Response to Vaccine-Derived Polioviruses Detected through Environmental Surveillance, Guatemala, 2019.

Guatemala implemented wastewater-based poliovirus surveillance in 2018, and three genetically unrelated vaccine-derived polioviruses (VDPVs) were detected in 2019. The Ministry of Health (MoH) response included event investigation through institutional and community retrospective case searches for acute flaccid paralysis (AFP) during 2018-2020 and a bivalent oral polio/measles, mumps, and rubella vaccination campaign in September 2019. This response was reviewed by an international expert team in July 2021. During the campaign, 93% of children 6 months <7 years of age received a polio-containing vaccine dose. No AFP cases were detected in the community search; institutional retrospective searches found 37% of unreported AFP cases in 2018‒2020. No additional VDPV was isolated from wastewater. No evidence of circulating VDPV was found; the 3 isolated VDPVs were classified as ambiguous VDPVs by the international team of experts. These detections highlight risk for poliomyelitis reemergence in countries with low polio vaccine coverage.

Early impact of COVID-19 vaccination on older populations in four countries of the Americas, 2021.

Objective: To estimate the early impact of coronavirus disease 2019 (COVID-19) vaccination on cases in older populations in four countries (Chile, Colombia, Guatemala, and the United States of America), and on deaths in Chile and Guatemala. Methods: Data were obtained from national databases of confirmed COVID-19 cases and deaths and vaccinations between 1 July 2020 and 31 August 2021. In each country, pre- and post-vaccination incidence ratios were calculated for COVID-19 cases and deaths in prioritized groups (50-59, 60-69, and ≥70 years) compared with those in the reference group (<50 years). Vaccination effect was calculated as the percentage change in incidence ratios between pre- and post-vaccination periods. Results: The ratio of COVID-19 cases in those aged ≥50 years to those aged <50 years decreased significantly after vaccine implementation by 9.8% (95% CI: 9.5 to 10.1%) in Chile, 22.5% (95% CI: 22.0 to 23.1%) in Colombia, 20.8% (95% CI: 20.6 to 21.1%) in Guatemala, and 7.8% (95% CI: 7.6 to 7.9%) in the USA. Reductions in the ratio were highest in adults aged ≥70 years. The effect of vaccination on deaths, with time lags incorporated, was highest in the age group ≥70 years in both Chile and Guatemala: 14.4% (95% CI: 11.4 to 17.4%) and 37.3% (95% CI: 30.9 to 43.7%), respectively. Conclusions: COVID-19 vaccination significantly reduced morbidity in the early post-vaccination period in targeted groups. In the context of a global pandemic with limited vaccine availability, prioritization strategies are important to reduce the burden of disease in high-risk age groups.

Large scale use of SARS-CoV-2 antigen-based detection tests: a three-month experience in Guatemala, June-August 2020.

Objectives: To measure protocol adherence and antigen-based detection tests (AgDT) negative predictive value after 3 months of massive use as a diagnostic tool for COVID-19 in Guatemala. Methods: The study period included nasopharyngeal swabs taken between March 12 and August 31, 2020, which results were entered in the national COVID-19 information system. Proportional increase in testing between one month before and one month after the introduction of AgDT (May 9-June 8 vs. June 9-July 8) was measured. Results: After AgDT introduction, there was a 139% increase in SARS-CoV-2 testing. Between June 9 and August 31, 7.8% of 110 657 AgDT-negative patients had follow-up RT-PCR testing. Of them, 30% were RT-PCR positive. Conclusions: While introducing AgDT improved access to diagnostics, ensuring the availability of timely RT-PCR capacities to confirm diagnosis is also key.

Objetivos: Evaluar la adherencia al protocolo y el valor predictivo negativo de las pruebas de detección basadas en antígeno (AgDT) después de 3 meses de uso masivo como método diagnóstico para la COVID-19 en Guatemala. Métodos: Se estudiaron hisopados nasofaríngeos tomados entre el 12 de marzo y el 31 de agosto de 2020, cuyos resultados constaban en el sistema de información nacional de COVID-19. Se midió el aumento proporcional del número de pruebas entre un mes antes y un mes después de la introducción de las AgDT (9 de mayo a 8 de junio, frente a 9 de junio a 8 de julio). Resultados: Después de la introducción de AgDT hubo un aumento del 139% en el número de pruebas de SARS-CoV-2. Entre el 9 de junio y el 31 de agosto, el 7,8% de 110 657 pacientes negativos según una AgDT se sometieron a una prueba de seguimiento con RT-PCR. De ellos, el 30% presentó una RT-PCR positiva. Conclusiones: Aunque la introducción de AgDT mejoró el acceso al diagnóstico, también es clave asegurar la disponibilidad oportuna de RT-PCR para confirmar el diagnóstico.

Interim 2017/18 influenza seasonal vaccine effectiveness: combined results from five European studies.

Between September 2017 and February 2018, influenza A(H1N1)pdm09, A(H3N2) and B viruses (mainly B/Yamagata, not included in 2017/18 trivalent vaccines) co-circulated in Europe. Interim results from five European studies indicate that, in all age groups, 2017/18 influenza vaccine effectiveness was 25 to 52% against any influenza, 55 to 68% against influenza A(H1N1)pdm09, -42 to 7% against influenza A(H3N2) and 36 to 54% against influenza B. 2017/18 influenza vaccine should be promoted where influenza still circulates.

Early 2016/17 vaccine effectiveness estimates against influenza A(H3N2): I-MOVE multicentre case control studies at primary care and hospital levels in Europe.

We measured early 2016/17 season influenza vaccine effectiveness (IVE) against influenza A(H3N2) in Europe using multicentre case control studies at primary care and hospital levels. IVE at primary care level was 44.1%, 46.9% and 23.4% among 0-14, 15-64 and ≥ 65 year-olds, and 25.7% in the influenza vaccination target group. At hospital level, IVE was 2.5%, 7.9% and 2.4% among ≥ 65, 65-79 and ≥ 80 year-olds. As in previous seasons, we observed suboptimal IVE against influenza A(H3N2).

Low 2016/17 season vaccine effectiveness against hospitalised influenza A(H3N2) among elderly: awareness warranted for 2017/18 season.

In a multicentre European hospital study we measured influenza vaccine effectiveness (IVE) against A(H3N2) in 2016/17. Adjusted IVE was 17% (95% confidence interval (CI): 1 to 31) overall; 25% (95% CI: 2 to 43) among 65-79-year-olds and 13% (95% CI: -15 to 30) among those ≥ 80 years. As the A(H3N2) vaccine component has not changed for 2017/18, physicians and public health experts should be aware that IVE could be low where A(H3N2) viruses predominate.

2015/16 seasonal vaccine effectiveness against hospitalisation with influenza A(H1N1)pdm09 and B among elderly people in Europe: results from the I-MOVE+ project.

We conducted a multicentre test-negative case-control study in 27 hospitals of 11 European countries to measure 2015/16 influenza vaccine effectiveness (IVE) against hospitalised influenza A(H1N1)pdm09 and B among people aged ≥ 65 years. Patients swabbed within 7 days after onset of symptoms compatible with severe acute respiratory infection were included. Information on demographics, vaccination and underlying conditions was collected. Using logistic regression, we measured IVE adjusted for potential confounders. We included 355 influenza A(H1N1)pdm09 cases, 110 influenza B cases, and 1,274 controls. Adjusted IVE against influenza A(H1N1)pdm09 was 42% (95% confidence interval (CI): 22 to 57). It was 59% (95% CI: 23 to 78), 48% (95% CI: 5 to 71), 43% (95% CI: 8 to 65) and 39% (95% CI: 7 to 60) in patients with diabetes mellitus, cancer, lung and heart disease, respectively. Adjusted IVE against influenza B was 52% (95% CI: 24 to 70). It was 62% (95% CI: 5 to 85), 60% (95% CI: 18 to 80) and 36% (95% CI: -23 to 67) in patients with diabetes mellitus, lung and heart disease, respectively. 2015/16 IVE estimates against hospitalised influenza in elderly people was moderate against influenza A(H1N1)pdm09 and B, including among those with diabetes mellitus, cancer, lung or heart diseases.

Epidemiology of Epidemic Ebola Virus Disease in Conakry and Surrounding Prefectures, Guinea, 2014-2015.

In 2014, Ebola virus disease (EVD) in West Africa was first reported during March in 3 southeastern prefectures in Guinea; from there, the disease rapidly spread across West Africa. We describe the epidemiology of EVD cases reported in Guinea's capital, Conakry, and 4 surrounding prefectures (Coyah, Dubreka, Forecariah, and Kindia), encompassing a full year of the epidemic. A total of 1,355 EVD cases, representing ≈40% of cases reported in Guinea, originated from these areas. Overall, Forecariah had the highest cumulative incidence (4× higher than that in Conakry). Case-fatality percentage ranged from 40% in Conakry to 60% in Kindia. Cumulative incidence was slightly higher among male than female residents, although incidences by prefecture and commune differed by sex. Over the course of the year, Conakry and neighboring prefectures became the EVD epicenter in Guinea.

Mortality Rates during Cholera Epidemic, Haiti, 2010-2011.

The 2010 cholera epidemic in Haiti was one of the largest cholera epidemics ever recorded. To estimate the magnitude of the death toll during the first wave of the epidemic, we retrospectively conducted surveys at 4 sites in the northern part of Haiti. Overall, 70,903 participants were included; at all sites, the crude mortality rates (19.1-35.4 deaths/1,000 person-years) were higher than the expected baseline mortality rate for Haiti (9 deaths/1,000 person-years). This finding represents an excess of 3,406 deaths (2.9-fold increase) for the 4.4% of the Haiti population covered by these surveys, suggesting a substantially higher cholera mortality rate than previously reported.

Contact Tracing Activities during the Ebola Virus Disease Epidemic in Kindia and Faranah, Guinea, 2014.

The largest recorded Ebola virus disease epidemic began in March 2014; as of July 2015, it continued in 3 principally affected countries: Guinea, Liberia, and Sierra Leone. Control efforts include contact tracing to expedite identification of the virus in suspect case-patients. We examined contact tracing activities during September 20-December 31, 2014, in 2 prefectures of Guinea using national and local data about case-patients and their contacts. Results show less than one third of case-patients (28.3% and 31.1%) were registered as contacts before case identification; approximately two thirds (61.1% and 67.7%) had no registered contacts. Time to isolation of suspected case-patients was not immediate (median 5 and 3 days for Kindia and Faranah, respectively), and secondary attack rates varied by relationships of persons who had contact with the source case-patient and the type of case-patient to which a contact was exposed. More complete contact tracing efforts are needed to augment control of this epidemic.

Molecular epidemiology of enteroviruses from Guatemalan wastewater isolated from human lung fibroblasts.

The Global Specialized Polio Laboratory at CDC supports the Global Poliovirus Laboratory Network with environmental surveillance (ES) to detect the presence of vaccine strain polioviruses, vaccine-derived polioviruses, and wild polioviruses in high-risk countries. Environmental sampling provides valuable supplementary information, particularly in areas with gaps in surveillance of acute flaccid paralysis (AFP) mainly in children less than 15 years. In collaboration with Guatemala's National Health Laboratory (Laboratorio Nacional de Salud Guatemala), monthly sewage collections allowed screening enterovirus (EV) presence without incurring additional costs for sample collection, transport, or concentration. Murine recombinant fibroblast L-cells (L20B) and human rhabdomyosarcoma (RD) cells are used for the isolation of polioviruses following a standard detection algorithm. Though non-polio-Enteroviruses (NPEV) can be isolated, the algorithm is optimized for the detection of polioviruses. To explore if other EV's are present in sewage not found through standard methods, five additional cell lines were piloted in a small-scale experiment, and next-generation sequencing (NGS) was used for the identification of any EV types. Human lung fibroblast cells (HLF) were selected based on their ability to isolate EV-A genus. Sewage concentrates collected between 2020-2021 were isolated in HLF cells and any cytopathic effect positive isolates used for NGS. A large variety of EVs, including echoviruses 1, 3, 6, 7, 11, 13, 18, 19, 25, 29; coxsackievirus A13, B2, and B5, EV-C99, EVB, and polioviruses (Sabin 1 and 3) were identified through genomic typing in NGS. When the EV genotypes were compared by phylogenetic analysis, it showed many EV's were genomically like viruses previously isolated from ES collected in Haiti. Enterovirus occurrence did not follow a seasonality, but more diverse EV types were found in ES collection sites with lower populations. Using the additional cell line in the existing poliovirus ES algorithm may add value by providing data about EV circulation, without additional sample collection or processing. Next-generation sequencing closed gaps in knowledge providing molecular epidemiological information on multiple EV types and full genome sequences of EVs present in wastewater in Guatemala.

Impact of the 'Health on Wheels' (HoW) strategy on COVID-19 vaccination coverage in hard-to-reach communities in Alta Verapaz, Guatemala, 2022.

BACKGROUND: In April 2022, after a year of COVID-19 vaccination, there were large differences in coverage between urban and rural areas in Guatemala. To address barriers in rural communities, the "Health on Wheels" (HoW) strategy was implemented. The strategy deployed mobile brigades with a dedicated team of health workers and a culturally sensitive health promotion plan in selected communities in 15 districts in Alta Verapaz, a health area with low COVID-19 vaccination uptake and a high-level of COVID-19 vaccine hesitancy. This study evaluates the impact of the HoW strategy. METHODS: We measured the relative increase in COVID-19 doses administered prior and during the HoW implementation period in the 190 intervened communities and compared to 188 communities without the intervention. Communities were grouped by health district and the impact analyses were stratified by number of COVID-19 vaccine dose (1st, 2nd, and 3rd doses) and history of vaccine hesitancy. RESULTS: The increase in 1st, 2nd, and 3rd dose-COVID-19 vaccination coverage between before and during HoW implementation was 2.4, 2.2 and 2.6 times higher in intervened communities (20 %, 21 % and 37 % increase in 1st, 2nd and 3rd dose, respectively) than in non-intervened communities (8 %, 10 % and 14 % increase in 1st, 2nd and 3rd dose respectively). For the 1st dose, increase in dose administration was 2.9 times higher in intervened communities (n = 24) with hesitancy (24 % increase) compared to non-intervened communities (n = 188) without hesitancy (8 % increase). CONCLUSION: The deployment of mobile brigades with a dedicated team of vaccinators and culturally sensitive health promotion through the HoW strategy successfully accelerated the increase in COVID-19 vaccination coverage in rural communities in Guatemala.

Quantifying transmission of norovirus during an outbreak.

BACKGROUND: Healthcare workers are thought to play a role in nosocomial transmission of norovirus, but the level and direction of norovirus transmission between patients and healthcare workers in sustaining transmission during an outbreak have not been quantified. METHODS: We developed a method for finding plausible transmission trees of who acquired their infection from whom. We applied the method to data from an outbreak of norovirus in 4 wards of a psychiatric institution in the Netherlands in 2008. The simulated transmission trees were based on serial intervals for time between symptom onsets, weighted for the number of days that healthcare workers were present. The obtained transmission trees were linked to the Barthel Index, a measure of patient reliance on healthcare in their basic daily activities. RESULTS: The dominant recognized transmission route was from patient to patient (64%), followed by patient to healthcare worker (29%). The overall estimated reproduction number for healthcare workers was low compared with patients (0.25 vs. 1.20; mean difference = 0.95 [95% confidence interval (CI) = 0.60 to 1.30]). The average number of all subsequent cases attributable to the downstream branch of one single infected healthcare worker in the transmission tree was 4.4 compared with 6.5 for cases attributable to one single infected patient (mean difference = 2.1 [95% CI = -4.7 to 8.9]). In the ward with patients requiring the highest level of care from healthcare workers, the attack rate among healthcare workers was highest. CONCLUSION: This approach provides a framework to quantify the magnitude and direction of transmission between healthcare workers and patients during a norovirus outbreak. The utility of this method in outbreaks of other infections and in different settings should be explored.

Adoption of digital tools in the context of the COVID-19 pandemic in the Region of the Americas - the Go.Data experience.

The COVID-19 pandemic has accelerated the growth of digital health tools. Although a number of different tools exist to support field data collection in the context of outbreak response, they have not been sufficient. This prompted the World Health Organization (WHO) to collaborate with the Global Outbreak Alert and Response Network (GOARN) and GOARN partners to develop a comprehensive system, Go.Data. Go.Data, a digital tool for outbreak response has simplified how countries operationalize and monitor case and contact data. Since the start of the pandemic, WHO and GOARN partners have provided support to Go.Data projects in 65 countries and territories, yet the demand by countries to have documented success cases of Go.Data implementations continues to grow. This viewpoint documents the successful Go.Data implementation frameworks in two countries, Argentina and Guatemala and an academic institution, the University of Texas at Austin.

Field Evaluation of the Performance of Two Rapid Diagnostic Tests for Meningitis in Niger and Burkina Faso.

New lateral flow tests for the diagnosis of Neisseria meningitidis (Nm) (serogroups A, C, W, X, and Y), MeningoSpeed, and Streptococcus pneumoniae (Sp), PneumoSpeed, developed to support rapid outbreak detection in Africa, have shown good performance under laboratory conditions. We conducted an independent evaluation of both tests under field conditions in Burkina Faso and Niger, in 2018-2019. The tests were performed in the cerebrospinal fluid of suspected meningitis cases from health centers in alert districts and compared to reverse transcription polymerase chain reaction tests performed at national reference laboratories (NRLs). Health staff were interviewed about feasibility. A total of 327 cases were tested at the NRLs, with 26% confirmed Nm (NmC 63% and NmX 37%) and 8% Sp. Sensitivity and specificity were, respectively, 95% (95% CI: 89-99) and 90% (95% CI: 86-94) for Nm and 92% (95% CI: 75-99) and 99% (95% CI: 97-100) for Sp. Positive and negative predictive values were, respectively, 77% (95% CI: 68-85) and 98% (95% CI: 95-100) for Nm and 86% (95% CI: 67-96) and 99% (95% CI: 98-100) for Sp. Concordance showed 82% agreement for Nm and 97% for Sp. Interviewed staff evaluated the tests as easy to use and to interpret and were confident in their readings. Results suggest overall good performance of both tests and potential usefulness in meningitis outbreak detection.

A national cross-sectional study among drug-users in France: epidemiology of HCV and highlight on practical and statistical aspects of the design.

BACKGROUND: Epidemiology of HCV infection among drug users (DUs) has been widely studied. Prevalence and sociobehavioural data among DUs are therefore available in most countries but no study has taken into account in the sampling weights one important aspect of the way of life of DUs, namely that they can use one or more specialized services during the study period. In 2004-2005, we conducted a national seroepidemiologic survey of DUs, based on a random sampling design using the Generalised Weight Share Method (GWSM) and on blood testing. METHODS: A cross-sectional multicenter survey was done among DUs having injected or snorted drugs at least once in their life. We conducted a two stage random survey of DUs selected to represent the diversity of drug use. The fact that DUs can use more than one structure during the study period has an impact on their inclusion probabilities. To calculate a correct sampling weight, we used the GWSM. A sociobehavioral questionnaire was administered by interviewers. Selected DUs were asked to self-collect a fingerprick blood sample on blotting paper. RESULTS: Of all DUs selected, 1462 (75%) accepted to participate. HCV seroprevalence was 59.8% [95% CI: 50.7-68.3]. Of DUs under 30 years, 28% were HCV seropositive. Of HCV-infected DUs, 27% were unaware of their status. In the month prior to interview, 13% of DUs shared a syringe, 38% other injection parapharnelia and 81% shared a crack pipe. In multivariate analysis, factors independently associated with HCV seropositivity were age over 30, HIV seropositivity, having ever injected drugs, opiate substitution treatment (OST), crack use, and precarious housing. CONCLUSION: This is the first time that blood testing combined to GWSM is applied to a DUs population, which improve the estimate of HCV prevalence. HCV seroprevalence is high, indeed by the youngest DUs. And a large proportion of DUs are not aware of their status. Our multivariate analysis identifies risk factors such as crack consumption and unstable housing.

Early impact of COVID-19 vaccination on older populations in four countries of the Americas, 2021 / Impacto temprano de la vacunación contra la COVID-19 en adultos mayores en cuatro países de las Américas, 2021 / Impacto inicial da vacinação contra a COVID-19 em populações idosas em quatro países das Américas, 2021

ABSTRACT Objective. To estimate the early impact of coronavirus disease 2019 (COVID-19) vaccination on cases in older populations in four countries (Chile, Colombia, Guatemala, and the United States of America), and on deaths in Chile and Guatemala. Methods. Data were obtained from national databases of confirmed COVID-19 cases and deaths and vaccinations between 1 July 2020 and 31 August 2021. In each country, pre- and post-vaccination incidence ratios were calculated for COVID-19 cases and deaths in prioritized groups (50-59, 60-69, and ≥70 years) compared with those in the reference group (<50 years). Vaccination effect was calculated as the percentage change in incidence ratios between pre- and post-vaccination periods. Results. The ratio of COVID-19 cases in those aged ≥50 years to those aged <50 years decreased significantly after vaccine implementation by 9.8% (95% CI: 9.5 to 10.1%) in Chile, 22.5% (95% CI: 22.0 to 23.1%) in Colombia, 20.8% (95% CI: 20.6 to 21.1%) in Guatemala, and 7.8% (95% CI: 7.6 to 7.9%) in the USA. Reductions in the ratio were highest in adults aged ≥70 years. The effect of vaccination on deaths, with time lags incorporated, was highest in the age group ≥70 years in both Chile and Guatemala: 14.4% (95% CI: 11.4 to 17.4%) and 37.3% (95% CI: 30.9 to 43.7%), respectively. Conclusions. COVID-19 vaccination significantly reduced morbidity in the early post-vaccination period in targeted groups. In the context of a global pandemic with limited vaccine availability, prioritization strategies are important to reduce the burden of disease in high-risk age groups.

RESUMEN Objetivo. Estimar el impacto temprano sobre los casos de enfermedad por coronavirus 2019 (COVID-19) obtenido con la vacunación contra la COVID-19 en los grupos poblacionales de edad avanzada en cuatro países (Chile, Colombia, Estados Unidos de América y Guatemala), así como el efecto en la mortalidad en Chile y Guatemala. Métodos. Los datos se obtuvieron a partir de las bases de datos nacionales sobre vacunaciones y sobre casos de COVID-19 y muertes debidas a esta enfermedad entre el 1 de julio del 2020 y el 31 de agosto del 2021. Para cada país, se calcularon las razones de incidencia de casos de COVID-19 y de muertes por COVID-19 anteriores y posteriores a la vacunación en los grupos priorizados (50-59, 60-69 y ≥70 años) en comparación con las del grupo de referencia (<50 años). Se calculó el efecto de la vacunación expresado en forma de variación porcentual de la razón de las incidencias entre el período anterior y el posterior a la vacunación. Resultados. Tras la introducción de la vacuna, la razón de los casos de COVID-19 entre las personas ≥50 años y las <50 disminuyó significativamente en un 9,8% (IC del 95%: 9,5% a 10,1%) en Chile, en un 22,5% (IC del 95%: 22,0% a 23,1%) en Colombia, en un 7,8% (IC del 95%: 7,6% a 7,9%) en Estados Unidos de América y en un 20,8% (IC del 95%: 20,6% a 21,1%) en Guatemala. Las reducciones de la razón fueron máximas en las personas adultas ≥70 años. El efecto de la vacunación sobre las muertes, una vez incorporados los desfases cronológicos, fue máximo en el grupo de personas ≥70 años, tanto en Chile como en Guatemala: 14,4% (IC 95%: 11,4% a 17,4%) y 37,3% (IC 95%: 30,9% a 43,7%), respectivamente. Conclusiones. La vacunación contra la COVID-19 redujo significativamente la morbilidad en el período inmediato posterior a la vacunación en los grupos destinatarios. En el contexto de una pandemia con disponibilidad limitada de vacunas a nivel mundial, las estrategias de asignación de prioridades son un factor importante para reducir la carga de morbilidad en los grupos etarios de alto riesgo.

RESUMO Objetivo. Estimar o impacto inicial da vacinação contra a doença pelo coronavírus 2019 (COVID-19) nos casos em populações idosas de quatro países (Chile, Colômbia, Guatemala e Estados Unidos da América) e nas mortes no Chile e na Guatemala. Métodos. Os dados foram obtidos de bancos de dados nacionais de casos e mortes confirmados por COVID-19 e de vacinações entre 1º de julho de 2020 e 31 de agosto de 2021. Em cada país, foram calculadas taxas de incidência pré e pós-vacinação de casos e mortes por COVID-19 em grupos priorizados (50 a 59, 60 a 69 e ≥70 anos) em comparação com o grupo de referência (<50 anos). O efeito da vacinação foi calculado como a mudança percentual nas taxas de incidência entre os períodos pré e pós-vacinação. Resultados. A incidência de casos de COVID-19 em pessoas com idade ≥50 anos em relação às com idade <50 anos diminuiu significativamente após a implementação da vacina, em 9,8% (IC 95%: 9,5 a 10,1%) no Chile, 22,5% (IC 95%: 22,0 a 23,1%) na Colômbia, 20,8% (IC 95%: 20,6 a 21,1%) na Guatemala e 7,8% (IC 95%: 7,6 a 7,9%) nos EUA. As reduções na incidência foram maiores em adultos com idade ≥70 anos. O efeito da vacinação sobre as mortes, com defasagens temporais incorporadas, foi maior na faixa etária ≥70 anos no Chile e na Guatemala, 14,4% (IC de 95%: 11,4 a 17,4%) e 37,3% (IC de 95%: 30,9 a 43,7%), respectivamente. Conclusões. A vacinação contra a COVID-19 reduziu significativamente a morbidade no início do período pós-vacinação nos grupos-alvo. No contexto de uma pandemia mundial com disponibilidade limitada de vacinas, estratégias de priorização são importantes para reduzir a carga de doença em grupos etários de alto risco.

Effectiveness of influenza vaccines in preventing severe influenza illness among adults: A systematic review and meta-analysis of test-negative design case-control studies.

OBJECTIVES: Summary evidence of influenza vaccine effectiveness (IVE) against hospitalized influenza is lacking. We conducted a meta-analysis of studies reporting IVE against laboratory-confirmed hospitalized influenza among adults. METHODS: We searched Pubmed (January 2009 to November 2016) for studies that used test-negative design (TND) to enrol patients hospitalized with influenza-associated conditions. Two independent authors selected relevant articles. We calculated pooled IVE against any and (sub)type specific influenza among all adults, and stratified by age group (18-64 and 65 years and above) using random-effects models. RESULTS: We identified 3411 publications and 30 met our inclusion criteria. Between 2010-11 and 2014-15, the pooled seasonal IVE was 41% (95%CI:34;48) for any influenza (51% (95%CI:44;58) among people aged 18-64y and 37% (95%CI:30;44) among ≥65 years). IVE was 48% (95%CI:37;59),37% (95%CI:24;50) and 38% (95%CI:23;53) against influenza A(H1N1)pdm09, A(H3N2) and B, respectively. Among persons aged ≥65 year, IVE against A(H3N2) was 43% (95%CI:33;53) in seasons when circulating and vaccine strains were antigenically similar and 14% (95%CI:-3;30) when A(H3N2) variant viruses predominated. CONCLUSIONS: Influenza vaccines provided moderate protection against influenza-associated hospitalizations among adults. They seemed to provide low protection among elderly in seasons where vaccine and circulating A(H3N2) strains were antigenically variant.

Repeated seasonal influenza vaccination among elderly in Europe: Effects on laboratory confirmed hospitalised influenza.

In Europe, annual influenza vaccination is recommended to elderly. From 2011 to 2014 and in 2015-16, we conducted a multicentre test negative case control study in hospitals of 11 European countries to measure influenza vaccine effectiveness (IVE) against laboratory confirmed hospitalised influenza among people aged ≥65years. We pooled four seasons data to measure IVE by past exposures to influenza vaccination. We swabbed patients admitted for clinical conditions related to influenza with onset of severe acute respiratory infection ≤7days before admission. Cases were patients RT-PCR positive for influenza virus and controls those negative for any influenza virus. We documented seasonal vaccination status for the current season and the two previous seasons. We recruited 5295 patients over the four seasons, including 465A(H1N1)pdm09, 642A(H3N2), 278 B case-patients and 3910 controls. Among patients unvaccinated in both previous two seasons, current seasonal IVE (pooled across seasons) was 30% (95%CI: -35 to 64), 8% (95%CI: -94 to 56) and 33% (95%CI: -43 to 68) against influenza A(H1N1)pdm09, A(H3N2) and B respectively. Among patients vaccinated in both previous seasons, current seasonal IVE (pooled across seasons) was -1% (95%CI: -80 to 43), 37% (95%CI: 7-57) and 43% (95%CI: 1-68) against influenza A(H1N1)pdm09, A(H3N2) and B respectively. Our results suggest that, regardless of patients' recent vaccination history, current seasonal vaccine conferred some protection to vaccinated patients against hospitalisation with influenza A(H3N2) and B. Vaccination of patients already vaccinated in both the past two seasons did not seem to be effective against A(H1N1)pdm09. To better understand the effect of repeated vaccination, engaging in large cohort studies documenting exposures to vaccine and natural infection is needed.

Vaccine Effectiveness of Polysaccharide Vaccines Against Clinical Meningitis - Niamey, Niger, June 2015.

INTRODUCTION: In 2015, a large outbreak of serogroup C meningococcal meningitis hit Niamey, Niger, in response to which a vaccination campaign was conducted late April. Using a case-control study we measured the vaccine effectiveness (VE) of tri - (ACW) and quadrivalent (ACYW) polysaccharide meningococcal vaccines against clinical meningitis among 2-15 year olds in Niamey II district between April 28th and June 30th 2015. METHODS: We selected all clinical cases registered in health centers and conducted a household- vaccination coverage cluster survey (control group).  We ascertained vaccination from children/parent reports. Using odds of vaccination among controls and cases, we computed VE as 1-(Odds Ratio). To compute VE by day since vaccination, we simulated a density case control design randomly attributing recruitment dates to controls based on case dates of onset (3 controls per case). We calculated the number of days between vaccination and the date of onset/recruitment and computed VE by number of days since vaccination using a cubic-spline model. We repeated this simulated analysis 500 times and calculated the mean VE and the mean lower and upper bound of the 95% confidence interval (CI). RESULTS: Among 523 cases and 1800 controls, 57% and 92% were vaccinated respectively. Overall, VE at more than 10 days following vaccination was 84% (95%CI: 75-89) and 97% (94-99) for the tri- and quadrivalent vaccines respectively. VE at days 5 and 10 after trivalent vaccination was 84% (95% CI: 74-91) and 89% (95% CI: 83-93) respectively. It was 88% (95% CI: 75-94) and 95.8% (95% CI: 92 -98) respectively for the quadrivalent vaccine. CONCLUSION: Results suggest a high VE of the polysaccharide vaccines against clinical meningitis, an outcome of low specificity, and a rapid protection after vaccination. We identified no potential biases leading to VE overestimation. Measuring VE and rapidity of protection against laboratory confirmed meningococcal meningitis is needed.