Epidemiological, clinical, and public health response characteristics of a large outbreak of diphtheria among the Rohingya population in Cox's Bazar, Bangladesh, 2017 to 2019: A retrospective study

Health service providers' views on barriers and drivers to childhood vaccination of FDMN/Rohingya refugees: a qualitative study in Cox's Bazar, Bangladesh

Background

Despite established vaccination programs, vaccine-preventable diseases persist among about 900,000 Forcibly Displaced Myanmar Nationals (FDMN)/Rohingya refugees in the world's largest refugee settlement in Bangladesh. Health service providers (HSPs) play a key role in the delivery of childhood vaccination programs. This study explored their views on individual and context barriers and drivers to childhood vaccination in this setting.

Methods

Informed by the theoretical framework of the Capability-Opportunity-Motivation-Behavior (COM-B) model for behavior change, this qualitative study collected data through eight focus group discussions (FGDs) with community health workers (CHWs) and vaccinators in selected camps with high or low vaccination coverage rates, and through 11 in-depth interviews (IDIs) with key informants working in strategic, management, and administrative roles.

Findings

Barriers and drivers were evident across all COM factors for HSPs and caregivers. Among HSPs, knowledge around vaccination acted both as a barrier and driver, while communication skills and confidence in vaccination served as drivers. Caregivers' lack of awareness of vaccination, concerns and mistrust were described as main barriers. Context barriers included information system deficiencies, family dynamics, HSPs' working conditions, and vaccination site accessibility. Context drivers included effective communication, mobilization, and incentives. Differences between high and low coverage camps in Cox's Bazar included variations in HSPs' knowledge, communication strategies, incentive use, and stakeholder collaboration.

Discussion

For better vaccination coverage in the camps, context-related changes regarding collaboration, health workforce and the use of incentives seem necessary. Caregivers' mistrust toward vaccination needs to be considered under the social and historical background of the Rohingya community, and further addressed with targeted communication and campaigning.

Corynebacterium diphtheriae and Corynebacterium ulcerans: development of EUCAST methods and generation of data on which to determine breakpoints

BACKGROUND

Evidence-based clinical susceptibility breakpoints have been lacking for antimicrobial agents used for diphtheria.

OBJECTIVES

We aimed to evaluate broth microdilution and disc diffusion methods and create a dataset of MIC values and inhibition zone diameters (ZDs) from which breakpoints could be determined.

METHODS

We included 400 recent clinical isolates equally distributed by species (Corynebacterium diphtheriae and Corynebacterium ulcerans) and by national surveillance programmes (France and Germany). Non-duplicate toxigenic and non-toxigenic isolates were chosen to enable the inclusion of a diversity of susceptibility levels for the 13 agents tested. Broth microdilution and disc diffusion, using EUCAST methodology for fastidious organisms, were used.

RESULTS

The distributions of MIC and ZD values were largely in agreement among methods and countries. Breakpoints to allow categorization of WT isolates as susceptible, i.e. susceptible (S) or susceptible, increased exposure (I) were determined for 12 agents. The data supported a breakpoint for benzylpenicillin and amoxicillin of resistant (R) > 1 mg/L since WT isolates were inhibited by 1 mg/L or less. WT isolates were categorized as I (S ≤ 0.001 mg/L) for benzylpenicillin, emphasizing the need for increased exposure, and S (S ≤ 1 mg/L) for amoxicillin. Erythromycin breakpoints were set at S ≤ 0.06 mg/L and R > 0.06 mg/L. The corresponding ZD breakpoints were determined for all agents except amoxicillin, for which categorization was based on benzylpenicillin results.

CONCLUSIONS

This work provided a large set of antimicrobial susceptibility data for C. diphtheriae and C. ulcerans, using a harmonized methodology. The dataset allowed EUCAST and experts in the diphtheria field to develop evidence-based breakpoints in January 2023.

COVID-19 preventive measures in Rohingya refugee camps: An assessment of knowledge, attitude and practice

BACKGROUND

Although many studies were conducted on COVID-19 knowledge, attitude, and practice (KAP) among the general population in many countries, very little is known about refugees, particularly Rohingya refugees in Cox's Bazar. A vast array of risk communication and community engagement (RCCE) interventions were implemented in Cox's Bazar with the intent of reducing disease transmission by empowering the community to adopt public health measures.

OBJECTIVES

The study aimed to assess the level of knowledge, attitude and practice (KAP) of COVID-19 preventive measures among the Rohingya refugees in Cox's Bazar, and to identify their socio-demographic determinants.

MATERIALS AND METHODS

A cross-sectional study was conducted with 500 Rohingya individuals. Participants in the study were Rohingya refugees residing in five randomly selected camps where International Organization for Migration (IOM) Health was operating. Using a structured questionnaire, skilled community health workers surveyed the Rohingya population. In addition to the survey on knowledge, attitude, and practice, the study gathered information on the perspectives and relevance of sociodemographic factors that influence KAP.

RESULTS

The study findings indicate that the mean scores for knowledge, attitude, and practice were 9.93, 7.55, and 2.71 respectively. Association was found between knowledge and practice level and age group-the elderly age group (>/ = 61 years) had less level of knowledge (AOR 0.42, P value = 0.058) and the late mid-age group (46-60 years) had better practice level (AOR 2.67, P value <0.001).

CONCLUSIONS

Our study found that the Rohingya refugee community in Cox's Bazar has improved knowledge and attitude toward COVID-19 preventive measures. However, the practice level of these measures remains low compared to the knowledge and positive attitude. The reason behind the poor practice of preventive measures needs to be identified and addressed engaging the community in similar future outbreaks.

Multidrug-resistant Corynebacterium diphtheriae in people with travel history from West Africa to France, March to September 2023

We describe 10 unlinked cases of Corynebacterium diphtheriae infection (nine cutaneous, one respiratory) in France in 2023 in persons travelling from Guinea, Mali, Senegal, Niger or Nigeria and Central African Republic. Four isolates were toxigenic. Seven genomically unrelated isolates were multidrug-resistant, including a toxigenic respiratory isolate with high-level resistance to macrolides and beta-lactams. The high rates of resistance, including against first-line agents, call for further microbiological investigations to guide clinical management and public health response in ongoing West African outbreaks.

Outbreak of Corynebacterium diphtheriae among asylum seekers in Belgium in 2022: operational challenges and lessons learnt

Since 2022, European countries have been facing an outbreak of mainly cutaneous diphtheria caused by toxigenic Corynebacterium diphtheriae among asylum seekers. In Belgium, between 1 March and 31 December 2022, 25 cases of toxigenic C. diphtheriae infection were confirmed among asylum seekers, mostly among young males from Afghanistan. Multi-locus sequence typing showed that most isolates belonged to sequence types 574 or 377, similar to the majority of cases in other European countries. The investigation and management of the outbreak, with many asylum seekers without shelter, required adjustments to case finding, contact tracing and treatment procedures. A test-and-treat centre was organised by non-governmental organisations, the duration of the antimicrobial treatment was shortened to increase compliance, and isolation and contact tracing of cases was not possible. A vaccination centre was opened, and mobile vaccination campaigns were organised to vaccinate a maximum of asylum seekers. No more cases were detected between end December 2022 and May 2023. Unfortunately, though, three cases of respiratory diphtheria, including one death, were reported at the end of June 2023. To prevent future outbreaks, specific attention and sufficient resources should be allocated to this vulnerable population, in Belgium and at international level.

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.

National public health response to an outbreak of toxigenic Corynebacterium diphtheriae among asylum seekers in England, 2022: a descriptive epidemiological study

BACKGROUND

In July, 2022, an increase in diphtheria cases caused by toxigenic Corynebacterium diphtheriae (C diphtheriae) was reported among asylum seekers arriving by small boats to England. Rising case numbers presented challenges for case and contact management in initial reception centres, prompting changes to national guidance and implementation of population-based control measures. This study aimed to describe the outbreak of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022 by use of national surveillance data.

METHODS

We undertook a descriptive epidemiological analysis of cases of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022, incorporating genomic sequencing data, antibiotic susceptibility testing results, and epidemiological data obtained through the UK Health Security Agency's national enhanced surveillance programme. Health Protection Teams conducted risk assessments, and operational data (including details regarding offer and uptake of antibiotics and vaccinations) were obtained from National Health Service partners supporting the intervention programme.

FINDINGS

In 2022, C diphtheriae isolates from 86 asylum seekers arriving by small boats were submitted to the National Reference Laboratory for confirmation and testing. Toxigenic C diphtheriae was confirmed for 72 (84%) cases and one individual with typical diphtheritic lesions but from whom no C diphtheriae was isolated from clinical swabs was also included as a probable case, resulting in 73 cases of diphtheria. 71 (97%) were male, 39 (53%) were younger than 18 years, and 36 (49%) presented with cutaneous diphtheria. The prevalence of diphtheria was highest among Afghans (1·3%) compared with all other nationalities (<0·1%). Local antibiotic susceptibility testing identified six cases with a macrolide resistant strain.

INTERPRETATION

The increase in diphtheria coincided with a high volume of asylum seekers arriving by small boats to England during 2022, and subsequently increased clinical awareness of the disease among this population. Long-term disruption to vaccination programmes in origin countries along with barriers to accessing health care along migrant routes puts asylum seekers arriving by small boats at risk of disease. With arrivals expected to continue in 2023, the UK Health Security Agency has recommended continuation of population-based control measures in England until October, 2023, subject to ongoing review.

FUNDING

The UK Health Security Agency.

Imported Toxigenic Corynebacterium Diphtheriae in Refugees with Polymicrobial Skin Infections, Germany, 2022

During August-December 2022, toxigenic Corynebacterium diphtheriae was isolated from 25 refugees with skin infections and 2 refugees with asymptomatic throat colonization at a refugee reception center in Germany. None had systemic toxin-mediated illness. Of erosive/ulcerative skin infections, 96% were polymicrobial. Erosive/ulcerative wounds in refugees should undergo testing to rule out cutaneous diphtheria.

Perspectives on the current diphtheria outbreak among asylum seekers in the UK

An outbreak of diphtheria has been reported among asylum seekers to the UK, with a 7-fold increase in annual cases in 2022. The UK response involves a mass screening, vaccination and prophylaxis programme for all individuals who have been through an asylum seeker reception centre.

Genomic characterization of cocirculating Corynebacterium diphtheriae and non-diphtheritic Corynebacterium species among forcibly displaced Myanmar nationals, 2017-2019

Respiratory diphtheria is a serious infection caused by toxigenic Corynebacterium diphtheriae, and disease transmission mainly occurs through respiratory droplets. Between 2017 and 2019, a large diphtheria outbreak among forcibly displaced Myanmar nationals densely settled in Bangladesh was investigated. Here we utilized whole-genome sequencing (WGS) to characterize recovered isolates of C. diphtheriae and two co-circulating non-diphtheritic Corynebacterium (NDC) species - C. pseudodiphtheriticum and C. propinquum. C. diphtheriae isolates recovered from all 53 positive cases in this study were identified as toxigenic biovar mitis, exhibiting intermediate resistance to penicillin, and formed four phylogenetic clusters circulating among multiple refugee camps. Additional sequenced isolates collected from two patients showed co-colonization with non-toxigenic C. diphtheriae biovar gravis, one of which exhibited decreased susceptibility to the first-line antibiotics and harboured a novel 23-kb multidrug resistance plasmid. Results of phylogenetic reconstruction and virulence-related gene contents of the recovered NDC isolates indicated they were likely commensal organisms, though 80.4 %(45/56) were not susceptible to erythromycin, and most showed high minimum inhibition concentrations against azithromycin. These results demonstrate the high resolution with which WGS can aid molecular investigation of diphtheria outbreaks, through the quantification of bacterial genetic relatedness, as well as the detection of virulence factors and antibiotic resistance markers among case isolates.

Understanding the challenges and gaps in community engagement interventions for COVID-19 prevention strategies in Rohingya refugees: a qualitative study with frontline workers and community representatives

Background

Rohingya refugees in Bangladesh are vulnerable to infectious diseases such as COVID-19 due to the crowded living conditions with fragile shelters, and limited water, sanitation and hygiene facilities and practices. While risk communication and community engagement (RCCE) is the cornerstone of outbreak control, there is limited evidence available on the effectiveness of the RCCE strategies in this setting.

Objectives

The goal of this study is to evaluate the effectiveness of RCCE strategies and to explore the challenges and community recommendations in relation to COVID-19 preventive measures in the context of Rohingya refugee camps in Bangladesh.

Materials and methods

It was a qualitative study. Methods used were (a) observation of RCCE intervention by 3 clinical supervisors accompanying 25 Community Health Workers (CHWs) and (b) 5 focus group discussions engaging 60 community representatives. Data were analyzed using a thematic analysis approach, separately for observation and focus group discussions.

Results

The study identified a number of good practices of RCCE, including selecting CHWs from the local community, engaging female CHWs, using local dialect, and collaborating with community/religious leaders. Certain good practices need scaling up, such as utilization of multiple communication methods and interpersonal communication skills. Some areas need improvement, such as CHWs being overburdened with multiple tasks, less effort to active listening, repeated delivery of same messages, inadequate linkage to culture, context, and resources, and less effort to empower the community. Engaging the community, five critical themes were identified in relation to poor COVID-19 preventive practices: culture, religion, and language; local context and resources; community trust and interaction with aid workers; communication methods; and gender and social inclusion. Religious misinterpretation, cultural barriers, physical barriers, lack of resources, breach of trust between the community and aid workers, inconsistent/complex messages, lack of gender and social inclusion, and stigmatization are among some key factors. Some key actions were recommended to improve COVID-19 RCCE strategy.

Conclusion

We urge the RCCE partners to make use of the findings and recommendations to develop a robust RCCE strategy relevant to local culture and context, responsive to people's concerns and needs, and inclusive of gender, age and social vulnerabilities.

Genomic Epidemiology of Corynebacterium diphtheriae in New Caledonia

An increasing number of isolations of Corynebacterium diphtheriae has been observed in recent years in the archipelago of New Caledonia. We aimed to analyze the clinical and microbiological features of samples with C. diphtheriae. All C. diphtheriae isolates identified in New Caledonia from May 2015 to May 2019 were included. For each case, a retrospective consultation of the patient files was conducted. Antimicrobial susceptibility phenotypes, tox gene and diphtheria toxin expression, biovar, and the genomic sequence were determined. Core genome multilocus sequence typing (cgMLST), 7-gene MLST, and search of genes of interest were performed from genomic assemblies. Fifty-eight isolates were included, with a median age of patients of 28 years (range: 9 days to 78 years). Cutaneous origin accounted for 51 of 58 (87.9%) isolates, and C. diphtheriae was associated with Staphylococcus aureus and/or Streptococcus pyogenes in three-quarters of cases. Half of cases came either from the main city Noumea (24%, 14/58) or from the sparsely populated island of Lifou (26%, 15/58). Six tox-positive isolates were identified, associated with recent travel to Vanuatu; 5 of these cases were linked and cgMLST confirmed recent transmission. Two cases of endocarditis in young female patients with a history of rheumatic fever involved tox-negative isolates. The 58 isolates were mostly susceptible to commonly used antibiotics. In particular, no isolate was resistant to the first-line molecules amoxicillin or erythromycin. Resistance to tetracycline was found in a genomic cluster of 17 (29%) isolates, 16 of which carried the tetO gene. There were 13 cgMLST sublineages, most of which were also observed in the neighboring country Australia. Cutaneous infections may harbor nontoxigenic C. diphtheriae isolates, which circulate largely silently in nonspecific wounds. The possible introduction of tox-positive strains from a neighboring island illustrates that diphtheria surveillance should be maintained in New Caledonia, and that immunization in neighboring islands must be improved. Genomic sequencing uncovers how genotypes circulate locally and across neighboring countries. IMPORTANCE The analysis of C. diphtheriae from the tropical archipelago of New Caledonia revealed a high genetic diversity with sublineages that may be linked to Polynesia, Australia, or metropolitan France. Genomic typing allowed confirming or excluding suspected transmission events among cases and contacts. A highly prevalent tetracycline-resistant sublineage harboring the tetO gene was uncovered. Toxigenic isolates were observed from patients returning from Vanuatu, showing the importance of improving vaccination coverage in settings where it is insufficient. This study also illustrates the importance for diphtheria surveillance of the inclusion of isolates from cutaneous sources in addition to respiratory cases, in order to provide a more complete epidemiological picture of the diversity and transmission of C. diphtheriae.

Lateral flow immunoassay-based laboratory algorithm for rapid diagnosis of diphtheria

Background: In industrialised countries diphtheria is a rare but still life-threatening disease with a recent increase in cases due to migration and zoonotic aspects. Due to the rarity of the disease, laboratory diagnosis of diphtheria is often carried out in central reference laboratories and involves the use of sophisticated equipment and specially trained personnel. The result of the diphtheria agent detection can usually be obtained after 5-6 days or more. Authors suggest a Lateral Flow Immunoassay (LFIA)-based laboratory algorithm for the diagnosis of diphtheria, which may render less time in issuing a result and could promote the testing be performed in laboratories closer to the patient. Methods: LFIA for diphtheria toxin (DT) detection was designed using a pair of monoclonal antibodies to receptor-binding subunit B of the DT, and validated with 322 corynebacterial cultures as well as 360 simulated diphtheria specimens. Simulated diphtheria specimens were obtained by spiking of human pharyngeal samples with test strains of corynebacteria. The simulated specimens were plated on selective tellurite agar and after 18-24 hours of incubation, grey/black colonies characteristic of the diphtheria corynebacteria were examined for the DT using LFIA. Results: The diagnostic sensitivity of the LFIA for DT detection on bacterial cultures was 99.35%, and the specificity was 100%. Also, the LFIA was positive for all pharyngeal samples with toxigenic strains and negative for all samples with non-toxigenic strains. For setting LFIA, a 6-hour culture on Elek broth was used; thus, under routine conditions, the causative agent of diphtheria could be detected within two working days after plating of the clinical specimen on the tellurite medium of primary inoculation. Conclusions: The availability of such a simple and reliable methodology will speed up and increase the accuracy of diphtheria diagnosis globally.

The Biological Causes and Consequences of COVID-19: ACE I/D Polymorphism and In-Silico Screening of Potential Bioactive Phytochemicals Against COVID-19

The "Severe Acute Respiratory Syndrome" (SARS), which has relation to the coronavirus-2 considered to be a major cause of the disease addressed by COVID-19. COVID-19 requires the angiotensin converting enzyme 2 (ACE-2), which is considered to be the target receptor of the host cells. The intention of this practical research study was to observe ACE I/D polymorphism association with COVID-19 and also the in-silico screening of potential phytochemicals against COVID-19. This study incorporated total of 320 blood samples; of which 160 were collected from COVID-19 patients and 160 were collected from healthy controls. DNA extraction was conducted from whole genomic blood and afterward, the banding patterns of ACE polymorphism were identified by the application of a nested polymerase chain reaction. A significant discrepancy was recorded in the frequency of insertion/deletion (ID) and homozygous deletion (DD) between controls and patients. The frequency reported for ID was just 10% and that of DD (genetic constitution) was 90%. Predictably, a 100% DD genetic constitution was shown by all the controls. The inference of this study was that the DD genotype has a greater prevalence in COVID-19 as compared to II and ID. In-silico screening of potential phytochemicals against COVID-19 is very effective in its concentrated form showing no or fewer side effects and can be used as a drug against COVID-19 spike protein blockage to inhibit the interaction between ACE-2 receptors. The highest affinity and lowest binding energy were observed by Dictaminine.

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.

Seroepidemiology of pertussis and diphtheria among healthy adults in Shaanxi Province, northwest China: A large - scale cross-sectional study

To determine the estimated pertussis incidence in adults and the need for a booster dose by detecting pertussis and diphtheria antibody levels in adults in Shaanxi province, China. Blood samples were collected from healthy individuals aged 18-59 years in Shaanxi province in 2017. Serum immunoglobulin G (IgG) antibodies against pertussis toxin (PT) and diphtheria toxin (DT) were determined using enzyme-linked immunosorbent assay. The data on reported pertussis cases in Shaanxi province were collected from the China Information System for Disease Control and Prevention and compared with the results of this study. A total of 4307 subjects were enrolled. The mean concentration of anti-PT IgG was 19.6 IU/mL (95% CI = 18.9-20.3), and the positive rate (≥40 IU/mL) was 11.0% (474/4307), of which recent infections (≥100 IU/mL) accounted for 1.2% (53/4307). Only one adult case of pertussis was reported in 2017, which is much lower than the results of this study. The mean concentration of anti-DT IgG was 0.04 IU/mL (95% CI = 0.04-0.05), and the positive rate (≥0.01 IU/mL) was 82.3% (3543/4307). The mean concentration of anti-DT IgG decreased from 0.07 IU/mL in the 18-29 year-old group to 0.03 IU/mL in the 50-59 year-old-group, and the positivity rate decreased from 86.7% to 78.7%. Our study suggests that pertussis is not uncommon among adults. The existing surveillance system might have underestimated the true incidence of pertussis. The diphtheria antibody levels decreased with age. Booster vaccination against pertussis should be considered for adolescents and young adults.

Ongoing toxin-positive diphtheria outbreaks in a federal asylum centre in Switzerland, analysis July to September 2022

Two diphtheria outbreaks occurred in a Swiss asylum center from July to October 2022, one is still ongoing. Outbreaks mainly involved minors and included six symptomatic respiratory diphtheria cases requiring antitoxin. Phylogenomic analyses showed evidence of imported and local transmissions of toxigenic strains in respiratory and skin lesion samples. Given the number of cases (n = 20) and the large genetic diversity accumulating in one centre, increased awareness and changes in public health measures are required to prevent and control diphtheria outbreaks.

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.

The World Health Organization's Actions Within the United Nations System to Facilitate a Whole-of-Society Response to COVID-19 at Country Level

The coronavirus disease (COVID-19) pandemic highlighted that managing health emergencies requires more than an effective health response, but that operationalizing a whole-of-society approach is challenging. The World Health Organization (WHO), as the lead agency for health within the United Nations (UN), led the UN response at the global level through the Crisis Management Team, and at the country level through the UN Country Teams (UNCTs) in accordance with its mandate. Three case studies—Mali, Cox's Bazar in Bangladesh, and Uzbekistan—provide examples of how WHO contributed to the whole-of-society response for COVID-19 at the country level. Interviews with WHO staff, supplemented by internal and external published reports, highlighted that the action of WHO comprised technical expertise to ensure an effective whole-of-society response and to minimize social disruption, including those affecting peacekeeping in Mali, livelihood sectors in Cox's Bazar, and the education sector in Uzbekistan. Leveraging local level volunteers from various sectors led to both a stronger public health response and the continuation of other sectoral work. Risk communication and community engagement (RCCE) emerged as a key theme for UN engagement at country level. These collective efforts of operationalizing whole-of-society response at the country level need to continue for the COVID-19 response, but also in preparedness for other health and non-health emergencies. Building resilience for future emergencies requires developing and exercising multi-sectoral preparedness plans and benefits from collective UN support to countries. Coronavirus disease had many impacts outside of health, and therefore emergency preparedness needs to occur outside of health too.

Novel Use of Capture-Recapture Methods to Estimate Completeness of Contact Tracing during an Ebola Outbreak, Democratic Republic of the Congo, 2018-2020

Despite its critical role in containing outbreaks, the efficacy of contact tracing, measured as the sensitivity of case detection, remains an elusive metric. We estimated the sensitivity of contact tracing by applying unilist capture-recapture methods on data from the 2018–2020 outbreak of Ebola virus disease in the Democratic Republic of the Congo. To compute sensitivity, we applied different distributional assumptions to the zero-truncated count data to estimate the number of unobserved case-patients with any contacts and infected contacts. Geometric distributions were the best-fitting models. Our results indicate that contact tracing efforts identified almost all (n = 792, 99%) of case-patients with any contacts but only half (n = 207, 48%) of case-patients with infected contacts, suggesting that contact tracing efforts performed well at identifying contacts during the listing stage but performed poorly during the contact follow-up stage. We discuss extensions to our work and potential applications for the ongoing coronavirus pandemic.

Genomic Epidemiology and Strain Taxonomy of Corynebacterium diphtheriae

Corynebacterium diphtheriae is highly transmissible and can cause large diphtheria outbreaks where vaccination coverage is insufficient. Sporadic cases or small clusters are observed in high-vaccination settings. The phylogeography and short timescale evolution of C. diphtheriae are not well understood, in part due to a lack of harmonized analytical approaches of genomic surveillance and strain tracking. We combined 1,305 genes with highly reproducible allele calls into a core genome multilocus sequence typing (cgMLST) scheme. We analyzed cgMLST gene diversity among 602 isolates from sporadic clinical cases, small clusters, or large outbreaks. We defined sublineages based on the phylogenetic structure within C. diphtheriae and strains based on the highest number of cgMLST mismatches within documented outbreaks. We performed time-scaled phylogenetic analyses of major sublineages. The cgMLST scheme showed high allele call rate in C. diphtheriae and the closely related species C. belfantii and C. rouxii. We demonstrate its utility to delineate epidemiological case clusters and outbreaks using a 25 mismatches threshold and reveal a number of cryptic transmission chains, most of which are geographically restricted to one or a few adjacent countries. Subcultures of the vaccine strain PW8 differed by up to 20 cgMLST mismatches. Phylogenetic analyses revealed a short-timescale evolutionary gain or loss of the diphtheria toxin and biovar-associated genes. We devised a genomic taxonomy of strains and deeper sublineages (defined using a 500-cgMLST-mismatch threshold), currently comprising 151 sublineages, only a few of which are geographically widespread based on current sampling. The cgMLST genotyping tool and nomenclature was made publicly accessible (https://bigsdb.pasteur.fr/diphtheria). Standardized genome-scale strain genotyping will help tracing transmission and geographic spread of C. diphtheriae. The unified genomic taxonomy of C. diphtheriae strains provides a common language for studies of ecology, evolution, and virulence heterogeneity among C. diphtheriae sublineages.