Global Epidemiology of Diphtheria, 2000-20171

Diphtheria transmission prediction by extended Kalman filter

Diphtheria transmission in West Java becomes our concern in this paper. The findings of this article are implementation of isolation and estimation technique of parameters using extended Kalman filter on the model of diphtheria transmission. From the eigenvalues of next generation matrix, the basic reproduction number is obtained. Then, the implementation of using extended Kalman filter provides the trend of the basic reproduction number of the diphtheria model with several cases: DPT only, Booster only, and a combination of DPT and booster. Based on the values of RMSE, NRMSE, and MAPE, the Extended Kalman Filter method provides significant results in estimating the basic reproduction number on actual data of diphtheria cases in West Java. We also studied the quarantined population in this article, because the rate of isolation has a significant impact on the profile of the susceptible, infected, quarantined, and recovered populations. Based on the results obtained, DPT only gives the smallest number when compared to Booster only and the combination of DPT and Booster. This is likely when DPT only is given, the body forms an immune system so giving Booster only does not provide significant results in reducing the level of effectiveness of diphtheria transmission (reducing the basic reproduction number).•This paper purposes to get the prediction of diphtheria transmission by using Extended Kalman Filter.•The basic reproduction number is also studied for the DPT only, booster only, and the combinations of DPT and booster.•The Extended Kalman Filter shows the good performance based on the RMSE, NRMSE, and MAPE.

Diphtheria transmission dynamics - Unveiling generation time and reproduction numbers from the 2022-2023 outbreak in Kano state, Nigeria

Background

Diphtheria, caused by Corynebacterium diphtheriae, remains a serious public health threat in areas with low vaccination coverage, despite global declines due to widespread immunization and improved clinical management. A major outbreak in Nigeria from 2022 to 2023 underscored the persistent risk in regions with inadequate vaccination. This study aims to assess the transmission dynamics of diphtheria in Kano State, the epicenter of the outbreak, by estimating key epidemiological parameters, including the generation time (GT), approximated in our study by serial interval, and effective reproduction number (Rₜ).

Methods

We analyzed diphtheria case-based data from Kano State, Nigeria, collected between August 18, 2022, and November 29, 2023. Generation time was approximated using serial intervals in confirmed cases within the same geographical areas. The effective reproduction number (Rₜ) was calculated using four methods: Maximum Likelihood Estimation (MLE), Exponential Growth (EG), Sequential Bayesian (SB), and Time-Dependent (TD), focusing on the period of maximum exponential growth. A sensitivity analysis was conducted to quantify the impact of uncertainties in the GT derived from our data on the estimation of Rₜ.

Results

Over the 469-day outbreak period, 13,899 diphtheria cases were reported, with complete data available for 9406 cases. The estimated mean generation time was 2.8 days (SD = 3.48 days), with 97% of cases having a GT of less than 21 days. The Rₜ estimates varied across methods, with the TD method producing the highest reproduction number of 2.21 during the peak growth period. Sensitivity analysis showed that Rₜ estimates increased with longer generation times. The models, except for the SB method, demonstrated a generally strong fit with the outbreak exponential growth period.

Conclusion

The ongoing diphtheria outbreak in Nigeria highlights the critical threat posed by declining vaccination coverage. This study provides valuable insights into the transmission dynamics of diphtheria during a prolonged and widespread outbreak, enhancing our understanding of disease spread in this context. While certain limitations may influence the interpretation of our estimates, the findings offer valuable information for future diphtheria outbreak preparedness and response in the African context.

A population-level analysis of armed conflict and diphtheria at the subnational level in the WHO African Region 2017-2024

BACKGROUND

Diphtheria has been re-emerging around the world at alarming rates, raising concerns about emergency preparedness, especially when global supplies of life-saving diphtheria antitoxin are insufficient. Outbreaks have occurred in areas with suboptimal coverage of the three-dose diphtheria tetanus and pertussis (DTP3) vaccine and regions experiencing conflict, but systematic studies assessing the association between these variables and the risk of diphtheria emergence are limited. This population-level study investigated the relationship between fatalities from armed conflict, childhood DTP3 vaccination coverage, and the presence of reported diphtheria cases in countries in the World Health Organization's (WHO) African region from 2017 to 2024.

METHODS

The analysis was conducted at a subnational geographic scale (I countries = 35, N subnational regions = 541). Data sources include DTP3 coverage from the Demographic Health Surveys (DHS), conflict-related fatalities from the Armed Conflict Location and Event Database (ACLED), and diphtheria cases from the WHO. We first assessed whether a history of fatalities from armed conflict is a predictor of childhood DTP3 coverage using mixed-effects beta regression. To assess the relationship between conflict and diphtheria emergence, we fit a crude logistic regression model to assess their overall association in the study period, as well as repeated measures mixed-effects models to estimate the relationship between time-varying rates of conflict-related fatalities and diphtheria status, adjusting for diphtheria vaccine coverage estimates.

RESULTS

Conflict and subsequent childhood DTP3 vaccine coverage were negatively associated (odds ratio [OR] = 0.93, 95% CI 0.88-0.98). Conflict is also a significant predictor of diphtheria presence, both in the crude (OR = 1.41, 95% CI 1.17-1.68) and best-fitting repeated measures model (OR = 30.30, 95% CI 23.30-39.39), though risk varied by location. The best-fit model also associated lower estimates of diphtheria risk in areas with high (> 80%) and low (< 25%) vaccine coverage, though this is possibly due to underreporting of the true burden of disease in low-resource settings.

CONCLUSIONS

This exploratory analysis indicates that conflict-related fatalities are potentially helpful indicators of subnational diphtheria risk in countries in the WHO African region from 2017 to 2024. Further, it may be especially useful in cases where estimates of population-level diphtheria immunity are limited.

The role of childhood diphtheria in the popularization of the tracheostomy

INTRODUCTION

In the mid-nineteenth century, with the world in the grip of repeated diphtheria epidemics, tracheostomy evolved as a potentially lifesaving tool for pediatric patients. Though intubation and antitoxin eventually made the procedure all but unnecessary in diphtheria, this period spurred discussion of technique, complications, and aftercare that advanced the field of airway surgery. Growing acceptance for tracheostomy allowed twentieth-century physicians to adapt the procedure to chronic respiratory failure and pulmonary toilet and paved the way for it to become one of the most common airway surgeries performed today.

METHODS

We performed a literature review with an emphasis on the use of primary sources with the objective of describing the development of tracheostomy during the mid-nineteenth to twentieth century.

RESULTS

Tracheostomy has been used in the treatment of upper airway obstruction from foreign body since the second and third centuries B.C.E. In the nineteenth century, obstruction from pharyngeal pseudomembrane related to Corynebacterium diphtheriae infection became commonplace and associated with significant risk of mortality. Pierre Fidele Bretonneau and his pupil Armand Trousseau were the first to perform tracheostomy in cases of diphtheria. By 1887, over 20,000 tracheostomies had been performed in the treatment of diphtheria in Europe and America. Disagreements abounded over preferred timing, the role of anesthesia, placement technique, and post-operative care, with widespread discussion in the medical literature. Though intubation and diphtheria antitoxin ultimately replaced tracheostomy in the treatment of these patients, the use of tracheostomy in the management of upper airway obstruction from other etiologies increased after this period.

DISCUSSION

The use of tracheostomy in pediatric patients with diphtheria was instrumental in standardizing the procedure, identifying its complications and their management, and promoting public acceptance of the practice as a treatment for upper airway obstruction. Today, although most of us will never see a case of diphtheria, we continue to face patients in what Scottish surgeon James Spence called "the agonies of suffocation." That we have the tools to manage complex airway obstruction comes in part from the heroic efforts of the physicians of the nineteenth century who, despite heartbreaking losses, advanced the technique of tracheostomy in their fight against childhood diphtheria.

Assessing the geographic and socioeconomic determinants of vaccine coverage in Ethiopia: A spatial and multistage analysis at the district level

BACKGROUND

Despite substantial progress over the past decades, many Ethiopian children still lack the full WHO-recommended immunization schedule. Notably, diphtheria-pertussis-tetanus-Hib-HepB and measles vaccines present large coverage disparities in Ethiopia. This study integrated routine, survey and census data from health, geographic and socioeconomic sources at the district level. We then explored associations between extracted covariates and coverage of measles (1st dose, MCV1) and diphtheria-pertussis-tetanus-Hib-HepB (3rd dose, Penta3). Lastly, we developed prediction models of immunization coverage.

METHODS

We utilized multiple data sources, including district (known as woreda) immunization coverage estimates from the District Health Information Software (DHIS-2), Demographic and Health Surveys, demographic census, and public databases on electricity, administrative boundaries and health facility geolocations. We sought to develop parsimonious beta-regression models of immunization coverage using variable selection, so as to identify covariates with high predictive power. We then fitted and internally validated generalized additive models to predict MCV1 and Penta3 coverage.

RESULTS

Our analysis identified access time to health centers, electrification levels, and woreda sizes as major factors associated with district-level immunization. Our prediction models estimated district-level MCV1 and Penta3 coverage with mean absolute errors of 11-12 %.

CONCLUSIONS

This study highlights the significant potential of geospatial models for public health policy and planning in low- and middle-income countries. By integrating diverse data sources and focusing on the district level, we provide a quantitative framework for identifying gaps in immunization coverage. The approach, using geographic and socio-economic data, can be effectively applied to a wide range of public health interventions.

Diphtheritic Myocarditis in an Unvaccinated Child

BACKGROUND

Diphtheria, a preventable yet potentially fatal childhood disease, remains a significant threat to unimmunized children, despite its decreased prevalence due to widespread vaccination.

CASE SUMMARY

A 6-year-old unvaccinated Spanish boy presented with diphtheritic myocarditis. His condition rapidly deteriorated, leading to cardiogenic shock and ventricular tachycardia, necessitating the use of venoarterial extracorporeal membrane oxygenation and the international procurement of diphtheritic antitoxin (DAT).

DISCUSSION

Myocarditis stands as the primary cause of mortality in diphtheria. Early DAT administration is crucial, but its effectiveness diminishes once the diphtheria toxin binds to tissues, and global accessibility may be challenging due to limited production. In scenarios of refractory cardiogenic shock, the employment of mechanical circulatory support, specifically with left cavity drainage systems, can be vital.

TAKE HOME MESSAGES

Timely vaccination is crucial in preventing diphtheria-related fatalities. Global access to essential treatments like DAT remains a significant challenge.

Corynebacterium diphtheriae Infections, South Africa, 2015-2023

We reviewed Corynebacterium spp. infection cases reported in South Africa during 2015-2023. We analyzed 84 isolates from 83 patients with C. diphtheriae, as well as 1 C. belfantii and 3 C. ulcerans isolates. Among C. diphtheriae cases, we observed respiratory diphtheria (26/83 patients [31%]), endocarditis (14/83 [17%]), cutaneous diphtheria (22/83 [27%]), nonspecific respiratory illnesses (5/83 [6%]), and asymptomatic carriage (16/83 [19%]). The median patient age was 19 (range 0-88) years. Diphtheria-tetanus-pertussis vaccination was incomplete for 26% (5/19) or unknown for 68% (13/19) of children 0-9 years of age. C. diphtheriae was intermediately resistant to penicillin (82/84 [98%] isolates; MIC90 0.5 μg/mL) but susceptible to erythromycin (83/84 [99%] isolates; MIC90 0.25 μg/mL). Eighteen unique sequence types were identified, corroborating C. diphtheriae heterogeneity. Toxin-producing strains were detected among cutaneous and respiratory diphtheria cases, indicating all forms of disease require monitoring and prompt public health action to curb transmission.

Concurrent diphtheria and COVID-19 infection in an unvaccinated child

We report the case of a girl in her middle childhood who presented with progressive neck swelling, sore throat, dysphagia, low-grade fever and malaise, and with no prior vaccinations. Examination revealed a 'bull neck' appearance with pseudomembranous pharyngitis, which showed bleeding on membrane removal. The patient did not have any respiratory distress, but RT-PCR confirmed the concurrent coinfection of DPT with SARS-CoV-2. The laboratory investigations exhibited a leucocyte count of 17.2 × 10⁹/L and ALT raised at 113 U/L, indicative of systemic involvement. Imaging showed mild tonsillar calcifications with ground-glass opacities on the chest CT, which placed a CT severity score for cough severity of 13/25, indicating moderate COVID-19 pneumonia. Treatment was intravenous DPT antitoxin (100 000 units) and cefotaxime (1 g two times per day for 14 days). Symptomatic resolution occurred within 10 days, including clearing inflammatory markers and membranes. Recovery was complete and uncomplicated, with no sequelae after 3 months.

Infectious Neuropathies

This review explores diverse infectious etiologies of peripheral nervous system (PNS) dysfunction, spanning sensory and motor neurons, nerves, and associated structures. Progress in viral and bacterial infections reveals multifaceted mechanisms underlying neuropathies, including viral neurotoxicity and immune-mediated responses. Latest diagnostic advances facilitate early PNS complication detection, with ongoing research offering promising treatment avenues. Emerging pathogens like severe acute respiratory syndrome coronavirus 2, Zika virus, and EV-D68 highlight the evolving infectious neuropathy paradigm. Recognizing characteristic patterns and integrating clinical factors are pivotal for precise diagnosis and tailored intervention. Challenges persist in assessment and management due to varied pathogenic mechanisms. Advancements in understanding pathogenesis have improved targeted therapies, yet gaps remain in effective treatments. Ongoing research is crucial for optimizing approaches and improving patient outcomes.

Addressing the re-emergence and resurgence of vaccine-preventable diseases in Africa: A health equity perspective

Vaccination is one of the greatest public health achievements of the 20th century, with a tremendous impact in the prevention and control of diseases. However, the recent reemergence of vaccine-preventable diseases calls for a need to evaluate current vaccination practices and disparities in vaccination between high-income countries and low-and-middle-income countries. There are massive deficits in vaccine availability and coverage in resource-constrained settings. Therefore, this perspective seeks to highlight the reemergence of vaccine-preventable diseases in Africa within the lens of health equity and offer recommendations on how the continent should be prepared to deal with the myriad of its health systems challenges. Among the notable factors contributing to the reemergence, stand health inequities affecting vaccine availability and the dynamic vaccine hesitancy. Strengthening health systems and addressing health inequities could prove useful in halting the reemergence of vaccine-preventable diseases.

Seroprevalence of antibodies against diphtheria, tetanus, and pertussis across various age groups during the post-COVID-19 pandemic period in Chonburi Province, Thailand

BACKGROUND

Limited data exists regarding population immunity against diphtheria, tetanus, and pertussis in Thailand during the post-COVID-19 pandemic period. This study aimed to evaluate the age-specific seroprevalence of anti-diphtheria toxoid (anti-DT) IgG, anti-tetanus toxoid (anti-TT) IgG, and anti-pertussis toxin (anti-PT) IgG in individuals across diverse age groups in Chonburi province, Thailand following the COVID-19 pandemic.

METHODS

Between October 2022 and January 2023, a total of 657 participants from Chonburi Province, Thailand, were included in this study. The participants were categorized into 9 age groups: <5, 5-10, 11-20, 21-30, 31-40, 41-50, 51-60, 61-70, and >70 years. Analysis of anti-DT, anti-TT, and anti-PT IgG levels was conducted using commercial ELISA kits (EUROIMMUN, Lübeck, Germany).

RESULTS

Overall, 65.4 % of the population had seroprotection against diphtheria (antibody level ≥0.1 IU/mL), while 95.1 % had seroprotection against tetanus (antibody level ≥0.1 IU/mL). The 31-40 years age group exhibited the lowest seroprotection for diphtheria (48.9 %), and the >70 years age group had the lowest seroprotection for tetanus (73.3 %). The <5 years age group showed the highest seropositive rate and highest geometric mean titers for anti-PT IgG. On the contrary, the majority of individuals over 11 years of age displayed anti-PT IgG levels below 40 IU/mL.

CONCLUSIONS

To prevent diphtheria and pertussis outbreaks in Chonburi province, implementing catch-up vaccination is necessary. Targeted interventions should be deployed to enhance vaccination coverage among the susceptible population.

Influence of Hematocrit and Storage Temperature on the Stability of Dried Blood Samples in Serological Analyses of Tetanus, Diphtheria, and Pertussis

BACKGROUND

Dried blood spots (DBSs) enable the study of serological markers of various pathogens without the need to obtain serum/plasma through venipuncture.

METHODS

Sixty-four blood samples were prepared on Whatman™ 903 cards using specimens obtained by venipuncture to study the detection of serological markers of diphtheria, tetanus, and pertussis in DBSs, and their stability 4 months post-collection. An automated chemiluminescent immunoassay was used to investigate diphtheria, tetanus, and pertussis IgG levels from both DBSs and plasma samples.

RESULTS

An optimal cut-off value for DBSs was calculated to improve the performance of diphtheria and tetanus serological markers in DBSs, achieving high sensitivity (95% and 98%, respectively) and specificity (91.7% and 92.3%, respectively). No protection against pertussis was found in the population studied. The correlation observed between the plasma and the DBSs processed after sample collection was high (0.967-0.970) for all antibodies studied except pertussis (0.753), both considering hematocrit before sample elution or not. The correlation between DBSs and plasma for diphtheria and tetanus remained strong following a 4-month delay in DBS processing at 4 °C (0.925-0.964) and -20 °C (0.924-0.966), with only a minor decrease observed for diphtheria at room temperature (0.889), while maintaining a strong correlation for tetanus (0.960). For pertussis, the correlation between DBSs and plasma was drastically reduced after delaying its processing for 4 months at any temperature.

CONCLUSIONS

To summarize, hematocrit levels within the normal range do not affect the processing of DBSs in the study of serological markers of diphtheria, tetanus, and pertussis. The DBS stability for serological diagnosis of diphtheria and tetanus is adequate when samples are stored at -20 °C for a period of 4 months. The pertussis serological marker does not appear to remain stable after 4 months, even when the DBS is stored frozen at -20 °C.

Risk factors of diphtheria outbreak in damt district of Al Dhalea Governorate, 2023 -Yemen: a case-control study

BACKGROUND

In Yemen, diphtheria has become an important health problem since 2017 when diphtheria re-emergence as a consequence of war and the collapse of the health system. In 2023, there has been a 57% increase in diphtheria cases compared to 2021 and 2022. Damt district of Al Dhalea Governorate had the highest reported cases for year 2023. The study aims to determine the risk factors associated with diphtheria outbreak in Damt District.

METHODS

A retrospective matched case-control (1:2) was used. All confirmed cases based on the WHO case definition reported from Damt district during 2023 were considered cases. Two age-matched (± 5years) neighborhood controls were recruited per case. A pretested questionnaire was used for collecting data during household interviews including demographic and household characteristics, knowledge of diphtheria, vaccination status, contact with a case of diphtheria, and travel history. Frequency and proportion for quantitative and median with interquartile range (IQR) for quantitative variables. Chi-square and Mann-Whitney tests to compare the distribution of categorical and numerical variables between cases and controls. Univariate and multivariate conditional binary logistic regression, and Adjusted Odds ratio (AOR) with a 95% confidence interval at P < 0.05 were used to identify risk factors.

RESULTS

A total of 118 cases and 236 controls were enrolled, 56% were females (63% of cases vs. 53% of controls). The median (IQR) age was 14 (9,22) years for cases vs 12(7,23) of control, it was significantly higher for females than males in the case group: (16(10,29) Vs 10(6,18), P < 0.001) and control group: (15(8,25) vs 12(7,18), p-value = 0.022). Partial vaccination status AOR = 13.7(6.1-31.1), P-value < 0.001), contacts with a case of diphtheria AOR = 8.5(2.3-31.0), P value < 0.001) and Female gender, AOR = 3.3(CI; 1.1-9.5, P value = 0.029), were the main risk factors.

CONCLUSIONS

Poor vaccination and contact with a case of diphtheria were the main contributors to diphtheria in the Damt district particularly among adult females. Increasing the vaccination coverage with a diphtheria-containing vaccine through routine immunization as well as tetanus-diphtheria vaccine for childbearing age females along with community awareness regarding protection measures during home care of diphtheria cases. Vaccination services as well as gender barriers related to Td vaccination should be investigated.

Alpha-1 antitrypsin inhibits Clostridium botulinum C2 toxin, Corynebacterium diphtheriae diphtheria toxin and B. anthracis fusion toxin

The bacterium Clostridium botulinum, well-known for producing botulinum neurotoxins, which cause the severe paralytic illness known as botulism, produces C2 toxin, a binary AB-toxin with ADP-ribosyltranferase activity. C2 toxin possesses two separate protein components, an enzymatically active A-component C2I and the binding and translocation B-component C2II. After proteolytic activation of C2II to C2IIa, the heptameric structure binds C2I and is taken up via receptor-mediated endocytosis into the target cells. Due to acidification of endosomes, the C2IIa/C2I complex undergoes conformational changes and consequently C2IIa forms a pore into the endosomal membrane and C2I can translocate into the cytoplasm, where it ADP-ribosylates G-actin, a key component of the cytoskeleton. This modification disrupts the actin cytoskeleton, resulting in the collapse of cytoskeleton and ultimately cell death. Here, we show that the serine-protease inhibitor α1-antitrypsin (α1AT) which we identified previously from a hemofiltrate library screen for PT from Bordetella pertussis is a multitoxin inhibitor. α1AT inhibits intoxication of cells with C2 toxin via inhibition of binding to cells and inhibition of enzyme activity of C2I. Moreover, diphtheria toxin and an anthrax fusion toxin are inhibited by α1AT. Since α1AT is commercially available as a drug for treatment of the α1AT deficiency, it could be repurposed for treatment of toxin-mediated diseases.

Eleven-Year Report of High Number of Diphtheria Cases in Children in East Java Province, Indonesia

A high incidence of diphtheria cases in children in East Java province, Indonesia, has been observed since the beginning of this century. Despite many efforts, the outbreaks continue. This study aims to explain the high incidence of diphtheria in children in East Java province since 2013. This cross-sectional surveillance report-based study used data from 38 districts in East Java since 1 January 2013. Collected data included demographics, clinical information, additional examinations, immunization history, and close contact management. Over eleven years, there were 4009 diphtheria patients, of whom 2921 (72.86%) were under 18 years of age. Boys (59.77%) outnumbered girls, and the most common age category was >60-144 months (51.66%). Most cases had incomplete or zero immunization (76.16%). Tonsillopharyngeal diphtheria was the most common type (69.60%). The five top districts with the most cases were Surabaya, Sidoarjo, Kabupaten Blitar, Kota Malang, and Kabupaten Malang. The eleven-year case fatality rate (CFR) was 2.36% (69/2921). This study shows that diphtheria cases in children and adolescents in East Java have consistently been high, and low immunization coverage might still be the leading cause. There has also been a shift in the district distribution. Diphtheria outbreaks require complete and sustainable efforts, not just outbreak response immunizations.

Rare manifestations of cutaneous diphtheria: a case report

BACKGROUND

This case report presents an exceptionally rare and atypical presentation of diphtheria in a 17-year-old female of Hausa ethnicity residing in an area with an elevated incidence within Kano State, Nigeria. By the end of 39th epidemiological week of 2023, only two cases of cutaneous diphtheria have been reported among 5,811 cases managed at MMSH diphtheria treatment center (DTC), representing approximately 0.035% of all diphtheria cases during that time period.

CASE PRESENTATION

A 17-year-old Hausa female presented with a 3-day history of throat discomfort, malaise, and muffled speech. Physical examination revealed a pseudomembrane covering the tonsillar pillars, grade 3 tonsillar enlargement, and an unusual genital manifestation characterized by extensive vulval edema, severe pain, and a large, greyish patch extending into the vaginal introitus. Her medical history was significant for recent exposure to diphtheria and the emotional impact of her sibling's death from the same disease. Diagnostic tests, including throat swab culture and histocytology, confirmed diphtheria in the throat and vulvovaginal regions. The patient was promptly initiated on diphtheria antitoxin, Azithromycin, and innovative sitz baths with hydrogen peroxide. After 4 days of Sitz bath therapy, complete pseudomembrane clearance was observed, and the patient's symptoms resolved.

CONCLUSION

This case underscores the complexity of diphtheria presentations, particularly with rare pseudomembranes in both throat and vaginal regions. The successful management, combining traditional and innovative therapies, highlights the importance of recognizing and addressing unusual manifestations promptly. The potential role of auto-inoculation and the efficacy of interventions like hydrogen peroxide sitz baths warrant further investigation. Overall, this case contributes to the understanding of diverse diphtheria presentations, guiding future clinical strategies for management of diphtheria cases and emphasizing the imperative of comprehensive vaccination efforts.

Comparison of Diphtheria Cases in Children Before and During the Pandemic Era in Surabaya, Indonesia: A Study of Six-Year Data

Introduction Indonesia has a high incidence of diphtheria, especially in children. Surabaya has become a government regional reference center, as it is the capital of East Java province, which has the highest rate of diphtheria across the 38 regions. The aim of this study is to report our six-year pediatric diphtheria data, focusing on comparisons between before and during the pandemic era. Method This surveillance report was collected from community health centers and hospitals throughout Surabaya from January 1, 2017 to December 31, 2022. Collected data included demographic characteristics, clinical and laboratory aspects, the health centers, immunization history, and management. As per Indonesian guidelines, the diagnosis of diphtheria in this country requires a positive microbiological culture or approval from the National Experts on Diphtheria Committee. Results In total, there were 112 cases, of which 89 were found before the pandemic era. Although the number of cases declined during 2020-2022, the predominant age group, the immunization status, and the most common type of diphtheria remained consistent with pre-pandemic trends. Most cases had incomplete immunization or unimmunized children (67.8%), with the age group of 5-12 years old (44.6%), and with tonsillar diphtheria (83%). The case fatality ratio was 1.8%. Regarding the biovar of Corynebacterium diphtheriae, gravis is the most frequent finding. Conclusion The incidence of diphtheria cases in children in Surabaya was significantly lower during the pandemic. Although immunization coverage was not better, preventive measures during the pandemic may have played a role. Most patients did not have complete immunization histories during the study period, and the predominant type was tonsillar diphtheria. Since the trend in 2021-2022 increased, routine surveillance is essential.

Diphtheria and Tetanus Immunity Status among Greek Adults: Results from a Nationwide Seroprevalence Study

Diphtheria and tetanus could lead to serious morbidity. We aimed to evaluate immunity levels by measuring specific IgG antibodies for diphtheria and tetanus in serum samples from a nationally expanded sample of the Greek population. A geographically stratified sampling approach based on regional units (NUTS level 2) was applied by considering variables such as age group (30-80+) and sex. In total, 1201 persons (47.7% males and 52.3% females) participated in the survey. Bivariate analysis revealed a negative relationship between diphtheria and tetanus median antibody titers and age. The overall seropositivity rate for diphtheria IgG antibodies (≥0.10 IU/mL) was estimated at 31.5%. Regarding tetanus, the total seropositivity rate was estimated at 59.5% (tetanus IgG antibodies ≥0.10 IU/mL). Logistic regression analysis indicated that age groups <40 years and 40-59 years were independently associated with tetanus seropositivity. Logistic regression also revealed that male sex and being aged 60-69 years were independent risk factors for diphtheria-related seropositivity. Lastly, being resident of some regions was an independent risk factor for both diphtheria- and tetanus-related seropositivity. The present study shows that Greek adults are still not completely immune to diphtheria and tetanus. It is likely possible to achieve optimal immunization coverage by implementing serviceable public health initiatives after comprehending real community needs.

Membranous tonsillitis: Aetiology, prevalence and prescribing patterns in patients with upper respiratory tract infection

Background Membranous tonsillitis is one of the most common forms of acute tonsillitis in childhood. Although many different microorganisms may cause this disease, clinicians generally consider bacterial agents as a possible cause and prescribe a penicillin-group of antibiotic. This study aimed to determine the aetiology of membranous tonsillitis and prescribing errors. In addition, we investigated the effectiveness of epidemiological, clinical and laboratory parameters and their role in guiding treatment. Methods We did this retrospective study at the paediatric emergency department of a tertiary referral hospital including 423 outpatient children aged 0 to 18 years diagnosed with membranous tonsillitis. Results Group A beta-haemolytic streptococcus was found in 132 (31.2%) patients, Epstein-Barr virus (EBV) in 103 (24.3%), and other viral aetiologies in 188 (44.4%). The prescription rate of antibiotics in the EBV-positive group was 27%, and Downey cells were seen at a rate of 98% in this group. Only 7% of patients with a positive throat culture were started on appropriate antibiotics. Conclusion EBV and group A beta-haemolytic streptococcus were the most common causes of membranous tonsillitis. Throat culture and peripheral blood smears are the most useful tests for paediatric emergency clinicians; these are fast and can help ensure correct diagnosis and guide treatment in almost all patients.

Assessing the impact of booster vaccination on diphtheria transmission: Mathematical modeling and risk zone mapping

The COVID-19 pandemic caused significant disruptions in the healthcare system, affecting vaccinations and the management of diphtheria cases. As a consequence of these disruptions, numerous countries have experienced a resurgence or an increase in diphtheria cases. West Java province in Indonesia is identified as one of the high-risk areas for diphtheria, experiencing an upward trend in cases from 2021 to 2023. To analyze the situation, we developed an SIR model, which integrated DPT and booster vaccinations to determine the basic reproduction number, an essential parameter for infectious diseases. Through spatial analysis of geo-referenced data, we identified hotspots and explained diffusion in diphtheria case clusters. The calculation of R0 resulted in an R0 = 1.17, indicating the potential for a diphtheria outbreak in West Java. To control the increasing cases, one possible approach is to raise the booster vaccination coverage from the current 64.84% to 75.15%, as suggested by simulation results. Furthermore, the spatial analysis revealed that hot spot clusters were present in the western, central, and southern regions, posing a high risk not only in densely populated areas but also in rural regions. The diffusion pattern of diphtheria clusters displayed an expansion-contagious pattern. Understanding the rising trend of diphtheria cases and their geographic distribution can offer crucial insights for government and health authorities to manage the number of diphtheria cases and make informed decisions regarding the best prevention and intervention strategies.

The Re-emergence of Diphtheria Amidst Multiple Outbreaks in Nigeria

Diphtheria, a vaccine-preventable disease, has resurfaced in Nigeria, where many outbreaks have been reported in recent years. The outbreaks have occurred across the country, including in areas with high vaccination coverage. Corynebacterium diphtheriae, the causal agent, is a highly contagious bacteria that can cause severe respiratory and systemic symptoms and can be fatal if not treated. The reemergence of diphtheria in Nigeria is most likely due to a combination of factors, including gaps in routine immunization regimens. The outbreak is further aggravated by multiple epidemics, which have diverted resources and attention away from the emergency of other infectious diseases. Furthermore, there is a lack of awareness of diphtheria in Nigeria. With a focus on the difficulties in controlling the disease, methods of diagnosis, available treatments, and preventive measures, this study provides a thorough analysis of diphtheria, covering its historical context, clinical presentation, associated complications, and current outbreaks. It emphasizes how important vaccination, early detection, and better access to healthcare are in reducing diphtheria outbreaks. The study highlights the serious effects of diphtheria on public health, particularly in regions with scarce resources and vaccine resistance, and offers a number of suggestions to overcome these challenges and prevent further outbreaks.

Modifiable risk factors for diphtheria: A systematic review and meta-analysis

Objective

To identify modifiable risk factors for diphtheria and assess their strengths of association with the disease.

Methods

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Electronic databases and grey literature were searched from inception until January 2023. Studies had to report on diphtheria cases and estimates of association for at least one potential risk factor or sufficient data to calculate these. The quality of non-ecological studies was assessed using the Newcastle-Ottawa Scale (NOS), while the quality of evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

Results

The search yielded 37,705 papers, of which 29 were ultimately included. All the non-ecological studies were of moderate to high quality. Meta-analysis of 20 studies identified three factors increasing the risk of diphtheria: incomplete vaccination (<3 doses) (pooled odds ratio (POR) = 2.2, 95% confidence interval (CI) = 1.4-3.4); contact with a person with skin lesions (POR = 4.8, 95% CI = 2.1-10.9); and low knowledge of diphtheria (POR = 2.4, 95% CI = 1.2-4.7). Contact with a case of diphtheria; sharing a bed or bedroom; sharing utensils, cups, and glasses; infrequent bathing; and low parental education were associated with diphtheria in multiple studies. Evidence for other factors was inconclusive. The quality of evidence was low or very low for all the risk factors.

Conclusions

Findings from the review suggest that countries seeking to control diphtheria need to strengthen surveillance, improve vaccination coverage, and increase people's knowledge of the disease. Future research should focus on understudied or inconclusive risk factors.

Regional differences in historical diphtheria and scarlet fever notification rates in The Netherlands, 1905-1925: a spatial-temporal analysis

BACKGROUND

We describe how rates of two frequently occurring notifiable diseases-diphtheria and scarlet fever-varied between regions of The Netherlands in the early twentieth century, and identify potential factors underlying this variation.

METHODS

Digitized weekly mandatory notification data for 1905-1925, municipality level, were aggregated into 27 'spatial units' defined by unique combinations of province and population density category (high: more than 4500; mid : 1250-4500; low: less than 1250 inhabitants km-2). Generalized additive regression models were fitted to estimate the associations between notification rates and population density, infant mortality rate and household income, while adjusting for temporal trends per spatial unit.

RESULTS

Annual per capita notification rates for both diphtheria and scarlet fever tended to rise from the beginning of the period 1905-1925 until peaking around 1918/1919. Adjusted diphtheria notification rates were higher for high- and mid- compared with low-density municipalities (by 71.6 cases per 100 000, 95% confidence interval (CI) : 52.7-90.5; 39.0/100 k, 95% CI : 24.7-53.3, respectively). Scarlet fever showed similar associations with population density (35.7 cases per 100 000, 95% CI : 9.4-62.0; 21.4/100 k, 95% CI: 1.5-41.3).

CONCLUSIONS

There was considerable spatial variation in notification rates for both diseases in early twentieth century Netherlands, which could partly be explained by factors capturing variation in living conditions and socio-economic circumstances. These findings aid understanding of contemporary respiratory infection transmission.

Recurrent diphtheria outbreaks in Nigeria: A review of the underlying factors and remedies

INTRODUCTION

The introduction of the diphtheria-tetanus-pertussis (DTP) vaccine into childhood immunization programs resulted in its widespread elimination in high-income countries. However, Nigeria is currently experiencing an outbreak. The primary cause of diphtheria outbreaks and its high mortality rates in Nigeria was waning herd immunity due to low DTP coverage and a lack of diphtheria antitoxin (DAT), respectively. However, the underlying causes of Nigeria's low DTP coverage and DAT supply remain unknown.

METHOD

Relevant studies and reports included in our review were obtained by a search through Google Scholar, PubMed, and organization websites using the terms "Diphtheria-Pertussis-Tetanus vaccine OR Diphtheria antitoxin and Nigeria OR Diphtheria Outbreak." All articles considering diphtheria outbreaks, DTP vaccine, and DAT supply in Nigeria were considered without time restriction due to the paucity of data. We used the narrative synthesis approach to critically appraise, analyze, and draw inferences from the selected articles.

RESULTS

The main causes of low DTP coverage are insufficient supply, an inefficient cold chain system, and low uptake due to poor health literacy and negative sociocultural and religious beliefs, whereas the key barriers to DAT availability are insufficient production by pharmaceutical industries because of low demand and priority.

CONCLUSION

The underlying causes of Nigeria's low DTP coverage and DAT supply are multifactorial. Both short-term and long-term measures are needed to control this outbreak and prevent future occurrences.

The Role of Dexmedetomidine in Airway Management for Tracheostomy in Pediatric Patient with Obstructed Airway Due to Diphtheria: A Case Report

Introduction

Diphtheria is an infectious disease caused by exotoxin-producing Corynebacterium diphteriae and was a leading cause of death in childhood during the prevaccine era. This toxin is usually localized in the upper respiratory tract and may cause fatal airway obstruction. Many have used orotracheal intubation to secure the airway in diphtheria cases. However, the efficacy of tracheostomy under sedation while maintaining spontaneous ventilation and analgesia using trans-tracheal and superficial cervical block remains to be elucidated.

Case Presentation

A 6-year-old presented to the emergency room with respiratory distress and was diagnosed with diphtheria. A thick membrane in the oropharyngeal area and chest X-ray showed infiltrations indicative of pneumonia. The patient successfully underwent emergency tracheostomy under sedation using a combination of sevoflurane and dexmedetomidine to achieve prompt sedation and trans-tracheal injection and bilateral superficial cervical block as analgesia for the intra-tracheal and the incision. The patient's condition deteriorated the next day, and the bronchoscopy showed that the carina and main bronchus were covered by a pseudomembrane, obstructing the airway below the tracheostomy. The patient eventually died two days after admission.

Conclusions

Dexmedetomidine has minimal impact on ventilatory function and anti-sialagogue properties, while sevoflurane has minimal effect on respiratory depression. This case presentation showed that a combination of sevoflurane and dexmedetomidine with spontaneous assisted ventilation could be helpful in tracheostomy procedures in pediatric patients with airway obstruction due to diphtheria, along with the use of trans-tracheal and superficial cervical block as the analgesia. This report also indicates that being vigilant in rapidly-progressing and fatal pediatric diphtheria cases is vital.

Surveillance of diphtheria in the Netherlands between 2000-2021: cutaneous diphtheria supersedes the respiratory form

BACKGROUND

Diphtheria is a severe respiratory or cutaneous infectious disease, caused by exotoxin producing Corynebacterium diphtheriae, C. ulcerans and C. pseudotuberculosis. Diphtheria is once again prevalent due to breakdown of immunisation programmes, social disruption and unrest.

AIM

This study describes the notified diphtheria cases in the Netherlands between 2000-2021 and isolates that were sent to the National Institute for Public Health and the Environment (RIVM).

METHODS

File investigation was performed including all notified cases and isolates of C. diphtheriae, C. ulcerans and C. pseudotuberculosis that were tested for toxin production using a toxin-PCR and Elek test. An exploratory review was performed to understand transmission in populations with a high vaccination uptake.

RESULTS

Eighteen diphtheria notifications were made with confirmed toxigenic C. diphtheriae (n = 9) or ulcerans (n = 9) between 2000 and 2021. Seventeen (94.4%) presented with a cutaneous infection. All cases with a suspected source abroad (n = 8) concerned infection with C. diphtheriae. In contrast, 9/10 cases infected in the Netherlands were caused by C. ulcerans, a zoonosis. Secondary transmission was not reported. Isolates of C. ulcerans sent to the RIVM produced more often the diphtheria exotoxin (11/31; 35%) than C. diphtheriae (7/89; 7.9%).

CONCLUSION

Both human-to-human transmission of C. diphtheriae and animal-to-human transmission of C. ulcerans rarely occurs in the Netherlands. Cases mainly present with a cutaneous infection. Travel-related cases remain a risk for transmission to populations with low vaccination coverage, highlighting the importance of immunization and diphtheria control measures.

Collaborative study for the calibration of a replacement International Standard for Diphtheria Antitoxin Equine

The International Standard for Diphtheria Antitoxin Equine is essential for the standardisation of assays used to determine the potency of therapeutic diphtheria antitoxin products produced from equine serum. This paper describes the production and characterization of the 2nd International Standard for Diphtheria Antitoxin Equine and its calibration in International Units. Calibration was performed by toxin neutralization test in vivo and in vitro (Vero cell assay), and potency was expressed relative to the 1st International Standard to ensure continuity of the International Unit. The candidate standard (NIBSC product code 18/180) was assigned a unitage of 57 IU/ampoule based on results from 14 laboratories in 9 different countries and was established by the World Health Organisation Expert Committee on Biological Standardization in 2021.

High-Throughput IgG Epitope Mapping of Tetanus Neurotoxin: Implications for Immunotherapy and Vaccine Design

Tetanus is an acute, fatal disease caused by exotoxins released from Clostridium tetani during infections. A protective humoral immune response can be induced by vaccinations with pediatric and booster combinatorial vaccines that contain inactivated tetanus neurotoxin (TeNT) as a major antigen. Although some epitopes in TeNT have been described using various approaches, a comprehensive list of its antigenic determinants that are involved with immunity has not been elucidated. To this end, a high-resolution analysis of the linear B-cell epitopes in TeNT was performed using antibodies generated in vaccinated children. Two hundred sixty-four peptides that cover the entire coding sequence of the TeNT protein were prepared in situ on a cellulose membrane through SPOT synthesis and probed with sera from children vaccinated (ChVS) with a triple DTP-vaccine to map continuous B-cell epitopes, which were further characterized and validated using immunoassays. Forty-four IgG epitopes were identified. Four (TT-215-218) were chemically synthesized as multiple antigen peptides (MAPs) and used in peptide ELISAs to screen post-pandemic DTP vaccinations. The assay displayed a high performance with high sensitivity (99.99%) and specificity (100%). The complete map of linear IgG epitopes induced by vaccination with inactivated TeNT highlights three key epitopes involved in the efficacy of the vaccine. Antibodies against epitope TT-8/G can block enzymatic activity, and those against epitopes TT-41/G and TT-43/G can interfere with TeNT binding to neuronal cell receptors. We further show that four of the epitopes identified can be employed in peptide ELISAs to assess vaccine coverage. Overall, the data suggest a set of select epitopes to engineer new, directed vaccines.

In Silico Identification of 1-DTP Inhibitors of Corynebacterium diphtheriae Using Phytochemicals from Andrographis paniculata

A number of phytochemicals have been identified as promising drug molecules against a variety of diseases using an in-silico approach. The current research uses this approach to identify the phyto-derived drugs from Andrographis paniculata (Burm. f.) Wall. ex Nees (AP) for the treatment of diphtheria. In the present study, 18 bioactive molecules from Andrographis paniculata (obtained from the PubChem database) were docked against the diphtheria toxin using the AutoDock vina tool. Visualization of the top four molecules with the best dockscore, namely bisandrographolide (-10.4), andrographiside (-9.5), isoandrographolide (-9.4), and neoandrographolide (-9.1), helps gain a better understanding of the molecular interactions. Further screening using molecular dynamics simulation studies led to the identification of bisandrographolide and andrographiside as hit compounds. Investigation of pharmacokinetic properties, mainly ADMET, along with Lipinski's rule and binding affinity considerations, narrowed down the search for a potent drug to bisandrographolide, which was the only molecule to be negative for AMES toxicity. Thus, further modification of this compound followed by in vitro and in vivo studies can be used to examine itseffectiveness against diphtheria.

Seroepidemiology and Carriage of Diphtheria in Epidemic-Prone Area and Implications for Vaccination Policy, Vietnam

In 2019, a community-based, cross-sectional carriage survey and a seroprevalence survey of 1,216 persons 1-55 years of age were conducted in rural Vietnam to investigate the mechanism of diphtheria outbreaks. Seroprevalence was further compared with that of an urban area that had no cases reported for the past decade. Carriage prevalence was 1.4%. The highest prevalence, 4.5%, was observed for children 1-5 years of age. Twenty-seven asymptomatic Coerynebacterium diphtheriae carriers were identified; 9 carriers had tox gene-bearing strains, and 3 had nontoxigenic tox gene-bearing strains. Child malnutrition was associated with low levels of diphtheria toxoid IgG, which might have subsequently increased child carriage prevalence. Different immunity patterns in the 2 populations suggested that the low immunity among children caused by low vaccination coverage increased transmission, resulting in symptomatic infections at school-going age, when vaccine-induced immunity waned most. A school-entry booster dose and improved infant vaccination coverage are recommended to control transmissions.

Waning rate of immunity and duration of protective immunity against diphtheria toxoid as a function of age and number of doses: Systematic review and quantitative data analysis

Although the burden of diphtheria has declined greatly since the introduction of vaccines, sporadic outbreaks continue to be reported. WHO recommends booster doses after a primary series, but questions remain about the optimal interval between these doses. We conducted a systematic review and quantitative data analysis to quantify the duration of protective immunity after different numbers of doses. Fifteen cross-sectional seroprevalence studies provided data on geometric mean concentration (GMC). Single-year age-stratified GMCs were analyzed using a mixed-effect linear regression model with a random intercept incorporating the between-country variability. GMC was estimated to decline to 0.1 IU/ml in 2.5 years (95% CI: 0.9-4.0), 10.3 years (95% CI: 7.1-13.6), and 25.1 years (95% CI: 7.6-42.6) after receiving three, four and five doses, respectively. The results drawn from cross-sectional data collected in countries with different epidemiologies, vaccines, and schedules had several limitations. However, these analyses contribute to the discussion of optimal timing between booster doses of diphtheria toxoid-containing vaccine.

Reasons underlying the intention to vaccinate children aged 5-11 against COVID-19: A cross-sectional study of parents in Israel, November 2021

Vaccination is a key tool to mitigate impacts of the COVID-19 pandemic. In Israel, COVID-19 vaccines became available to adults in December 2020 and to 5-11-year-old children in November 2021. Ahead of the vaccine roll-out in children, we aimed to determine whether surveyed parents intended to vaccinate their children and describe reasons for their intentions. We collected information on parental socio-demographic characteristics, COVID-19 vaccine history, intention to vaccinate their children against COVID-19, and reasons for parental decisions using an anonymous online survey. We identified associations between parental characteristics and plans to vaccinate children using a logistic regression model and described reasons for intentions to vaccinate or not. Parental non-vaccination and having experienced major vaccination side effects were strongly associated with non-intention to vaccinate their children (OR 0.09 and 0.18 respectively, p < .001). Parents who were younger, lived in the socio-economically deprived periphery, and belonged to the Arab population had lower intentions to vaccinate their children. Reasons for non-intention to vaccinate included concerns about vaccine safety and efficacy (53%, 95%CI 50-56) and the belief that COVID-19 is a mild disease (73%, 95%CI 73-79), while a frequent motive for vaccination was the return to normal social and educational life (89%, 95%CI 87-91). Understanding rationales for COVID-19 vaccine rejection or acceptance, as well as parental demographic data, can pave the way for intentional educational campaigns to encourage not only vaccination against COVID-19, but also regular childhood vaccine programming.

Need to Study the Health Impact and Economics of Adult Vaccination with India in Focus

Vaccination is undoubtedly the most effective and economical way of dealing with the diseases which can affect masses. Pediatric immunization against vaccine preventable disease (VPD) is being supported by most of the international health agencies, making them accessible and affordable to even the poorest of the countries. However, adult vaccination is needed to protect the most productive age group and improve the quality of life of the aging population and is left to those who can afford it. In most of the low- and middle-income countries including India, adult vaccination did not even find a mention in national vaccination policies. Although recommendation exists from various health associations in India for adult vaccination, they have not been given enough publicity as data on burden of VPDs and cost-effectiveness of these vaccines in adults are not available. Most of the general population and a substantial proportion of health care professionals in India lack awareness on the availability and need for these adult vaccinations. Now with improved childhood immunization and increased life expectancies, many diseases are showing epidemiological shift to the later part of life, thereby bringing the focus on adult immunization through the life course approach to reduce morbidity and mortality because of VPDs in adults and improve the quality of life of those left vulnerable because of aging or their existing medical condition.

A combined DTaP-IPV vaccine (Tetraxim®/Tetravac®) used as school-entry booster: a review of more than 20 years of clinical and post-marketing experience

INTRODUCTION

Routine infant primary series and toddler booster vaccination are associated with waning of antibody levels over time, which can lead to an increased incidence of vaccine-preventable diseases. A diphtheria-tetanus-pertussis (DTP) booster vaccination at school-entry (aged 4-7 years) allows continued protection against these diseases and is included in many national immunization programs.

AREAS COVERED

The available immunogenicity and safety data from 6 clinical studies of a diphtheria-tetanus-acellular pertussis-inactivated poliovirus vaccine (DTaP-IPV [Tetraxim®]) used as a school-entry booster vaccination were identified using a PubMed search or on file at Sanofi. The studies spanned a 15-year period (1995-2010) and were performed in different populations using different study designs, so all data were reviewed descriptively (no meta-analyses were conducted). Additionally, post-marketing experience was reviewed.

EXPERT OPINION

Each vaccine antigen is highly immunogenic, and the safety profile of the vaccine is satisfactory. Post-marketing evaluations have shown the effectiveness of a school-age booster, particularly against increased pertussis disease incidence around the time of school entry and the associated risk of spreading the disease through contact with younger vulnerable infants. School-entry provides an ideal opportunity to implement DTaP-IPV vaccination to close the gap between waning immunity from the previous infant/toddler vaccination and future adolescent vaccination.

Requirement of Peptidyl-Prolyl Cis/Trans isomerases and chaperones for cellular uptake of bacterial AB-type toxins

Bacterial AB-type toxins are proteins released by the producing bacteria and are the causative agents for several severe diseases including cholera, whooping cough, diphtheria or enteric diseases. Their unique AB-type structure enables their uptake into mammalian cells via sophisticated mechanisms exploiting cellular uptake and transport pathways. The binding/translocation B-subunit facilitates binding of the toxin to a specific receptor on the cell surface. This is followed by receptor-mediated endocytosis. Then the enzymatically active A-subunit either escapes from endosomes in a pH-dependent manner or the toxin is further transported through the Golgi to the endoplasmic reticulum from where the A-subunit translocates into the cytosol. In the cytosol, the A-subunits enzymatically modify a specific substrate which leads to cellular reactions resulting in clinical symptoms that can be life-threatening. Both intracellular uptake routes require the A-subunit to unfold to either fit through a pore formed by the B-subunit into the endosomal membrane or to be recognized by the ER-associated degradation pathway. This led to the hypothesis that folding helper enzymes such as chaperones and peptidyl-prolyl cis/trans isomerases are required to assist the translocation of the A-subunit into the cytosol and/or facilitate their refolding into an enzymatically active conformation. This review article gives an overview about the role of heat shock proteins Hsp90 and Hsp70 as well as of peptidyl-prolyl cis/trans isomerases of the cyclophilin and FK506 binding protein families during uptake of bacterial AB-type toxins with a focus on clostridial binary toxins Clostridium botulinum C2 toxin, Clostridium perfringens iota toxin, Clostridioides difficile CDT toxin, as well as diphtheria toxin, pertussis toxin and cholera toxin.

Sustaining Maternal and Neonatal Tetanus Elimination (MNTE) in countries that have been validated for elimination - progress and challenges

BACKGROUND

As of October 2021, 47 (80%) of the 59 countries, identified at highest risk for Maternal and Neonatal Tetanus (MNT), had been validated for elimination. We assessed sustainability of MNT elimination (MNTE) in 28 countries that were validated during 2011‒2020.

METHODS

We assessed the attainment of the following MNTE sustainability indicators: 1) ≥ 90% coverage with three doses of Diphtheria-Tetanus-Pertussis vaccine (DTP3) among infants < 1 year, 2) ≥ 80% coverage with at least two doses of tetanus toxoid-containing vaccine (TTCV2 +) among pregnant women, 3) ≥ 80% protection at birth (PAB), 4) ≥ 70% skilled birth attendance (SBA), and 4) ≥ 80% first (ANC1) and fourth antenatal care (ANC4) visits. We assessed the introduction of TTCV booster doses. Data sources included the 2020 WHO /UNICEF Joint Reporting Forms, and the latest Demographic and Health Survey (DHS) or Multi-Indicator Cluster Surveys (MICS) for each country, if available. We reviewed literature and used DHS/MICS data to identify barriers to sustaining MNTE.

RESULTS

Of 28 assessed countries, 7 (25%) reported ≥ 90% DTP3 coverage, 4 of 26 (16%) reported ≥ 80% TTCV2 + coverage, and 23 of 27 (85%) reported ≥ 80% PAB coverage. Based on DHS/MICS in 15 of the 28 countries, 10 (67%) achieved ≥ 70% SBA delivery, 13 (87%) achieved ≥ 80% ANC1 visit coverage, and 3 (20%) ≥ 80% ANC4 visit coverage. We observed sub-optimal coverage in many countries at the subnational level. The first, second and third booster doses of TTCV respectively have been introduced in 6 (21%), 5 (18%), and 1 (4%) of 28 countries. Only three countries conducted post-MNTE validation assessments. Barriers to MNTE sustainability included: competing program priorities, limited resources to introduce TTCV booster doses and implement corrective immunization in high-risk districts and socio-economic factors.

CONCLUSIONS

Despite good performance of MNTE indicators in several countries, MNTE sustainability appears threatened in some countries. Integration and coordination of MNTE activities with other immunization activities in the context of the Immunization Agenda 2030 lifecourse vaccination strategy such as providing tetanus booster doses in school-based vaccination platforms, during measles second dose and HPV vaccination, and integrating MNTE post-validation assessments with immunization program reviews will ensure MNTE is sustained.

Interactions between the Re-Emerging Pathogen Corynebacterium diphtheriae and Host Cells

Corynebacterium diphtheriae, the etiological agent of diphtheria, is a re-emerging pathogen, responsible for several thousand deaths per year. In addition to diphtheria, systemic infections, often by non-toxigenic strains, are increasingly observed. This indicates that besides the well-studied and highly potent diphtheria toxin, various other virulence factors may influence the progression of the infection. This review focuses on the known components of C. diphtheriae responsible for adhesion, invasion, inflammation, and cell death, as well as on the cellular signaling pathways activated upon infection.

Seroprevalence against Diphtheria in Pregnant Women and Newborns in Colombia: New Arguments to Promote Maternal Immunization

The tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine is recommended during pregnancy for neonatal protection against pertussis, although little is known of the protection it provides against diphtheria. The work used a cross-sectional design to estimate seroprevalence against diphtheria in 805 pregnant women with ≥37 gestation weeks and their newborns whose deliveries were attended in eight hospitals randomly chosen from a subregion of Antioquia, Colombia and to explore factors related with maternal protection. Levels of IgG antibodies were determined by using a commercial enzyme-linked immunosorbent assay test. Placental transfer of antibodies and crude and adjusted prevalence ratio (aPR) were analyzed to describe factors related with maternal protection against diphtheria. Protection against diphtheria was observed in 91.7% (95% CI 90.3-93.0) of the pregnant women and 93.1% (95% CI 91.7-94.4) of newborns, whose antibody levels were positively correlated (Spearman's r = 0.769; p = 0.000). Maternal protection could be influenced by having been vaccinated during the current pregnancy (aPR 0.85, 95% CI: 0.82-0.93). The protective effect of vaccination during pregnancy and the efficiency of maternal antibody transfers were detected. Public health efforts should focus on increasing Tdap vaccination during each pregnancy to protect mothers and newborns against diphtheria.

Differential health impact of intervention programs for time-varying disease risk: a measles vaccination modeling study

BACKGROUND

Dynamic modeling is commonly used to evaluate direct and indirect effects of interventions on infectious disease incidence. The risk of secondary outcomes (e.g., death) attributable to infection may depend on the underlying disease incidence targeted by the intervention. Consequently, the impact of interventions (e.g., the difference in vaccination and no-vaccination scenarios) on secondary outcomes may not be proportional to the reduction in disease incidence. Here, we illustrate the estimation of the impact of vaccination on measles mortality, where case fatality ratios (CFRs) are a function of dynamically changing measles incidence.

METHODS

We used a previously published model of measles CFR that depends on incidence and vaccine coverage to illustrate the effects of (1) assuming higher CFR in "no-vaccination" scenarios, (2) time-varying CFRs over the past, and (3) time-varying CFRs in future projections on measles impact estimation. We used modeled CFRs in alternative scenarios to estimate measles deaths from 2000 to 2030 in 112 low- and middle-income countries using two models of measles transmission: Pennsylvania State University (PSU) and DynaMICE. We evaluated how different assumptions on future vaccine coverage, measles incidence, and CFR levels in "no-vaccination" scenarios affect the estimation of future deaths averted by measles vaccination.

RESULTS

Across 2000-2030, when CFRs are separately estimated for the "no-vaccination" scenario, the measles deaths averted estimated by PSU increased from 85.8% with constant CFRs to 86.8% with CFRs varying 2000-2018 and then held constant or 85.9% with CFRs varying across the entire time period and by DynaMICE changed from 92.0 to 92.4% or 91.9% in the same scenarios, respectively. By aligning both the "vaccination" and "no-vaccination" scenarios with time-variant measles CFR estimates, as opposed to assuming constant CFRs, the number of deaths averted in the vaccination scenarios was larger in historical years and lower in future years.

CONCLUSIONS

To assess the consequences of health interventions, impact estimates should consider the effect of "no-intervention" scenario assumptions on model parameters, such as measles CFR, in order to project estimated impact for alternative scenarios according to intervention strategies and investment decisions.

Chinese expert consensus on immunoprophylaxis of common respiratory pathogens in children (2021 edition)

Respiratory tract infections are infectious diseases involving the respiratory tract (such as the sinuses, throat, airways or lungs), which are the common respiratory disorders in children. With the development of society and the improvement of economic conditions, great progress has been made in China in the prevention of common respiratory pathogens in children. As a result, the incidence and mortality of respiratory tract infections in children have dropped sharply in the past decades. However, there is still a certain gap compared with the international leading levels, which can be partly attribute to insufficient public awareness of vaccination, uneven vaccination services of vaccinators, and so on. On the basis of comprehensive analysis of the clinical evidence of immunoprophylaxis of common respiratory pathogens among children in China and abroad, combined with the clinical situation and the experience of experts, the consensus focuses on the characteristics of transmission, clinical manifestations and immunoprophylaxis of common respiratory pathogens in children, so as to provide reference for clinical practice. This consensus document applies to all Centers for Disease Control and Prevention (CDC) staff levels engaged in the prevention and control of related pathogens, vaccinators at vaccination sites, and medical staff in pediatric, respiratory, and infectious diseases departments at all levels in medical institutions.

Novel Clinical Monitoring Approaches for Reemergence of Diphtheria Myocarditis, Vietnam

Diphtheria is a life-threatening, vaccine-preventable disease caused by toxigenic Corynebacterium bacterial species that continues to cause substantial disease and death worldwide, particularly in vulnerable populations. Further outbreaks of vaccine-preventable diseases are forecast because of health service disruptions caused by the coronavirus disease pandemic. Diphtheria causes a spectrum of clinical disease, ranging from cutaneous forms to severe respiratory infections with systemic complications, including cardiac and neurologic. In this synopsis, we describe a case of oropharyngeal diphtheria in a 7-year-old boy in Vietnam who experienced severe myocarditis complications. We also review the cardiac complications of diphtheria and discuss how noninvasive bedside imaging technologies to monitor myocardial function and hemodynamic parameters can help improve the management of this neglected infectious disease.

Diphtheria in the WHO European Region, 2010 to 2019

BackgroundDiphtheria is uncommon in the World Health Organization (WHO) European Region. Nevertheless, sporadic cases, sometimes fatal, continue to be reported.AimTo report on diphtheria cases and coverage with first and third doses of diphtheria, tetanus and pertussis vaccines (DTP1 and DTP3, respectively) for 2010-19 in the Region with a focus on 2019.MethodsData on diphtheria cases were obtained from WHO/United Nations International Children's Emergency Fund (UNICEF) Joint Reporting Forms submitted annually by the Region's Member States. WHO/UNICEF Estimates of National Immunization Coverage for DTP1 and DTP3 were summarised for 2010-19. For 2019, we analysed data on age, and vaccination status and present data by country on DTP1 and DTP3 coverage and the percentage of districts with ≥ 90% and < 80% DTP3 coverage.ResultsFor 2010-19, 451 diphtheria cases were reported in the Region. DTP1 and DTP3 coverage was 92-96% and 95-97%, respectively. For 2019, 52 cases were reported by 11 of 48 countries that submitted reports (including zero reporting). Thirty-nine countries submitted data on percentage of their districts with ≥ 90% and < 80% DTP3 coverage; 26 had ≥ 90% districts with ≥ 90% coverage while 11 had 1-40% districts with < 80% coverage.ConclusionLong-standing high DTP3 coverage at Regional level probably explains the relatively few diphtheria cases reported in the Region. Suboptimal surveillance systems and inadequate laboratory diagnostic capacity may also be contributing factors. Still, the observed cases are of concern. Attaining high DTP3 coverage in all districts and implementing recommended booster doses are necessary to control diphtheria and prevent outbreaks.

Seroprevalence of IgG antibodies against diphtheria antitoxin among migrant workers in Singapore, 2016-2019

Background

Since the last local case of diphtheria in 1992, there had not been any case in Singapore until an autochthonous case was reported in 2017. This fatal diphtheria case of a migrant worker raised concerns about the potential re-emergence of locally transmitted toxigenic diphtheria in Singapore. We conducted a seroprevalence study to assess the immunity levels to diphtheria among migrant workers in Singapore.

Methods

Residual sera from migrant workers who hailed from Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines were tested for anti-diphtheria toxoid immunoglobulin G (IgG) antibodies. These migrant workers previously participated in a survey between 2016 and 2019 and had provided blood samples as part of the survey procedure.

Results

A total of 2176 migrant workers were included in the study. Their overall mean age was 27.1 years (standard deviation 5.0), range was 20–43 years. The proportion having at least basic protection against diphtheria (antitoxin titres ≥ 0.01 IU/ml) ranged from 77.9% (95% confidence interval [CI] 72.8 – 82.3%) among migrant workers from Bangladesh to 96.7% (95% CI 92.5 – 98.6%) in those hailing from Malaysia. The proportion showing full protection (antitoxin titres ≥ 0.10 IU/ml) ranged from 10.1% (95% CI 6.5 – 15.4%) in Chinese workers to 23.0% (95% CI 17.1 – 30.3%) in Malaysian workers. There were no significant differences in the proportion with at least basic protection across birth cohorts, except for those from Bangladesh where the seroprevalence was significantly lower in younger migrant workers born after 1989.

Conclusions

The proportions having at least basic protection against diphtheria in migrant workers from five out of seven Asian countries (India, Indonesia, Malaysia, Myanmar and the Philippines) were higher than 85%, the threshold for diphtheria herd immunity. Seroprevalence surveys should be conducted periodically to assess the level of immunity against diphtheria and other vaccine preventable diseases in migrant worker population, so that appropriate interventions such as booster vaccination can be implemented proactively to prevent sporadic outbreaks.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12528-y.

Leveraging serology to titrate immunization program functionality for diphtheria in Madagascar

Diphtheria is a potentially devastating disease whose epidemiology remains poorly described in many settings, including Madagascar. Diphtheria vaccination is delivered in combination with pertussis and tetanus antigens and coverage of this vaccine is often used as a core measure of health system functioning. However, coverage is challenging to estimate due to the difficulty in translating numbers of doses delivered into numbers of children effectively immunised. Serology provides an alternative lens onto immunisation, but is complicated by challenges in discriminating between natural and vaccine-derived seropositivity. Here, we leverage known features of the serological profile of diphtheria to bound expectations for vaccine coverage for diphtheria, and further refine these using serology for pertussis. We measured diphtheria antibody titres in 185 children aged 6–11 months and 362 children aged 8–15 years and analysed them with pertussis antibody titres previously measured for each individual. Levels of diphtheria seronegativity varied among age groups (18.9% of children aged 6–11 months old and 11.3% of children aged 8–15 years old were seronegative) and also among the districts. We also find surprisingly elevated levels of individuals seropositive to diphtheria but not pertussis in the 6–11 month old age group suggesting that vaccination coverage or efficacy of the pertussis component of the DTP vaccine remains low or that natural infection of diphtheria may be playing a significant role in seropositivity in Madagascar.