts vaccinated in immediate clusters versus 16 cases (7 clusters affected) among all eligible individuals in delayed clusters. Vaccine efficacy was 100% (95% CI 68·9-100·0, p=0·0045), and the calculated intraclass correlation coefficient was 0·035. Additionally, we defined 19 non-randomised clusters in which we enumerated 2745 contacts and contacts of contacts, 2006 of whom were eligible and 1677 were immediately vaccinated, including 194 children. The evidence from all 117 clusters showed that no cases of Ebola virus disease occurred 10 days or more after randomisation among all immediately vaccinated contacts and contacts of contacts versus 23 cases (11 clusters affected) among all eligible contacts and contacts of contacts in delayed plus all eligible contacts and contacts of contacts never vaccinated in immediate clusters. The estimated vaccine efficacy here was 100% (95% CI 79·3-100·0, p=0·0033). 52% of contacts and contacts of contacts assigned to immediate vaccination and in non-randomised clusters received the vaccine immediately; vaccination protected both vaccinated and unvaccinated people in those clusters. 5837 individuals in total received the vaccine (5643 adults and 194 children), and all vaccinees were followed up for 84 days. 3149 (53·9%) of 5837 individuals reported at least one adverse event in the 14 days after vaccination; these were typically mild (87·5% of all 7211 adverse events). Headache (1832 [25·4%]), fatigue (1361 [18·9%]), and muscle pain (942 [13·1%]) were the most commonly reported adverse events in this period across all age groups. 80 serious adverse events were identified, of which two were judged to be related to vaccination (one febrile reaction and one anaphylaxis) and one possibly related (influenza-like illness); all three recovered without sequelae. INTERPRETATION: The results add weight to the interim assessment that rVSV-ZEBOV offers substantial protection against Ebola virus disease, with no cases among vaccinated individuals from day 10 after vaccination in both randomised and non-randomised clusters. FUNDING: WHO, UK Wellcome Trust, the UK Government through the Department of International Development, Médecins Sans Frontières, Norwegian Ministry of Foreign Affairs (through the Research Council of Norway's GLOBVAC programme), and the Canadian Government (through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre and Department of Foreign Affairs, Trade and Development).

Efficacy and effectiveness of an rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomised trial.

BACKGROUND: A recombinant, replication-competent vesicular stomatitis virus-based vaccine expressing a surface glycoprotein of Zaire Ebolavirus (rVSV-ZEBOV) is a promising Ebola vaccine candidate. We report the results of an interim analysis of a trial of rVSV-ZEBOV in Guinea, west Africa. METHODS: For this open-label, cluster-randomised ring vaccination trial, suspected cases of Ebola virus disease in Basse-Guinée (Guinea, west Africa) were independently ascertained by Ebola response teams as part of a national surveillance system. After laboratory confirmation of a new case, clusters of all contacts and contacts of contacts were defined and randomly allocated 1:1 to immediate vaccination or delayed (21 days later) vaccination with rVSV-ZEBOV (one dose of 2 × 10(7) plaque-forming units, administered intramuscularly in the deltoid muscle). Adults (age ≥18 years) who were not pregnant or breastfeeding were eligible for vaccination. Block randomisation was used, with randomly varying blocks, stratified by location (urban vs rural) and size of rings (≤20 vs >20 individuals). The study is open label and masking of participants and field teams to the time of vaccination is not possible, but Ebola response teams and laboratory workers were unaware of allocation to immediate or delayed vaccination. Taking into account the incubation period of the virus of about 10 days, the prespecified primary outcome was laboratory-confirmed Ebola virus disease with onset of symptoms at least 10 days after randomisation. The primary analysis was per protocol and compared the incidence of Ebola virus disease in eligible and vaccinated individuals in immediate vaccination clusters with the incidence in eligible individuals in delayed vaccination clusters. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201503001057193. FINDINGS: Between April 1, 2015, and July 20, 2015, 90 clusters, with a total population of 7651 people were included in the planned interim analysis. 48 of these clusters (4123 people) were randomly assigned to immediate vaccination with rVSV-ZEBOV, and 42 clusters (3528 people) were randomly assigned to delayed vaccination with rVSV-ZEBOV. In the immediate vaccination group, there were no cases of Ebola virus disease with symptom onset at least 10 days after randomisation, whereas in the delayed vaccination group there were 16 cases of Ebola virus disease from seven clusters, showing a vaccine efficacy of 100% (95% CI 74·7-100·0; p=0·0036). No new cases of Ebola virus disease were diagnosed in vaccinees from the immediate or delayed groups from 6 days post-vaccination. At the cluster level, with the inclusion of all eligible adults, vaccine effectiveness was 75·1% (95% CI -7·1 to 94·2; p=0·1791), and 76·3% (95% CI -15·5 to 95·1; p=0·3351) with the inclusion of everyone (eligible or not eligible for vaccination). 43 serious adverse events were reported; one serious adverse event was judged to be causally related to vaccination (a febrile episode in a vaccinated participant, which resolved without sequelae). Assessment of serious adverse events is ongoing. INTERPRETATION: The results of this interim analysis indicate that rVSV-ZEBOV might be highly efficacious and safe in preventing Ebola virus disease, and is most likely effective at the population level when delivered during an Ebola virus disease outbreak via a ring vaccination strategy. FUNDING: WHO, with support from the Wellcome Trust (UK); Médecins Sans Frontières; the Norwegian Ministry of Foreign Affairs through the Research Council of Norway; and the Canadian Government through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre, and Department of Foreign Affairs, Trade and Development.

Genital human papillomaviruses among women of reproductive age in Jamaica.

OBJECTIVE: To characterize the prevalence and distribution of genital human papillomavirus (HPV) types among women in Jamaica, and to explore risk factors associated with HPV infection. METHODS: This was a cross-sectional study that took place in April-July 2010 with 852 sexually-active women, 16-49 years of age, who had attended a selected public or private primary health clinic in one of Jamaica's four health authority regions. Sociodemographic data was collected from each participant by trained study staff. Each participant had a gynecological examination that included a clinical Pap test and a cervical sample for HPV detection and typing-performed using the Research Use Only Linear Array (LA) genotyping assay (Roche Diagnostics Corp., Indianapolis, Indiana, United States). Overall and type-specific prevalence of HPV infection was calculated for 37 HPV types included in the LA genotyping assay. RESULTS: HPV DNA was detected in 460 of the 852 women (54.0%). Oncogenic HPV was detected in 297 women (34.9%) and HPV types 16/18 were found in 86 women (10.1%). The most frequently occurring HPV types were: 16 (6.2%); 35 (6.0%); 62 and 83 (5.5%); 61 and 58 (5.4%); 84 (4.7%); 18 (4.3%); and, 66 and 81 (4.2%). HPV prevalence was highest among women who were single, young (16-19 years), and had had more than three sexual partners in their lifetime. CONCLUSIONS: These results, coupled with high rates of cervical cancer, support introducing HPV vaccines while maintaining and strengthening cervical cancer screening services. Policy decision-making that reflects these results is instrumental to establishing a comprehensive cervical cancer program in Jamaica.

Rubella and congenital rubella syndrome elimination activities: Colombia, 2005-2006.

As part of regional commitments in the Americas aimed at elimination of rubella and congenital rubella syndrome, and consolidation of measles elimination, Colombia conducted mass vaccination of males and females aged 14-39 years in 2005-2006. The target population included 18,238< 443 persons (44% of the entire population). Vaccination activities were extended because of limited participation and public concerns about vaccine safety. Over a 10-month peroid, 17,697,717 doses of measles-rubella vaccine were administered, reaching 97% of the target population, including 96.4% of females and 97.6% of males. Estimated coverage exceeded 95% in 33 of 36 departments and districts, and in 3 others, it ranged from 92% to 95%. In rapid monitoring conducted in 504 (45%) of 1119 municipalities, 95% of persons in the target population were vaccinated. The Colombian experience underscores the importance of social mobilization at the local level, political commitment, and microplanning and offers lessons for future mass vaccination campaigns.

Epidemiology and risk factors related to severity of clinical manifestations of COVID-19 in outpatients: A retrospective study in Haiti.

BACKGROUND: Haiti's first COVID-19 cases were confirmed on March 18, 2020, and subsequently spread throughout the country. The objective of this study was to describe clinical manifestations of COVID-19 in Haitian outpatients and to identify risk factors for severity of clinical manifestations. METHODS: We conducted a retrospective study of COVID-19 outpatients diagnosed from March 18-August 4, 2020, using demographic, epidemiological, and clinical data reported to the Ministry of Health (MoH). We used univariate and multivariate analysis, including multivariable logistic regression, to explore the risk factors and specific symptoms related to persons with symptomatic COVID-19 and the severity of symptomatic COVID-19 disease. RESULTS: Of 5,389 cases reported to MOH during the study period, 1,754 (32.5%) were asymptomatic. Amongst symptomatic persons 2,747 (75.6%) had mild COVID-19 and 888 (24.4%) had moderate-to-severe disease; the most common symptoms were fever (69.6%), cough (51.9%), and myalgia (45.8%). The odds of having moderate-to-severe disease were highest among persons with hypertension (aOR = 1.72, 95% Confidence Interval [CI] (1.34, 2.20), chronic pulmonary disease (aOR = 3.93, 95% CI (1.93, 8.17)) and tuberculosis (aOR = 3.44, 95% CI (1.35, 9.14)) compared to persons without those conditions. The odds of having moderate-to-severe disease increased with age but was also seen among children aged 0-4 years (OR: 1.73, 95% CI (0.93, 3.08)), when using 30-39 years old as the reference group. All of the older age groups, 50-64 years, 65-74 years, 75-84 years, and 85+ years, had significantly higher odds of having moderate-to-severe COVID-19 compared with ages 30-39 years. Diabetes was associated with elevated odds of moderate-to-severe disease in bivariate analysis (OR = 2.17, 95% CI (1.58,2.98) but, this association did not hold in multivariable analyses (aOR = 1.22,95%CI (0.86,1.72)). CONCLUSION: These findings from a resource-constrained country highlight the importance of surveillance systems to track emerging infections and their risk factors. In addition to co-morbidities described elsewhere, tuberculosis was a risk factor for moderate-to-severe COVID-19 disease.

Seasonal Influenza Prevention and Control Progress in Latin America and the Caribbean in the Context of the Global Influenza Strategy and the COVID-19 Pandemic.

Each year in Latin America and the Caribbean, seasonal influenza is associated with an estimated 36,500 respiratory deaths and 400,000 hospitalizations. Since the 2009 influenza A(H1N1) pandemic, the Region has made significant advances in the prevention and control of seasonal influenza, including improved surveillance systems, burden estimates, and vaccination of at-risk groups. The Global Influenza Strategy 2019-2030 provides a framework to strengthen these advances. Against the backdrop of this new framework, the University of Colorado convened in October 2020 its Immunization Advisory Group of Experts to review and discuss current surveillance, prevention, and control strategies for seasonal influenza in Latin America and the Caribbean, also in the context of the COVID-19 pandemic. This review identified five areas for action and made recommendations specific to each area. The Region should continue its efforts to strengthen surveillance and impact evaluations. Existing data on disease burden, seasonality patterns, and vaccination effectiveness should be used to inform decision-making at the country level as well as advocacy efforts for programmatic resources. Regional and country strategic plans should be prepared and include specific targets for 2030. Existing investments in influenza prevention and control, including for immunization programs, should be optimized. Finally, regional partnerships, such as the regional networks for syndromic surveillance and vaccine effectiveness evaluation (SARInet and REVELAC-i), should continue to play a critical role in continuous learning and standardization by sharing experiences and best practices among countries.

Second-order modeling of variability and uncertainty in microbial hazard characterization.

This study describes an analytical framework that permits quantitative consideration of variability and uncertainty in microbial hazard characterization. Second-order modeling that used two-dimensional Monte Carlo simulation and stratification into homogeneous population subgroups was applied to integrate uncertainty and variability. Specifically, the bootstrap method was used to simulate sampling error due to the limited sample size in microbial dose-response modeling. A data set from human feeding trials with Campylobacter jejuni was fitted to the log-logistic dose-response model, and results from the analysis of FoodNet surveillance data provided further information on variability and uncertainty in Campylobacter susceptibility due to the effect of age. Results of our analyses indicate that uncertainty associated with dose-response modeling has a dominating influence on the analytical outcome. In contrast, inclusion of the age factor has a limited impact. While the advocacy of more closely modeling variability in hazard characterization is warranted, the characterization of key sources of uncertainties and their consistent propagation throughout a microbial risk assessment actually appear of greater importance.

Ring vaccination with rVSV-ZEBOV under expanded access in response to an outbreak of Ebola virus disease in Guinea, 2016: an operational and vaccine safety report.

BACKGROUND: In March, 2016, a flare-up of Ebola virus disease was reported in Guinea, and in response ring vaccination with the unlicensed rVSV-ZEBOV vaccine was introduced under expanded access, the first time that an Ebola vaccine has been used in an outbreak setting outside a clinical trial. Here we describe the safety of rVSV-ZEBOV candidate vaccine and operational feasibility of ring vaccination as a reactive strategy in a resource-limited rural setting. METHODS: Approval for expanded access and compassionate use was rapidly sought and obtained from relevant authorities. Vaccination teams and frozen vaccine were flown to the outbreak settings. Rings of contacts and contacts of contacts were defined and eligible individuals, who had given informed consent, were vaccinated and followed up for 21 days under good clinical practice conditions. FINDINGS: Between March 17 and April 21, 2016, 1510 individuals were vaccinated in four rings in Guinea, including 303 individuals aged between 6 years and 17 years and 307 front-line workers. It took 10 days to vaccinate the first participant following the confirmation of the first case of Ebola virus disease. No secondary cases of Ebola virus disease occurred among the vaccinees. Adverse events following vaccination were reported in 47 (17%) 6-17 year olds (all mild) and 412 (36%) adults (individuals older than 18 years; 98% were mild). Children reported fewer arthralgia events than adults (one [<1%] of 303 children vs 81 [7%] of 1207 adults). No severe vaccine-related adverse events were reported. INTERPRETATION: The results show that a ring vaccination strategy can be rapidly and safely implemented at scale in response to Ebola virus disease outbreaks in rural settings. FUNDING: WHO, Gavi, and the World Food Programme.

Development of a cholera vaccination policy on the Island of Hispaniola, 2010-2013.

Deployment of oral cholera vaccine (OCV) on the Island of Hispaniola has been considered since the emergence of the disease in October of 2010. At that time, emergency response focused on the time-tested measures of treatment to prevent deaths and sanitation to diminish transmission. Use of the limited amount of vaccine available in the global market was recommended for demonstration activities, which were carried out in 2012. As transmission continues, vaccination was recommended in Haiti as one component of a comprehensive initiative supported by an international coalition to eliminate cholera on the Island of Hispaniola. Leveraging its delivery to strengthen other cholera prevention measures and immunization services, a phased OCV introduction is pursued in accordance with global vaccine supply. Not mutually exclusive or sequential deployment options include routine immunization for children over the age of 1 year and campaigns in vulnerable metropolitan areas or rural areas with limited access to health services.

Human papillomavirus vaccine introduction--the first five years.

The availability of prophylactic human papillomavirus (HPV) vaccines has provided powerful tools for primary prevention of cervical cancer and other HPV-associated diseases. Since 2006, the quadrivalent and bivalent vaccines have each been licensed in over 100 countries. By the beginning of 2012, HPV vaccine had been introduced into national immunization programs in at least 40 countries. Australia, the United Kingdom, the United States, and Canada were among the first countries to introduce HPV vaccination. In Europe, the number of countries having introduced vaccine increased from 3 in 2007 to 22 at the beginning of 2012. While all country programs target young adolescent girls, specific target age groups vary as do catch-up recommendations. Different health care systems and infrastructure have resulted in varied implementation strategies, with some countries delivering vaccine in schools and others through health centers or primary care providers. Within the first 5 years after vaccines became available, few low- or middle-income countries had introduced HPV vaccine. The main reason was budgetary constraints due to the high vaccine cost. Bhutan and Rwanda implemented national immunization after receiving vaccine through donation programs in 2010 and 2011, respectively. The GAVI Alliance decision in 2011 to support HPV vaccination should increase implementation in low-income countries. Evaluation of vaccination programs includes monitoring of coverage, safety, and impact. Vaccine safety monitoring is part of routine activities in many countries. Safety evaluations are important and communication about vaccine safety is critical, as events temporally associated with vaccination can be falsely attributed to vaccination. Anti-vaccination efforts, in part related to concerns about safety, have been mounted in several countries. In the 5 years since HPV vaccines were licensed, there have been successes as well as challenges with vaccine introduction and implementation. Further progress is anticipated in the coming years, especially in low- and middle-income countries where the need for vaccine is greatest. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Genital human papillomaviruses among women of reproductive age in Jamaica / Virus de los papilomas humanos genitales en mujeres en edad reproductiva de Jamaica

OBJECTIVE: To characterize the prevalence and distribution of genital human papillomavirus (HPV) types among women in Jamaica, and to explore risk factors associated with HPV infection. METHODS: This was a cross-sectional study that took place in April-July 2010 with 852 sexually-active women, 16-49 years of age, who had attended a selected public or private primary health clinic in one of Jamaica's four health authority regions. Sociodemographic data was collected from each participant by trained study staff. Each participant had a gynecological examination that included a clinical Pap test and a cervical sample for HPV detection and typing-performed using the Research Use Only Linear Array (LA) genotyping assay (Roche Diagnostics Corp., Indianapolis, Indiana, United States). Overall and type-specific prevalence of HPV infection was calculated for 37 HPV types included in the LA genotyping assay. RESULTS: HPV DNA was detected in 460 of the 852 women (54.0%). Oncogenic HPV was detected in 297 women (34.9%) and HPV types 16/18 were found in 86 women (10.1%). The most frequently occurring HPV types were: 16 (6.2%); 35 (6.0%); 62 and 83 (5.5%); 61 and 58 (5.4%); 84 (4.7%); 18 (4.3%); and, 66 and 81 (4.2%). HPV prevalence was highest among women who were single, young (16-19 years), and had had more than three sexual partners in their lifetime. CONCLUSIONS: These results, coupled with high rates of cervical cancer, support introducing HPV vaccines while maintaining and strengthening cervical cancer screening services. Policy decisionmaking that reflects these results is instrumental to establishing a comprehensive cervical cancer program in Jamaica.

OBJETIVO: Determinar la prevalencia y la distribución de los tipos de virus de los papilomas humanos (VPH) genitales en las mujeres de Jamaica y explorar los factores de riesgo asociados con la infección por VPH. MÉTODOS: Este estudio transversal se llevó a cabo de abril a julio del 2010. Participaron 852 mujeres sexualmente activas, de 16 a 49 años de edad, que acudieron a uno de los consultorios públicos o privados de atención primaria seleccionados en cada una de las cuatro autoridades sanitarias regionales de Jamaica. Personal capacitado del estudio recopiló datos sociodemográficos de cada participante. Todas las participantes fueron sometidas a un examen ginecológico que comprendía una prueba clínica de Papanicolaou y la obtención de una muestra del cuello uterino a efectos de detectar y tipificarlos VPH mediante la prueba de genotipado Linear Array (LA) (Roche Diagnostics Corp., Indianápolis, Indiana, Estados Unidos), de uso exclusivo en investigación. Se calcularon las prevalencias global y específica de tipo de la infección por VPH para los 37 tipos de VPH incluidos en la prueba de genotipado LA. RESULTADOS: Se detectó ADN de VPH en 460 de las 852 mujeres (54,0%). Se detectaron VPH oncógenos en 297 mujeres (34,9%), y VPH de los tipos 16 y 18 en 86 mujeres (10,1%). Los tipos de VPH detectados con mayor frecuencia fueron 16 (6,2%), 35 (6,0%), 62 y 83 (5,5%), 61 y 58 (5,4%), 84 (4,7%), 18 (4,3%), y 66 y 81 (4,2%). La prevalencia de VPH fue más elevada en mujeres solteras, jóvenes (de 16 a 19 años) y que habían tenido más de tres compañeros sexuales en sus vidas. CONCLUSIONES: Estos resultados, junto a las elevadas tasas de cáncer cervicouterino, fundamentan la introducción de las vacunas contra el VPH al tiempo que se mantienen y refuerzan los servicios de tamizaje del cáncer cervicouterino. Las decisiones políticas que se adopten como consecuencia de estos resultados serán determinantes para establecer un programa integral contra el cáncer cervicouterino en Jamaica.