Symptoms Of Pertussis Research Articles

Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination-United States, 2010-2012.

In 2012, >48000 pertussis cases were reported in the United States. Many cases occurred in vaccinated persons, showing that pertussis vaccination does not prevent all pertussis cases. However, pertussis vaccination may have an impact on disease severity. We analyzed data on probable and confirmed pertussis cases reported through Enhanced Pertussis Surveillance (Emerging Infections Program Network) between 2010 and 2012. Surveillance data were collected through physician and patient interview and vaccine registries. We assessed whether having received an age-appropriate number of pertussis vaccines (AAV) (for persons aged ≥3 months) was associated with reduced odds of posttussive vomiting, a marker of more clinically significant illness, or of severe pertussis (seizure, encephalopathy, pneumonia, and/or hospitalization). Adjusted odds ratios were calculated using multivariable logistic regression. Among 9801 pertussis patients aged ≥3 months, 77.6% were AAV. AAV status was associated with a 60% reduction in odds of severe disease in children aged 7 months-6 years in multivariable logistic regression and a 30% reduction in odds of posttussive vomiting in persons aged 19 months-64 years. Serious pertussis symptoms and complications are less common among AAV pertussis patients, demonstrating that the positive impact of pertussis vaccination extends beyond decreasing risk of disease.

Real-Time Polymerase Chain Reaction–Based Detection of Bordetella pertussis in Mexican Infants and Their Contacts: A 3-Year Multicenter Study

To evaluate the usefulness of real-time polymerase chain reaction (RT-PCR) as a diagnostic method for the detection of Bordetella pertussis in hospitalized patients aged <1 year with a clinical diagnosis of whooping cough, as well as to identify the role of household contacts as a source of infection. This was a prospective, multicenter study of infants aged <1 year who were hospitalized with symptoms suggestive of whooping cough. Nasopharyngeal samples were obtained for culture and RT-PCR testing. The clinical and epidemiologic characteristics and outcomes were analyzed. B pertussis detection and symptoms in household contacts of patients diagnosed with pertussis were studied. A total of 286 patients were included; of these, 67.1% had B pertussis and 4.5% had Bordetella spp. Complications occurred in 20% of patients, and the mortality rate was 6.7%. Of 434 contacts studied, 111 were mothers of study infants, representing the most frequently B pertussis-infected group and the main symptomatic contact. The use of RT-PCR permits improved detection and diagnosis of pertussis and a better understanding of the epidemiology of sources of infection. The complications and mortality rate of pertussis continue to be high. Household contacts are confirmed as a frequent source of infection of B pertussis in young children.

The importance of Bordetella pertussis strains which do not produce virulence factors in the epidemiology of pertussis.

Bordetella pertussis strains, which have lost the ability to produce antigens, such as pertactin - Prn, pertussis toxin - Ptx, filamentous haemagglutinin - FHA, fimbriae type 2 and 3 - Fim 2 and 3, tracheal colonization factor - TcfA, have recently been isolated in countries with a high vaccination coverage. The emergence of such isolates might have resulted from B. pertussis natural evolution course or adaptive mechanisms, allowing increased circulation of the pathogen in vaccinated populations. So far, the majority of described mutants were deficient in the Prn production. Prn deficient isolates were found in countries which use acellular pertussis vaccines (aP) in routine immunization programmes. The increase of frequency of Prn¯ strains isolation was correlated with the period of routine vaccination with aP vaccines. In most countries, the spread of these isolates has resulted from independent mutations rather than from the expansion of a single clone. Prn¯ isolates were collected from patients showing typical clinical symptoms of pertussis found for Prn+ strains. Results of in vitro and in vivo studies have shown that Prn¯, Ptx¯ and FHA¯ isolates retain cytotoxic properties, and besides Ptx¯ isolates, were lethal in intranasally infected mice. Further explanation of the impact of antigen deficiencies on virulence and transmission of B. pertussis in the context of the continuous increase of pertussis incidence is necessary to develop a new, optimized strategy of pertussis prevention.

Underdetection and underreporting of pertussis in children attended in primary health care centers: Do surveillance systems require improvement?

Pertussis is an underestimated disease. Several European countries have developed models to account for underreporting of pertussis. The aim of this study was to estimate pertussis underdetection and underreporting in pediatric patients attending primary health care centers (PHCCs). We reviewed clinical records of PHCCs in Barcelona in 2012. Factors associated with underdetection and underreporting were analyzed by logistic regression. Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were calculated. We included 3,505 children aged < 7 years (mean age, 34 ± 20.7 months; range, 0-82 months) presenting with cough; 9.3% (326 out of 3,505) of patients also had ≥ 1 symptoms related to pertussis accompanied by cough for a duration ≥ 2 weeks. Of the 326 children receiving clinical criteria, only 31 (9.5%) were laboratory-confirmed and 6 (1.8%) were detected but not reported. There were 295 (90.5%) undetected suspected pertussis cases. Age ≥ 18 months (aOR, 8.51; 95% CI, 1.82-39.86), cyanosis (aOR, 6.71; 95% CI, 1.43-31.39), request for chest radiograph (aOR, 0.26; 95% CI, 0.07-0.99), and request for other laboratory tests (aOR, 5.39; 95% CI, 2.19-13.27) were associated with underdetection. Paroxysmal cough (aOR, 5.77; 95% CI, 1.05-31.76) and request for other laboratory tests (aOR, 2.91; 95% CI, 1.11-7.62) were associated with underreporting. Both underdetection and underreporting complicate the understanding of pertussis epidemiology. Correct assessment of pertussis symptoms and notification of cases must be improved to control pertussis.

Association of Vitamin D Receptor Polymorphism with Susceptibility to Symptomatic Pertussis.

Pertussis, caused by infection with the gram negative B. pertussis bacterium, is a serious respiratory illness that can last for months. While B. pertussis infection rates are estimated between 1–10% in the general population, notifications of symptomatic pertussis only comprise 0.01–0.1% indicating that most individuals clear B. pertussis infections without developing (severe) clinical symptoms. In this study we investigated whether genetic risk factors are involved in the development of symptomatic pertussis upon B. pertussis infection. Single-nucleotide polymorphisms (SNPs) in candidate genes, MBL2, IL17A, TNFα, VDR, and IL10 were genotyped in a unique Dutch cohort of symptomatic clinically confirmed (ex-)pertussis patients and in a Dutch population cohort. Of the seven investigated SNPs in five genes, a polymorphism in the Vitamin D receptor (VDR) gene (rs10735810) was associated with pertussis. The VDR major allele and its homozygous genotype were more present in the symptomatic pertussis patient cohort compared to the control population cohort. Interestingly, the VDR major allele correlated also with the duration of reported pertussis symptoms. Vitamin D3 (VD3) and VDR are important regulators of immune activation. Altogether, these findings suggest that polymorphisms in the VDR gene may affect immune activation and the clinical outcome of B. pertussis infection.

Sustained Transmission of Pertussis in Vaccinated, 1–5-Year-Old Children in a Preschool, Florida, USA

Abstract In September 2013, local county health officials in Tallahassee, Florida, USA, were notified of a laboratory-confirmed pertussis case in a 1-year-old preschool attendee. During a 5-month period, 26 (22%) students 1–5 years of age, 2 staff from the same preschool, and 11 family members met the national case definition for pertussis. Four persons during this outbreak were hospitalized for clinical management of pertussis symptoms. Only 5 students, including 2 students with pertussis, had not received the complete series of vaccinations for pertussis. Attack rates in 1 classroom for all students who received the complete series of vaccinations for pertussis approached 50%. This outbreak raises concerns about vaccine effectiveness in this preschool age group and reinforces the idea that recent pertussis vaccination should not dissuade physicians from diagnosing, testing, or treating persons with compatible illness for pertussis.

High frequency of pertussis in older children and adolescents with prolonged cough in Turkey.

This study aimed to determine the frequency of B. pertussis infection among Turkish children with prolonged cough. Nasopharyngeal specimens were collected from 7-18 year old children, presenting with prolonged cough of two to four weeks' duration. Specimens were examined for B. pertussis by PCR. Of 101 children with prolonged cough, 20 (19.8%) had a positive PCR testing for B. pertussis. Children who were vaccinated ≥5 years previously had a 6.13-fold higher risk of PCR-confirmed pertussis than those who were vaccinated < 5 years before. The classic symptoms of pertussis (paroxysmal cough, whooping and post-tussive vomiting) were seen in 30%, 15% and 25% of the patients with positive PCR, respectively; 55% of them had only a prolonged cough without any classic symptoms. Pertussis is common among Turkish children with prolonged cough, even after implementation of a fifth dose of pertussis vaccination and despite high vaccination coverage.

Correlation of Real Time PCR Cycle Threshold Cut-Off with Bordetella pertussis Clinical Severity.

Bordetella pertussis testing performed using real-time polymerase chain reaction (RT-PCR) is interpreted based on a cycle threshold (Ct) value. At Public Health Ontario Laboratories (PHOL), a Ct value <36 is reported as positive, and Ct values ≥36 and <40 are reported as indeterminate. PHOL reported indeterminate results to physicians and public health units until May 2012, after which these results were only reported to physicians. We investigated the association between Ct value and disease symptom and severity to examine the significance of indeterminate results clinically, epidemiologically and for public health reporting. B. pertussis positive and indeterminate RT-PCR results were linked to pertussis cases reported in the provincial Integrated Public Health Information System (iPHIS), using deterministic linkage. Patients with positive RT-PCR results had a lower median age of 10.8 years compared to 12.0 years for patients with indeterminate results (p = 0.24). Hospitalized patients had significantly lower Ct values than non-hospitalized patients (median Ct values of 20.7 vs. 31.6, p<0.001). The proportion of patients reporting the most indicative symptoms of pertussis did not differ between patients with positive vs. indeterminate RT-PCR results. Taking the most indicative symptoms of pertussis as the gold-standard, the positive predictive value of the RT-PCR test was 68.1%. RT-PCR test results should be interpreted in the context of the clinical symptoms, age, vaccination status, prevalence, and other factors. Further information on interpretation of indeterminate RT-PCR results may be needed, and the utility of reporting to public health practitioners should be re-evaluated.

Pertactin-negative Bordetella pertussis strains: evidence for a possible selective advantage.

A recent increase in Bordetella pertussis without the pertactin protein, an acellular vaccine immunogen, has been reported in the United States. Determining whether pertactin-deficient (PRN(-)) B. pertussis is evading vaccine-induced immunity or altering the severity of illness is needed. We retrospectively assessed for associations between pertactin production and both clinical presentation and vaccine history. Cases with isolates collected between May 2011 and February 2013 from 8 states were included. We calculated unadjusted and adjusted odds ratios (ORs) using multivariable logistic regression analysis. Among 753 isolates, 640 (85%) were PRN(-). The age distribution differed between cases caused by PRN(-) B. pertussis and cases caused by B. pertussis producing pertactin (PRN(+)) (P = .01). The proportion reporting individual pertussis symptoms was similar between the 2 groups, except a higher proportion of PRN(+) case-patients reported apnea (P = .005). Twenty-two case-patients were hospitalized; 6% in the PRN(+) group compared to 3% in the PRN(-) group (P = .11). Case-patients having received at least 1 pertussis vaccine dose had a higher odds of having PRN(-) B. pertussis compared with unvaccinated case-patients (adjusted OR = 2.2; 95% confidence interval [CI], 1.3-4.0). When restricted to case-patients at least 1 year of age and those age-appropriately vaccinated, the adjusted OR increased to 2.7 (95% CI, 1.2-6.1). The significant association between vaccination and isolate pertactin production suggests that the likelihood of having reported disease caused by PRN(-) compared with PRN(+) strains is greater in vaccinated persons. Additional studies are needed to assess whether vaccine effectiveness is diminished against PRN(-) strains.

Reply to Domenech de Cellès et al.: Infection and transmission of pertussis in the baboon model

We developed a nonhuman primate model to study whether pertussis vaccination is able to disrupt Bordetella pertussis colonization and transmission, and demonstrated that baboons vaccinated with the acellular pertussis vaccines (aP) were protected from classic pertussis symptoms (i.e., coughing and leukocytosis) but were highly colonized and transmitted pertussis to contacts in two of two experiments (1). In their letter to the editor, Domenech de Celles et al. question our extrapolation of results from the baboon model to transmission in human populations (2). We agree that these data should not be directly extrapolated to pertussis transmission in humans. Although baboons are >96% genetically similar to humans, there are likely differences in how the species respond to vaccination and infection. We also agree that aP-vaccinated infected people are likely less efficient at transmitting pertussis compared with unvaccinated infected people, although it is not clear to what extent. In our model, the time required for transmission was greater when the infected baboon was aP-vaccinated compared with unvaccinated animals (3). However, in the baboon model, aP did not prevent infection as well as whole-cell vaccine (wP); therefore, it is reasonable to conclude that circulation of B. pertussis will be higher in an aP-vaccinated population than in a wP-vaccinated population.

Time since last vaccine dose in PCR-positive and PCR-negative children with suspected pertussis to monitor pertussis vaccine effectiveness

We evaluated whether the results of diagnostic polymerase chain reaction (PCR) testing combined with time since last vaccine dose could be used to monitor the effectiveness of acellular pertussis vaccines. In 258 consecutive nasopharyngeal swabs from children and adolescents with typical pertussis symptoms, 80 were positive and 178 were negative in PCR for Bordetella pertussis DNA (IS 481). Time since last vaccine dose was available for 152 patients, of which 120 were fully immunised. Among the fully vaccinated patients, the median age of 41 PCR-positive patients was 8.4 years (range 0.9-12.3) and that of 79 PCR-negative cases was 3.3 years (range 0.4-14.1) (p < 0.01). The median time since last pertussis vaccine dose was 6.05 years [95 % confidence interval (CI): 0.5-10.9] in PCR-positive cases and 2.22 years (95 % CI: 0.04-9.23) in PCR-negative cases (p < 0.001). The use of diagnostic PCR results from pertussis cases together with time since last vaccine dose permits estimates of the duration of protection after vaccination with acellular pertussis vaccines that are in keeping with more complex studies.

Pertussis Vaccination of Health Care Workers

Pertussis Vaccination of Health Care Workers

Relationship between the population incidence of pertussis in children in New South Wales, Australia and emergency department visits with cough: a time series analysis

BackgroundLittle is known about the potential of syndromic surveillance to provide early warning of pertussis outbreaks. We conducted a time series analysis to assess whether an emergency department (ED) cough syndrome would respond to changes in the incidence of pertussis in children aged under 10 years in New South Wales (NSW), Australia, and to evaluate the timing of any association. A further aim was to assess the lag between the onset of pertussis symptoms and case notification in the infectious diseases surveillance system in NSW.MethodsUsing routinely collected data, we prepared a daily count time series of visits to NSW EDs assigned a provisional diagnosis of cough. Separate daily series were prepared for three independent variables: notifications of cases of pertussis and influenza and ED visits with bronchiolitis (a proxy measure of respiratory syncytial virus (RSV) infection). The study period was 1/1/2007-31/12/2010. A negative binomial multivariate model was used to assess associations between the outcome and independent variables. We also evaluated the median delay in days between the estimated onset of a case of pertussis and the date the local public health authority was notified of that case.ResultsWhen notified pertussis increased by 10 cases in one day, ED visits with cough increased by 5.2% (95% confidence interval (CI): 0.5%-10.0%) seven days later. Daily increases in the other independent variables had a smaller impact on cough visits. When notified influenza increased by 10 cases in one day, ED visits with cough increased by 0.8% (95% CI: 0%-1.7%) seven days later. When ED visits with bronchiolitis increased by 10 visits in one day, ED visits with cough increased by 4.8% (95% CI: 1.2%-8.6%) one day earlier. The median interval between estimated onset of pertussis and case notification was seven days.ConclusionsPertussis appears to be an important driver of ED visits with cough in children aged under 10 years. However, the median delay in notification of cases of pertussis was similar to the lag in the pertussis-associated short-term increases in ED visits with cough. Elevations in RSV and influenza activity may also explain increases in the ED cough syndrome. Real time monitoring of ED visits with cough in children is therefore unlikely to consistently detect a potential outbreak of pertussis before passive surveillance.

Pertussis Pseudo-outbreak Linked to Specimens Contaminated by Bordetella pertussis DNA From Clinic Surfaces

We investigated a pertussis outbreak characterized by atypical cases, confirmed by polymerase chain reaction (PCR) alone at a single laboratory, which persisted despite high vaccine coverage and routine control measures. We aimed to determine whether Bordetella pertussis was the causative agent and advise on control interventions. We conducted case ascertainment, confirmatory testing for pertussis and other pathogens, and an assessment for possible sources of specimen contamination, including a survey of clinic practices, sampling clinics for B pertussis DNA, and review of laboratory quality indicators. Between November 28, 2008, and September 4, 2009, 125 cases were reported, of which 92 (74%) were PCR positive. Cases occurring after April 2009 (n = 79; 63%) had fewer classic pertussis symptoms (63% vs 98%; P < .01), smaller amounts of B pertussis DNA (mean PCR cycle threshold value: 40.9 vs 33.1; P < .01), and a greater proportion of PCR-positive results (34% vs 6%; P < .01). Cultures and serology for B pertussis were negative. Other common respiratory pathogens were detected. We identified factors that likely resulted in specimen contamination at the point of collection: environmentally present B pertussis DNA in clinics from vaccine, clinic standard specimen collection practices, use of liquid transport medium, and lack of clinically relevant PCR cutoffs. A summer pertussis pseudo-outbreak, multifactorial in cause, likely occurred. Recommendations beyond standard practice were made to providers on specimen collection and environmental cleaning, and to laboratories on standardizing PCR protocols and reporting results, to minimize false-positive results from contaminated clinical specimens.

Does This Coughing Adolescent or Adult Patient Have Pertussis?

Pertussis is often overlooked as a cause of chronic cough, especially in adolescents and adults. Several symptoms are classically thought to be suggestive of pertussis, but the diagnostic value of each of them is uncertain. To systematically review the evidence regarding the diagnostic value of 3 classically described symptoms of pertussis: paroxysmal cough, posttussive emesis, and inspiratory whoop. We searched MEDLINE (January 1966-April 2010), EMBASE (January 1969 to April 2010), and the bibliographies of pertinent articles to identify relevant English-language studies. Articles were selected that included children older than 5 years, adolescents, or adults and confirmed the diagnosis of pertussis among patients with cough illness (of any duration) with an a priori-defined accepted reference standard. Two authors independently extracted data from articles that met selection criteria and resolved any discrepancies by consensus. Five prospective studies met inclusion criteria; 3 were used in the analysis. Presence of posttussive emesis (summary likelihood ratio [LR], 1.8; 95% confidence interval [CI], 1.4-2.2) or inspiratory whoop (summary LR, 1.9; 95% CI, 1.4-2.6) increases the likelihood of pertussis. Absence of paroxysmal cough (summary LR, 0.52; 95% CI, 0.27-1.0) or posttussive emesis (summary LR, 0.58; 95% CI, 0.44-0.77) reduced the likelihood. Absence of inspiratory whoop was less useful (summary LR, 0.78; 95% CI, 0.66-0.93). No studies evaluated combinations of findings. In a nonoutbreak setting, data to determine the diagnostic usefulness of symptoms classically associated with pertussis are limited and of relatively weak quality. The presence or absence of posttussive emesis or inspiratory whoop modestly change the likelihood of pertussis; therefore, clinicians must use their overall clinical impression to decide about additional testing or empirical treatment.

The role of adults in household outbreaks of pertussis

This study describes the role of adults in 57 household outbreaks of pertussis. Parents/guardians of children with suspected pertussis seen at a university hospital were interviewed. Once a case of pertussis was confirmed, all household members were enrolled in the study. The US Centers for Disease Control and Prevention (CDC) definitions for pertussis were used . Among 349 household members, 150 were adults and one in five had pertussis during the household outbreaks. Of the adult cases, 70.6% were aged 19-39 years. The secondary attack rate in adults was 12.6%. Adults were the primary case in a 21.1% of households, resulting in 43% of all secondary cases. Most adult cases had typical symptoms of pertussis, but none had been diagnosed before the investigation. Adults, particularly those aged between 19 and 39 years, play an important role in pertussis transmission in households. Pertussis vaccination in adolescents/young adults may decrease the dissemination of pertussis in households.

A Countywide Outbreak of Pertussis

To describe a large communitywide pertussis outbreak where aggressive diagnostic and treatment measures were used to control the outbreak. Retrospective analysis, May 2003 through February 2004. Fond du Lac County, Wisconsin (population 98,882). Health department personnel conducted case and contact investigations of suspected outbreak-associated illnesses using standard pertussis reporting forms and clinical evaluation and management protocols. Persons with compatible illness were tested for Bordetella pertussis using culture and for B pertussis DNA using polymerase chain reaction. Cases were classified using Council of State and Territorial Epidemiologists definitions. Health alerts and aggressive testing and treatment of suspected cases of pertussis illness and contact prophylaxis in the community. Incidences by age, onsets over time, and vaccine coverage in case patients. We identified 261 pertussis cases among county residents; 149 (57%) were laboratory confirmed. Of the first 57 case patients, 47% reported using a particular high school weight room. Pertussis incidence was high in all age groups; 86% of case patients were 10 years or older. Among 156 case patients with reported vaccination histories, 84% had received 5 or more doses of pertussis-containing vaccine. Adults reported significantly more severe pertussis symptoms than adolescents. Pertussis transmission among adolescents using a school weight room instigated a countywide outbreak with substantial incidence and morbidity among adolescents and adults. Aggressive testing and treatment in the outbreak response likely contributed to a sharp reduction in cases. This labor- and resource-intensive outbreak highlights potential benefits of pertussis booster vaccination among adolescent and adult populations.

Pertussis Symptoms in Adolescents and Children Versus Infants: The Influence of Vaccination and Age

This study compared the influence of age and immunization status on symptoms in pediatric patients with pertussis. The files of 60 children, aged 7 to 18 years and 20 infants aged up to 6 months, admitted to our pediatric hospital with a diagnosis of pertussis were reviewed. There were no between-group differences in day and night cough or vomiting. The older group had a longer mean interval to diagnosis than the infants, and the infant group had more symptoms of whooping cough, facial redness during cough, cyanosis, a higher white blood count, a higher percentage of lymphocytes, and more abnormal chest X-rays. Statistically significant differences were found between vaccinated and unvaccinated older children for whooping cough and white blood cell count. Daytime and nighttime coughs are common symptoms of pertussis in all pediatric age groups, regardless of vaccination status. High white blood count is related to immunization status, and percentage of lymphocytes is related to age. In infants, symptoms are more grave but are typical, leading to early diagnosis.

Pertussis: A cluster of linked cases in the United Kingdom, 2006

Pertussis is a vaccine-preventable disease with a high rate of complications, especially in young children. It often presents in an atypical fashion in adults and adolescents, making diagnosis difficult. This report describes a cluster of linked cases of three adults and one infant in a family, spread across the United Kingdom (UK). The initial follow-up was of a 20-year-old student with clinical symptoms of pertussis. This diagnosis led to the discovery of two other unvaccinated adult family members with symptoms that fit the case definition for pertussis and a laboratory-confirmed tertiary case in an unvaccinated infant who had to be hospitalised. This report aims to act as a reminder for including pertussis as a differential diagnosis in patients with a long duration of respiratory symptoms and highlights the importance of rapidly identifying and managing close contacts of cases. This is key in protecting the most vulnerable - namely, infants - from infection.

A modified “cover your cough” campaign prevents exposures of employees to pertussis at a children's hospital

In the 4th quarter of 2004, there was an increase in patients seeking medical care for pertussis symptoms at the Children's Hospital, Omaha, NE. The Hospital Epidemiology service noted a sharp rise in exposures of Children's Hospital employees to these patients, requiring employee testing, prophylactic antibiotic prescriptions, and relief from duty. Initial efforts at employee education failed to prevent the exposures. An exposure-control plan was then initiated by placing "Cover Your Cough" posters (in English and Spanish) describing appropriate cough etiquette at entrances to the emergency room, outpatient clinics, and hospital lobby. In addition, personal protective equipment (PPE) including child- and adult-sized masks, hand sanitizers, and tissues were provided at these stations for patients and their attendants. Prior to the initiation of the above exposure control measures, there were 166 reports of employee exposure to patients and other employees with pertussis symptoms during a 4-week period. Of these, 140 were given prophylactic antibiotics, and 31 underwent diagnostic testing for pertussis and required paid time off from work. The cost of antibiotics and diagnostic testing was $17,407.00. After the introduction of the modified "Cover Your Cough" campaign, the number of employee exposures declined significantly to 37 in the next 4-week period. Notably, the number of patients tested for pertussis during the second 4-week period was 290 compared to 162 in the first 4-week period, indicating continuation of the epidemic. Availability of PPE along with posters regarding cough etiquette at entry points of the hospital interrupted employee exposure to patients/personnel with pertussis symptoms significantly, when an employee educational initiative alone was unable to achieve this outcome.