Outbreak of pertussis on a college campus

A big pertussis outbreak in a primary school with high vaccination coverage in northern China: An evidence of the emerging of the disease in China

BACKGROUND

A big pertussis outbreak occurred in a primary school with high vaccination coverage in northern China. An investigation was carried out in order to calculate the attack rate and identify the risk factors.

METHODS

Between May 12 and July 29, an investigation was carried out in the primary school, which included 383 students and 27 teachers. Three definitions were used to distinguish the cases: confirmed, epidemiologically linked and suspected cases. A total of 232 blood samples were collected and examined by ELISA among healthy children in another primary school.

RESULTS

A total of 138 suspected pertussis cases were counted, of which 116 students were confirmed. The attack rate among students was as high as 30.29%. The pertussis outbreak lasted 88 days, and had quaternary cases of transmission. Migrant children were almost four times as likely to catch the disease as local children (p = 0.005). In addition, students who had received the last dose of pertussis vaccine more than 4 years prior were three times more likely of becoming ill than those less than 4 years (p = 0.006). The average level of antibodies to pertussis was 30.99 IU/mL among healthy children. No statistically significant difference was observed between DTaP and DTwP (p = 0.843).

CONCLUSIONS

This pertussis outbreak in a primary school with high vaccination coverage was an evidence of the pertussis resurgence in China. The major risk factor we identified was the waning of immunity in the years after pertussis vaccination. Booster vaccination for students should be given.

Clinically Diagnosing Pertussis-associated Cough in Adults and Children: CHEST Guideline and Expert Panel Report

BACKGROUND

The decision to treat a suspected case of pertussis with antibiotics is usually based on a clinical diagnosis rather than waiting for laboratory confirmation. The current guideline focuses on making the clinical diagnosis of pertussis-associated cough in adults and children.

METHODS

The American College of Chest Physicians (CHEST) methodologic guidelines and the Grading of Recommendations, Assessment, Development, and Evaluation framework were used. The Expert Cough Panel based their recommendations on findings from a systematic review that was recently published on the topic; final grading was reached by consensus according to Delphi methodology. The systematic review was carried out to answer the Key Clinical Question: In patients presenting with cough, how can we most accurately diagnose from clinical features alone those who have pertussis-associated cough as opposed to other causes of cough?

RESULTS

In adults, after pre-specified meta-analysis exclusions, pooled estimates of sensitivity and specificity were generated for only 4 clinical features: paroxysmal cough, post-tussive vomiting, inspiratory whooping, and absence of fever. Both paroxysmal cough and absence of fever had high sensitivity (93.2% [95% CI, 83.2-97.4] and 81.8% [95% CI, 72.2-88.7], respectively) and low specificity (20.6% [95% CI, 14.7-28.1] and 18.8% [95% CI, 8.1-37.9]). Inspiratory whooping and posttussive vomiting had a low sensitivity (32.5% [95% CI, 24.5-41.6] and 29.8% [95% CI, 18.0-45.2]) but high specificity (77.7% [95% CI, 73.1-81.7] and 79.5% [95% CI, 69.4-86.9]). In children, after pre-specified meta-analysis exclusions, pooled estimates of sensitivity and specificity were generated for only 1 clinical feature in children (0-18 years): posttussive vomiting. Posttussive vomiting in children was only moderately sensitive (60.0% [95% CI, 40.3-77.0]) and specific (66.0% [95% CI, 52.5-77.3]).

CONCLUSIONS

In adults with acute (< 3 weeks) or subacute (3-8 weeks) cough, the presence of whooping or posttussive vomiting should rule in a possible diagnosis of pertussis, whereas the lack of a paroxysmal cough or the presence of fever should rule it out. In children with acute (< 4 weeks) cough, posttussive vomiting is suggestive of pertussis but is much less helpful as a clinical diagnostic test. Guideline suggestions are made based upon these findings and conclusions.

Clinical Characteristics of Pertussis-Associated Cough in Adults and Children: A Diagnostic Systematic Review and Meta-Analysis

BACKGROUND

Pertussis (whooping cough) is a highly infective cause of cough that causes significant morbidity and mortality. Existing case definitions include paroxysmal cough, whooping, and posttussive vomiting, but diagnosis can be difficult. We determined the diagnostic accuracy of clinical characteristics of pertussis-associated cough.

METHODS

We systematically searched CINAHL, Embase, Medline, and SCI-EXPANDED/CPCI-S up to June 2016. Eligible studies compared clinical characteristics in those positive and negative for Bordetella pertussis infection, confirmed by laboratory investigations. Two authors independently completed screening, data extraction, and quality and bias assessments. For each characteristic, RevMan was used to produce descriptive forest plots. The bivariate meta-analysis method was used to generate pooled estimates of sensitivity and specificity.

RESULTS

Of 1,969 identified papers, 53 were included. Forty-one clinical characteristics were assessed for diagnostic accuracy. In adult patients, paroxysmal cough and absence of fever have a high sensitivity (93.2% [CI, 83.2-97.4] and 81.8% [CI, 72.2-88.7], respectively) and low specificity (20.6% [CI, 14.7-28.1] and 18.8% [CI, 8.1-37.9]), whereas posttussive vomiting and whooping have low sensitivity (32.5% [CI, 24.5-41.6] and 29.8% [CI, 8.0-45.2]) and high specificity (77.7% [CI, 73.1-81.7] and 79.5% [CI, 69.4-86.9]). Posttussive vomiting in children is moderately sensitive (60.0% [CI, 40.3-77.0]) and specific (66.0% [CI, 52.5-77.3]).

CONCLUSIONS

In adult patients, the presence of whooping or posttussive vomiting should rule in a possible diagnosis of pertussis, whereas the lack of a paroxysmal cough or the presence of fever should rule it out. In children, posttussive vomiting is much less helpful as a clinical diagnostic test.

When is cough functional, and how should it be treated?

Key points

Educational aims

Summary

Involuntary cough without an identified underlying organic reason has been given various names and recommended treatments. Current experience in children and adolescents suggests that “habit cough” best describes this entity, and suggestion therapy is a highly effective treatment that most physicians can learn.

Diagnosis of the functional disorder called habit cough can be readily made by the unique clinical characteristicshttp://ow.ly/Al5B3094oxj

The estimated incidence of pertussis in people aged 50 years old in the United States, 2006-2010

Background

Pertussis is believed to be widely underreported and under-recognized, particularly among adults. The aim of this study was to estimate the incidence of private practitioner-attended cough illness that could be attributed to Bordetella pertussis in adults aged ≥50 years in the US.

Methods

Multiple linear regressions were employed to estimate the overall incidence of pertussis. Data were extracted from IMS’ private practice database of longitudinal, patient-level claims and IMS’ commercial laboratory database during 4/1/2006–12/31/2010. Patients were ≥50 years old and had ≥1 ICD-9-CM claim for cough illness relating to pertussis, cough, or acute bronchitis. Pertussis positive laboratory tests, seasonal and secular variables were used for estimating the B. pertussis attributable fraction of cough illness.

Results

During the study period, there were 20.7 million cases of cough illness among people aged 50–64 and 27.5 million cases among those ≥65; of which the model attributed 2.5 and 1.7 %, respectively, to B. pertussis. The estimated incidences of cough illness attributed to B. pertussis during the study period were on average 202 and 257/100,000 among people aged 50–64 and ≥65 years, respectively, and increased over the years in both age groups. Depending on the year, estimated pertussis incidences were 42 to 105 times higher than medically attended ones in the same database.

Conclusions

These findings indicate that the B. pertussis disease incidence in adults aged ≥50 years is significantly higher than generally estimated. Additional research regarding pertussis reporting and diagnosis in the adult populations is needed to validate these findings.

Does working in hospital increases seroprevalence and carrier state against Bordetella pertussis?

Background:

Health care environments have been the setting for a number of pertussis outbreaks. Immunity after vaccination wanes overtime leading to a growing population of susceptible adolescents and adults. A number of pertussis outbreaks have occurred in hospitals resulting in transmission to health care workers (HCWs), and other patients. The aim of this study was to assess immunity status of a group of basic medical students and interns who worked in hospitals for about 4 years.

Materials and Methods:

In a cross-sectional study, we measured the serum antibody titer of cases by enzyme-linked immunosorbent assay test. All 70 subjects have received pertussis vaccine in the routine childhood vaccination schedule. All cases were healthy and had no symptoms of any respiratory diseases. We also obtained a pharyngeal culture on Bordet-Gengou Agar for isolating Bordetella pertussis.

Results:

The results of B. pertussis pharyngeal culture was positive for 5 (7.1%) cases and negative for 65 (92.9%). The IgM, IgA, and IgG serum antibody was positive in 1.4%, 7.1%, and 11.4% of cases, respectively. The mean age of cases had no significant effect on serum antibody titers (P = 0.23).

Conclusions:

This study showed that majority of cases do not have protective serum antibody against B. pertussis. Working in hospitals does not affect seroprevalence and carrier state of B. pertussis. Immunization schedules that include no booster doses are at increased risk of pertussis. Due to the importance of the transmission in health care settings, vaccination of HCWs is a priority.

Pertussis

Pertussis, or whopping cough, is an upper respiratory tract infection caused by Bordetella pertussis. It has long been a concern in pediatric populations, leading to aggressive vaccination strategies to help decrease pediatric disease. In recent years, recognition of pertussis infection in adult populations has increased, leading to more frequent diagnosis and recommendations for booster immunizations in the adult population. Early recognition and treatment as well as vaccination will help reduce the current increase in this disease.

Outbreak of atypical pertussis detected by polymerase chain reaction in immunized preschool-aged children

BACKGROUND

From October 2005 to March 2006, a laboratory-confirmed outbreak of pertussis occurred in preschool-aged children (1-4 years) in Toronto, Canada. A case-control study in children was done to identify the risk factors for being positive for Bordetella pertussis by polymerase chain reaction (PCR).

METHODS

A case was defined as an individual 0 to 18 years of age who tested positive for B. pertussis by PCR in Toronto from October 2005 to March 2006. Each case was matched to 2 controls (negative for B. pertussis by PCR) by: (1) age, (2) geographic region of testing, and (3) date of testing.

RESULTS

One hundred eighty-nine cases and 296 controls were enrolled. Only 42% of cases (vs. 25% controls, P < 0.0001) met a clinical definition of pertussis, 3 cases (4 controls) were hospitalized, and the secondary household attack rate was 8%. One-third of cases were positive for another respiratory pathogen and >90% of cases and controls were up-to-date with pertussis immunization. Children attending school (matched odds ratio [ORm] = 5.2; 95% confidence intervals [CI]: 1.4-19.0), day care (ORm = 2.2; 95% CI: 1.2-4.0), visiting a doctor's office (ORm = 1.6; 95% CI: 1.0-2.5), or exposed to a household member (median age: 4-5 years) with a pertussis-like cough (ORm = 1.9; 95% CI: 1.0-3.6) were significantly more likely to have a positive PCR test for B. pertussis.

CONCLUSIONS

The main risk factors for PCR positivity for B. pertussis were school or day care attendance. Atypical symptoms were likely moderated by high immunization rates or may have been caused by other respiratory pathogens. In some cases, a positive PCR result might simply have reflected transient nasopharyngeal carriage of B. pertussis.