Prevalence, diagnosis, and disease course of pertussis in adults with acute cough: a prospective, observational study in primary care

Understanding the impact of adult pertussis and current approaches to vaccination: A narrative review and expert panel recommendations

Pertussis has several notable consequences, causing economic burden, increased strain on healthcare facilities, and reductions in quality of life. Recent years have seen a trend toward an increase in pertussis cases affecting older children and adults. To boost immunity, and protect vulnerable populations, an enduring approach to vaccination has been proposed, but gaps remain in the evidence surrounding adult vaccination that are needed to inform such a policy. Gaps include: the true incidence of pertussis and its complications in adults; regional variations in disease recognition and reporting; and incidence of severe disease, hospitalizations, and deaths in older adults. Better data on the efficacy/effectiveness of pertussis vaccination in adults, duration of protection, and factors leading to poor vaccine uptake are needed. Addressing the critical evidence gaps will help highlight important areas of unmet need and justify the importance of adult pertussis vaccination to healthcare professionals, policymakers, and payers.

Assessing the Underestimation of Adult Pertussis Disease in Five Latin American Countries

INTRODUCTION

Pertussis, a contagious respiratory disease, is underreported in adults. The study objective was to quantify underestimation of pertussis cases in adults aged ≥ 50 years in five Latin American countries (Argentina, Brazil, Chile, Mexico, Peru).

METHODS

A previously published probabilistic model was adapted to adjust the number of pertussis cases reported to national surveillance systems by successive multiplication steps (proportion of pertussis cases seeking healthcare; proportion with a specimen collected; proportion sent for confirmatory testing; proportion positive for pertussis; proportion reported to passive surveillance). The proportions at each step were added in a random effects model to produce a pooled overall proportion, and a final multiplier was calculated as the simple inverse of this proportion. This multiplier was applied to the number of cases reported to surveillance to estimate the number of pertussis cases. Monte Carlo simulation with 10,000 iterations estimated median as well as upper and lower 90% values. Input data were obtained from surveillance systems and published sources.

RESULTS

The estimated median underestimation factor for pertussis cases in adults ranged from 104 (90% limits 40, 451) in Chile to 114 (90% limits 39, 419) in Argentina. In all five countries, the largest estimated number of cases was in the group aged 50-59 years. The highest number per 100,000 population was in the group aged ≥ 90 years in most countries. The estimated median underestimation factor for pertussis hospitalizations was 2.3 (90% limits 1.8, 3.3) in Brazil and 2.4 (90% limits 1.8, 3.2) in Chile (data not available for other countries).

CONCLUSION

This analysis indicates that the number of pertussis cases in adults aged ≥ 50 years in five Latin American countries is approximately 100 times higher than the number captured in surveillance data. These results could support decision-making in the diagnosis, management, and prevention of pertussis disease in adults.

Prevalence, aetiologies and prognosis of the symptom cough in primary care: a systematic review and meta-analysis

Background

Cough is a relevant reason for encounter in primary care. For evidence-based decision making, general practitioners need setting-specific knowledge about prevalences, pre-test probabilities, and prognosis. Accordingly, we performed a systematic review of symptom-evaluating studies evaluating cough as reason for encounter in primary care.

Methods

We conducted a search in MEDLINE and EMBASE. Eligibility criteria and methodological quality were assessed independently by two reviewers. We extracted data on prevalence, aetiologies and prognosis, and estimated the variation across studies. If justifiable in terms of heterogeneity, we performed a meta-analysis.

Results

We identified 21 eligible studies on prevalence, 12 on aetiology, and four on prognosis. Prevalence/incidence estimates were 3.8–4.2%/12.5% (Western primary care) and 10.3–13.8%/6.3–6.5% in Africa, Asia and South America. In Western countries the underlying diagnoses for acute cough or cough of all durations were respiratory tract infections (73–91.9%), influenza (6–15.2%), asthma (3.2–15%), laryngitis/tracheitis (3.6–9%), pneumonia (4.0–4.2%), COPD (0.5–3.3%), heart failure (0.3%), and suspected malignancy (0.2–1.8%). Median time for recovery was 9 to 11 days. Complete recovery was reported by 40.2- 67% of patients after two weeks, and by 79% after four weeks. About 21.1–35% of patients re-consulted; 0–1.3% of acute cough patients were hospitalized, none died. Evidence is missing concerning subacute and chronic cough.

Conclusion

Prevalences and incidences of cough are high and show regional variation. Acute cough, mainly caused by respiratory tract infections, is usually self-limiting (supporting a “wait-and-see” strategy). We have no setting-specific evidence to support current guideline recommendations concerning subacute or chronic cough in Western primary care. Our study presents epidemiological data under non non-pandemic conditions. It will be interesting to compare these data to future research results of the post-pandemic era.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01501-0.

Epidemiology of pertussis among adolescents, adults, and older adults in selected countries of Latin American: a systematic review

We aimed to describe the impact of pertussis on adolescents, adults, and older adults over 2007–2018 in selected Latin American countries by reviewing the literature. We searched the Medline, Embase, Scopus, LILACS, Scielo, Google Scholar, CAPES Journals Web-portal, and Cochrane databases for observational epidemiological studies, clinical trials, and systematic reviews of primary studies. Data were extracted and analyzed for all individuals aged ≥10 years. Of 6,891 studies identified only 25 were eligible. Studies were conducted in Brazil (14), Argentina (4), Colombia (4), Mexico (2) and Chile (1). Epidemiological data among target population were limited. No studies clearly assessed the status of asymptomatic or oligosymptomatic B. pertussis carriers in these age groups. Among all pertussis cases identified, the percentage of patients ≥10 years-old ranged between 2.1% and 66.7% depending on country and sample characteristics. The definition of cases, diagnostic methods, and age groups were not consistent across studies.

Burden of selected infectious diseases covered by UK childhood vaccinations: systematic literature review

Aim: An overview of recent epidemiology and disease burden, independent of patient age, of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and Hemophilus influenzae invasive disease in the UK. Materials & methods: A systematic review was undertaken. Outcomes included incidence, prevalence, risk factors and cost burden. Results: 39 publications were included. Hepatitis B prevalence is high among certain risk groups. A small pertussis risk remains in pregnancy and for infants, which led to the introduction of maternal vaccination. H. influenzae invasive disease cases are limited to rare serotypes. Polio, tetanus and diphtheria are well controlled. Conclusion: The evaluated diseases are currently well controlled, thanks to a comprehensive vaccination program, with a generally low clinical and cost burden.

Epidemiology and disease burden of pertussis in the United States among individuals aged 0-64 over a 10-year period (2006-2015)

Background: Pertussis incidence has increased in recent decades despite childhood vaccination programs and high vaccination rates. To quantify the burden of pertussis, incidence, healthcare resource utilization, and costs among pertussis patients were estimated in a US managed care setting.Methods: Patients aged 0-64 years with evidence of pertussis (ICD-9-CM codes 033.0, 033.9, 484.3, ICD-10-CM codes A37.0, A37.9) and commercial insurance from 1 January 2006-12 December 2015 were identified. Incidence rates were calculated and standardized to the 2010 US Census on age, sex, and geographic region. Healthcare costs and resource utilization were compared between patients and matched comparators (health plan members without pertussis).Results: From 2006 to 2015, 11,378 pertussis cases were identified. Adjusted pertussis incidence was 15.55 cases per 100,000 person-years. Incidence was highest among infants and children; however, 59.0% of total cases were among adolescents or adults. Average adjusted healthcare costs per episode were 3.17 times higher among pertussis patients versus comparators ($5195 versus $1637, p < .001). Stratifying by age group, adjusted incremental healthcare costs per episode were $5581, $827, $700, $1429, $2530, and $4849 for patients aged <1 year, 1-6 years, 7-10 years, 11-19 years, 20-49 years, and 50-64 years, respectively.Conclusions: Managing pertussis is associated with substantial economic burden. Incidence rate estimates from this study were higher than CDC-reported rates; however, similar overall trends were observed. Although pertussis incidence has been declining since CDC-recommended vaccination for all adults in 2012, this study highlights the importance of continued management and prevention strategies, especially among adolescents and adults as they represent an important source of transmission to infants.

The problem of pertussis in some regions of the world

Pertussis infection remains a high-priority issue both for Russian health care and abroad. A rise of pertussis incidence in various human age groups instigates a search for new ways to fight this infection and improve methods for its laboratory diagnostics. By taking into consideration a short-term effect induced by acellular and whole-cell vaccines, a feasibility of introducing the second or even the third pertussis revaccination is vigorously debated. Objective of the study was to analyze the experience and effectiveness of acellular pertussis vaccines in countries, which use the second and third pertussis revaccination in the National Immunization Schedule in order to have an insight into adjusting strategy and tactics of pertussis immunization In Russia. Analyzing pertussis prevalence demonstrated that despite a wide immunization coverage pertussis incidence in the last years (2008–2015) was increased in a large number of countries in the European region, as well as inAustralia,CanadaandUSA. However, the reasons for elevated pertussis incidence have not been clarified yet. On one hand, it may be accounted for by low vaccination coverage in adolescents and adults; weakened immune protection after vaccination; genetic changes in Bordetella pertussis; shortened durability of protective immunity in children vaccinated with acellular vs. whole-cell vaccine; improved monitoring and morbidity reporting, as well as improved laboratory diagnostics due to shifting from serological and bacteriological to molecular genetic assays. In an attempt to solve this issue, researchers from several countries collaborate to discuss and develop a strategy to reduce pertussis incidence. ForRussia, the most important is to empower and/or improve existing infant immunization strategy in order to provide wide coverage with the four dose pertussis vaccine for decreasing the risk of pertussis morbidity and mortality. It is worth noting the “cocoon” strategy given the high risk of pertussis infection in children of the first months of life. We believe that forRussiait is worth investigating an opportunity of using children 2–3 months of life an acellular vaccine as the first vaccination, which is expected to increase the coverage of this cohort and allow to increase proportion of children who might complete vaccination by 5 months of age. At the same time, more reasonable might be to preserve a number of age groups for pertussis vaccination in the current National Immunization Schedule, as expanding age limits for vaccination might put a risk at increasing pertussis morbidity in older individuals, which could be hard to diagnose. 

Seroprevalence of diphtheria and pertussis immunoglobulin G among children with pneumonia in Ji'nan, China

BACKGROUND

Vaccination is still one of the most important methods to control and prevent childhood infections including diphtheria and pertussis. This study evaluated the level of diphtheria (DT) and pertussis (PT)-related antibodies among children with pneumonia in Ji'nan, China.

METHODS

A total of 484 sera of children from 1 day to 13 years of age were collected from 2014 to 2015 in Ji'nan. Children with recent history of pertussis were excluded from this study. Anti-DT and PT IgG concentrations were measured by ELISA (Euroimmun, Lübeck, Germany).

RESULTS

Of the 484 subjects tested, the overall positivity rate of anti-DT IgG (≥0.1 IU/ml) was 48.97%, and the highest positivity rate of anti-DT IgG (68.55%) and proportion with long term protection (23.27%) were observed in children aged 6 m- < 3 y. For anti-PT IgG, 334 subjects (69.01%) had anti-PT IgG levels below the lower limit of detection (5 IU/ml). Even with detectable anti-PT antibodies, the majority (115/150, 76.67%) of them had antibody levels of 5- < 40 IU/ml. The highest proportion of subjects with detectable anti-PT IgG (≥5 IU/ml) was observed in children aged < 6 m (44.36%), then the proportion continually decreased to 15.0% at 3 y- < 6 y (χ2 = 24.05, p < 0.0001). The highest positivity rate (≥40 IU/ml) was only 8.27% in children aged < 6 m. Subjects with an anti-PT IgG ≥100 IU/ml were observed in all the groups and there were no significant differences in the proportions of subjects with a level ≥ 100 IU/ml among these age groups (χ2 = 2.572, p = 0.4624). A total of 5 subjects had anti-PT IgG ≥100 IU/ml (≥1 years post pertussis vaccination) which was considered to be indicative of a recent pertussis infection.

CONCLUSIONS

We demonstrated low antibody levels and protection against pertussis in our study population. The anti-PT IgG maintained a low level throughout all age groups, and even no immune responses were observed after the basic immunization and booster. Our study supported the need to reevaluate the immune response of DTP vaccine which was used in Shandong province after 2010.

Recommendations to control pertussis prioritized relative to economies: A Global Pertussis Initiative update

Pertussis is a vaccine-preventable disease that causes morbidity and mortality, particularly in infants and children <5 years of age. The Global Pertussis Initiative (GPI) recommendations represent a systematic evaluation and prioritization of strategies to prevent pertussis-related infant and child deaths, reduce global disease burden and prevent resurgence through vaccination strategies and public health policies at national, regional and local levels. The GPI recommendations are based on clinical trials and observational and surveillance data, which are essential in the planning, implementation and evaluation of vaccination practices and best use of available resources. Many low- and middle-income countries (LMIC) continue to use whole-cell pertussis (wP) vaccines for primary vaccination, while most high-income countries have replaced wP with the less-reactogenic acellular pertussis (aP) vaccines. This present manuscript pertains to discussions held during the GPI's meeting on November 11-13, 2016, in Cape Town, Republic of South Africa. The GPI recommends that LMIC aim for high coverage of infant series pertussis vaccines as a priority. In LMIC and countries with constrained vaccine funding, if wP vaccines are currently used, wP should continue to be used. Furthermore, given that protection against disease and death due to pertussis in neonates is a key priority of the GPI, it recommends that ap immunization in pregnancy should be implemented as a priority in all countries if resources allow. Given that surveillance and epidemiology data on which to base vaccine decisions are important, the GPI also suggests that, in areas where wP vaccines are implemented, standardization and calibration of wP vaccines are checked, considering the many different manufacturers and variable standards of production and quality control. In addition, as immunity to pertussis wanes following the primary infant series of vaccination, the GPI further recommends that toddlers, adolescents, healthcare and childcare workers receive booster vaccine doses, where resources allow.

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.

Prevention of pertussis: An unresolved problem

Pertussis is a highly contagious respiratory disease caused by Bordetella pertussis. However, after the introduction of the whole-cell pertussis vaccine (wP), the annual incidence rates of the disease progressively declined. Despite this result, the inclusion of wP in the national immunization schedule of infants and young children was debated regarding its safety. Several efforts to produce vaccines based on B. pertussis components capable of evoking protective immunity with no or limited adverse events were made. Of these others, five pertussis antigens were considered possible components of acellular vaccines (aPs): pertussis toxin (PT), filamentous haemagglutinin (FHA), pertactin (PRN) and fimbria proteins 2 and 3. However, the introduction of aPs was followed by a slight but progressive increase in the incidence of pertussis. This paper discusses the potential reasons for reduced aPs efficacy. Moreover, it attempts to evaluate the real effectiveness of aPs and the potential differences between available preparations. Data analysis showed that several boosters are needed to maintain protection against pertussis and additional studies are needed to confirm the antigens that should be included in aPs to improve the prevention of pertussis.

Pertussis surveillance and control: exploring variations and delays in testing, laboratory diagnostics and public health service notifications, the Netherlands, 2010 to 2013

Pertussis is most severe among unvaccinated infants (< 1 year of age), and still leads to several reported deaths in the Netherlands every year. In order to avoid pertussis-related infant morbidity and mortality, pertussis surveillance data are used to guide pertussis control measures. However, more insight into the accuracy of pertussis surveillance and control, and into the range of healthcare and public health-related factors that impede this are needed. We analysed a unique combination of data sources from one Dutch region of 1.1 million residents, including data from laboratory databases and local public health notifications between 2010 and 2013. This large study (n = 12,090 pertussis tests) reveals possible misdiagnoses, substantial under-notification (18%, 412/2,301 laboratory positive episodes) and a delay between patient symptoms and notification to the local public health services (median 34 days, interquartile range (IQR): 27–54). It is likely that the misdiagnoses, under-notification and overall delay in surveillance data are not unique to this area of the Netherlands, and are generalisable to other countries in Europe. In addition to preventive measures such as maternal immunisation, based on current findings, we further recommend greater adherence to testing guidelines, standardisation of test interpretation guidelines, use of automatic notification systems and earlier preventive measures.

Are pertussis cases reported too late for public health interventions? Retrospective analysis of cases in London and South East England, 2010 to 2015

In the United Kingdom, pertussis guidance recommends prophylaxis for household contacts within 21 days of case symptom onset if the household includes a vulnerable contact. The aim of our study was to identify characteristics associated with cases reported late for public health action. We reviewed the epidemiology of cases reported in London and South East England for the period 2010 to 2015. We characterised risk factors associated with late reporting of cases and described public health actions taken on timely reported cases. From 2010 to 2015, 9,163 cases of pertussis were reported to health protection teams. Only 11% of cases were reported within 21 days of onset, limiting opportunities for secondary prevention. Timely reporting was associated with younger age groups, pregnancy, being a healthcare worker and being reported by schools or hospital clinicians. Late reporting was associated with older age groups and general practitioner or laboratory reporting. Delays, such as those due to insidious onset and late presentation to healthcare, may be unavoidable; however, delay in reporting once a patient presents can be reduced since cases can be reported before laboratory confirmation. Thus we recommend working with clinicians and laboratories to determine causes and improve early reporting to public health.

Evaluation of the Immunization Program in the Federation of Bosnia and Herzegovina - Possible Modalities for Improvement

INTRODUCTION

Immunization is a lifelong preventive activity that helps prevent/reduce disease, prevent/ reduce mortality and prevent disability from specific infectious diseases.

MATERIAL AND METHODS

Authors of this paper researched the WHO extended program of mandatory immunization of children from birth to the age of 18 years and analyzed how it has been implemented in the Federation of Bosnia and Herzegovina (FB&H), because the guidelines of the specialist physician societies on immunization of adults, elderly people and risk groups of the population are missing.

RESULTS

The paper presents the basic characteristics of the immunization program in the FB&H and the world, points to the most frequent problems that the doctor practitioner has in carrying out immunization, and also presents possible modalities of improving immunization. It is pointed out the need to develop the national guidelines and individual immunization booklets, introduction of electronic registration of immunization, and continuous education of health professionals of all profiles, population, educators, teachers and harmonious partnership relations of health workers, population, social entities and the media with the aim of achieving an appropriate lifelong vaccination.

Aetiology of lower respiratory tract infection in adults in primary care: a prospective study in 11 European countries

Objectives

To describe the role of bacteria (including bacterial resistance), viruses (including those recently described) and mixed bacterial–viral infections in adults presenting to primary care with lower respiratory tract infection (LRTI).

Methods

In all, 3104 adults with LRTI were enrolled, of whom 141 (4.5%) had community-acquired pneumonia (CAP), and 2985 matched controls in a prospective study in 16 primary care networks in Europe, and followed patients up at 28–35 days. We detected Streptococcus pneumoniae and Haemophilus influenzae and assessed susceptibility, atypical bacteria and viruses.

Results

A potential pathogen was detected in 1844 (59%) (in 350 (11%) bacterial pathogens only, in 1190 (38%) viral pathogens only, and in 304 (10%) both bacterial and viral pathogens). The most common bacterial pathogens isolated were S. pneumoniae (5.5% overall, 9.2% in CAP patients) and H. influenzae (5.4% overall, 14.2% in CAP patients). Less than 1% of S. pneumoniae were highly resistant to penicillin and 12.6% of H. influenzae were β-lactamase positive. The most common viral pathogens detected were human rhinovirus (20.1%), influenza viruses (9.9%), and human coronavirus (7.4%). Influenza virus, human parainfluenza viruses and human respiratory syncytial virus as well as human rhinovirus, human coronavirus and human metapneumovirus were detected significantly more frequently in LRTI patients than in controls.

Conclusions

A bacterial pathogen is identified in approximately one in five adult patients with LRTI in primary care, and a viral pathogen in just under half, with mixed infections in one in ten. Penicillin-resistant pneumococci and β-lactamase-producing H. influenzae are uncommon. These new findings support a restrictive approach to antibiotic prescribing for LRTI and the use of first-line, narrow-spectrum agents in primary care.

Pertussis and parapertussis in children and adults with a persistent cough: an observational study

PURPOSE

We aimed to determine the prevalence, symptoms and course of pertussis and parapertussis among patients at any age with a cough of unknown aetiology that had lasted for ≥ 7 days and to assess the diagnostic value of the symptoms included in the World Health Organisations' (WHO) clinical case definition of pertussis.

METHODS

Patients were enrolled between the 23 April 2012 and 31 December 2014 at 25 general practitioner (GP) centres and three paediatric hospitals. Pertussis was confirmed by culture and/or polymerase chain reaction (PCR) and/or quantitative serology. Parapertussis was confirmed by culture and/or PCR.

RESULTS

Altogether, 549 patients were recruited. Of them, 22 (4.0%; 95% CI 2.5-6.0) had pertussis (predominately diagnosed by positive serology 17/22) and 7 (1.3%; 95% CI 0.5-2.6) had parapertussis. Patients with pertussis were more likely to have inspiratory whooping and posttussive emesis than those with a cough of another/unknown aetiology. However, the presence or absence of these two symptoms did not definitively confirm or exclude pertussis. The sensitivity and specificity of the WHO's clinical definition was 0.77 and 0.38, respectively.

CONCLUSIONS

The prevalence of pertussis and parapertussis among patients with a persistent cough of unknown aetiology in Estonia is low. As clinical symptoms alone cannot be used to distinguish pertussis, we recommend that laboratory testing for pertussis is performed in all patients with a persistent cough regardless of age.

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.

Prevalence of Atypical Pathogens in Patients With Cough and Community-Acquired Pneumonia: A Meta-Analysis

PURPOSE

Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae. The prevalence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature.

METHODS

We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions.

RESULTS

Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalences of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%).

CONCLUSIONS

Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalences in studies where all patients are tested for these pathogens. It is likely that these conditions are underreported, underdiagnosed, and undertreated in current clinical practice.

A Belgian Serosurveillance/Seroprevalence Study of Diphtheria, Tetanus and Pertussis Using a Luminex xMAP Technology-Based Pentaplex

Serosurveillance and seroprevalence studies are an essential tool to monitor vaccine-preventable diseases. We have developed a magnetic bead-based pentaplex immunoassay (MIA) for the simultaneous detection of IgG antibodies against diphtheria toxin (DT), tetanus toxin (TT), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (Prn). The in-house pentaplex MIA showed a good correlation with commercial ELISAs with correlation coefficients between 0.89 for PT and 0.98 for TT. Intra- and inter-assay variability was <10%. A total of 670 anonymized serum samples collected in 2012 in Belgian adults (ages 20–29.9 years) were analyzed. Geometric mean concentrations (GMC) were 0.2 (0.13–0.29) IU/mL for DT, 0.63 (0.45–0.82) IU/mL for TT, 3.9 (2.6–5.8) IU/mL for PT, 16.3 (11.7–22.7) IU/mL for FHA and 15.4 (10.1–23.6) IU/mL for Prn. Antibody concentrations were below the protective level of 0.1 IU/mL in 26.4% of the sera for DT and in 8.6% of the sera for TT. Anti-PT IgG concentrations indicative of recent pertussis infection (>125 IU/mL) were detected in 1.2% of the subjects. High anti-PT antibodies were not correlated with high antibodies against any of the four other vaccine antigens. This pentaplex MIA will be used for a new large-scale Belgian serosurveillance/seroprevalence study of diphtheria, tetanus and pertussis.