Pertussis IgG Research Articles

Influence of Hematocrit and Storage Temperature on the Stability of Dried Blood Samples in Serological Analyses of Tetanus, Diphtheria, and Pertussis.

Dried blood spots (DBSs) enable the study of serological markers of various pathogens without the need to obtain serum/plasma through venipuncture. Sixty-four blood samples were prepared on Whatman™ 903 cards using specimens obtained by venipuncture to study the detection of serological markers of diphtheria, tetanus, and pertussis in DBSs, and their stability 4 months post-collection. An automated chemiluminescent immunoassay was used to investigate diphtheria, tetanus, and pertussis IgG levels from both DBSs and plasma samples. An optimal cut-off value for DBSs was calculated to improve the performance of diphtheria and tetanus serological markers in DBSs, achieving high sensitivity (95% and 98%, respectively) and specificity (91.7% and 92.3%, respectively). No protection against pertussis was found in the population studied. The correlation observed between the plasma and the DBSs processed after sample collection was high (0.967-0.970) for all antibodies studied except pertussis (0.753), both considering hematocrit before sample elution or not. The correlation between DBSs and plasma for diphtheria and tetanus remained strong following a 4-month delay in DBS processing at 4 °C (0.925-0.964) and -20 °C (0.924-0.966), with only a minor decrease observed for diphtheria at room temperature (0.889), while maintaining a strong correlation for tetanus (0.960). For pertussis, the correlation between DBSs and plasma was drastically reduced after delaying its processing for 4 months at any temperature. To summarize, hematocrit levels within the normal range do not affect the processing of DBSs in the study of serological markers of diphtheria, tetanus, and pertussis. The DBS stability for serological diagnosis of diphtheria and tetanus is adequate when samples are stored at -20 °C for a period of 4 months. The pertussis serological marker does not appear to remain stable after 4 months, even when the DBS is stored frozen at -20 °C.

Pilot Study on Evaluating the Impact of Tetanus, Diphtheria, and Pertussis (Tdap), Influenza, and COVID-19 Vaccinations on Antibody Responses in Pregnant Women.

This study assessed IgG levels to influenza/pertussis and neutralizing antibody (Nab) responses of COVID-19 vaccines in blood of pregnant women following immunization with pertussis (Tdap), influenza, and COVID-19 vaccines. We prospectively collected 71 participants categorized by the following vaccine combinations: 3TI, 4TI, 3T, and 4T groups (three and four doses of COVID-19 vaccines plus Tdap/influenza or Tdap vaccines alone). Our findings have indicated that the 3TI group exhibited elevated IgG levels for influenza B compared to the 3T group (12.90 vs. 7.75 U, p = 0.001); this pattern was not observed for influenza A. Pertussis IgG levels remained uniform across all groups. The 4TI group demonstrated a greater Nab inhibition rate from COVID-19 vaccines compared to both the 3TI and 3T groups (61.34% vs. 22.5% and 15.16%, respectively, p = 0.001). We observed no correlation between Nab inhibition rate and IgG levels for Tdap/influenza, with the exception of a moderate correlation with influenza B in the 3TI group. The efficacy of Tdap vaccine in pregnant women remained consistent, regardless of the administration of COVID-19 or influenza vaccines. Interestingly, without the influenza vaccine, both three and four doses of the COVID-19 vaccine still offered protection against influenza A, but not B. Hence, co-administering COVID-19, influenza, and Tdap vaccines during prenatal care maintains immunogenicity and is highly advised to safeguard pregnant women fully.

Impact of pregnancy on polyfunctional IgG and memory B cell responses to Tdap immunization

BackgroundMaternal pertussis immunization using Tdap vaccine is recommended in many countries to protect newborns from severe post-natal infection. Immunological changes during pregnancy may influence the response to vaccines. The quality of IgG and memory B cell responses to Tdap immunization in pregnant women has not yet been described. MethodsThe impact of pregnancy on the response to Tdap vaccination was assessed by comparing humoral immune responses in 42 pregnant and 39 non-pregnant women. The levels of serum pertussis antigens and tetanus toxoid-specific IgG, IgG subclasses, IgG Fc-mediated effector functions, as well as memory B cell frequencies were assessed before and at several time points after vaccination. ResultsTdap immunization induced similar levels of pertussis and tetanus-specific IgG and IgG subclasses in pregnant and non-pregnant women. Pregnant women produced IgG promoting complement deposition, and neutrophils and macrophages phagocytosis at levels comparable to non-pregnant women. They were also able to expand pertussis and tetanus-specific memory B cells at similar frequencies as non-pregnant women, suggesting equivalent “boostability”. Higher levels of vaccine-specific IgG, IgG subclasses, and IgG Fc-mediated effector functions were detected in cord blood as compared to maternal blood, indicating efficient transport across the placenta. ConclusionsThis study demonstrates that pregnancy does not affect the quality of effector IgG and memory B cell responses to Tdap immunization and that polyfunctional IgG are efficiently transferred across the placenta. Registry's URL and the trial's registration numberClinicalTrials.Gov (NCT03519373).

Biomarkers detected in cord blood predict vaccine responses in young infants.

Factors influencing vaccine immune priming in the first year of life involve both innate and adaptive immunity but there are gaps in understanding how these factors sustain vaccine antibody levels in healthy infants. The hypothesis was that bioprofiles associated with B cell survival best predict sustained vaccine IgG levels at one year. Longitudinal study of plasma bioprofiles in 82 term, healthy infants, who received standard recommended immunizations in the United States, with changes in 15 plasma biomarker concentrations and B cell subsets associated with germinal center development monitored at birth, soon after completion of the initial vaccine series at 6 months, and prior to the 12-month vaccinations. Post vaccination antibody IgG levels to Bordetella pertussis, tetanus toxoid, and conjugated Haemophilus influenzae type B (HiB) were outcome measures. Using a least absolute shrinkage and selection operator (lasso) regression model, cord blood (CB) plasma IL-2, IL-17A, IL-31, and soluble CD14 (sCD14) were positively associated with pertussis IgG levels at 12 months, while CB plasma concentrations of APRIL and IL-33 were negatively associated. In contrast, CB concentrations of sCD14 and APRIL were positively associated with sustained tetanus IgG levels. A separate cross-sectional analysis of 18 mother/newborn pairs indicated that CB biomarkers were not due to transplacental transfer, but rather due to immune activation at the fetal/maternal interface. Elevated percentages of cord blood switched memory B cells were positively associated with 12-month HiB IgG levels. BAFF concentrations at 6 and 12 months were positively associated with pertussis and HiB IgG levels respectively. Sustained B cell immunity is highly influenced by early life immune dynamics beginning prior to birth. The findings provide important insights into how germinal center development shapes vaccine responses in healthy infants and provide a foundation for studies of conditions that impair infant immune development.

Sero-Epidemiological Study of Bordetella pertussis Infection in the Italian General Population.

A multicenter study was conducted to estimate the prevalence of pertussis IgG antibodies (anti-PTx) in the Italian population. Serum samples (4154) collected in the years 2019−2020 from subjects aged 6 to 90 years were tested. The anti-PTx IgG levels were determined by ELISA test. The limit of detection was 5 IU/mL (International Units per milliliter); values ≥ 40 IU/mL and ≥100 IU/mL indicate an infection that has occurred in recent years and a recent infection (occurred during the last year), respectively. The mean concentration of anti-PTx IgG antibodies in the tested samples was 13 IU/mL; 1.0% of subjects had a titer ≥ 100 IU/mL, 5.3% a titer between 40 and 100 IU/mL, and 38.9% a titer < 5 IU/mL. The mean antibody concentration was significantly higher in males than in females. The age group 25−39 years had the lowest percentage of negative subjects (36.9%) and the highest prevalence of subjects with antibody titers ≥ 100 IU/mL (1.3%). In the age group ≥ 65 years, the prevalence of subjects with titers between 40 and 100 IU/mL (6.7%) and the percentage of negative subjects (44.8%) was higher than in the other age groups. The results highlight the possible role of adolescents and adults in the transmission of B. pertussis.

Mucosal Immunization with DTaP Confers Protection against Bordetella pertussis Infection and Cough in Sprague-Dawley Rats.

ABSTRACTPertussis is a respiratory disease caused by the Gram-negative pathogen, Bordetella pertussis. The transition from a whole-cell pertussis vaccine (wP and DTP) to an acellular pertussis vaccine (aP, DTaP, and Tdap) correlates with an increase in pertussis cases, despite widespread vaccine implementation and coverage, and it is now appreciated that the protection provided by aP rapidly wanes. To recapitulate the localized immunity observed from natural infection, mucosal vaccination with aP was explored using the coughing rat model of pertussis. Overall, our goal was to evaluate the route of vaccination in the coughing rat model of pertussis. Immunity induced by both oral gavage and intranasal vaccination of aP in B. pertussis challenged rats over a 9-day infection was compared to intramuscular wP (IM-wP)- and IM-aP-immunized rats that were used as positive controls. Our data demonstrate that mucosal immunization of aP resulted in the production of anti-B. pertussis IgG antibody titers similar to IM-wP- and IM-aP-vaccinated controls postchallenge. IN-aP also induced anti-B. pertussis IgA antibodies in the nasal cavity. Immunization with IM-wP, IM-aP, IN-aP, and OG-aP immunization protected against B. pertussis-induced cough, whereas OG-aP immunization did not protect against respiratory distress. Mucosal immunization by both intranasal and oral gavage administration protected against acute inflammation and decreased bacterial burden in the lung compared to mock-vaccinated challenge rats. The data presented in this study suggest that mucosal vaccination with aP can induce a mucosal immune response and provide protection against B. pertussis challenge. This study highlights the potential benefits and uses of the coughing rat model of pertussis; however, further questions regarding waning immunity still require additional investigation.

Analysis of capability to pertussis etiology and serological diagnosis for GradeⅡ and Ⅲmedical institutions in Shandong Province in 2018

Objective: Investigate and analyze the etiology and serological diagnosis capabilities of pertussis in medical institutions in Shandong Province in 2018. Methods: Using the census method, a questionnaire survey was conducted among 603 second and above level medical institutions in Shandong Province. The deadline for the survey was December 2018, and a total of 543 questionnaires have been recovered, and the validity rate of the questionnaires was 90%. Surveyed the pertussis etiology and serology test items (pertussis IgM and IgG, pertussis nucleic acid and pertussis bacterial culture) and the start time of each test item by questionnaire. The reported cases (confirmed cases and clinically diagnosed cases) between January 1, 2012 and December 31, 2018 were derived from the Chinese Disease Control and Prevention Information System according to the onset date. We used indicators such as fixed-base development speed, chain development speed, and chain growth speed for analysis. The chi test was used to analyze the differences in the composition ratio of medical institutions with detection ability in different levels and regions, and analyze the changes in the number of reported cases before and after the development of pertussis etiology and serology testing. Results: A total of 543 medical institutions accounted for 90.0% (543/603) of all secondary and above level medical institutions in the province, 356 secondary medical institutions (65.6%), and 187 tertiary medical institutions (34.4%). There were 10 medical institutions that carry out pertussis IgM, IgG and nucleic acid testing, accounting for 1.8% (10/543) of the surveyed medical institutions respectively. 2 medical institutions that carried out bacterial culture, accounting for 0.4% of the surveyed medical institutions (2/543). 20 medical institutions have carried out the above tests (8 secondary medical institutions and 12 tertiary medical institutions), accounting for 3.7% (20/543). The proportion of tertiary medical institutions with pertussis IgM, IgG detection and nucleic acid detection capabilities [6.42% (12/187)] was significantly higher than that of secondary medical institutions [2.25% (8/356)] (χ²=6.01, P=0.014). From 2012 to 2018, the fixed base ratio development speed of reported cases was 3 834.69% in Shandong Province, among which medical institutions with etiology and serological testing capabilities reached 4 533.33%. In 13 medical institutions, the average annual number of reported cases after pertussis etiology and serological testing were higher than that of reported cases before testing. Conclusion: The ability of pertussis etiology and serology diagnosis of secondary and above medical institutions in Shandong Province needs to be improved.

The epidemic process of whooping cough at contemporary stage in the Republic of Kyrgyzstan

The causes of epidemic outbreaks of pertussis infection in the Kyrgyz Republic were studied in order to optimize immunological surveillance of this infection. The object of the study was the epidemic process of whooping cough, and the subject of the study was the incidence of pertussis infection in 2009-2018 and official data on the outbreak of pertussis in 2018. To diagnose pertussis the bacteriological method was applied. The bacteriological inoculation of the samples was carried out in the laboratory of the Republican Clinical Infectious Diseases Hospital. The smear from posterior pharyngeal wall was collected from 2153 patients. The level of pertussis antibodies was determined by enzyme-linked immunosorbent assay (ELISA) using the RIDASCREEN Pertussis IgG test system (R-Biopharm, Germany) in various series. The study data testifies that despite the vaccine prevention and high inoculation coverage, the epidemic increases occurred in incidence of whooping cough in 2015 and 2018 with an intensive rate of 4.7 and 9.6 per hundred thousand of population, respectively. The evaluation of vaccination status of patients demonstrated that out of them 80.7% were non-immunized; the percentage of vaccinated patients made up to 13.1%. The analysis of the age structure testifies that the main group of the diseased consisted of children under one year of life (63.1%), the second group consisted of children aged 1-4 years (33.1%). The severe forms of infection were observed among children under one year of age (95.8%). According to the territorial distribution, the largest percentage of cases fall on Bishkek - 70% (426 cases) and Chuyskaya Oblast - 22.4% (137 cases). The sero-epidemiological study revealed high proportion of seronegative individuals in all studied groups, and the highest percentage was observed in the group of children 5-9 years old and adolescents of 15-19 years old - 62.8% and 62%, respectively.

Survey of antibody levels of pertussis, diphtheria and tetanus in 495 pregnant women in Nanshan District of 2019, Shenzhen

Objective: The purpose of this study was to investigate the IgG antibody levels of whooping cough, diphtheria, and tetanus in pregnant women in Nanshan District. Methods: From January to March 2019, 495 pregnant women who met the inclusion criteria in a hospital in Nanshan District, Shenzhen were selected as the survey subjects. The enzyme-linked immunosorbent assay was used to detect serum levels of pertussis, diphtheria, and tetanus IgG antibodies and we compared the differences in antibody levels of pregnant women with different characteristics. Results: The maternal age was (29.23±4.08) years old. The geometric mean concentration of pertussis antibody was 2.589 (1.172-4.953) IU/ml, 1.01% (5 cases) of pregnant women had pertussis antibody concentration ≥ 40 IU/ml, and 75.15% (372 cases) of pregnant women had pertussis antibody concentration<5 IU/ml. The GMC value and antibody positive rate of diphtheria in pregnant women were 0.024(0.009-0.065) IU/ml and 72.53% (359 cases), respectively. The GMC value and antibody positive rate of tetanus in pregnant women were 0.014 (0.006-0.034) IU/ml and 53.74% (266 cases), respectively. There was no statistical difference in the antibody level and antibody positive rate among pregnant women of diphtheria and tetanus, respectively. Conclusion: The concentration of antibodies against pertussis, diphtheria, and tetanus in pregnant women are all at a low level, which is not enough to protect themselves from disease infection.

Seroprevalence of an antibody against diphtheria, tetanus, and pertussis among the elderly in Khon Kaen, Thailand

BackgroundOwing to a declining birth rate and longer lifespan, the number of elderly people (≥ 60 years) in Thailand has grown rapidly. However, the elderly are at significant risk of infectious diseases because they have never been immunized, because they have not been completely immunized, or because their immunity has waned. Immunity against infectious diseases in the elderly is an important means of controlling diseases in the community. Our objective was to evaluate the seroprotective rate against diphtheria, tetanus, and pertussis in the elderly Thai population.MethodsIn total, 430 healthy individuals from the northeastern region of Thailand were enrolled in this study and stratified into five age groups: 60–65, 66–70, 71–75, 76–80, and > 80 years. Serum samples were collected and quantitatively analyzed for diphtheria, tetanus, and pertussis IgG antibody by using commercial ELISA kits. For anti-diphtheria toxoid and anti-tetanus toxoid ELISA, values < 0.01 IU/ml were interpreted as seronegative, and for anti-Bordetella pertussis toxin ELISA, values < 5 IU/ml were interpreted as seronegative; these definitions were in accord with previous studies.ResultsFor diphtheria toxoid Ab, the majority of the population had antibody levels > 0.01 IU/ml. For tetanus anti-toxoid Ab, the majority of the population had antibody levels of > 0.01 IU/ml, of which approximately 34% had durable antibody protection levels (DAPL) of ≥ 1 IU/ml. Meanwhile, nearly 45% of the population had an Ab level against pertussis lower than the protectivity level.ConclusionsIn total, 97.2%, 83.5%, and 55.8% of the population had a higher antibody level than the minimal protective level for diphtheria, tetanus, and pertussis, respectively. In order to prevent an outbreak of these diseases in the future, the elderly should be administered with Tdap revaccination to provide diphtheria herd immunity in the population; this will increase cocoon phenomenon for pertussis and protect the population from tetanus-prone injury.

Pertussis seroimmunity in mother-neonate pairs and other pediatric age groups from Egypt

Background: Despite the widespread availability of 2 classes of effectivevaccines, whole cell and acellular, pertussis has resurged as a seriouspublic health problem. We sought to investigate the pertussis immune statusof mother-neonate pairs and children in our country where pertussisvaccination is obligatory. Methods: This cross-sectional study included 75healthy full-term neonates and their mothers, 100 infants (2-24 months), 170children (2-12 years) and 80 adolescents (12-18 years). Serum pertussisIgG was measured in all enrolled subjects. A positive titre was defined as>24 U/ml. Results: Positive pertussis IgG levels were detected in 69 of themothers (92%), in 63 of their newborns (84%). Seroimmunity to pertussiswas positively noted in 55% of infants, 82.2% of preschool children, 77.5%of school-aged children and 75% in adolescents. Serum pertussis IgG titersamong the neonates showed a significant positive correlation with thematernal titers (P=0.00001). Higher rates of pertussis seroimmunity wasobserved among residents in urban and suburban areas as compared tothose living in rural areas (P<0.05) . Conclusion: This pilot study maysuggest the presence of sufficient pertussis seroimmunity rates in the studiedage groups. Still, there were some failures in immune acquisition probablydue to inefficient vaccination in some localities or waning of immunity withage. Wider scale studies would allow better insight into the pertussisimmune status in our country and hence the need for booster immunization.

Seroprevalence of diphtheria and pertussis immunoglobulin G among children with pneumonia in Ji\u2019nan, China

BackgroundVaccination 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.MethodsA 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).ResultsOf 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.ConclusionsWe 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.

670. Estimating Bordetella pertussis Seroprevalence in Persons Aged 10–25 Years in Mexico Using the 2012 National Health and Nutrition Survey (ENSANUT): Challenges and Lessons Learned

BackgroundLow vaccination rates and under-detection of cases in adolescents and young adults have been implicated in the transmission of Pertussis to children. In this study, the proportion of adolescents and young adults with anti Bordetella pertussis IgG antibodies was estimated in a population-based survey in Mexico.MethodsFrozen sera and data from 1,581 subjects—1,102 adolescents and 479 young adults (10–19 and 20–25 years old, respectively)—56% female were randomly selected from the Mexico’s National Health and Nutrition Survey (ENSANUT) 2012. CDC/FDA validated PT ELISA test was used to detect anti-pertussis toxin (PT) antibodies. A subset of 300 samples was also tested with Bp-IgG PT ELISA kit (Euroimmun AG, Lubeck, Germany®), both tests used international standards. Threshold values were established to identify vaccination or infection within the previous year, according to a US survey (Baughman et al.). Population-weighted estimates of seroprevalence were calculated.ResultsOverall Bp seroprevalence was 3.9% (95% CI: 2.3, 6.3); 3.1% (1.9, 5.0) in adolescents, and 4.9% (2.2, 11) in young adults. Seroprevalence did not significantly vary by gender, socioeconomic status, region or rural/urban location. Compared with the CDC/FDA PT ELISA, the Euroimmun® test showed 76% sensitivity, 88% specificity.ConclusionBooster vaccination to Bp after toddlerhood is not in the Mexican national policy; therefore, anti-PT IgG seropositivity may reasonably be attributed to recent Bp infection. Our weighted estimates of recent Bp infection, which are based on a national population-based serosurvey and a standardized serological test, represent a considerable burden of infections in adolescents and young adults that sharply contrast with the official surveillance reports. Also, the Bp-IgG PT ELISA commercial kit lower sensitivity than the CDC/FDA PT ELISA may lead underestimation of recent infections. In conclusion, assessing pertussis seroprevalence requires careful consideration of the right tests and epidemiological model for interpretation.Disclosures All authors: No reported disclosures.

Bordetella pertussis IgG level among pregnant women and their newborns in Najran, Southwestern, Saudi Arabia, an evidence for urgent update of the local maternal vaccination guidelines

Objective: To determine the pertussis IgG among pregnant women and their newborns at delivery in Najran Maternity and Children Hospital, Saudi Arabia. Methods: paired maternal-neonatal cord blood samples collected at delivery between November 2016 and July 2017 at Najran Maternity and Children hospital. Using ELISA, sera analyzed for pertussis IgG. According to the manufacturer instructions (Diagnostic Automation, INC, DA-B. Pertussis IgG, USA). Results: Out of 271 samples, the maternal mean age was 28 years (range 16-46) and that of gestation age was 38.5 weeks (range 33-42). Forty mothers (14.76%) were seropositive, thirty-five (12.91%) were borderline and 196 (72.32%) were seronegative. Only two (0.73%) infants were seropositive and their maternal antibodies were > 40 U/ml. Conclusion: this is the first report of maternal pertussis immunity from Saudi Arabia, which will stimulate serious discussion on updating maternal vaccination policy in our country. Maternal immunization with Tdap before pregnancy or during the second or third trimester could provide protective immunity to the newborns, covering the gap between birth and the first dose of Tdap. However, still further larger research on safety and effectiveness of maternal vaccination would be very valuable.

A National Seroepidemiologic Survey of Pertussis Among School Children in Taiwan.

In 2009, a booster dose of acellular pertussis vaccine for children at or before entry to elementary school was added to the national immunization program in Taiwan, which includes pertussis vaccination at 2, 4, 6 and 18 months of age. In 2013, a study to assess the level of humoral immunity against pertussis in elementary and junior high school children and adolescents was conducted. A multistage stratified systematic sampling method was applied to randomly selected grade 1 to 9 school children for testing. Serum samples were tested for IgG antibodies to Bordetella pertussis using commercial enzyme-linked immunosorbent assay kits. The study collected information on sociodemographic characteristics, vaccination history, sibling number and disease history of pertussis. The study recruited 2782 school children from 58 schools around the country. By questionnaire, only 1% (28/2782) students had history of pertussis. The overall positivity rate of anti-B. pertussis IgG was 42.5%, and the rates were not different between the 5 geographical areas (range from 39.6% to 44.6%, P = 0.375). Age-stratified data showed that the positivity rates were 43.6-48.8% among grade 1-3 students, 26.6-28.7% in grade 4-5 students and increased progressively from 39.4% to 51.3% in grade 6-9 students. The overall positivity rate was significantly higher in the nonbooster group (46.4% versus 38.6%, P < 0.01). The prevalence of anti-B. pertussis antibody was 42.5% in grade 1-9 students under the current vaccination program in Taiwan. Antibody induced by the booster vaccination before entry of primary school waned rapidly in 3-4 years. Rapid waning of anti-B. pertussis antibody may explain the resurgence of whooping cough in recent decades. Additional booster doses should be considered in adolescents and adults.

The effect of body mass index on post-vaccination maternal and neonatal pertussis antibody levels

The objective was to determine if there is an association between maternal body mass index (BMI) and maternal and neonatal pertussis antibody concentrations following vaccination. This is a nested cohort study of 123 women who received the Tdap vaccine during pregnancy. Women were stratified by BMI into three groups – normal, overweight, and obese, based on first trimester or pre-pregnancy BMI. Maternal and umbilical cord serum samples were tested for post-vaccination pertussis IgG antibody. The mean maternal pertussis antibody concentration was 167.5U/mL for normal BMI (n=29), 169.8U/mL for overweight BMI (n=54), and 175.5U/mL for the obese BMI groups (n=40). The mean fetal pertussis antibody concentrations were 182.3U/mL, 191.4U/mL, and 197.7U/mL for these groups respectively. Seroprotection was achieved in 89.7% of neonates (26/29) in the normal BMI group, 87.0% (47/54) in the overweight BMI group, and 97.5% (39/40) in the obese BMI group. None of these differences reached statistical significance. Maternal BMI does not affect the maternal or neonatal pertussis antibody response to the Tdap vaccine in women who receive the vaccine in pregnancy. Maternal BMI is unlikely to affect the neonatal protective effects of a standard dose of Tdap vaccine in pregnancy. PrécisMaternal and umbilical cord antibody response to the pertussis vaccine is not affected by maternal body mass index.

Susceptibility and Factors of Pertussis Vaccination Adherence in Korean Health Care Workers

To examine pertussis susceptibility and identify factors that might influence commitment to pertussis vaccination plan among Korean health care workers. The susceptibilities were examined using Bordetella pertussis IgG ELISA. The individual and related behaviors and cognition and affect factors were measured. Approximately 20% of subjects were susceptible to pertussis. Only perceived sensitivity and social support system were found to have significant direct effects on commitment to vaccination plan. Vaccination with pertussis among health care workers is certainly needed in Korea. In practice, when developing educational programs, perceived sensitivity and support systems need to be specifically considered.

Bordetella pertussisattachment to respiratory epithelial cells can be impaired by fimbriae-specific antibodies

Bordetella pertussis attachment to host cells is a crucial step in colonization. In this study, we investigated the specificity of antibodies, induced either by vaccination or infection, capable of reducing bacterial adherence to respiratory epithelial cells. Both sera and purified anti-B. pertussis IgG or IgA fractions efficiently reduced attachment. This effect was found to be mediated mainly by fimbriae-specific antibodies. Antibodies with other specificities did not significantly interfere in the interaction of B. pertussis with respiratory epithelial cells, with the exception of antifilamentous hemaglutinin antibodies, which reduced bacterial attachment. However, this effect was smaller in magnitude than that observed in the presence of fimbriae-specific antibodies. The strong agglutinating activity of antifimbriae antibodies seems to be involved in this phenomenon.

A boarding school outbreak of pertussis in adolescents: value of laboratory diagnostic methods

Culture for Bordetella pertussis (B. pertussis) is the traditional gold standard for laboratory diagnosis of pertussis but is insensitive, especially later in the course of illness and in vaccinated persons. Interpretation of serology is limited by the lack of an appropriate reference standard. An outbreak of pertussis in a crowded boarding-school dormitory allowed evaluation of laboratory correlates of infection. Questionnaires, serum samples and throat swabs were collected from members of the exposed group. Serum samples from unexposed controls of a similar age group were used for comparison. B. pertussis PCR was performed on throat swabs, and sera were tested for IgA antibodies against whole-cell (WC) B. pertussis antigen and IgG antibodies to pertussis toxin (PT). The Centers for Disease Control and Prevention definition for pertussis was used to define clinical cases. We evaluated the use of a previously published cut-off for PT IgG of 125 EIA units (EU)/ml. Completed questionnaires were obtained from 115 students, of whom 85 (74%) reported coughing symptoms, including 32 (28%) who met the clinical case definition for pertussis. B. pertussis was detected by PCR in 17 (15%) and WC IgA in 22 (19%) students; neither correlated with symptoms, but dormitory of residence strongly predicted PCR status. The mean PT IgG geometric mean concentration, in this situation of high pertussis exposure, correlated with severity of symptoms and was significantly higher in both symptomatic and asymptomatic children exposed during the outbreak (P < 0.001) than in control children. A cut-off for PT IgG of 125 EU/ml was too high in an outbreak situation to be sensitive enough to identify pertussis cases. A case of pertussis in a crowded boarding-school dormitory resulted rapidly in an outbreak. Serology and PCR were useful in identifying the outbreak and commencing disease control measures. The use of serology has mostly been evaluated in community serosurveys, where it is not possible to determine if immunity reflects vaccination, asymptomatic disease or symptomatic disease. This outbreak gave us the opportunity to evaluate the value of serology and PCR in the presence of confirmed exposure to pertussis.

Pertussis antibody levels in infants immunized with an acellular pertussis component vaccine, measured using whole-cell pertussis ELISA.

A commercially available whole-cell pertussis IgG ELISA was used to test the response of 137 2-month-old infants to immunization with a trivalent acellular pertussis vaccine. The pre-immunization geometric mean (GM) IgG index was 6.96 (95% confidence interval (CI) 5.88-8.04) and the postimmunization GM index was 13.16 (95% CI 12. 20-14.11), P < 0.001. Eighty percent of subjects (110/137) had a significant 1.5-fold increase of pertussis IgG index (97/137, 71%) or a postimmunization IgG index > 10 (93/137, 68%). In single antigen ELISA, 83% showed at least a fourfold increase in pertussis toxin-specific IgG (PT-IgG) and 91% showed an increase in IgG specific for filamentous haemagglutinin (FHA-IgG). Four percent had high pre- immunization antibody levels (index > 20), likely to reflect recent maternal exposure to pertussis. This correlated with a smaller increase in pertussis IgG index. A decline in pertussis IgG index postimmunization occurred in 17/24 infants (71%) whose pre-immunization IgG index was > 10. This postimmunization pertussis IgG index was not significantly different to that of infants with a low pre-immunization index. A similar trend was noted with PT-IgG and FHA-IgG results. The whole-cell ELISA can detect a response to acellular pertussis vaccination in most infants if both antibody index and degree of seroconversion are calculated and at least one criterion is satisfied.