Vacinas passado e futuro ­ Reflexões para discussão / The past and future of vaccines ­ Reflections for discussion

Neste artigo de opinião, apresento uma breve história do desenvolvimento de vacinas, comentando sobre as formas clássicas de produção de vacinas utilizando o próprio agente infeccioso. Em seguida, abordo as vacinas virais, discutindo seus benefícios e dificuldades e a questão dos sorotipos virais, bem como as vacinas bacterianas e seu relativo sucesso. Apresento nossos estudos sobre doença cardíaca reumática e o desenvolvimento de uma vacina contra infecções estreptocócicas. Também discuto plataformas vacinais, especialmente os sucessos alcançados com vacinas de vetores virais não replicantes e, acima de tudo, o grande êxito das vacinas de RNA mensageiro (mRNA). As vacinas de mRNA tornaram-se possíveis somente após os avanços obtidos com a substituição de nucleotídeos que reduziam a ação da imunidade inata. Serão todas as vacinas desenvolvidas a partir de mRNA no futuro? Em seguida, abordo a questão das vias de administração de vacinas, seja por via subcutânea, intradérmica, intramuscular ou nasal. Exponho dados do meu laboratório sobre o desenvolvimento de uma vacina de instilação nasal que induziu uma resposta de proteção da mucosa, prevenindo a infecção e, consequentemente, a transmissão do SARS-CoV-2. Posteriormente, discuto quais vacinas futuras poderiam ser desenvolvidas para além das doenças infecciosas agudas. Por fim, discuto as vantagens do desenvolvimento de vacinas seguras, eficazes e de uso múltiplo, bem como a forma de torná-las acessíveis à população mundial, promovendo a equidade em saúde.

In this opinion article, I provide a brief history of vaccine development, commenting on the classic ways of producing vaccines using the infectious agent itself. I address viral vaccines, discussing their benefits and challenges and the issue of viral serotypes, as well as bacterial vaccines and their relative success. I present our studies on rheumatic heart disease and the development of a vaccine against streptococcal infection. I also discuss vaccine platforms, highlighting the success achieved with non-replicating viral vector-based vaccines and, especially, with messenger RNA (mRNA) vaccines. mRNA vaccines only became possible after the advances provided by the replacement of nucleotides that reduced the action of the innate immune system. Will all vaccines be made from mRNA in the future? Then, I address the issue of vaccine administration routes, whether subcutaneously, intradermally, intramuscularly, or intranasal. I present data from my laboratory on the development of an intranasal vaccine that induced a protective mucosal response, preventing infection and, consequently, the transmission of SARSCoV- 2. I discuss which future vaccines could be developed beyond acute infectious diseases. Finally, I discuss the advantages of developing safe, effective, multiple-use vaccines and how to make them accessible worldwide by promoting health equity.

Vacunas contra el virus chikungunya: avances y perspectivas

El virus chikungunya (CHIKV) es un alfavirus cuya infección provoca una enfermedad caracterizada principalmente por fiebre y dolores articulares/musculares. Entre 25-50% de las infecciones se presentan con enfermedad crónica que puede durar de meses a años. El primer brote de CHIKV en Paraguay corresponde al año 2015, siendo el último en el año 2022/2023. Diversos candidatos vacunales contra CHIKV se encuentran en diferentes etapas de desarrollo, e incluso recientemente (noviembre/2023) fue aprobada la primera vacuna contra CHIKV llamada VLA1553 (Ixchiq). Adicionalmente, al menos 30 candidatos vacunales se encuentran en ensayos preclínicos/clínicos. Con la aprobación de la primera vacuna contra CHIKV y la posibilidad de otras que lleguen al mercado prontamente, debido al estado avanzado de otros candidatos vacunales, se abrirá un nuevo escenario en esta enfermedad. Se espera que la introducción de vacunas efectivas genere un avance importante para la prevención de esta enfermedad, disminuyendo los casos agudos y los efectos crónicos de la infección por el virus. En este trabajo de revisión se analiza el avance de las vacunas contra CHIKV, además de examinar los desafíos de vigilancia epidemiológica que plantean la introducción de estas vacunas.

Chikungunya virus (CHIKV) is an alphavirus that causes an illness characterized mainly by fever and joint/muscle pain. Between 25-50% of infections present with chronic diseases that can last from months to years. The first outbreak of CHIKV in Paraguay occurred in 2015, with the last outbreak occurring in 2022/2023. Several vaccine candidates against CHIKV are in different stages of development, and even recently (November/2023), the first vaccine against CHIKV, called VLA1553 (Ixchiq), was approved. In addition, at least 30 vaccine candidates are available for preclinical and clinical trials. With the approval of the first vaccine against CHIKV and the possibility of others coming to the market soon, due to the advanced status of other vaccine candidates, a new scenario will open for this disease. The introduction of effective vaccines is expected to generate an important advance in the prevention of this disease, reducing acute cases and the chronic effects of viral infection. This review analyzes the progress of CHIKV vaccines and examines the epidemiological surveillance challenges posed by the introduction of these vaccines.

Testing the genomic stability of the Brazilian yellow fever vaccine strain using next-generation sequencing data.

The live attenuated yellow fever (YF) vaccine was developed in the 1930s. Currently, the 17D and 17DD attenuated substrains are used for vaccine production. The 17D strain is used for vaccine production by several countries, while the 17DD strain is used exclusively in Brazil. The cell passages carried out through the seed-lot system of vaccine production influence the presence of quasispecies causing changes in the stability and immunogenicity of attenuated genotypes by increasing attenuation or virulence. Using next-generation sequencing, we carried out genomic characterization and genetic diversity analysis between vaccine lots of the Brazilian YF vaccine, produced by BioManguinhos-Fiocruz, and used during 11 years of vaccination in Brazil. We present 20 assembled and annotated genomes from the Brazilian 17DD vaccine strain, eight single nucleotide polymorphisms and the quasispecies spectrum reconstruction for the 17DD vaccine, through a pipeline here introduced. The V2IDA pipeline provided a relationship between low genetic diversity, maintained through the seed lot system, and the confirmation of genetic stability of lots of the Brazilian vaccine against YF. Our study sets precedents for use of V2IDA in genetic diversity analysis and in silico stability investigation of attenuated viral vaccines, facilitating genetic surveillance during the vaccine production process.

VacciPharma 2020. V International Congress on Pharmacology of Vaccines

Dear colleagues: The Organizing Committee of the V International Congress on Pharmacology of Vaccines (VacciPharma 2020) organized by the Cuban Society of Pharmacology, BioCubaFarma and the International Union of Basic and Clinical Pharmacology (IUPHAR) would like to invite you to participate in this important event, scheduled for June 14 to 18, 2020 at the Convention Centre of the Melia Marina Varadero Hotel, Varadero Beach, Matanzas, Cuba. The Congress will be formed by different workshops and symposia such as: Meningococcal and Gonococcal vaccines Pneumococcal vaccines Pertussis and combined vaccines Enteric vaccines Leptospira vaccines Viral vaccines Animal models in vaccine development, QC and 3Rs Vaccine technology and bioprocess Vaccine technology transfers Patent, business and international cooperation VacciPharma 2020 is sponsored by: Cuban Society of Pharmacology (SCF) International Union of Basic and Clinical Pharmacology (IUPHAR) Latin-American Association of Pharmacology (ALF) PAHO / WHO BioCubaFarma National research centers: Finlay Vaccine Institute (IFV); Center of Genetic Engineering and Biotechnology (CIGB); Center of Molecular Immunology (CIM); Center for Control of Drugs, Equipment and Medical Devices (CECMED); National Center for Animal and Plant Health (CENSA); Tropical Medicine Institute Pedro Kourí (IPK); National Center for Biopreparations (BioCEN); Center for Drug Research and Development (CIDEM); Center for Clinical Trials (CENCEC); among others International Manufacturers and Companies The key objectives of the Congress are: To provide a progressive state-of-the-art report for scientists, manufacturers, governmental authorities and healthcare workers, who need to be updated about the latest scientific developments for human vaccines, including basic science, product development, market introduction, immunization programs and epidemiological surveillance. To promote the scientific collaboration among experts and institutions through the experience exchange, the presentation of results and the discussion on the conference topics. To accelerate progress in the development of vaccines and the acceptance and introduction of new methods and technologies. Opening lectures, oral presentations and posters will provide you the opportunity to be involved in a high quality congress to discuss about the progress in the field of vaccinology and pharmacology sciences. Deadline for registration and abstract submission: April 15th, 2020 Further information can be found at the VacciPharma 2020 Website: www.immunovaccipharma.com

Detection of Yellow Fever Virus by Quantitative Real-Time PCR (qPCR).

The recent resurgence of yellow fever virus (YFV) activity in the tropical regions of Africa and South America has sparked renewed interest in this infamous arboviral disease. Also, the development and production of viral vaccines involve several steps that need the monitoring of viral load throughout the process (antigen production, purification, and inactivation). Currently, these steps are followed by plaque lysis titration assay, whose results take about 7-10 days to come out and thus resulting in a laborious and time-consuming approach. With the advent of quantitative real-time PCR (qPCR), we have a faster method to be applied during vaccine production and also to be effectively used for the diagnosis of YFV infection. The technique herein standardized proved to be effective for determining YF viral load both in vivo and in vitro, thus becoming a very important tool for laboratory analysis to verify the vaccination status of individuals, beyond acting as a quality control for vaccine production and diagnosis.

Protocol for the Production of a Vaccine Against Argentinian Hemorrhagic Fever.

Argentinian hemorrhagic Fever (AHF) is a febrile, acute disease caused by Junín virus (JUNV), a member of the Arenaviridae. Different approaches to obtain an effective antigen to prevent AHF using complete live or inactivated virus, as well as molecular constructs, have reached diverse development stages. This chapter refers to JUNV live attenuated vaccine strain Candid #1, currently used in Argentina to prevent AHF. A general standardized protocol used at Instituto Nacional de Enfermedades Virales Humanas (Pergamino, Pcia. Buenos Aires, Argentina) to manufacture the tissue culture derived Candid #1 vaccine is described. Intermediate stages like viral seeds and cell culture bank management, bulk vaccine manufacture, and finished product processing are also separately presented in terms of Production and Quality Control/Quality Assurance requirements, under the Adminitracion Nacional de Medicamentos, Alimentos y Tecnología Medica (ANMAT), the Argentine national regulatory authority.

Evaluation of incubation yield, vaccine response, and performance of broilers submitted to in-ovo vaccination at different embryonic ages

The aim of this study was to evaluate the effects of in-ovo vaccination on different incubation days of broiler embryos derived from young and old breeders on incubation indexes, vaccine response, and broiler performance. A number of 20,160 fertile eggs was distributed according to a completely randomized design in a 4 x 2 factorial arrangement (in-ovo vaccination on 16, 17, 18, or 19 days of incubation, and breeders of 31 or 52 weeks of age), totaling eight treatments with 15 replicates of 168 eggs each. Vaccination procedures and vaccines (strains and doses) were those routinely applied in commercial hatcheries. After hatch, 960 male chicks were housed and distributed according to the same experimental design previously applied in the hatchery. There were hatching losses (p < 0.05) when eggs were vaccinated before 18 days of incubation. Greater Marek's disease antibody titers were obtained when the in-ovo vaccination was performed on day 19 of incubation, regardless breeder age. Embryonic age at vaccination did not compromise broiler performance in the field, and the flexibility of embryonic age for in-ovo vaccination can reduces incubation costs.(AU)

Evaluation of incubation yield, vaccine response, and performance of broilers submitted to in-ovo vaccination at different embryonic ages

The aim of this study was to evaluate the effects of in-ovo vaccination on different incubation days of broiler embryos derived from young and old breeders on incubation indexes, vaccine response, and broiler performance. A number of 20,160 fertile eggs was distributed according to a completely randomized design in a 4 x 2 factorial arrangement (in-ovo vaccination on 16, 17, 18, or 19 days of incubation, and breeders of 31 or 52 weeks of age), totaling eight treatments with 15 replicates of 168 eggs each. Vaccination procedures and vaccines (strains and doses) were those routinely applied in commercial hatcheries. After hatch, 960 male chicks were housed and distributed according to the same experimental design previously applied in the hatchery. There were hatching losses (p < 0.05) when eggs were vaccinated before 18 days of incubation. Greater Marek's disease antibody titers were obtained when the in-ovo vaccination was performed on day 19 of incubation, regardless breeder age. Embryonic age at vaccination did not compromise broiler performance in the field, and the flexibility of embryonic age for in-ovo vaccination can reduces incubation costs.

New approaches for the standardization and validation of a real-time qPCR assay using TaqMan probes for quantification of yellow fever virus on clinical samples with high quality parameters.

The development and production of viral vaccines, in general, involve several steps that need the monitoring of viral load throughout the entire process. Applying a 2-step quantitative reverse transcription real time PCR assay (RT-qPCR), viral load can be measured and monitored in a few hours. In this context, the development, standardization and validation of a RT-qPCR test to quickly and efficiently quantify yellow fever virus (YFV) in all stages of vaccine production are extremely important. To serve this purpose we used a plasmid construction containing the NS5 region from 17DD YFV to generate the standard curve and to evaluate parameters such as linearity, precision and specificity against other flavivirus. Furthermore, we defined the limits of detection as 25 copies/reaction, and quantification as 100 copies/reaction for the test. To ensure the quality of the method, reference controls were established in order to avoid false negative results. The qRT-PCR technique based on the use of TaqMan probes herein standardized proved to be effective for determining yellow fever viral load both in vivo and in vitro, thus becoming a very important tool to assure the quality control for vaccine production and evaluation of viremia after vaccination or YF disease.

Formulação vacinal trivalente voltada para o controle profilático/terapêutico de tumores induzidos pelo vírus do papiloma humano tipo 16 (HPV-16) e infecções pelos vírus da imunodeficiência adquirida (HIV) e herpes vírus humano (HSV) / Trivalent vaccine formulation focused on the prophylactic / therapeutic control of tumors induced by human papillomavirus type 16 (HPV-16) and infection by human immunodeficiency virus (HIV) and human herpes virus (HSV)

As proteínas E7 (HPV), p24 (HIV) e gD (HSV) são exclusivamente expressas por células infectadas ou tumorais e, por isso, são utilizadas como alvos para vacinas com características terapêuticas. Foram desenvolvidas duas vacinas de DNA capazes de expressar as três proteínas virais por meio de um vetor de expressão bicistrônico baseado na sequência IRES. As vacinas, denominadas pIRES I e pIRES II, diferem entre si por transportarem os genes que codificam as proteínas E7 do HPV-16 e p24 do HIV fusionadas à proteína gD do HSV-1 em ordem inversa. Células COS-7 transfectadas com os plasmídeos vacinais expressaram as proteínas alvo, como determinado por imunofluorecência com anticorpos específicos para as proteínas gD, p24 e E7. As vacinas foram testadas em modelo murino quanto à capacidade de gerar anticorpos e células T CD8+ específicas. Observamos que animais vacinados desenvolveram baixas taxas de anticorpos contra gD, p24 e E7. Em contrapartida, demonstramos a indução de células T CD8+ específicas para os três antígenos testados. Os plasmídeos vacinais foram capazes de proteger camundongos inoculados com células tumorais TC-1 (que expressam a proteína E7 do HPV-16), embora apresentando diferentes níveis de proteção em ensaios profiláticos e terapêuticos. As formulações foram testadas em relação à capacidade de proteger animais frente a desafio com o HSV-1 sendo que apenas um deles gerou efeito protetor. Em conclusão, os resultados demonstram que vacinas voltadas para o controle terapêutico de infecções ou processos tumorais associados aos vírus HPV, HIV e HSV representam uma meta viável e promissora

The proteins E7 (HPV), p24 (HIV) and gD (HSV) are exclusively expressed by infected cells or tumors and therefore are used as targets for vaccines with therapeutic characteristics. We developed two DNA vaccines capable of expressing these three viral proteins using a bicistronic expression vector based on IRES sequence. The plasmid vaccines, named pIRES I and pIRES II, differ by carrying the genes that encode proteins of HPV-16 E7 and p24 fused to the HIV protein gD of HSV-1 in reverse order. Transfected COS-7 cells expressed the target proteins, as determined by immunofluorescence with specific antibodies for gD, p24 and E7. The vaccines were tested in mice for their ability to generate antibodies and specific CD8+ T cells. We observed that vaccinated animals developed low levels of antibodies against gD, E7 and p24. In contrast, we demonstrate the induction of specific CD8+ T cells for the three antigens. The plasmid vaccines were able to protect mice inoculated with TC-1 tumor cells (which express the E7 protein of HPV-16), although with different levels of protection in prophylactic and therapeutic trials. The formulations were tested for ability to protect animals against challenge with HSV-1 and only one of them generated a protective effect. In conclusion, the results show that vaccines directed to therapeutic control of infections or tumor process associated with HPV, HSV or HIV represents a promising and viable goal

Antibody responses to Hepatitis B and measles-mumps-rubella vaccines in children who received chemotherapy for acute lymphoblastic leukemia.

OBJECTIVE: To evaluate viral vaccine antibody levels in children with acute lymphoblastic leukemia after chemotherapy and after vaccine booster doses. METHODS: Antibody levels against hepatitis B, rubella, measles and mumps vaccine antigens were evaluated in 33 children after completing chemotherapy (before and after vaccine booster doses) and the results were compared to the data of 33 healthy children matched for gender, age and social class. RESULTS: After chemotherapy, 75.9%, 67.9%, 59.3% and 51.7% of the patients showed low antibody titers that would be unlikely to protect against exposure to measles, rubella, hepatitis B and mumps, respectively. After receiving a vaccine booster dose for these antigens the patients had high antibody levels consistent with potential protection against measles, mumps and hepatitis B, but not against rubella. CONCLUSION: Extra doses of measles-mumps-rubella plus hepatitis B vaccines are recommended in acute lymphoblastic leukemia patients submitted to treatment after hematologic recovery. After this, viral vaccine antibody levels should be verified to define the individual's protective status.

Antibody responses to Hepatitis B and measles-mumps-rubella vaccines in children who received chemotherapy for acute lymphoblastic leukemia

OBJECTIVE: To evaluate viral vaccine antibody levels in children with acute lymphoblastic leukemia after chemotherapy and after vaccine booster doses. METHODS: Antibody levels against hepatitis B, rubella, measles and mumps vaccine antigens were evaluated in 33 children after completing chemotherapy (before and after vaccine booster doses) and the results were compared to the data of 33 healthy children matched for gender, age and social class. RESULTS: After chemotherapy, 75.9%, 67.9%, 59.3% and 51.7% of the patients showed low antibody titers that would be unlikely to protect against exposure to measles, rubella, hepatitis B and mumps, respectively. After receiving a vaccine booster dose for these antigens the patients had high antibody levels consistent with potential protection against measles, mumps and hepatitis B, but not against rubella. CONCLUSION: Extra doses of measles-mumps-rubella plus hepatitis B vaccines are recommended in acute lymphoblastic leukemia patients submitted to treatment after hematologic recovery. After this, viral vaccine antibody levels should be verified to define the individual's protective status.

Importancia de las vacunas contra los virus de las hepatitis A y B en Chile / Vaccines against hepatitis A and B in Chile

The mode of transmission and epidemiological approach for hepatitis A and B are different. However, both are preventable with vaccines whose efficacy and long lasting protection has been demonstrated. This review describes the secular tendency of both infections in Chile, their risk factors that have contributed to their persistence in the country and the interventions that have been carried out to reduce the disease burden. Although the vaccine for hepatitis B was incorporated to the immunization program in 2005, the vaccine for hepatitis A persists in the list of interventions that must be assumed with priority by the Ministry of Health. If Chilean health authorities pretend to reach the enteric disease indicators of developed countries, they must accelerate the epidemiological transition towards the elimination of hepatitis A.

Vaccines against dengue: a review of current candidate vaccines at advanced development stages / Vacunas contra el dengue: una revisión de las vacunas candidatas en etapas avanzadas de desarrollo

Los esfuerzos sistemáticos para desarrollar una vacuna contra el dengue comenzaron durante la Segunda Guerra Mundial, inspirados en el desarrollo exitoso de una vacuna contra la fiebre amarilla. Sin embargo, la falta de modelos adecuados de la enfermedad, la información incompleta acerca de los mecanismos patogénicos y los insuficientes incentivos económicos han dificultado los avances. Debido al impacto actual del dengue en todo el mundo y su explosiva diseminación, ha aumentado el interés en el desarrollo de vacunas contra el dengue y se ha avanzado considerablemente en el camino hacia la evaluación clínica de vacunas candidatas. La Iniciativa para la Investigación en Vacunas, de la Organización Mundial de la Salud, está facilitando el desarrollo de y los ensayos con las vacunas candidatas. Las vacunas contra el dengue que se encuentran actualmente en etapas avanzadas de desarrollo son de tres tipos fundamentales: 1) vivas atenuadas; 2) vivas recombinantes; y 3) de subunidades e inactivadas. La mayoría de las vacunas en cartera son vivas atenuadas, siguiendo el camino exitoso de otras vacunas vivas contra flavivirus, especialmente de la desarrollada contra la fiebre amarilla. En general, las vacunas contra el dengue que se encuentran actualmente en desarrollo están bastante avanzadas y son muy diversas. Muy pronto comenzará la evaluación de estas vacuna candidatas en ensayos de eficacia basados en poblaciones expuestas, lo que requerirá resolver varios problemas técnicos, operacionales y regulatorios.

Análisis de la utilidad de la vacuna Candid 1 en la prevención de la fiebre hemorrágica argentina en niños / Analysis of the usefulness of Candid 1 vaccine in preventing Argentine hemorrhagic fever in children

OBJETIVO: Determinar la estrategia más racional de vacunación con Candid 1 para prevenir la fiebre hemorrágica argentina (FHA) en los menores de 15 años que viven en el área endémica. MÉTODOS: Para el análisis de la efectividad estimada se diseñó un modelo de árbol de decisión, con dos posibles opciones: vacunar a todos los menores del área endémica (vacunación ampliada) o vacunar solamente a los menores de 15 años con mayor riesgo (vacunación selectiva). Estas opciones se compararon con la alternativa de no vacunar. La evaluación se complementó con un análisis de sensibilidad para identificar los valores umbral de las variables críticas que podrían modificar la decisión tomada. Las probabilidades empleadas se tomaron de estudios clínicos y epidemiológicos previos. RESULTADOS: Según el modelo empleado, la estrategia de vacunación ampliada fue la mejor opción, con una utilidad total esperada de 9,99998 (siendo 10 el valor máximo posible). El análisis de sensibilidad demostró que la vacunación selectiva sería la estrategia de mayor utilidad si la incidencia en la población de bajo riesgo se reduce a menos de 3 por 1 000 000 habitantes o si la tasa de reacciones adversas graves a la vacuna asciende a más de 9 por 100 000 habitantes. Ninguna variación de los parámetros empleados en el modelo respaldó la opción de no vacunar. CONCLUSIONES: Con los parámetros de riesgo y de beneficio empleados, se recomienda vacunar con Candid 1 a todos los menores de 15 años que viven en el área endémica de FHA. El modelo propuesto puede adaptarse a las necesidades futuras y ayudar a tomar decisiones mediante la incorporación de los datos prospectivos de la vigilancia de la enfermedad. Estos resultados pueden usarse como base para estudios de costo y eficacia y para otros análisis cuantitativos.

Objective. To determine the most rational strategy of vaccination with Candid 1 vaccine in order to prevent Argentine hemorrhagic fever among children under 15 years old living an endemic area. Methods. To analyze the estimated effectiveness, a decision tree model was designed, with two possible options: vaccinate all the children under age 15 in the endemic area ("expanded vaccination") or vaccinate only the children at greater risk ("selective vaccination"). These two options were compared with the alternative of not vaccinating. The evaluation was complemented with a sensitivity analysis to identify Results. According to the model that we used, the expanded vaccination strategy was the best option, with a total expected utility of 9.99998 (out of a maximum possible 10.0). The sensitivity analysis showed that selective vaccination would be the best strategy if the incidence in the population with low risk drops to less than 3 per 1 000 000 population or if the rate of serious adverse reactions to the vaccine reaches more than 9 per 100 000 inhabitants. No variation in the parameters used in the model supported the option of not vaccinating. Conclusions. Given the risk and benefit parameters that we used, we recommend vaccinating with Candid 1 all the children under age 15 who live in the area endemic for Argentine hemorrhagic fever. The proposed model can be fitted to future needs, and it can help in decision-making by incorporating prospective disease surveillance data. These results can be used as a basis for cost and efficacy studies and for other quantitative analyses