The production of health news by the press: the context of the coverage of the 2007/2008 yellow fever epidemic. / A produção de notícias de saúde pela imprensa: o contexto da cobertura da epizootia da febre amarela 2007/2008.

The COVID-19 pandemic scenario raises the amplification of the debate around the production and circulation of information about epidemics. In this sense, the objective of this article is to discuss how social contexts shape the news, taking as an example the case of the news coverage that transformed an epizootic of yellow fever, in the summer of 2007/2008, into an epidemic of urban yellow fever. This is a qualitative research with journalists who worked in two large circulation newspapers and actively participated in the coverage of the event. The interviews were recorded, transcribed and submitted to discourse analysis, which allowed the identification of three factors that influenced the production of a media epidemic of yellow fever: the working conditions and the modus operandi of the newsrooms; the political-ideological dimension of the newspapers; and the difficulties of translation of technical-scientific information. A critical understanding of the production process of the journalistic text can contribute to the construction of communication strategies that minimize the circulation of misinformation on public health in traditional media (newspapers, magazines, radio, TV and news portals).

O cenário da pandemia de COVID-19 suscita a ampliação do debate em torno da produção e circulação de informações sobre epidemias. Nesse sentido, o objetivo deste artigo é discutir como os contextos sociais configuram as notícias, tomando como exemplo o caso da cobertura jornalística que transformou uma epizootia de febre amarela, no verão 2007/2008, em uma epidemia de febre amarela urbana. Trata-se de uma pesquisa qualitativa com jornalistas que trabalhavam em dois jornais de grande circulação e participaram ativamente da cobertura do evento. As entrevistas foram gravadas, transcritas e submetidas à análise de discurso, o que permitiu identificar três fatores que influenciaram a produção de uma epidemia midiática de febre amarela: as condições de trabalho e o modus operandi das redações; a dimensão político-ideológica dos jornais; e as dificuldades de tradução das informações técnico-científicas. A compreensão crítica do processo de produção do texto jornalístico pode contribuir para a construção de estratégias comunicacionais que minimizem a circulação de desinformação em saúde pública nas mídias tradicionais (jornais, revistas, rádio, tevê e portais de notícias).

Changes in vaccination coverage before and after COVID-19 pandemic in children under one year in the health district of Commune V in Bamako, Mali (preprint)

Introduction Although an essential frontline service in the prevention of child morbidity and mortality, there are indications that routine vaccinations have been disrupted during the COVID-19 pandemic. The present study aimed to compare vaccination coverage before COVID-19 in Mali in 2019 and one year after COVID-19 in 2020. Objective To compare vaccination coverages before COVID-19 in Mali in 2019 and one year after COVID-19 in 2020. Design Cross-sectional study. Setting and participants We collected routine immunization data from 2019 and 2020 of children under one year in the health district of Commune V in Bamako which includes twelve community health centers (CSCom). Results Overall, vaccination coverage of the nine vaccines was higher in 2019 (89.4%) compared to 2020 (79%; p < 10− 3). In 2020, low proportions of children vaccinated were observed in May (54.8%) two months after the first COVID-19 case in Mali on March 25, 2020. For all vaccines, the mean number of children vaccinated in 2019 (before COVID-19) was significantly higher than those vaccinated in 2020 after COVID-19 (p < 0.05). However, in January 2019, the number of children vaccinated with Meningococcal A vaccine in Africa (MenAfriVac), Yellow fever vaccine (VAA) and Measles vaccine (VAR) was lower in 2019 compared to 2020 (p < 10− 3). Likewise in January 2019, in September 2019 and October 2019 BCG vaccine coverage was lower in 2019 compared to 2020 (p < 10− 3). Conclusion COVID-19 pandemic has affected routine childhood vaccine coverage in Commune V of Bamako, particularly in May 2020. Therefore, new strategies are needed to improve vaccine coverage in young children below 1.

A Perspective on Current Flavivirus Vaccine Development: A Brief Review.

The flavivirus genus contains several clinically important pathogens that account for tremendous global suffering. Primarily transmitted by mosquitos or ticks, these viruses can cause severe and potentially fatal diseases ranging from hemorrhagic fevers to encephalitis. The extensive global burden is predominantly caused by six flaviviruses: dengue, Zika, West Nile, yellow fever, Japanese encephalitis and tick-borne encephalitis. Several vaccines have been developed, and many more are currently being tested in clinical trials. However, flavivirus vaccine development is still confronted with many shortcomings and challenges. With the use of the existing literature, we have studied these hurdles as well as the signs of progress made in flavivirus vaccinology in the context of future development strategies. Moreover, all current licensed and phase-trial flavivirus vaccines have been gathered and discussed based on their vaccine type. Furthermore, potentially relevant vaccine types without any candidates in clinical testing are explored in this review as well. Over the past decades, several modern vaccine types have expanded the field of vaccinology, potentially providing alternative solutions for flavivirus vaccines. These vaccine types offer different development strategies as opposed to traditional vaccines. The included vaccine types were live-attenuated, inactivated, subunit, VLPs, viral vector-based, epitope-based, DNA and mRNA vaccines. Each vaccine type offers different advantages, some more suitable for flaviviruses than others. Additional studies are needed to overcome the barriers currently faced by flavivirus vaccine development, but many potential solutions are currently being explored.

Yellow fever vaccination before and during the covid-19 pandemic in Brazil.

OBJECTIVE: To analyze the number of yellow fever vaccine doses administered before and during the covid-19 pandemic in Brazil. METHODS: This is an ecological, time series study based on data from the National Immunization Program. Differences between the median number of yellow fever vaccine doses administered in Brazil and in its regions before (from April/2019 to March/2020) and after (from April/2020 to March/2021) the implementation of social distancing measures in the country were assessed via the Mann-Whitney test. Prais-Winsten regression models were used for time series analyses. RESULTS: We found a reduction in the median number of yellow fever vaccine doses administered in Brazil and in its regions: North (-34.71%), Midwest (-21.72%), South (-63.50%), and Southeast (-34.42%) (p < 0.05). Series showed stationary behavior in Brazil and in its five regions during the covid-19 pandemic (p > 0.05). Brazilian states also showed stationary trends, except for two states which recorded an increasing trend in the number of administered yellow fever vaccine doses, namely: Alagoas State (before: ß = 64, p = 0.081; after: ß = 897, p = 0.039), which became a yellow fever vaccine recommendation zone, and Roraima State (before: ß = 68, p = 0.724; after: ß = 150, p = 0.000), which intensified yellow fever vaccinations due to a yellow fever case confirmation in a Venezuelan State in 2020. CONCLUSION: The reduced number of yellow fever vaccine doses administered during the covid-19 pandemic in Brazil may favor the reemergence of urban yellow fever cases in the country.

Leveraging Lessons Learned from Yellow Fever and Polio Immunization Campaigns during COVID-19 Pandemic, Ghana, 2021.

Ghana is a yellow fever-endemic country and experienced a vaccine-derived polio outbreak in July 2019. A reactive polio vaccination campaign was conducted in September 2019 and preventive yellow fever campaign in November 2020. On March 12, 2020, Ghana confirmed its first COVID-19 cases. During February-August 2021, Ghana received 1,515,450 COVID-19 vaccines through the COVID-19 Vaccines Global Access initiative and other donor agencies. We describe how systems and infrastructure used for polio and yellow fever vaccine deployment and the lessons learned in those campaigns were used to deploy COVID-19 vaccines. During March-August 2021, a total of 1,424,008 vaccine doses were administered in Ghana. By using existing vaccination and health systems, officials in Ghana were able to deploy COVID-19 vaccines within a few months with <5% vaccine wastage and minimal additional resources despite the short shelf-life of vaccines received. These strategies were essential in saving lives in a resource-limited country.

Five decades of infectious diseases outbreaks in the African region (1970-2018) A geographic snapshot (preprint)

This paper is being written at a time when the recent pandemic, namely COVID-19 has shaken the entire world in a manner that has never been seen in modern history. The ecology, socio-economy and weak health systems make Africa an area favorable to the occurrence of various diseases and disease outbreaks. This paper explores forty-eight (48) years of disease outbreaks in the WHO African region of the World Health Organization (WHO). Twenty-five (25) Integrated Disease Surveillance and Response priority diseases were selected, and their outbreaks described and analyzed. Using inferential spatial statistics, spatial clusters at the health district level, specifically hot spots of those outbreaks were produced and analyzed. Population at risk those hot spots were estimated. Results show a consistent report of outbreaks during the selected period with 52 outbreaks on average per year. Poliomyelitis, cholera, yellow fever, meningococcal disease and measles were the most reported epidemics. Democratic Republic of the Congo (DRC) and Nigeria were the countries reporting the highest number of outbreaks (5 on average per year) with the latter country having the highest population at risk (39M people). Despite efforts to limit their number, some disease outbreaks such as malaria, cholera, and measles continue to have a burden in terms of morbidity and mortality, while others such as poliomyelitis, yellow fever and diarrhoeal disease have shown a declining trend and the wild polio virus transmission has been eliminated in the region. Results suggest that concerted public health action may help reduce the occurrences of outbreaks in the region. Results can be used to inform preparedness and prevention activities. Priority public health actions should target DRC and Nigeria, but also identified hot spots and areas with existing risk factors within other countries.

Epidemiological description of and response to a large yellow fever outbreak in Edo state Nigeria, September 2018 - January 2019.

BACKGROUND: Edo State Surveillance Unit observed the emergence of a disease with "no clear-cut-diagnosis", which affected peri-urban Local Government Areas (LGAs) from September 6 to November 1, 2018. On notification, the Nigeria Centre for Disease Control deployed a Rapid Response Team (RRT) to support outbreak investigation and response activities in the State. This study describes the epidemiology of and response to a large yellow fever (YF) outbreak in Edo State. METHODS: A cross-sectional descriptive outbreak investigation of YF outbreak in Edo State. A suspected case of YF was defined as "Any person residing in Edo State with acute onset of fever and jaundice appearing within 14 days of onset of the first symptoms from September 2018 to January 2019". Our response involved active case search in health facilities and communities, retrospective review of patients' records, rapid risk assessment, entomological survey, rapid YF vaccination coverage assessment, blood sample collection, case management and risk communication. Descriptive data analysis using percentages, proportions, frequencies were made. RESULTS: A total of 209 suspected cases were line-listed. Sixty-seven (67) confirmed in 12 LGAs with 15 deaths [Case fatality rate (CFR 22.4%)]. Among confirmed cases, median age was 24.8, (range 64 (1-64) years; Fifty-one (76.1%) were males; and only 13 (19.4%) had a history of YF vaccination. Vaccination coverage survey involving 241 children revealed low YF vaccine uptake, with 44.6% providing routine immunisation cards for sighting. Risk of YF transmission was 71.4%. Presence of Aedes with high-larval indices (House Index ≥5% and/or Breteau Index ≥20) were established in all the seven locations visited. YF reactive mass vaccination campaign was implemented. CONCLUSION: Edo State is one of the states in Nigeria with the highest burden of yellow fever. More males were affected among the confirmed. Major symptoms include fever, jaundice, weakness, and bleeding. Majority of surveillance performance indicators were above target. There is a high risk of transmission of the disease in the state. Low yellow fever vaccination coverage, and presence of yellow fever vectors (Ae.aegypti, Ae.albopictus and Ae.simpsoni) are responsible for cases in affected communities. Enhanced surveillance, improved laboratory sample management, reactive vaccination campaign, improved yellow fever case management and increased risk communication/awareness are very important mitigation strategies to be sustained in Edo state to prevent further spread and mortality from yellow fever.

Live-attenuated YF17D-vectored COVID-19 vaccine protects from lethal yellow fever virus infection in mouse and hamster models.

BACKGROUND: The live-attenuated yellow fever vaccine YF17D holds great promise as alternative viral vector vaccine platform, showcased by our previously presented potent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidate YF-S0. Besides protection from SARS-CoV-2, YF-S0 also induced strong yellow fever virus (YFV)-specific immunity, suggestive for full dual activity. A vaccine concomitantly protecting from SARS-CoV-2 and YFV would be of great benefit for those living in YFV-endemic areas with limited access to current SARS-CoV-2 vaccines. However, for broader applicability, pre-existing vector immunity should not impact the potency of such YF17D-vectored vaccines. METHODS: The immunogenicity and efficacy of YF-S0 against YFV and SARS-CoV-2 in the presence of strong pre-existing YFV immunity were evaluated in mouse and hamster challenge models. FINDINGS: Here, we show that a single dose of YF-S0 is sufficient to induce strong humoral and cellular immunity against YFV as well as SARS-CoV-2 in mice and hamsters; resulting in full protection from vigorous YFV challenge in either model; in mice against lethal intracranial YF17D challenge, and in hamsters against viscerotropic infection and liver disease following challenge with highly pathogenic hamster-adapted YFV-Asibi strain. Importantly, strong pre-existing immunity against the YF17D vector did not interfere with subsequent YF-S0 vaccination in mice or hamsters; nor with protection conferred against SARS-CoV-2 strain B1.1.7 (Alpha variant) infection in hamsters. INTERPRETATION: Our findings warrant the development of YF-S0 as dual SARS-CoV-2 and YFV vaccine. Contrary to other viral vaccine platforms, use of YF17D does not suffer from pre-existing vector immunity. FUNDING: Stated in the acknowledgments.

A modelling assessment of short- and medium-term risks of programme interruptions for gambiense human African trypanosomiasis in the DRC (preprint)

Gambiense human African trypanosomiasis (gHAT) is a deadly vector-borne, neglected tropical disease found in West and Central Africa targeted for elimination of transmission (EoT) by 2030. The recent pandemic has illustrated how it can be important to quantify the impact that unplanned disruption to programme activities may have in achieving elimination of transmission. We used a previously developed model of gHAT fitted to data from the Democratic Republic of Congo, a country with the highest global case burden, to explore how interruptions to intervention activities, due to e.g. COVID-19, Ebola or political instability, could impact progress towards EoT and gHAT burden. We simulated transmission and reporting dynamics in 38 health zones under six interruption scenarios lasting for nine or twenty-one months. Included in the interruption scenarios are the cessation of active screening in all scenarios and a reduction in passive detection rates and a delay or suspension of vector control deployments in some scenarios. Our results indicate that, even under the most extreme 21-month interruption scenario, EoT is not predicted to be delayed by more than one additional year compared to the length of the interruption. If existing vector control deployments continue, we predict no delay in achieving EoT even when both active and passive screening activities are interrupted. If passive screening remains fully functional, we expect a marginal negative impact on transmission, however this depends on the strength of passive screening in each health zone. We predict a pronounced increase in additional gHAT disease burden (morbidity and mortality) in many health zones if both active and passive screening were interrupted compared to the interruption of active screening alone. The ability to continue existing vector control during medical activity interruption is also predicted to avert a moderate proportion of disease burden. Author Summary Whilst the COVID-19 pandemic has produced wide-spread disruption for many disease programmes there are also a range of other factors that continue to risk programme interruptions including other disease outbreaks (e.g. Ebola, cholera, yellow fever, and measles) and the potential for political instability. In this study we examine the impact of interruptions by external factors to the gambiense human African trypanosomiasis (gHAT, sleeping sickness) elimination programme of the Democratic Republic of the Congo, a country which has the highest global case burden. We use our previously fitted gHAT model to simulate how transmission dynamics might be impacted by disruption to medical interventions and (where relevant) vector control activities in 38 health zones of the former Bandundu province. For each of the six interruption scenarios we use the model to forecast case numbers and disease burden as well as estimating the expected years and probabilities of elimination of transmission. This analysis provides invaluable insight into the impact that interruptions of any persuasion could have on burden, case reporting and time to achieve elimination of transmission of gHAT in the Democratic Republic of the Congo.

FluoRNT: A robust, efficient assay for the detection of neutralising antibodies against yellow fever virus 17D.

There is an urgent need for better diagnostic and analytical methods for vaccine research and infection control in virology. This has been highlighted by recently emerging viral epidemics and pandemics (Zika, SARS-CoV-2), and recurring viral outbreaks like the yellow fever outbreaks in Angola and the Democratic Republic of Congo (2016) and in Brazil (2016-2018). Current assays to determine neutralising activity against viral infections in sera are costly in time and equipment and suffer from high variability. Therefore, both basic infection research and diagnostic population screenings would benefit from improved methods to determine virus-neutralising activity in patient samples. Here we describe a robust, objective, and scalable Fluorescence Reduction Neutralisation Test (FluoRNT) for yellow fever virus, relying on flow cytometric detection of cells infected with a fluorescent Venus reporter containing variant of the yellow fever vaccine strain 17D (YF-17D-Venus). It accurately measures neutralising antibody titres in human serum samples within as little as 24 h. Samples from 32 vaccinees immunised with YF-17D were tested for neutralising activity by both a conventional focus reduction neutralisation test (FRNT) and FluoRNT. Both types of tests proved to be equally reliable for the detection of neutralising activity, however, FluoRNT is significantly more precise and reproducible with a greater dynamic range than conventional FRNT. The FluoRNT assay protocol is substantially faster, easier to control, and cheaper in per-assay costs. FluoRNT additionally reduces handling time minimising exposure of personnel to patient samples. FluoRNT thus brings a range of desirable features that can accelerate and standardise the measurement of neutralising anti-yellow fever virus antibodies. It could be used in applications ranging from vaccine testing to large cohort studies in systems virology and vaccinology. We also anticipate the potential to translate the methodology and analysis of FluoRNT to other flaviviruses such as West Nile, Dengue and Zika or to RNA viruses more generally.

[Effects of Covid-19 Pandemic on the Vaccine Activities on a Reference Immunization Center in Treichville, Côte D'ivoire]. / Effets de la Pandémie à Covid-19 sur les Activités Vaccinales D'un Centre de Vaccination de Référence de Treichville en Côte D'ivoire.

Introduction: Since March 11, 2020, Côte d'Ivoire has been affected by the coronavirus epidemic, declared that same day as pandemic by WHO. March 11, 2021, one year after the pandemic, Côte d'Ivoire has notified 36,824 cases of Covid-19 patients and among them 211 have died. As of May 31, 2020, Côte d'Ivoire had already notified 2,833 cases and 33 deaths. At that time, false rumors were circulating in Africa about the setting up of clinical trials on candidate vaccines. The impact of these rumors on the overall use of health services had to be measured and in particular on vaccination centers. Objectives: The objective of this study was to determine the effects of the pandemic on the activities of the immunization services of the National Institute of Public Hygiene in Abidjan, which comprises four departments: International Vaccination Center, Community Vaccination Service, Rabies Center, and Vaccination Unit of the Expanded Program on Immunization. The study was based on activity reports of the immunization services. Results: At the International Vaccination Center, activities fell by about 50% in March, 86% in April and 82% in May in comparison with 2018 and 2019. Activities of Community Vaccination Service decreased by about 26% in March and 99% in April and May. At the Rabies Control Center, this reduction was estimated at 38% in April and 45% in May. The highest losses were for yellow fever and meningitis vaccines. Conclusion: The drop in attendance at vaccination services could increase the risk of epidemics, especially yellow fever, which are recurrent in Abidjan. Intensive awareness and catch-up actions should be carried out and further studies performed to assess the impact of the pandemic on immunization activities.

Travel vaccines throughout history.

Vaccinations are an important component of travel medicine. Beyond protection of travelers, vaccines are administered to prevent the importation of vaccine-preventable diseases at home and at destination. Proof of immunization to travel dates back to the first smallpox vaccine, developed by Edward Jenner in 1796. However, it took one century to generate the next vaccines against cholera, rabies, and typhoid fever. During the 20th century the armamentarium of vaccines used in travelers largely expanded with yellow fever, poliomyelitis, tetravalent meningococcal, and hepatitis A vaccines. The International Certificate of Inoculation and Vaccination was implemented in 1933. Currently there are vaccines administered to travelers following risk assessment, but also vaccines required according to the 2005 International Health Regulations and vaccines required at certain countries. Finally, within less than one year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic, the first COVID-19 vaccines were launched and approved for emergency use to control the pandemic. Despite practical and ethical challenges, COVID-19 vaccine verifications have been widely used since spring 2021 in many activities, including international travel. In this article, we review the course of development of travel vaccines focusing on those for which a proof of vaccination has been or is required.

Aedes mosquitoes in the emerging threat of urban yellow fever transmission.

This last decade has seen a resurgence of yellow fever (YF) in historical endemic regions and repeated attempts of YF introduction in YF-free countries such as the Asia-Pacific region and the Caribbean. Infected travellers are the main entry routes in these regions where competent mosquito vectors proliferate in appropriate environmental conditions. With the discovery of the 17D vaccine, it was thought that YF would be eradicated. Unfortunately, it was not the case and, contrary to dengue, chikungunya and Zika, factors that cotribute to YF transmission remain under investigation. Today, all the signals are red and it is very likely that YF will be the next pandemic in the YF-free regions where millions of people are immunologically naïve. Unlike COVID-19, YF is associated with a high case-fatality rate and a high number of deaths are expected. This review gives an overview of global YF situation, including the non-endemic Asia-Pacific region and the Caribbean where Aedes aegypti is abundantly distributed, and also proposes different hypotheses on why YF outbreaks have not yet occurred despite high records of travellers importing YF into these regions and what role Aedes mosquitoes play in the emergence of urban YF.

Biodistribution and Environmental Safety of a Live-attenuated YF17D-vectored SARS-CoV-2 Vaccine Candidate (preprint)

New platforms are urgently needed for the design of novel prophylactic vaccines and advanced immune therapies. Live-attenuated yellow fever vaccine YF17D serves as vector for several licensed vaccines and platform for novel vaccine candidates. Based on YF17D, we developed YF-S0 as exceptionally potent COVID-19 vaccine candidate. However, use of such live RNA virus vaccines raises safety concerns, i.e., adverse events linked to original YF17D (yellow fever vaccine-associated neurotropic; YEL-AND, and viscerotropic disease; YEL-AVD). In this study, we investigated the biodistribution and shedding of YF-S0 in hamsters. Likewise, we introduced hamsters deficient in STAT2 signaling as new preclinical model of YEL-AND/AVD. Compared to parental YF17D, YF-S0 showed an improved safety with limited dissemination to brain and visceral tissues, absent or low viremia, and no shedding of infectious virus. Considering yellow fever virus is transmitted by Aedes mosquitoes, any inadvertent exposure to the live recombinant vector via mosquito bites is to be excluded. The transmission risk of YF-S0 was hence evaluated in comparison to readily transmitting YFV-Asibi strain and non-transmitting YF17D vaccine, with no evidence for productive infection of vector mosquitoes. The overall favorable safety profile of YF-S0 is expected to translate to other novel vaccines that are based on the same YF17D platform.

Ecological and environmental factors affecting transmission of sylvatic yellow fever in the 2017-2019 outbreak in the Atlantic Forest, Brazil.

BACKGROUND: Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years. METHODS: To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017-2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections. RESULTS: A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors. CONCLUSIONS: Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases.