A review of the current diphtheria outbreaks

Corynebacterium diphtheriae is responsible for both endemic and epidemic diphtheria. The predisposing factor for this disease is the failure to immunize during childhood. Humans are the only hosts of the organism and is present in the upper respiratory tract. The organism is transmitted via airborne route and can cause respiratory obstruction and heart failure because of the exotoxin it produces. There is presently a resurgence of diphtheria outbreaks in Nigeria. The Nigeria Center for Disease Control (NCDC) was notified of suspected diphtheria outbreaks in Lagos and Kano States, Nigeria, in December 2022 and has been issuing monthly reports since that time. This review of the diphtheria outbreaks following online database searches on PubMed and Google Scholar as well as the NCDC/WHO websites and grey literatures, describes the current trend of the outbreaks globally, elucidated the different strains of Corynebacterium responsible for the outbreaks, identified the recent vaccine formulation developed to tackle the outbreaks, and provide information on vaccine delivery and efficacy studies in the country and globally.

Comunicação de risco: caso suspeito de difteria / Risk communication: suspected case of diphtheria

A comunicação de risco tem como objetivo apoiar na divulgação rápida e eficaz de conhecimento às populações, parceiros e partes intervenientes possibilitando o acesso às informações fidedignas que possam apoiar nos diálogos para tomada de medidas de proteção e controle em situações de emergência em saúde pública. Em Goiás na SE 16/2022, foi notificado 01 caso suspeito de difteria, sexo feminino, 16 anos, do município de Santa Helena de Goiás, com histórico de 03 doses da vacina DTP+HIB (08/2010), não foi identificada doses de reforço, conforme preconizados pelo PNI

Risk communication aims to support the rapid and effective dissemination of knowledge to populations, partners and stakeholders, enabling access to reliable information that can support dialogues for taking protection and control measures in emergency situations in public health. In Goiás on SE 16/2022, 01 suspected case of diphtheria was reported, female, 16 years old, from the municipality of Santa Helena de Goiás, with a history of 03 doses of the DTP+HIB vaccine (08/2010), no doses were identified reinforcement, as recommended by the PNI

Identification and analysis of 2 Corynebacterium diphtheria strains in Guangdong Province / 中华预防医学杂志

Objective: To identify and analyze two strains of C. diphtheriae in Guangdong Province by combining whole genome sequencing with traditional detection methods. Methods: The C. diphtheriae was isolated from Guangzhou in 2010 and Zhuhai in 2020 respectively. Isolates were identified by API Coryne strips and MALDI-TOF-MS. Genomic DNA was sequenced by using Illumina. The assembly was performed for each strain using CLC software. J Species WS online tool was used for average nucleoside homology identification, then narKGHIJ and tox gene were detected by NCBI online analysis tool BLSATN. MEGA-X was used to build a wgSNP phylogenetic tree. Results: GD-Guangzhou-2010 was Belfanti and GD-Zuhai-2020 was Gravis. ANIb between GD-Guangzhou-2010 and C. belfantii was 99.61%. ANI between GD-Zhuhai-2020 and C. diphtheriae was 97.64%. BLASTN results showed that the nitrate reduction gene narKGHIJ and tox gene of GD-Guangzhou-2010 was negative, while GD-Zhuhai-2020 nitrate reduction gene narKGHIJ was positive. There were two obvious clades in wgSNP phylogenetic tree. The first clades included all Mitis and Gravis types strains as well as GD-Zhuhai-2020. The second clades contained all isolates of C.belfantii, C.diphtheriae subsp. lausannense and GD-guangzhou-2010. Conclusion: Two non-toxic C. diphtheriae strains are successfully isolated and identified. The phylogenetic tree suggests that GD-Guangzhou-2010 and GD-Zhuhai-2020 are located in two different evolutionary branches.

Ocorrência de eventos adversos após o uso da vacina adsorvida difteria, tétano e pertussis (acelular) - dTpa -, São Paulo, SP, 2015-2016 / Aparecimiento de eventos adversos después del uso de la vacuna adsorbida difteria, tétanos y tosferina (acelular) - dTpa -, São Paulo, SP, Brasil, 2015-2016 / Adverse event occurrence following use of tetanus, diphtheria and acellular pertussis adsorbed vaccine - Tdap -, São Paulo, SP, Brazil, 2015-2016

Objetivo: descrever a ocorrência de eventos adversos pós-vacinação (EAPV) com a vacina dTpa durante a gestação. Métodos: estudo descritivo, com dados de relatos das participantes de estudo de efetividade e imunogenicidade realizado em dois hospitais de São Paulo, SP, Brasil, entre 2015 e 2016. Resultados: das 201 mães incluídas no estudo, 48 (23,9%) apresentaram pelo menos um EAPV; foram identificados 60 sintomas relacionados ao uso da dTpa - dor (22,4%), inchaço (2,5%), febre (1,5%), sono (1,0%), vermelhidão (0,5%), vômito (0,5%), dor de cabeça (0,5%), reação local (0,5%) e cansaço (0,5%); não foram registrados eventos adversos raros, muito raros ou extremamente raros; todos os eventos foram considerados esperados e estão descritos em bula; todos tiveram desfecho para cura sem sequelas. Conclusão: a dTpa, na forma adotada pelo Programa Nacional de Imunizações (PNI), é segura; não foram identificados eventos adversos inesperados entre as gestantes imunizadas com a vacina.

Objetivo: describir el aparecimiento de eventos adversos posvacunación (EAPV) con la vacuna dTpa durante el embarazo. Métodos: estudio descriptivo con datos de relatos de las participantes del estudio de efectividad e inmunogenicidad realizado en dos hospitales de São Paulo, SP, Brasil, entre 2015 y 2106. Resultados: de las 201 madres del estudio, 48 (23,9%) tuvieron al menos un EAPV; se identificaron 60 síntomas relacionados al uso de dTpa - dolor (22.4%), hinchazón (2.5%), fiebre (1.5%), somnolencia (1.0%), enrojecimiento (0.5%), vómitos (0.5 %), dolor de cabeza (0.5%), reacción local (0.5%) y cansancio (0.5%) -; no se informaron eventos adversos raros, muy raros o extremadamente raros; todos los eventos se consideraron esperados y se describen en el prospecto; todos tuvieron resultados curativos sin secuelas. Conclusión: el estudio mostró que la vacuna dTpa utilizada por el Programa Nacional de Inmunización (PNI) es segura y no se identificaron eventos adversos inesperados entre las mujeres embarazadas vacunadas.

Objective: to describe occurrence of adverse events following immunization (AEFI) with Tdap vaccine during pregnancy. Methods: this was a descriptive study using data from reports by participants in an effectiveness and immunogenicity study conducted in two hospitals in São Paulo, SP, Brazil, from 2015 to 2016. Results: of the 201 mothers included in the study, 48 (23.9%) had at least one AEFI; 60 symptoms related to Tdap use were identified - pain (22.4%), swelling (2.5%), fever (1.5%), somnolence (1.0%), redness (0.5%), vomiting (0.5%), headache (0.5%), local reaction (0.5%), and fatigue (0.5%); no rare, very rare, or extremely rare adverse events were reported; all events were considered to be expected, as they are described in the vaccine package insert; outcome of all events was recovery without sequelae. Conclusion: Tdap vaccine in the form adopted by the National Immunization Program is safe; no unexpected adverse events were identified among vaccinated pregnant women.

Updates of adult immunization in Korea

An increase in the number of patients with infectious diseases in Korea, can be attributed to various factors, such as the prevalence of new infectious diseases of the 21st century, the re-emergence of past infectious diseases, an increase in the number of elderly individuals, patients with chronic diseases, immune deficiency, and globalization. In this context, vaccination becomes vital for the adult population. Although, the guidelines for adult immunization are currently being updated, the rate of adult vaccination remains lower than that of infant vaccination. At present, the major challenges for increasing the rate of adult immunization include negative views on the need for some immunizations and a lack of understanding of group immunity among the youth. Consequently, a successful immunization program will be required to direct efforts towards educating patients and spreading awareness. Based on the current guidelines and practical applications, varicella zoster; Japanese encephalitis; tetanus, diphtheria, and pertussis; pneumococcus; measles, mumps, and rubella; and hepatitis A vaccines could effectively be considered for adult vaccination.

A Phase III Study to Evaluate the Immunogenicity and Safety of GC1107 (Adult Tetanus Diphtheria Vaccine) in Healthy Adults

BACKGROUND: This study was conducted to assess the immunogenicity and safety of GC1107 (adult tetanus diphtheria [Td] vaccine). The primary goal was to evaluate the non-inferiority of the immunogenicity of GC1107 compared to the control vaccine. Additionally, the safety profiles of GC1107 and the control vaccine were compared. METHODS: The subjects were adults ≥ 18 years old who were not injected with Td or adult tetanus-diphtheria-pertussis (TdaP) vaccine within the recent 5 years. A total of 253 subjects were enrolled and randomized to either the GC1107 group or the control group. For immunogenicity assessment, blood samples were collected at baseline and 28 days after vaccination and antibody titer of diphtheria and tetanus were assessed. RESULTS: The seroprotection rates of diphtheria and tetanus were 89.76% and 91.34%, respectively, in the GC1107 group, and 87.80% and 86.99% in the control group. The geometric mean titer (GMT) of the anti-diphtheria antibody increased after vaccination in both groups, showing no significant difference between the groups (P = 0.139). The anti-tetanus GMTs after vaccination also showed comparable increases in both groups, and showed no significant difference (P = 0.860). In the safety evaluation, solicited local adverse reactions occurred in 81.2% of the subjects in the GC1107 group and in 86.4% of the subjects in the control group. Solicited systemic adverse events occurred in 33.2% of the subjects in the GC1107 group and in 47.2% of the subjects in the control group, which did not reach statistical significance. CONCLUSION: This phase III study demonstrated non-inferiority in immunogenicity and comparable safety of GC1107 compared with the control Td vaccine. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02361866

Development and implementation of standardized method for detecting immunogenicity of acellular pertussis vaccines in Korea

PURPOSE: There is no standard method for confirming the immunogenicity of acellular pertussis vaccines. We tried to develop a local standard method for evaluating the immunogenicity of the three-component of acellular pertussis vaccines which was developed by a Korean local company. MATERIALS AND METHODS: The developed pertussis antigens (pertussis toxin, filamentous hemagglutinin, pertactin) were evaluated by in-house enzyme-linked immunosorbent assay (ELISA) using 189 negative sera, 25 positive sera, and 73 paired sera (pre- and post-Tdap [tetanus, diphtheria, and acellular pertussis] vaccinated sera). ELISA units were calculated by the reference line method, compared with World Health Organization reference sera, and the cut-off value was calculated using negative sera. RESULTS: When compared to National Institute for Biological Standards and Control control antigen (NIBSC) control antigens, the developed pertussis toxin (PT) and filamentous haemagglutinin (FHA) antigens were 203.48 and 61.60 IU/µg, respectively. Each in-house ELISA was established by validating the coefficients of variation % (PT, 11.53%; FHA, 8.60%; pertactin [PRN], 9.86%) obtained from the results of inter- and intra-assay variation. Also, the cut-off values of PT, FHA, and PRN were 11.65, 38.95, and 5.66 EU/mL, respectively. The distributions of antibody levels in paired showed that 93.15% (68/73) in anti-PT IgG, 97.26% (72/73) in anti-FHA IgG, and 100% in anti-PRN IgG were higher than a 100% increase after vaccination. Additionally, the values of 89.04% (65/73) in anti-PT IgG, 97.26% (72/73) in anti-FHA IgG, and 100% in anti-PRN IgG were below each cut-off point. CONCLUSION: We established an in-house ELISA method using self-developed antigens, and these immunoassays have provided a way to standardize measuring the immunogenicity of newly developed vaccines, through single- and dual-serology.

Comparison of Immune Responses to Two Quadrivalent Meningococcal Conjugate Vaccines (CRM197 and Diphtheria Toxoid) in Healthy Adults

BACKGROUND: After the introduction of the meningococcal ACWY-CRM197 conjugate vaccine (MenACWY-CRM) in 2012 and the meningococcal ACWY-diphtheria toxoid conjugate vaccine (MenACWY-DT) in 2014, immunization was recommended for certain high-risk groups including new military recruits in Korea. However, comparative immunogenicity studies for these vaccines have not been performed in Korea. Here, we compared the immunogenicity of these two vaccines in healthy adults. METHODS: A total of 64 adults, 20–49 years of age, were randomly divided into two groups (1:1) to receive either of the two vaccines. The sera were obtained before and 1 month after vaccination and tested for serogroup-specific serum bactericidal activity using baby rabbit complement. RESULTS: There were no significant differences post-vaccination in the geometric mean indices and the seropositive rate to all serogroups between the vaccines. The proportion of seropositive subjects after vaccination ranged from 88% to 100%. CONCLUSION: Both meningococcal conjugate vaccines showed good immunogenicity in healthy Korean adults without statistically significant differences. Further investigations for serotype distribution of circulating meningococci and the immune interference between other diphtheria toxin-containing vaccines concomitantly used for military recruits are needed to optimize immunization policies. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0002460

A 6-year Prospective, Observational, Multi-Center Post-Marketing Surveillance of the Safety of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis (Tdap) Vaccine in Korea

BACKGROUND: Incidence of whooping cough is increasing in Korea. Since 2011, occurrence among adolescents and adults has risen putting vulnerable neonates at risk. National immunization guidelines now include Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccination during pregnancy and as a cocooning strategy (i.e., vaccinating adults and adolescents in contact with neonates). This study assessed post-marketing Tdap (Boostrix®, GSK, Belgium) vaccine safety in subjects ≥ 10 years. METHODS: This open, non-comparative multi-center study was conducted over six years at 10 hospitals in Korea. Subjects received Tdap in normal clinical practice according to local prescribing information. All adverse events (AEs) were recorded, classified as expected or unexpected, and severity and relationship to Tdap were assessed. RESULTS: The analysis included 672 Korean subjects (mean age, 44 years; range, 11–81), 451 were women and 211 were pregnant. Ninety subjects experienced 124 AEs (incidence 13.39%) of which six were serious AEs (SAEs) assessed as not related to vaccination, and 51 were non-SAEs related to vaccination (mostly administration site reactions). Overall 65/124 AEs were unexpected; the most common were 14 constipation, 5 dyspepsia, 4 common cold and 4 premature labor cases. One case of common cold was assessed as possibly related to vaccination. Pregnancy outcome was ‘live infant, no apparent congenital anomaly’ in 195 subjects (92.42%) or ‘lost to follow-up’ in 16 subjects. CONCLUSION: Tdap administration to Korean subjects ≥ 10 years, including pregnant women, for the prevention of diphtheria, tetanus and pertussis was shown to have a well-tolerated safety profile. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01929291

Protocolo del Sistema Nacional de Vigilancia Epidemiológica de enfermedades inmunoprevenibles. No. 06 / Protocol of the National Epidemiological Surveillance System of immunoprevenible diseases. No. 06

Estos protocolos están dirigido a personal médico, paramédico y otros profesionales que realizan acciones gerenciales y operativas de vigilancia epidemiológica en los servicios de salud del país, y están divididos en varios tomos para dar a conocer y actualizar la identificación y medidas de control para diversos padecimientos a fin de continuar con el mejoramiento de las capacidades técnicas de los trabajadores de salud, que permita planificar la prestación de servicios con decisiones partiendo de un enfoque epidemiológico comprobado, para responder a los cambios de tendencias epidemiológicas y con ello contribuir al fortalecimiento de prácticas asertivas de la salud pública de nuestro país. La vigilancia epidemiológica de las enfermedades prevenibles con vacuna, busca reducir la mortalidad y morbilidad por infecciones inmunoprevenibles. La vigilancia epidemiológica, es fundamental para evaluar el impacto de las intervenciones y la toma de decisiones de acuerdo al análisis permanente de la situación de salud.

Validación de un ensayo inmunoenzimático tipo ELISA para cuantificar niveles de antitoxina diftérica en suero humano / Validation of an ELISA-type immune-enzymatic test to quantify levels of diphtheria antitoxin in human serum

Introducción: La difteria aún persiste en numerosos países. En Cuba, estudios realizados en diferentes grupos etarios han demostrado que existen niveles no protectores de antitoxina diftérica en la población, por lo que es necesario contar con métodos que permitan la estimación serológica de la inmunidad poblacional. La cuantificación de anticuerpos contra antígenos vacunales como la toxina diftérica es además un método útil, rápido y económico para evaluar la respuesta inmune. Objetivo: Validar un ensayo inmunoenzimático tipo ELISA para cuantificar los niveles de antitoxina diftérica en suero humano. Material y Método: Se realizó un estudio experimental de desarrollo tecnológico, en el cual se determinaron los valores óptimos de las variables que influyen en el resultado de un ensayo inmunoenzimático heterogéneo indirecto para la cuantificación de antitoxina diftérica, desarrollado en el laboratorio de Inmunología del Centro Nacional de Genética Médica de Cuba. La curva de calibración se evaluó contra el estándar de la OMS (Diphtheria Antitoxin Human Serum 00/496). Se realizó la validación analítica del método estandarizado. Resultados: Los coeficientes de variación intraensayo e interensayo fueron inferiores a 10 por ciento y 20 por ciento, respectivamente. En la exactitud y selectividad se encontraron valores de recobrado entre 90 y 110 por ciento. El paralelismo entre la curva estándar y las muestras estudiadas presentó un coeficiente de variación menor o igual a 10 por ciento. El límite de cuantificación fue 0,015 UI/mL y el de detección 0,0039 UI/mL. Conclusiones: El resultado obtenido en la precisión, exactitud y selectividad del ensayo inmunoenzimático tipo ELISA desarrollado demostró que puede ser utilizado en la práctica clínica para cuantificar los valores de antitoxina diftérica en suero humano(AU)

Introduction: Diphtheria still persists in many countries. In Cuba, studies conducted in different age groups have demonstrated that there are non-protective levels of diphtheria antitoxin in the population, so it is necessary to have methods that allow the serologic survey of population immunity. The quantification of antibodies against vaccine antigens such as diphtheria toxin is also a useful, rapid and economic method to evaluate the immune response. Objective: To validate an ELISA-type immune-enzymatic test to quantify the levels of diphtheria antitoxin in human serum. Material and Method: An experimental study of technological development was carried out in the Immunology Laboratory of the National Medical Genetics Center, Havana, Cuba. The optimal values ​​of the variables that influence on the result of the indirect heterogeneous immune-enzymatic test for the quantification of diphtheria antitoxin were determined. The calibration curve obtained was evaluated against the WHO standard (Diphtheria Antitoxin Human Serum 00/496). The analytical validation of the standardized method was performed. Results: The intra-assay and inter-assay coefficients of variation were less than 10 percent and 20 percent, respectively. Recovery values ​​between 90 and 110% were found in accuracy and selectivity. The parallelism between the standard curve and the samples studied showed a coefficient of variation lower or equal to 10 percent. The limit of quantification was 0,015 IU/mL and the one of detection was 0,0039 IU/mL. Conclusions: The result obtained in the precision, accuracy and selectivity of the ELISA-type immune-enzymatic test developed and validated in the National Medical Genetics Center demonstrated that it can be used in the clinical practice to quantify the values ​​of diphtheria antitoxin in human serum(AU)

A Review of Traditional Vaccine-Preventable Diseases and the Potential Impact on the Otolaryngologist

Abstract Introduction A majority of otolaryngologists have not had direct experience with many vaccine-preventable diseases since the creation of national vaccination programs. Despite the elimination of endemic transmission of some of these diseases in the United States, outbreaks can occur anywhere and still pose a threat to public health around the world. Recent outbreaks and changing trends in exemption rates indicate that it is important for physicians to maintain a working knowledge of how these diseases present and of the recommended treatment guidelines. Objectives This review will evaluate the current state of vaccination rates, vaccine exemption rates and disease incidence in the United States and in the world. It will also examine the clinical presentation and treatment recommendations of these diseases. Data Synthesis United States estimated vaccination rates, vaccine exemption rates and vaccine-preventable disease incidences were obtained from data compiled by the Centers for Disease Control and Prevention. World vaccination rates and disease incidences were obtained from the World Health Organization databases, which compile official figures reported by member states. A PubMed literature review provided information on the current state of vaccination exemptions and outbreaks in the United States. Conclusion Vaccination and vaccine exemption rates continue to put the United States and many areas of the world at risk for outbreaks of vaccine-preventable diseases. Clinical guidelines should be reviewed in the event of a local outbreak.

Evaluation of Potency on Diphtheria and Tetanus Toxoid for Adult Vaccines by In Vivo Toxin Neutralization Assay Using National Reference Standards

OBJECTIVES: Vaccinations against diphtheria and tetanus are essential in providing immunity against these bacterial infections. The potency of diphtheria and tetanus toxoid vaccines can be measured using the in vivo toxin neutralization assay. The limit of potency of this assay was determined only for children. Therefore, we assessed the potency of adult vaccines using this assay to identify the feasibility of limit for adult vaccines. METHODS: Fifteen lots of tetanus-reduced diphtheria and tetanus-diphtheria-acellular pertussis vaccines were used. In vivo toxin neutralization and lethal challenge assays were conducted on each vaccine to calculate the potencies of the toxoids. National reference standards for toxins and antitoxins were used for in vivo toxin neutralization assay. RESULTS: All 15 lots satisfied the limits of potency for lethal challenge assay. The potency of diphtheria and tetanus toxoids exceeded 1 and 8 units/mL, respectively, for in vivo toxin neutralization assay. CONCLUSION: Although additional studies are required for new assays and limits, the current level of potency for adult vaccines as determined by in vivo toxin neutralization assay, was demonstrated in this study. Such efforts to improve assays are expected to promote the development of diphtheria and tetanus vaccines for adults and to contribute to vaccine self-sufficiency.

Diphtheria in Yemen

Since October 2017, Yemen is experiencing a diphtheria outbreak in 19 out of 23 governorates. From epi week 33 [2017] to week 2 [2018], a total of 713 clinically diagnosed cases and 52 associated deaths were reported [CFR: 7.29%]. The most affected governorates are Ibb [46% of cases] and Al Hudeydah [12%]

Diphtheria vaccination campaign in Yemen

The WHO, national authorities and partners have recently completed a largescale vaccination campaign in response to the ongoing diphtheria outbreak in Yemen. More than 6000 health workers were mobilized during the campaign

Disease outbreaks in Eastern Mediterranean Region [EMR], January to June 2018

Since beginning of the year 2018, the WHO Eastern Mediterranean Region [EMR] has experienced ongoing and new outbreaks of emerging and re-emerging infectious disease in many countries. A number of these outbreaks are continuing from the previous year

Emergency risk communication in outbreaks

To provide WHO Member States, partners and stakeholders involved in emergency preparedness and response with the most up-to-date best practices on Emergency Risk Communication, this year WHO published "Communicating risk in public health emer-gencies - A WHO guideline for emergency risk communication (ERC) policy and prac-tice"

HLIP I in EMR countries

From 2014 to 2017, seven countries in the Eastern Mediterranean Region of WHO benefited from the Pandemic Influenza Preparedness [PIP] Framework - Partnership Contribution [PC] to enhance their surveillance and laboratory capacities using the High-level Partnership Contribution Implementation Plan I [HLIP I] 2013-2016

GOARN and outbreak response in EMR

The Global Outbreak Alert and Response Network [GOARN] convened its 23rd steering committee meeting in New York, 20-21 June 2018. The aim of the meeting was to review recent deployments, activities and overall achievements of the network since it was established

Global strategy to Eliminate Yellow fever Epidemics [EYE]

On 10 April 2018, WHO and partners launched the Global Strategy to Eliminate Yellow fever Epidemics [EYE]. At a meeting in Abuja Nigeria, WHO, UNICEF, Gavi and health officials across the African continent reaffirmed their commitment to eliminate Yellow fever