RESUMEN
Ebola virus disease (Ebola) is a rare but severe illness in humans, with an average case fatality rate of approximately 50%. Two licensed vaccines are currently available against Orthoebolavirus zairense, the virus that causes Ebola: the 1-dose rVSVΔG-ZEBOV-GP (ERVEBO [Merck]) and the 2-dose regimen of Ad26.ZEBOV and MVA-BN-Filo (Zabdeno/Mvabea [Johnson & Johnson]). The Strategic Advisory Group of Experts on Immunization recommends the use of 1-dose ERVEBO during Ebola outbreaks, and in 2021, a global stockpile of ERVEBO was established to ensure equitable, timely, and targeted access to vaccine doses for future Ebola outbreaks. This report describes the use of Ebola vaccines and the role of the stockpile developed and managed by the International Coordinating Group (ICG) on Vaccine Provision during 2021-2023. A total of 145,690 doses have been shipped from the ICG stockpile since 2021. However, because outbreaks since 2021 have been limited and rapidly contained, most doses (139,120; 95%) shipped from the ICG stockpile have been repurposed for preventive vaccination of high-risk groups, compared with 6,570 (5%) used for outbreak response. Repurposing doses for preventive vaccination could be prioritized in the absence of Ebola outbreaks to prevent transmission and maximize the cost-efficiency and benefits of the stockpile.
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Brotes de Enfermedades , Vacunas contra el Virus del Ébola , Salud Global , Fiebre Hemorrágica Ebola , Humanos , Vacunas contra el Virus del Ébola/administración & dosificación , Fiebre Hemorrágica Ebola/prevención & control , Fiebre Hemorrágica Ebola/epidemiología , Brotes de Enfermedades/prevención & control , Reserva Estratégica , Adulto , Niño , AdolescenteRESUMEN
With the availability of authorized COVID-19 vaccines in early 2021, vaccination became an effective tool to reduce COVID-19-associated morbidity and mortality. Initially, the World Health Organization (WHO) set an ambitious target to vaccinate 70% of the global population by mid-2022. However, in July 2022, WHO recommended that all countries, including those in the African Region, prioritize COVID-19 vaccination of high-risk groups, including older adults and health care workers, to have the greatest impact on morbidity and mortality. As of December 31, 2023, approximately 860 million doses of COVID-19 vaccine had been delivered to countries in the African Region, and 646 million doses had been administered. Cumulatively, 38% of the African Region's population had received ≥1 dose, 32% had completed a primary series, and 21% had received ≥1 booster dose. Cumulative total population coverage with ≥1 dose ranged by country from 0.3% to 89%. Coverage with the primary series among older age groups was 52% (range among countries = 15%-96%); primary series coverage among health care workers was 48% (range = 13%-99%). Although the COVID-19 public health emergency of international concern was declared over in May 2023, current WHO recommendations reinforce the need to vaccinate priority populations at highest risk for severe COVID-19 disease and death and build more sustainable programs by integrating COVID-19 vaccination into primary health care, strengthening immunization across the life course, and improving pandemic preparedness.
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Vacunas contra la COVID-19 , COVID-19 , Humanos , Anciano , Cobertura de Vacunación , COVID-19/epidemiología , COVID-19/prevención & control , Programas de Inmunización , Vacunación , Organización Mundial de la SaludRESUMEN
BACKGROUND: Health care workers (HCW) are more likely to be exposed to Ebola virus (EBOV) during an outbreak compared to people in the general population due to close physical contact with patients and potential exposure to infectious fluids. However, not all will fall ill. Despite evidence of subclinical and paucisymptomatic Ebola virus disease (EVD), prevalence and associated risk factors remain unknown. METHODS: We conducted a serosurvey among HCW in Boende, Tshuapa Province, Democratic Republic of Congo. Human anti-EBOV glycoprotein IgG titers were measured using a commercially available ELISA kit. We assessed associations between anti-EBOV IgG seroreactivity, defined as ≥2.5 units/mL, and risk factors using univariable and multivariable logistic regression. Sensitivity analyses explored a more conservative cutoff, >5 units/mL. RESULTS: Overall, 22.5% of HCWs were seroreactive for EBOV. In multivariable analyses, using any form of personal protective equipment when interacting with a confirmed, probable, or suspect EVD case was negatively associated with seroreactivity (adjusted odds ratio, 0.23; 95% confidence interval, .07-.73). DISCUSSION: Our results suggest high exposure to EBOV among HCWs and provide additional evidence for asymptomatic or minimally symptomatic EVD. Further studies should be conducted to determine the probability of onward transmission and if seroreactivity is associated with immunity.
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Ebolavirus , Fiebre Hemorrágica Ebola , República Democrática del Congo/epidemiología , Brotes de Enfermedades , Personal de Salud , Humanos , Inmunoglobulina G , Factores de RiesgoRESUMEN
The US Centers for Disease Control and Prevention (CDC) supports international partners in introducing vaccines, including those against SARS-CoV-2 virus. CDC contributes to the development of global technical tools, guidance, and policy for COVID-19 vaccination and has established its COVID-19 International Vaccine Implementation and Evaluation (CIVIE) program. CIVIE supports ministries of health and their partner organizations in developing or strengthening their national capacities for the planning, implementation, and evaluation of COVID-19 vaccination programs. CIVIE's 7 priority areas for country-specific technical assistance are vaccine policy development, program planning, vaccine confidence and demand, data management and use, workforce development, vaccine safety, and evaluation. We discuss CDC's work on global COVID-19 vaccine implementation, including priorities, challenges, opportunities, and applicable lessons learned from prior experiences with Ebola, influenza, and meningococcal serogroup A conjugate vaccine introductions.
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COVID-19 , Vacunas contra la Influenza , Estados Unidos/epidemiología , Humanos , Vacunas contra la COVID-19 , SARS-CoV-2 , COVID-19/prevención & control , Centers for Disease Control and Prevention, U.S.RESUMEN
BACKGROUND: Vaccination efforts to eradicate polio currently focus on children under 5 years of age, among whom most cases of poliomyelitis still occur. However, in the Democratic Republic of the Congo (DRC), an outbreak of wild poliovirus type 1 occurred in 2010-2011 in which 16% of cases occurred among adults; in a related outbreak in the neighboring Republic of Congo, 75% of cases occurred among the same adult age-group. Given that infected adults may transmit poliovirus, this study was designed to assess adult immunity against polioviruses. METHODS: We assessed poliovirus seroprevalence using dried blood spots from 5,526 adults aged 15-59 years from the 2013-2014 Demographic and Health Survey in the DRC. RESULTS: Among adults in the DRC, 74%, 72%, and 57% were seropositive for neutralizing antibodies for poliovirus types 1, 2, and 3, respectively. For all three serotypes, seroprevalence tended to be higher among older age groups, those living in households with more children, and among women. CONCLUSIONS: Protection against poliovirus is generally low among adults in the DRC, particularly for type 3 poliovirus. The lack of acquired immunity in adults suggests a potentially limited poliovirus circulation over the lifetime of those surveyed (spanning 1954 through 2014) and transmission of vaccine-derived poliovirus in this age group while underscoring the risk of these outbreaks among adults in the DRC.
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Poliomielitis , Poliovirus , Adulto , Anciano , Niño , Preescolar , Estudios Transversales , República Democrática del Congo/epidemiología , Brotes de Enfermedades , Femenino , Humanos , Lactante , Poliomielitis/epidemiología , Poliomielitis/prevención & control , Vacuna Antipolio Oral , Estudios SeroepidemiológicosRESUMEN
BACKGROUND: Female sex workers are vulnerable to HIV, sexually transmitted diseases, and unintended pregnancies; however, the literature on female sex workers (FSW) focuses primarily on HIV and is limited regarding these other health issues. METHODS: We conducted a respondent-driven sampling (RDS) survey during April-December 2012 to characterize the reproductive health of and access to contraceptives FSW in Kampala, Uganda. Eligibility criteria included age ≥ 15 years, residence in greater Kampala, and having sold sex to men in ≤ 6 months. Data were analyzed using RDS-Analyst. Survey logistic regression was used in SAS. RESULTS: We enrolled 1,497 FSW with a median age of 27 years. Almost all FSW had been pregnant at least once. An estimated 33.8% of FSW were currently not using any form of family planning (FP) to prevent pregnancy; 52.7% used at least moderately effective FP. Among those using FP methods, injectable contraception was the most common form of FP used (55.4%), followed by condoms (19.7%), oral contraception (18.1%), and implants (3.7%). HIV prevalence was 31.4%, syphilis prevalence was 6.2%, and 89.8% had at least one symptom of a sexually transmitted disease in the last six months. Using at least a moderately effective method of FP was associated with accessing sexually transmitted disease treatment in a stigma-free environment in the last six months (aOR: 1.6, 95% CI: 1.1-2.4), giving birth to 2-3 children (aOR: 2.5, 95% CI: 1.4-4.8) or 4-5 children (aOR: 2.9, 95% CI: 1.4-5.9). It is plausible that those living with HIV are also less likely than those without it to be using a moderately effective method of FP (aOR: 0.7, 95% CI: 0.5-1.0). CONCLUSIONS: The provision of integrated HIV and sexual and reproductive health services in a non-stigmatizing environment has the potential to facilitate increased health service uptake by FSW and decrease missed opportunities for service provision.
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Infecciones por VIH , Trabajadores Sexuales , Enfermedades de Transmisión Sexual , Adolescente , Adulto , Niño , Servicios de Planificación Familiar , Femenino , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Humanos , Masculino , Embarazo , Salud Reproductiva , Enfermedades de Transmisión Sexual/epidemiología , Enfermedades de Transmisión Sexual/prevención & control , Uganda/epidemiologíaRESUMEN
To assess transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a detention facility experiencing a coronavirus disease outbreak and evaluate testing strategies, we conducted a prospective cohort investigation in a facility in Louisiana, USA. We conducted SARS-CoV-2 testing for detained persons in 6 quarantined dormitories at various time points. Of 143 persons, 53 were positive at the initial test, and an additional 58 persons were positive at later time points (cumulative incidence 78%). In 1 dormitory, all 45 detained persons initially were negative; 18 days later, 40 (89%) were positive. Among persons who were SARS-CoV-2 positive, 47% (52/111) were asymptomatic at the time of specimen collection; 14 had replication-competent virus isolated. Serial SARS-CoV-2 testing might help interrupt transmission through medical isolation and quarantine. Testing in correctional and detention facilities will be most effective when initiated early in an outbreak, inclusive of all exposed persons, and paired with infection prevention and control.
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Prueba de COVID-19/estadística & datos numéricos , COVID-19/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Transmisión de Enfermedad Infecciosa/estadística & datos numéricos , SARS-CoV-2/aislamiento & purificación , Adulto , COVID-19/diagnóstico , COVID-19/transmisión , Femenino , Humanos , Incidencia , Louisiana/epidemiología , Masculino , Prisiones , Estudios ProspectivosRESUMEN
Transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), by asymptomatic and presymptomatic persons poses important challenges to controlling spread of the disease, particularly in congregate settings such as correctional and detention facilities (1). On March 29, 2020, a staff member in a correctional and detention facility in Louisiana developed symptoms and later had a positive test result for SARS-CoV-2. During April 2-May 7, two additional cases were detected among staff members, and 36 cases were detected among incarcerated and detained persons at the facility; these persons were removed from dormitories and isolated, and the five dormitories that they had resided in before diagnosis were quarantined. On May 7, CDC and the Louisiana Department of Health initiated an investigation to assess the prevalence of SARS-CoV-2 infection among incarcerated and detained persons residing in quarantined dormitories. Goals of this investigation included evaluating COVID-19 symptoms in this setting and assessing the effectiveness of serial testing to identify additional persons with SARS-CoV-2 infection as part of efforts to mitigate transmission. During May 7-21, testing of 98 incarcerated and detained persons residing in the five quarantined dormitories (A-E) identified an additional 71 cases of SARS-CoV-2 infection; 32 (45%) were among persons who reported no symptoms at the time of testing, including three who were presymptomatic. Eighteen cases (25%) were identified in persons who had received negative test results during previous testing rounds. Serial testing of contacts from shared living quarters identified persons with SARS-CoV-2 infection who would not have been detected by symptom screening alone or by testing at a single time point. Prompt identification and isolation of infected persons is important to reduce further transmission in congregate settings such as correctional and detention facilities and the communities to which persons return when released.
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Técnicas de Laboratorio Clínico/métodos , Infecciones por Coronavirus/prevención & control , Pandemias/prevención & control , Neumonía Viral/prevención & control , Prisioneros/estadística & datos numéricos , Prisiones , Adulto , COVID-19 , Prueba de COVID-19 , Servicios de Laboratorio Clínico , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/transmisión , Femenino , Humanos , Louisiana/epidemiología , Masculino , Neumonía Viral/epidemiología , Neumonía Viral/transmisiónRESUMEN
Healthcare settings have played a major role in propagation of Ebola virus (EBOV) outbreaks. Healthcare workers (HCWs) have elevated risk of contact with EBOV-infected patients, particularly if safety precautions are not rigorously practiced. We conducted a serosurvey to determine seroprevalence against multiple EBOV antigens among HCWs of Boende Health Zone, Democratic Republic of the Congo, the site of a 2014 EBOV outbreak. Interviews and specimens were collected from 565 consenting HCWs. Overall, 234 (41.4%) of enrolled HCWs were reactive to at least 1 EBOV protein: 159 (28.1%) were seroreactive for anti-glycoprotein immunoglobulin G (IgG), 89 (15.8%) were seroreactive for anti-nucleoprotein IgG, and 54 (9.5%) were VP40 positive. Additionally, sera from 16 (2.8%) HCWs demonstrated neutralization capacity. These data demonstrate that a significant proportion of HCWs have the ability to neutralize virus, despite never having developed Ebola virus disease symptoms, highlighting an important and poorly documented aspect of EBOV infection and progression.
Asunto(s)
Anticuerpos Antivirales/sangre , Ebolavirus/inmunología , Personal de Salud , Estudios Seroepidemiológicos , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/sangre , República Democrática del Congo , Femenino , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Monkeypox, caused by a zoonotic orthopoxvirus, is endemic in Central and West Africa. Monkeypox has been sporadically reported in the Republic of the Congo. During March 22-April 5, 2017, we investigated 43 suspected human monkeypox cases. We interviewed suspected case-patients and collected dried blood strips and vesicular and crust specimens (active lesions), which we tested for orthopoxvirus antibodies by ELISA and monkeypox virus and varicella zoster virus DNA by PCR. An ecologic investigation was conducted around Manfouété, and specimens from 105 small mammals were tested for anti-orthopoxvirus antibodies or DNA. Among the suspected human cases, 22 met the confirmed, probable, and possible case definitions. Only 18 patients had available dried blood strips; 100% were IgG positive, and 88.9% (16/18) were IgM positive. Among animals, only specimens from Cricetomys giant pouched rats showed presence of orthopoxvirus antibodies, adding evidence to this species' involvement in the transmission and maintenance of monkeypox virus in nature.
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Ecología , Monkeypox virus , Mpox/epidemiología , Mpox/virología , Adolescente , Adulto , Animales , Niño , Preescolar , Congo/epidemiología , Brotes de Enfermedades , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Lactante , Masculino , Mpox/diagnóstico , Monkeypox virus/genética , Monkeypox virus/inmunología , Reacción en Cadena de la Polimerasa , Vigilancia en Salud Pública , Vigilancia de Guardia , Adulto JovenRESUMEN
Background: Previous studies suggest that cases of Ebola virus disease (EVD) may go unreported because they are asymptomatic or unrecognized, but evidence is limited by study designs and sample size. Methods: A large population-based survey was conducted (n = 3415) to assess animal exposures and behaviors associated with Ebolavirus antibody prevalence in rural Kasai Oriental province of the Democratic Republic of Congo (DRC). Fourteen villages were randomly selected and all healthy individuals ≥1 year of age were eligible. Results: Overall, 11% of subjects tested positive for Zaire Ebolavirus (EBOV) immunoglobulin G antibodies. Odds of seropositivity were higher for study participants older than 15 years of age and for males. Those residing in Kole (closer to the outbreak site) tested positive at a rate 1.6× higher than Lomela, with seropositivity peaking at a site located between Kole and Lomela. Multivariate analyses of behaviors and animal exposures showed that visits to the forest or hunting and exposure to rodents or duikers predicted a higher likelihood of EBOV seropositivity. Conclusions: These results provide serologic evidence of Ebolavirus exposure in a population residing in non-EBOV outbreak locations in the DRC and define statistically significant activities and animal exposures that associate with EBOV seropositivity.
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Anticuerpos Antivirales/sangre , Ebolavirus/inmunología , Fiebre Hemorrágica Ebola/epidemiología , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Conducta , Niño , Preescolar , República Democrática del Congo/epidemiología , Exposición a Riesgos Ambientales , Femenino , Geografía , Voluntarios Sanos , Humanos , Inmunoglobulina G/sangre , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Población Rural , Estudios Seroepidemiológicos , Factores Sexuales , Adulto JovenRESUMEN
One year after a Zaire ebolavirus (EBOV) outbreak occurred in the Boende Health Zone of the Democratic Republic of the Congo during 2014, we sought to determine the breadth of immune response against diverse filoviruses including EBOV, Bundibugyo (BDBV), Sudan (SUDV), and Marburg (MARV) viruses. After assessing the 15 survivors, 5 individuals demonstrated some degree of reactivity to multiple ebolavirus species and, in some instances, Marburg virus. All 5 of these survivors had immunoreactivity to EBOV glycoprotein (GP) and EBOV VP40, and 4 had reactivity to EBOV nucleoprotein (NP). Three of these survivors showed serologic responses to the 3 species of ebolavirus GPs tested (EBOV, BDBV, SUDV). All 5 samples also exhibited ability to neutralize EBOV using live virus, in a plaque reduction neutralization test. Remarkably, 3 of these EBOV survivors had plasma antibody responses to MARV GP. In pseudovirus neutralization assays, serum antibodies from a subset of these survivors also neutralized EBOV, BDBV, SUDV, and Taï Forest virus as well as MARV. Collectively, these findings suggest that some survivors of naturally acquired ebolavirus infection mount not only a pan-ebolavirus response, but also in less frequent cases, a pan-filovirus neutralizing response.
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Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Ebolavirus/clasificación , Fiebre Hemorrágica Ebola/epidemiología , Fiebre Hemorrágica Ebola/inmunología , Anticuerpos Monoclonales , Anticuerpos Neutralizantes/sangre , Especificidad de Anticuerpos , Antígenos Virales , República Democrática del Congo/epidemiología , Ebolavirus/inmunología , Glicoproteínas/inmunología , Fiebre Hemorrágica Ebola/virología , Humanos , Virus Lassa/inmunología , Marburgvirus/inmunología , Pruebas de NeutralizaciónRESUMEN
The first reported outbreak of Ebola virus disease occurred in 1976 in Yambuku, Democratic Republic of Congo. Antibody responses in survivors 11 years after infection have been documented. However, this report is the first characterization of anti-Ebola virus antibody persistence and neutralization capacity 40 years after infection. Using ELISAs we measured survivor's immunological response to Ebola virus Zaire (EBOV) glycoprotein and nucleoprotein, and assessed VP40 reactivity. Neutralization of EBOV was measured using a pseudovirus approach and plaque reduction neutralization test with live EBOV. Some survivors from the original EBOV outbreak still harbor antibodies against all 3 measures. Interestingly, a subset of these survivors' serum antibodies could still neutralize live virus 40 years postinitial infection. These data provide the longest documentation of both anti-Ebola serological response and neutralization capacity within any survivor cohort, extending the known duration of response from 11 years postinfection to at least 40 years after symptomatic infection.
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Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Brotes de Enfermedades , Ebolavirus/inmunología , Fiebre Hemorrágica Ebola/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antígenos Virales/inmunología , República Democrática del Congo/epidemiología , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , Encuestas y Cuestionarios , Sobrevivientes , Factores de Tiempo , Ensayo de Placa Viral , Adulto JovenRESUMEN
Reports of 10 suspected cases of monkeypox in Likouala Department, Republic of the Congo, triggered an investigation and response in March 2017 that included community education and surveillance strengthening. Increasing numbers of outbreaks suggest that monkeypox virus is becoming a more prevalent human pathogen. Diverse approaches are necessary for disease control and prevention.
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Brotes de Enfermedades , Monkeypox virus , Mpox/epidemiología , Mpox/virología , Animales , Congo/epidemiología , Humanos , Mpox/diagnóstico , Vigilancia de la PoblaciónRESUMEN
BACKGROUND: Ebola virus disease (EVD) can be clinically severe and highly fatal, making surveillance efforts for early disease detection of paramount importance. In areas with limited access to laboratory testing, the Integrated Disease Surveillance and Response (IDSR) strategy in the Democratic Republic of Congo (DRC) may be a vital tool in improving outbreak response. METHODS: Using DRC IDSR data from the nation's four EVD outbreak periods from 2007-2014, we assessed trends of Viral Hemorrhagic Fever (VHF) and EVD differential diagnoses reportable through IDSR. With official case counts from active surveillance of EVD outbreaks, we assessed accuracy of reporting through the IDSR passive surveillance system. RESULTS: Although the active and passive surveillance represent distinct sets of data, the two were correlated, suggesting that passive surveillance based only on clinical evaluation may be a useful predictor of true cases prior to laboratory confirmation. There were 438 suspect VHF cases reported through the IDSR system and 416 EVD cases officially recorded across the outbreaks examined. CONCLUSION: Although collected prior to official active surveillance cases, case reporting through the IDSR during the 2007, 2008 and 2012 outbreaks coincided with official EVD epidemic curves. Additionally, all outbreak areas experienced increases in suspected cases for both malaria and typhoid fever during EVD outbreaks, underscoring the importance of training health care workers in recognising EVD differential diagnoses and the potential for co-morbidities.
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Toma de Decisiones Clínicas , Brotes de Enfermedades , Ebolavirus , Fiebre Hemorrágica Ebola/diagnóstico , Vigilancia de la Población/métodos , República Democrática del Congo/epidemiología , Diagnóstico Diferencial , Epidemias , Fiebre Hemorrágica Ebola/epidemiología , Fiebre Hemorrágica Ebola/virología , Humanos , LaboratoriosRESUMEN
BACKGROUND: In 2016, outbreaks of yellow fever in Angola and the Democratic Republic of the Congo led to a global vaccine shortage. A fractional dose of 17DD yellow fever vaccine (containing one-fifth [0·1 ml] of the standard dose) was used during a pre-emptive mass campaign in August, 2016, in Kinshasa, Democratic Republic of the Congo among children aged 2 years and older and non-pregnant adults (ie, those aged 18 years and older). 1 year following vaccination, 97% of participants were seropositive; however, the long-term durability of the immune response is unknown. We aimed to conduct a prospective cohort study and invited participants enrolled in the previous evaluation to return 5 years after vaccination to assess durability of the immune response. METHODS: Participants returned to one of six health facilities in Kinshasa in 2021, where study staff collected a brief medical history and blood specimen. We assessed neutralising antibody titres against yellow fever virus using a plaque reduction neutralisation test with a 50% cutoff (PRNT50). Participants with a PRNT50 titre of 10 or higher were considered seropositive. The primary outcome was the proportion of participants seropositive at 5 years. FINDINGS: Among the 764 participants enrolled, 566 (74%) completed the 5-year visit. 5 years after vaccination, 539 (95·2%, 95% CI 93·2-96·7) participants were seropositive, including 361 (94·3%, 91·5-96·2) of 383 who were seronegative and 178 (97·3%, 93·8-98·8) of 183 who were seropositive at baseline. Geometric mean titres (GMTs) differed significantly across age groups for those who were initially seronegative with the lowest GMT among those aged 2-5 years and highest among those aged 13 years and older. INTERPRETATION: A fractional dose of the 17DD yellow fever vaccine induced an immunologic response with detectable titres at 5 years among the majority of participants in the Democratic Republic of the Congo. These findings support the use of fractional-dose vaccination for outbreak prevention with the potential for sustained immunity. FUNDING: Gavi, the Vaccine Alliance through the CDC Foundation. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.
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Anticuerpos Antivirales , Brotes de Enfermedades , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Humanos , República Democrática del Congo/epidemiología , Fiebre Amarilla/prevención & control , Fiebre Amarilla/inmunología , Fiebre Amarilla/epidemiología , Estudios Prospectivos , Vacuna contra la Fiebre Amarilla/inmunología , Vacuna contra la Fiebre Amarilla/administración & dosificación , Brotes de Enfermedades/prevención & control , Masculino , Femenino , Niño , Preescolar , Adolescente , Adulto , Anticuerpos Antivirales/sangre , Adulto Joven , Vacunación , Persona de Mediana Edad , Anticuerpos Neutralizantes/sangre , Virus de la Fiebre Amarilla/inmunologíaRESUMEN
BACKGROUND: In 2016, the World Health Organization recommended that a fractional dose of yellow fever (YF) vaccine could be used in persons 2 years of age or older in response to an emergency that resulted in a global shortage of available YF vaccine. However, this recommendation did not extend to the youngest age group licensed for YF vaccine because there were no published data on the use or safety of fractional dose YF vaccination in children aged 9-23 months. We conducted a single-blind randomized controlled trial, comparing the immunogenicity and safety of fractional one-fifth and one-half doses of Bio-Manguinhos 17DD YF vaccine with full dose in children aged 9-23 months old in Uganda. In this paper, we present the interim analysis on safety. METHODS: Children aged 9-23 months presenting for routine well-child services were recruited for inclusion at one of three study sites. We collected data during March 26, 2019-August 31, 2020, on all adverse events following immunization (AEFI) during active surveillance for 28 days post-vaccination using multiple collection tools including a diary card with an objective measurement of fever. An independent team from the Uganda national AEFI Committee investigated and classified serious AEFI (SAE) according to Brighton Collaboration Criteria. RESULTS: Among 1053 enrolled children, 672 (64%) were reported to have a non-serious AEFI (NSAE) and 17 (2%) were reported to have a SAE. The most common AEFI were diarrhoea, fever, and rash, each reported by 355 (34%), 338 (33%), and 188 (18%) participants, respectively. Among 17 participants with SAE, eight were reported to have had seizures and five were hospitalised for seizures or other causes (respiratory symptoms, gastrointestinal illness, malaria). Four SAEs (deaths) occurred >28 days after vaccination. There were no reported cases of pre-specified or vaccine-related SAEs. We observed no significant difference in frequency or severity of adverse events among the study groups. CONCLUSIONS: Using comprehensive active surveillance monitoring, we did not identify any unexpected safety concerns among children aged <2 years receiving YF vaccination, including with the fractional doses. Although we identified a high number of both serious and non-serious AEFI, none were determined to be causally related to YF vaccination. These results provide evidence for the safety of fractional dose YF vaccination among children aged 9-23 months.
RESUMEN
Background: Low levels of COVID-19 vaccination coverage in many countries prompted the use of rapid assessments to characterize barriers to vaccination and identify corrective measures. The World Health Organization recommended the use of intra-action reviews (IARs) to identify best practices, gaps, and lessons learned to make real-time improvements to the COVID-19 vaccination response. Objective: The Democratic Republic of the Congo (DRC) implemented a national IAR in July 2021 that was poorly attended by the provincial health level, where vaccination activities are planned and implemented. To bridge this gap, we proposed sub-national IARs focused on COVID-19 vaccine program implementation at the provincial level. Methods: Using the WHO methodology, we organized a four-day provincial IAR workshop and invited national, provincial and health zone Ministry of Health (MoH) representatives and private and non-governmental organizations involved in the provincial COVID-19 vaccination response. Participants were divided into six groups based on their expertise, affiliation, and role within the health system to assess and identify lessons learned, challenges and the solutions within each of the six technical areas: (1) coordination, planning and monitoring; (2) service delivery; (3) risk communication and community engagement; (4) adverse effects following immunization (AEFI); (5) logistics; (6) and data management, monitoring and evaluation. Results: The first provincial COVID-19 IAR was conducted in Goma, North Kivu, from January 19-22, 2022. A total of 56 participants came from provincial and health zone offices, and non-governmental organizations. Through work group discussions, they identified best practices, challenges, and lessons learned, and made recommendations to improve implementation of vaccination activities and reach coverage targets. Activities were proposed to operationalize recommendations and address challenges to improve the provincial response. Conclusion: This provincial IAR was a useful tool for reviewing progress and areas of improvement, while evaluating aspects of the COVID-19 vaccine rollout. It provided a means to share information with vaccination partners on areas of intervention, tailored to the local context.
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The tenth Ebola Virus Disease (EVD) outbreak (2018-2020, North Kivu, Ituri, South Kivu) in the Democratic Republic of the Congo (DRC) was the second-largest EVD outbreak in history. During this outbreak, Ebola vaccination was an integral part of the EVD response. We evaluated community perceptions toward Ebola vaccination and identified correlates of Ebola vaccine uptake among high-risk community members in North Kivu, DRC. In March 2021, a cross-sectional survey among adults was implemented in three health zones. We employed a sampling approach mimicking ring vaccination, targeting EVD survivors, their household members, and their neighbors. Outbreak experiences and perceptions toward the Ebola vaccine were assessed, and modified Poisson regression was used to identify correlates of Ebola vaccine uptake among those offered vaccination. Among the 631 individuals surveyed, most (90.2%) reported a high perceived risk of EVD and 71.6% believed that the vaccine could reduce EVD severity; however, 63.7% believed the vaccine had serious side effects. Among the 474 individuals who had been offered vaccination, 397 (83.8%) received the vaccine, 180 (45.3%) of those vaccinated received the vaccine after two or more offers. Correlates positively associated with vaccine uptake included having heard positive information about the vaccine (RR 1.30, 95% CI 1.06-1.60), the belief that the vaccine could prevent EVD (RR 1.23, 95% CI 1.09-1.39), and reporting that religion influenced all decisions (RR 1.13, 95% CI 1.02-1.25). Ebola vaccine uptake was high in this population, although mixed attitudes and vaccine delays were common. Communicating positive vaccine information, emphasizing the efficacy of the Ebola vaccine, and engaging religious leaders to promote vaccination may aid in increasing Ebola vaccine uptake during future outbreaks.
RESUMEN
BACKGROUND: Recent studies suggest measles-induced immune amnesia could have long-term immunosuppressive effects via preferential depletion of memory CD150+ lymphocytes, and associations with a 2-3 year period of increased mortality and morbidity from infectious diseases other than measles has been shown in children from wealthy and low-income countries. To further examine the associations previous measles virus infection may have on immunologic memory among children in the Democratic Republic of the Congo (DRC), we assessed tetanus antibody levels among fully vaccinated children, with and without a history of measles. METHODS: We assessed 711 children 9-59 months of age whose mothers were selected for interview in the 2013-2014 DRC Demographic and Health Survey. History of measles was obtained by maternal report and classification of children who had measles in the past was completed using maternal recall and measles IgG serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. Tetanus IgG antibody serostatus was similarly obtained. A logistic regression model was used to identify association of measles and other predictors with subprotective tetanus IgG antibody. RESULTS: Subprotective geometric mean concentration tetanus IgG antibody values were seen among fully vaccinated children 9-59 months of age, who had a history of measles. Controlling for potential confounding variables, children classified as measles cases were less likely to have seroprotective tetanus toxoid antibody (odds ratio: 0.21; 95% confidence interval: 0.08-0.55) compared with children who had not had measles. CONCLUSIONS: History of measles was associated with subprotective tetanus antibody among this sample of children in the DRC who were 9-59 months of age and fully vaccinated against tetanus.