Reduced pertussis disease severity in infants following the introduction of pertussis vaccination of pregnant women in Spain, 2015-2019

BACKGROUND

Maternal pertussis vaccination during the third trimester of pregnancy was implemented in 2015 in Spain, reaching a national coverage of 84% in 2019. In this ecological study, we investigated whether there was a change in the disease severity for pertussis in infants upon introduction of prenatal pertussis vaccination.

METHODS

We performed a time-trend analysis of infant pertussis hospitalizations during 2005-2019 in Spain using national register data. Annual hospitalization rates per 100,000 population and the mean length of hospitalization were calculated for infants < 3 months of age (target group benefiting from the prenatal vaccination) and a reference group aged 3-11 months. We compared overall rates and annual percent changes of the above variables in both groups for the time period before (2005-2014) and after vaccination introduction (2015-2019), using segmented Poisson regression.

RESULTS

During the pre-vaccination period, infants aged 0-2 months had a 5-times higher rate of pertussis hospitalization and spent on average 50 % longer in hospital than the reference group. After the maternal vaccination introduction, the hospitalization rate decreased more rapidly in infants aged 0-2 months than in infants aged 3-11 months: annual reduction of 34 % (95 % CI: 31-38) versus 26 % (95 % CI: 21-31) in the hospitalization rate and 13 % (95 % CI: 11-15) versus 6 % (95 % CI: 2-9) in the mean hospital stay, respectively. In 2019, the mean hospital stay for pertussis was about 4.5 days in both groups.

CONCLUSIONS

Maternal pertussis vaccination in Spain led to a reduction in disease severity in the target group as compared to older infants, highlighting the need for increased efforts on educating healthcare professionals on the importance of maternal vaccinations.

Laboratory Performance and Clinical Correlation of Real-time Polymerase Chain Reaction as a Diagnostic Test for Bordetella Pertussis Isolated from Patients in Oman

Objectives

To evaluate real-time polymerase chain reaction (PCR) as a diagnostic tool for pertussis (whooping cough), vis-à-vis culture, the long-time gold standard, with emphasis on the importance of clinical correlation in determining specificity.

Methods

Nasopharyngeal/throat swab samples in charcoal media received from all over Oman at Central Public Health Laboratories from January 2014 to December 2016 were included in this study. These samples were tested using both culture and real-time PCR. PCR was compared with culture to calculate its sensitivity and specificity. Further clinical correlation was conducted for the discrepant cases using different case definitions.

Results

A total of 590 nasopharyngeal/throat samples were included in the study. Out of the 590 samples, 73 were positive by PCR compared with 26 positive samples by culture (which were also positive by PCR). The sensitivity and specificity of PCR compared with those of culture were 100% (95% CI: 86.77−100) and 91.7% (95% CI: 89.07−93.81), respectively. To rule out false-positive results by PCR, clinical correlation was performed. Out of 47 cases that were positive by PCR but negative by culture, 44 cases were clinically evaluated by accessing clinical details. Out of these 44 cases, 21 (47.7%) met the pertussis clinical criteria according to the CDC-2014 case definition, 41 (93.2%) according to the Europe-2008 case definition, and 44 (100%) according to the Canada-2009 and Australia-2014 case definitions. With only positive PCR, these cases were classified as confirmed according to these case definitions, which increased the specificity of PCR to 95.7–100%. The mean turnaround time was 3.5 days for PCR compared to 6.2 days for culture.

Conclusions

Real-time PCR is a highly sensitive and specific test for the diagnosis of Bordetella pertussis infection. Based on our results, we recommend setting up PCR diagnostic facilities in regional hospitals in Oman as this will lead to a timely and accurate diagnosis of pertussis.

Recent increase in pertussis incidence in South Korea: An age-period-cohort analysis

OBJECTIVES

Pertussis or whooping cough—one of the most contagious diseases—is caused by the Gram-negative bacterium Bordetella pertussis. Despite a high vaccination rate, Korea recently experienced a resurgence of pertussis. This study explores patterns and possible explanations for this resurgence through an age-period-cohort analysis.

METHODS

Using secondary data from the infectious disease portal of the Korea Disease Control and Prevention Agency and the Korea Statistical Information Service of Statistics Korea, this study analyzed the incidence of pertussis in Korea to determine which factors contributed to the recent increase using an age-period-cohort model.

RESULTS

Analysis of the age effect indicated that the age group most vulnerable to pertussis was 0-year to 2-year-olds. Analysis of the period effect showed a sharp increase in the incidence rate after 2016. Analysis of the cohort effect showed a significant decrease in incidence beginning with the 1955 birth cohort, with the risk increasing again with the 2000s birth cohort.

CONCLUSIONS

Previous studies have suggested 3 main possible explanations for our results. First, the increased incidence rate can be attributed to contact rates. Second, the rate of immunity through natural exposure has decreased due to the low number of circulating pathogens, in turn affecting the trend of infection. Lastly, variations in pathogens may have also contributed to the increase in incidence. Given that the most significant increase in incidence was observed among infants younger than 1 year old, sufficient maternal immunity must be prioritized to provide passive immunity to newborns via the placenta.

A 6-year Prospective, Observational, Multi-Center Post-Marketing Surveillance of the Safety of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis (Tdap) Vaccine in Korea

BACKGROUND

Incidence of whooping cough is increasing in Korea. Since 2011, occurrence among adolescents and adults has risen putting vulnerable neonates at risk. National immunization guidelines now include Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccination during pregnancy and as a cocooning strategy (i.e., vaccinating adults and adolescents in contact with neonates). This study assessed post-marketing Tdap (Boostrix^®, GSK, Belgium) vaccine safety in subjects ≥ 10 years.

METHODS

This open, non-comparative multi-center study was conducted over six years at 10 hospitals in Korea. Subjects received Tdap in normal clinical practice according to local prescribing information. All adverse events (AEs) were recorded, classified as expected or unexpected, and severity and relationship to Tdap were assessed.

RESULTS

The analysis included 672 Korean subjects (mean age, 44 years; range, 11-81), 451 were women and 211 were pregnant. Ninety subjects experienced 124 AEs (incidence 13.39%) of which six were serious AEs (SAEs) assessed as not related to vaccination, and 51 were non-SAEs related to vaccination (mostly administration site reactions). Overall 65/124 AEs were unexpected; the most common were 14 constipation, 5 dyspepsia, 4 common cold and 4 premature labor cases. One case of common cold was assessed as possibly related to vaccination. Pregnancy outcome was 'live infant, no apparent congenital anomaly' in 195 subjects (92.42%) or 'lost to follow-up' in 16 subjects.

CONCLUSION

Tdap administration to Korean subjects ≥ 10 years, including pregnant women, for the prevention of diphtheria, tetanus and pertussis was shown to have a well-tolerated safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01929291.

Clinical Diagnosis of Bordetella Pertussis Infection: A Systematic Review

BACKGROUND

Bordetella pertussis (BP) is a common cause of prolonged cough. Our objective was to perform an updated systematic review of the clinical diagnosis of BP without restriction by patient age.

METHODS

We identified prospective cohort studies of patients with cough or suspected pertussis and assessed study quality using QUADAS-2. We performed bivariate meta-analysis to calculate summary estimates of accuracy and created summary receiver operating characteristic curves to explore heterogeneity by vaccination status and age.

RESULTS

Of 381 studies initially identified, 22 met our inclusion criteria, of which 14 had a low risk of bias. The overall clinical impression was the most accurate predictor of BP (positive likelihood ratio [LR+], 3.3; negative likelihood ratio [LR-], 0.63). The presence of whooping cough (LR+, 2.1) and posttussive vomiting (LR+, 1.7) somewhat increased the likelihood of BP, whereas the absence of paroxysmal cough (LR-, 0.58) and the absence of sputum (LR-, 0.63) decreased it. Whooping cough and posttussive vomiting have lower sensitivity in adults. Clinical criteria defined by the Centers for Disease Control and Prevention were sensitive (0.90) but nonspecific. Typical signs and symptoms of BP may be more sensitive but less specific in vaccinated patients.

CONCLUSIONS

The clinician's overall impression was the most accurate way to determine the likelihood of BP infection when a patient initially presented. Clinical decision rules that combine signs, symptoms, and point-of-care tests have not yet been developed or validated.

Study on Toxicity Reduction and Potency Induction in Whole-cell Pertussis Vaccine by Developing a New Optimal Inactivation Condition Processed on Bordetella pertussis

Background

Whooping cough is caused by Bordetella pertussis, and it remains a public health concern. Whole-cell pertussis vaccines have been commonly employed for expanded immunization. There is no doubt of the efficacy of whole cell pertussis vaccine, but it is necessary to improve the vaccine to decrease its toxicity.

Objectives

In this study, an inactivation process of dealing with pertussis bacteria is optimized in order to decrease the bacteria content in human doses of vaccines and reduce the vaccine’s toxicity.

Materials and Methods

The bacterial suspensions of pertussis strains 509 and 134 were divided into 21 sample parts from F₁ to F₂₁ and inactivated under different conditions. The inactivated suspensions of both strains were tested for opacity, non-viability, agglutination, purity, and sterility; the same formulation samples that passed quality tests were then pooled together. The pool of inactivated suspensions were analyzed for sterility, agglutination, opacity, specific toxicity, and potency.

Results

The harvest of both bacterial strains showed purity. The opacity of various samples were lost under different treatment conditions by heat from 8% to 12%, formaldehyde 6% to 8%, glutaraldehyde 6% to 8%, and thimerosal 5% to 8%. Tests on suspensions after inactivation and on pooled suspensions showed inactivation conditions not degraded agglutinins of both strains. The samples of F₂, F₄, F₈, F₁₂, F₁₅, and F₁₇ passed the toxicity test. The potency (ED50) of these samples showed following order F₁₇ > F₁₂ > F₈ > F₁₅, F₄ > F₂, and F₁₇ revealed higher potency compared to other formulations.

Conclusions

It can be concluded that F₁₇ showed desirable outcomes in the toxicity test and good immunogenicity with a low bacterial number content. Consequently, lower adverse effects and good immunogenicity are foreseeable for vaccine preparation with this method.

The First Report of Epidemic Pertussis by Bahaodowle Razi From the 15th Century Anno Domini

Background:

Pertussis or “whooping cough” is an acute, communicable infection of the respiratory tract caused by the Gram-negative bacterium Bordetella pertussis. It has been recorded in history of medicine that the first pertussis epidemic was reported in 1578 by a French scientist, Guillaume de Baillou, in Paris. Furthermore, the causative agent was first isolated in 1906 by Jules Jean Baptiste Vincent Bordet and his brother-in-law Octave Gengou. However, it seems that earlier reports can be found in history of medicine.

Objectives:

The aim of this study as to analyze the first Report of Epidemic Pertussis by Bahaodowle Razi From the 15th Century Anno Domini

Materials and Methods:

We investigated a copy (Persian lithograph) of the book named “a summary of experiences in medicine”, written by Bahaoddin-bin-Ghasem-Bahaoddin Razi (well known as Bahaodowle Razi) in 1502 to find the earliest existing report of epidemic pertussis in the history.

Results:

Bahaodowle Razi, a Persian physician from the 15th century Anno Domini (AD), reported two epidemics in Harat and one in Rey (inold Persia) for the first time, one century before Baillou. He named it as Sorfe-ie-Am (meaning public cough). Those occurred during his lifetime. Explaining about his observations and experiences about this epidemic, Bahaodowle Razi elaborated on prognosis, symptoms, etiology and predisposing factors of pertussis.

Conclusions:

This document shows that Bahaodowle Razi’s report was the first report of epidemic pertussis in the medical history.

High Seroprevalence of Bordetella pertussis in Patients with Chronic Obstructive Pulmonary Disease: A Case-Control Study

BACKGROUND

Bordetella pertussis has been suggested to take part in the acute exacerbation of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the association between B. pertussis and COPD.

MATERIALS AND METHODS

In this case-control study, 90 patients with COPD and 90 age- and sex- matched control subjects were included. Serum samples were tested for anti-B. pertussis IgG and IgA by ELISA. A physician completed a questionnaire including demographic characteristics, habitual history and spirometric findings for each patient.

RESULTS

Of 90 patients with chronic obstructive pulmonary disease, 66 (51%) had mild, 31 (34.4%) had moderate, and 13 (14.4%) had severe disease. There was no significant association between B. pertussis IgA seropositivity and COPD. Serum levels of anti- B. pertussis IgG were significantly higher in patients with COPD than in the control subjects (P < 0.001). No association was observed between B. pertussis infection and severity of COPD.

CONCLUSION

The results suggest that there is an association between B. pertussis infection and COPD. Further studies should be planned to investigate the potential pathogenic mechanisms underlying these associations.

Status of pertussis in iran

BACKGROUND

Pertussis is a respiratory and contagious disease which is mostly caused by Bordetella pertussis and B. parapertussis. It usually spreads from person to personduring the incubation or catarrhal phase of the disease. Despite of large-scale vaccination, whooping cough is still an endemic disease with several outbreaks.

OBJECTIVES

The aim of this study was to determine the prevalence of pertussis and identify its causative agents, B. pertussis or B. parapertussis, from specimens collected from Iranian patients from 2004 to 2008.

PATIENTS AND METHODS

Nasopharyngeal swab samples from 347 suspected pertussis cases were collected from 18 provinces of Iran. The patients were in different age groups and were either unvaccinated or vaccinated for pertussis with whole cell vaccine (WCV). Bacterial culture, agglutination tests and quantitative PCR (qPCR) targeting IS481 and IS1001 for B. pertussis and B. parapertussis were done for every specimen, respectively.

RESULTS

The results showed that seven nasopharyngeal swab samples (2%) were positive for B. pertussis (1.7%) and B. parapertussis (0.3%) by culture and agglutination test and 30 patients had positive qPCR test results (9%).

CONCLUSIONS

Despite the fact that bacterial culture is the golden standard for the detection of B. pertussis, direct detection of bacteria from nasopharyngeal specimens can be performed by a rapid qPCR assay. In this study, high percentage of positive qPCR cases may indicate that the patients might have recovered from pertussis following antibiotic treatment before samples were collected. Rapid detection by qPCR could be important for immediate diagnosis and treatment of patients with pertussis.

Bordetella pertussis infection in a child with completed primary immunization: A case report

A 20 mo old male child, born at 31 weeks, presented to an out-of-hours General Practitioner (GP) with a 7 d history of cough and fever. There was history of post-tussive vomiting. On assessment a pernasal swab was cultured from which B. pertussis was isolated. This child had received a complete course of primary immunization. In the light of recent increase in Pertussis cases in the United Kingdom we would like to use this case report to increase the awareness among clinicians to the possibility of a diagnosis of whooping cough even in children with completed primary immunization and particularly in preterm infants.

A Multicenter Study of Pertussis Infection in Adults with Coughing in Korea: PCR-Based Study

BACKGROUND

Limited data on the incidence and clinical characteristics of adult pertussis infections are available in Korea.

METHODS

Thirty-one hospitals and the Korean Centers for Disease Control and Prevention collaborated to investigate the incidence and clinical characteristics of pertussis infections among adults with a bothersome cough in non-outbreak, ordinary outpatient settings. Nasopharyngeal aspirates or nasopharyngeal swabs were collected for polymerase chain reaction (PCR) and culture tests.

RESULTS

The study enrolled 934 patients between September 2009 and April 2011. Five patients were diagnosed as confirmed cases, satisfying both clinical and laboratory criteria (five positive PCR and one concurrent positive culture). Among 607 patients with cough duration of at least 2 weeks, 504 satisfied the clinical criteria of the US Centers for Disease Control and Prevention (i.e., probable case). The clinical pertussis cases (i.e., both probable and confirmed cases) had a wide age distribution (45.7±15.5 years) and cough duration (median, 30 days; interquartile range, 18.0~50.0 days). In addition, sputum, rhinorrhea, and myalgia were less common and dyspnea was more common in the clinical cases, compared to the others (p=0.037, p=0.006, p=0.005, and p=0.030, respectively).

CONCLUSION

The positive rate of pertussis infection may be low in non-outbreak, ordinary clinical settings if a PCR-based method is used. However, further prospective, well-designed, multicenter studies are needed.