Epidemiological Observations in the Halifax Epidemic

Wheeler, S. M.; Morton, Allan R.

doi:10.2105/ajph.32.9.947

Cited by 24 publications

(5 citation statements)

References 3 publications

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“…During a diphtheria outbreak in Texas in 1971, the vaccine effectiveness for preventing a case of diphtheria was estimated to be 97% among fully vaccinated school-age children compared with nonvaccinated children [5]. After an outbreak in Canada in 1942, the vaccine effectiveness among persons of all age groups was estimated to be 85% [6]. Following a diphtheria outbreak in the Yemen Arab Republic, the vaccine effectiveness for receipt of three doses of DTP was estimated at 87% [7].…”

Section: Discussionmentioning

confidence: 99%

Diphtheria Toxoid Vaccine Effectiveness: A Case‐Control Study in Russia

Bisgard¹,

Rhodes²,

Hardy³

et al. 2000

J INFECT DIS

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Prior to the completion of this and other studies, low effectiveness of diphtheria toxoid-containing vaccine was suspected to be a major contributing factor to the diphtheria epidemic that began in the Russian Federation in 1990. A vaccine effectiveness study was done in Moscow by enrolling physician-diagnosed cases and 10 control subjects per case. Controls were matched to cases by age (+/-3 months) and clinic registration. Vaccination history was abstracted from a standardized form for case-patients and from clinic vaccination records for control subjects. Two hundred seventeen case-patients and 2169 matched controls were included in the study. Most controls (92%) had received three or more doses of a diphtheria toxoid vaccine, compared with 72% of case-patients. The vaccine effectiveness for three or more doses was 97% (95% confidence interval: 94.3-98.4). Low vaccine effectiveness was not a contributing factor to the diphtheria epidemic in the Russian Federation. To control and prevent diphtheria epidemics, it is necessary to achieve and maintain high vaccination coverage with three or more doses of diphtheria toxoid among adults and children.

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Section: Discussionmentioning

confidence: 99%

Diphtheria Toxoid Vaccine Effectiveness: A Case‐Control Study in Russia

Bisgard¹,

Rhodes²,

Hardy³

et al. 2000

J INFECT DIS

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“…In contrast, worldwide, 7097 diphtheria cases were reported in 2016, mainly in low-income countries (www.who.it). In the 1900s−1950s, infections with C. diphtheriae were among the most severe infections during childhood, especially in pre-school children where case fatality rates of 2–25% were reported (87, 88). Prior to the availability of toxoid-vaccines, nearly 70% of the cases were in children younger than 15 years of age (89).…”

Section: The Return Of An Old Foementioning

confidence: 99%

“…Prior to the availability of toxoid-vaccines, nearly 70% of the cases were in children younger than 15 years of age (89). With the introduction of vaccines in the 1940s and 1950s, a significant decrease in incidence was observed (87, 88, 90–93), although no controlled clinical trial to evaluate the efficacy of the toxoid-vaccines in preventing diphtheria has ever been performed.…”

Section: The Return Of An Old Foementioning

confidence: 99%

Whole Genome Sequencing for Surveillance of Diphtheria in Low Incidence Settings

Seth-Smith

Egli

2019

Front. Public Health

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Corynebacterium diphtheriae ( C. diphtheriae ) is a relatively rare pathogen in most Western countries. While toxin producing strains can cause pharyngeal diphtheria with potentially fatal outcomes, the more common presentation is wound infections. The diphtheria toxin is encoded on a prophage and can also be carried by Corynebacterium ulcerans and Corynebacterium pseudotuberculosis . Currently, across Europe, infections are mainly diagnosed in travelers and refugees from regions where diphtheria is more endemic, patients from urban areas with poor hygiene, and intravenous drug users. About half of the cases are non-toxin producing isolates. Rapid identification of the bacterial pathogen and toxin production is a critical element of patient and outbreak management. Beside the immediate clinical management of the patient, public health agencies should be informed of toxigenic C. diphtheriae diagnoses as soon as possible. The collection of case-related epidemiological data from the patient is often challenging due to language barriers and social circumstances. However, information on patient contacts, vaccine status and travel/refugee route, where appropriate, is critical, and should be documented. In addition, isolates should be characterized using high resolution typing, in order to identify transmissions and outbreaks. In recent years, whole genome sequencing (WGS) has become the gold standard of high-resolution typing methods, allowing detailed investigations of pathogen transmissions. De-centralized sequencing strategies with redundancy in sequencing capacities, followed by data exchange may be a valuable future option, especially since WGS becomes more available and portable. In this context, the sharing of sequence data, using public available platforms, is essential. A close interaction between microbiology laboratories, treating physicians, refugee centers, social workers, and public health officials is a key element in successful management of suspected outbreaks. Analyzing bacterial isolates at reference centers may further help to provide more specialized microbiological techniques and to standardize information, but this is also more time consuming during an outbreak. Centralized communication strategies between public health agencies and laboratories helps considerably in establishing and coordinating effective surveillance and infection control. We review the current literature on high-resolution typing of C. diphtheriae and share our own experience with the coordination of a Swiss-German outbreak.

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“…Single nasopharyngeal cultures of 60 cotntacts of 17 epidemic cases of meningitis yielded 3 Group I strains and 10 Group II strains. All but 1 of the Group II carriers were found in a single household, comprising 17 members.…”

Section: Discussionmentioning

confidence: 99%

“…Some were sporadic cases in the city of Boston, while others were seen during an epidemic of meningococcal meningitis in Halifax, Nova Scotia. Certain clinical and epidemiological aspects of the epidemic cases have already been reported (2,3), and a more detailed study of the other cases will be the subject of a later report. All degrees of severity of illness were observed, ranging from mild, almost abortive infections, to the most fulminating type.…”

mentioning

confidence: 91%