Outbreak of pertussis in a university laboratory.

OBJECTIVE: Analysis of an outbreak of Bordetella pertussis infection in a university laboratory. To prevent and control the outbreak, we conducted a survey of the laboratory staff and their family members, and we investigated the clinical features of adult pertussis. PATIENTS AND METHODS: During the outbreak, four out of the 10 laboratory staff and five out of 16 family members had a primary complaint of cough. Seven of nine patients were diagnosed as definitive B. pertussis infection using serology and PCR. RESULTS: Clinical findings and laboratory data in adult patients with B. pertussis infection demonstrated non-specific cough and normal WBC and lymphocyte count. The patients who received clarithromycin prior to 14 days after clinical onset demonstrated a shorter duration of cough symptoms than patients who received clarithromycin at 14 days or more after clinical onset (duration of cough after administration of clarithromycin: 17.8 ± 6.48 days versus 35.3 ± 5.38 days; duration of total cough after clinical onset: 24.8 ± 6.65 days versus 56.8 ± 6.50 days). CONCLUSION: The clinical findings of adult pertussis are different from pertussis in children. The efficacy of macrolide therapy clearly differed between the catarrhal phase and paroxysmal phase. Physicians should consider B. pertussis in the differential diagnosis of an outbreak of non-specific respiratory infection even in adult populations.

[The risk of pertussis and diphtheria infections among pediatric healthcare workers in Japan].

For infection control in pediatric hospitals, we investigated the risk of pertussis and diphtheria infections among pediatric healthcare workers. Forty-nine Japanese pediatric healthcare workers in 12 general hospitals were screened for antibodies of pertussis toxin (PT), filamentous hemagglutinin (FHA), and diphtheria toxin (DT). The seropositive rates of anti-PT IgG (protective level, > 10 U/mL), anti-FHA IgG (> 10 U/ mL), and anti-DT (> 0.11 U/mL) were 50, 82, and 59%, respectively. During this survey period (Oct. 2003-Feb. 2004), 16 (33%) of the healthcare workers were in contact with pertussis-infant (s). However, all culture and PCR tests for Bordetella pertussis were negative. One of the 16 exposed healthcare workers, a male pediatrician, had serological evidence of a pertussis infection, but no disease symptomatic of pertussis. Our observations indicate that i) 50 and 41% of Japanese pediatric healthcare workers were seronegative for pertussis (anti-PT IgG) and diphtheria antibodies, respectively, and ii) although the healthcare workers had a high rate of contact with pertussis-infant (s), the infection rate was low. For pertussis and diphtheria infection control in pediatric hospitals, it is important for healthcare workers to be aware of their own protection levels against these diseases.

Seroprevalence of IgG antibodies to pertussis toxin in the Slovene population.

BACKGROUND: The use of pertussis vaccines has reduced the morbidity and mortality of whooping cough. Immunity following the natural disease or vaccination is not life-long and reinfections causing an increase of pertussis antibodies can occur. In this study, the distribution of IgG antibodies to pertussis toxin (anti-PT IgG) among different age groups in Slovenia was determined. METHODS: The seroprevalence of anti-PT IgG antibodies to Bordetella pertussis was investigated in 3418 persons (49.1% males). The population under study was stratified into 27 age groups. The serological results were assigned to five groups, according to their titer levels. The geometric mean titers (GMT) were calculated. RESULTS: In 11.5% sera tested, no IgG antibodies to pertussis toxin were detected. High titers (> or =125 U/ml) were confirmed in 2.3% sera. There were no statistically significant differences between age groups in the proportion of antibody levels. Pre-school children from three to five years of age had the lowest anti-PT IgG GMTs (9.6-10.7 U/ml). Vaccinated children (aged from one to two years) and adolescents from 17-18 years of age had the highest GMTs (>20 U/ml). GMTs were not statistically significantly different between males and females. CONCLUSIONS: The study demonstrated an early decline of anti-PT IgG after vaccination. According to the serological profile, school-age children and adolescents have the highest rate of infection. The large proportion of seropositive adults indicates that reinfection with B. pertussis is relatively common.

Seroprevalence of Bordetella pertussis antibodies in mothers and their newborn infants.

BACKGROUND: Pertussis is a highly communicable, vaccine-preventable respiratory disease. Although the largest number of reported cases is among young infants, the most rapidly increasing incidence in the USA is in adolescents and young adults. Importantly, adult family members are the likely major reservoir, infecting susceptible infants before completion of childhood vaccination. We studied maternal-neonatal paired blood samples for the presence of pertussis-related antibodies to assess level of immunity and passive transplacental antibody passage. METHODS: Unselected maternal-neonatal cord blood samples were collected from 101 term deliveries in a single urban uninsured/underinsured hospital setting. Sera were analyzed for anti-pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) IgG antibodies by enzyme-linked immunosorbent assay (ELISA). Antibody titers were calculated using reference line methodology. Antibody values were log-transformed to establish geometric mean titers (GMT) for analysis. Student's t-test, Mann-Whitney, Pearson correlation and chi square were used for statistical comparisons as appropriate. RESULTS: Mean (SD) maternal age, gestational age and birth weight were 26.8 (6.8) years, 38.9 (1.4) weeks and 3239 (501) g, respectively. Detectable maternal levels of anti-PT, FHA and PRN were found in 34.7%, 95.0% and 80.2%, respectively. Maternal GMT (SD) for PT, FHA and PRN were 4.4 (2.6), 26.6 (3.1) and 12.3 (2.9), respectively. There was no significant relationship between PT, FHA or PRN detection or antibody GMT and maternal age. Maternal anti-PT, FHA and PRN were highly correlated with neonatal cord blood values. CONCLUSION: Despite previous childhood immunization, a large number of parous women have low or undetectable pertussis-related antibody levels, suggesting susceptibility to infection. Even with efficient transplacental passage of these antibodies, neonates similarly have limited measurable protection as detected by cord blood sampling. These data support the need for adolescent or adult vaccination against Bordetella pertussis. Healthcare providers and their clients should be aware of the risk for infant infection via family member transmission.

The seroepidemiology of B. pertussis infection in Catalonia, Spain.

A survey of the seroprevalence of pertussis antibodies in a representative sample of the population from Catalonia was carried out. Ninety-seven municipalities and 30 schools were randomly selected to recruit the 2126 subjects who participated in the study. A serum sample was obtained from all individuals participating in the study in order to determine levels of pertussis toxin (PT) and filamentous hemagglutinin (FHA) antibodies by ELISA test. Sociodemographic data were collected for all subjects. The prevalence of PT antibodies was 75% and that of FHA antibodies 89%. Significant increments were observed with age, both in the prevalence of PT (P < 0.0001) and of FHA (P = 0.018). Of the sociodemographic variables studied, only urban habitat was significantly associated to PT antibodies. The agreement observed among the two types of antibodies studied was weak (K = 0.264). Routine revaccination with the acellular vaccine in children over 7 years of age, in adolescents and adults seems a reasonable strategy to prevent the appearance of cases of pertussis in the community.

Higher anti-hepatitis B response with combined DTPw-HBV vaccine compared with separate administration in healthy infants at 3, 4 and 5 months of age in Slovakia.

To help achieve universal infant immunisation against hepatitis B, the World Health Organisation has recommended the development of a combined diphtheria, tetanus and pertussis (DTP) and hepatitis B vaccine (HBV). The advantages come from the fact that DTP coverage is estimated to be over 80% worldwide and a combined DTP-HB vaccine would increase the coverage of HBV. This study was conducted to compare the immunogenicity and reactogenicity of a combined DTP-HB vaccine with separate, concomitant administration of DTP and HBV vaccines. One hundred and twenty infants were randomised in a 1:1 ratio to one of the two vaccination regimens, given as three injections at approximately 3, 4 and 5 months of age. The only difference in immunogenicity between the two regimens was a higher antibody response to hepatitis B in the group given the combined vaccine, possibly as a result of the adjuvant effect of the whole cell pertussis component of the DTP vaccine. Both vaccine regimens were well tolerated.

Pertussis encephalopathy with high cerebrospinal fluid antibody titers to pertussis toxin and filamentous hemagglutinin.

A 7-year-old unimmunized girl with pertussis presented with respiratory failure and electroencephalographic evidence of an encephalopathy. The cerebrospinal fluid (CSF)/serum ratio of antibodies to pertussis toxin and filamentous hemagglutinin were 11- and ninefold higher than the CSF/serum ratio of total immunoglobulin G. The CSF/serum ratio of albumin was normal. These findings indicate production of antibodies in the central nervous system to Bordetella pertussis antigens and imply, therefore, that the pertussis encephalopathy in this girl was associated with the entry of pertussis antigens into the central nervous system.

Acellular pertussis vs meningococcal vaccine: trial in hospital workers during the 1993 Cincinnati pertussis epidemic

The Cincinnati pertussis epidemic of 1993 (NEJM 1994; ICHE 1995; AJPH 1997) involved pertussis in all ages. The 14 year threshold of 20 cases per month was exceeded in July, with 195 excess cases from July through September. This study was designed to determine the safety, immunogenicity and effectiveness of acellular pertussis vaccine (AP) in outbreak control and the use of serology for diagnosing pertussis using a randomized, double-blind, controlled trial. It began September 23, 1993 at the 361-bed regional paediatric hospital in Cincinnati (1.7 million) where the epidemic continued unabated, despite erythromycin use in >500 of about 3,764 adult hospital workers. 199 healthy adult hospital workers took part. Participants received UMBL AP vaccine which contained 25 Fg pertussis toxoid (PT) and 3 Fg filamentous hemagglutinin (FHA), or licensed meningococcal vaccine (MN). Local and systemic reactions were monitored for three days after immunization. Sera were assayed for antibody levels before and at one and six months after immunization. Coughing illnesses were evaluated for clinical and laboratory confirmed pertussis. Local reactions following 102 AP vs 97 MN were: pain or tenderness, 73 percent vs 91 percent redness, 11 percent vs 22 percent; swelling, 20 percent vs 26 percent; and hardness, 16 percent vs 33 percent. Systemic reactions included: fever, 0 percent vs 2 percent; sleepiness or lethargy, 18 percent vs 20 percent; and irritability, 4 percent vs 10 percent. One month post AP, IgG anti-PT ELISA geometric mean in 100 people was 33.1 Fg/ml. Two-fold rises occurred in 85 percent and 4-fold rises in 73 percent for IgG anti-FHA ELISA, respective values were 34.7 Fg/ml, 92 percent and 63 percent. In 6 months follow up 9/102 AP and 7/97 MN recipients had >2 weeks of cough; IgG ELISA assays for PT, FHA and pertactin and CHO and agglutinin titers, showed no evidence of pertussis in symptomatic or asymptomatic subjects. However, recent evidence of pertussis infection prior to immunization was shown, as 44 percent MN recipients (population surrogate) had >4 fold antibody declines to either PT, FHA, or both six months. In conclusion, AP vaccine was safe and immunogenic in adults. After three months of the outbreak, many CHMC employees already had serological evidence of recent pertussis infection and AP vaccination did not have an impact on the epidemic. AP should be introduced early in an epidemic to be effective in outbreak control.(AU)

Pertussis immunization with acellular vaccines in Ghanaian children.

In the present study, the persistence of antibodies to pertussis antigens was assessed in 51 Ghanaian children immunized with one of two acellular vaccines and one whole cell vaccine in early infancy. The effect of a booster dose 1 year after primary immunization was also examined. Antibody titres to pertussis toxin (PT) and filamentous haemagglutinin (FHA) were measured 1 month and 1 year after primary immunization and 1 month after the booster dose. Although geometric titres (GMTs) to FHA were significantly higher in the two types of acellular vaccinees in the whole cell vaccinees 1 month after primary immunization, GMTs to FHA and PT after 1 year were not significantly different in the three groups. Geometric mean titres to PT and FHA following the booster dose were significantly higher in the acellular vaccinees than in the whole cell vaccinees. Seropositivity rates to PT and FHA in the acellular vaccinees, which were more than 93.3% 1 month after primary immunization, ranged from 50.0 to 77.8% after 1 year. In conclusion, the acellular vaccines did not produce higher antibody levels than the whole cell vaccine 1 year after primary immunization. The booster dose was essential to maintaining sufficient seropositivity to pertussis antigens.

A randomized controlled trial of two acellular pertussis-diphtheria-tetanus vaccines in primary immunization in Ghana: antibody responses and adverse reactions.

Two acellular pertussis vaccines combined with diphtheria and tetanus toxoids (APDT vaccines) were compared with a whole cell PDT (WCPDT) vaccine in primary immunization in Ghana. One is a liquid vaccine which is used for general immunization in Japan and the other is a freeze-dried vaccine newly developed as a heat-stable vaccine. Eighty-nine infants were recruited in the study. Sixty-eight who completed three doses of the immunization were assessed for immunological responses. Twenty-one dropped out because of sickness or moving from the study area. A total of 242 vaccinations in 89 infants were followed up for adverse reactions. Geometric mean titres (GMTs) to filamentous haemagglutinin in the two APDT vaccinees were significantly higher than in the WCPDT recipients. GMTs to pertussis toxin, diphtheria and tetanus toxoids were not significantly different among the three groups. Seropositive rates to pertussis antigens, tetanus and diphtheria toxoids were 94.4 to 100% in the two APDT vaccines. Systemic reactions within 7 days of inoculation were similarly low in the three groups, but significantly fewer infants had local reactions after either of the two APDT vaccines than after the WCPDT vaccine.

Severe reactions associated with diphtheria-tetanus-pertussis vaccine: detailed study of children with seizures, hypotonic-hyporesponsive episodes, high fevers, and persistent crying.

OBJECTIVE: The pathophysiology of severe reactions to diphtheria-tetanus-pertussis (DTP)vaccine is not well understood. Active pertussis toxin in DTP vaccine has been proposed to cause severe DTP vaccine reactions. Large doses of pertussis toxin cause hyperinsulinemia and hypoglycemia as well as leukocytosis with a predominant lymphocytosis in animal models. To learn more about the causes of and risk factors for severe DTP vaccine reactions, children experiencing severe DTP vaccine reactions were studied. DESIGN: Prospective, referral-based surveillance. SETTING: Los Angeles, CA. SUBJECTS: Children experiencing severe reactions within 48 hours of DTP immunization and evaluated within 24 hours of the reaction. Severe reactions included encephalopathy, persistent crying > or = 3 hours, hypotonic-hyporesponsive episodes (collapse episodes), fever > or = 40.5 degrees C, or seizures. Some comparisons were made between children with DTP vaccine-associated seizures and a comparison group of children experiencing febrile seizures unrelated to immunization. OUTCOME MEASURES: A history and physical examination were performed. Follow-up examinations were performed 1 month later. Blood was collected for complete blood cell count with leukocyte differential count, serum chemistry measurements, and insulin and glucose values. Serum was assayed for active pertussis toxin, both in free and immune-complex masked states. RESULTS: Sixty children experienced severe reactions within 48 hours of DTP immunization: 32 children had seizures only, 14 subjects had hypotonic-hyporesponsive episodes, 2 subjects had fever > or = 40.5 degrees C only, 4 subjects had persistent crying > or = 3 hours, 6 children had seizures and fever > or = 40.5 degrees C, and 2 children had persistent crying and seizures. The children with seizures had a high rate of personal and family histories of seizures, and 90% had documented fevers (> or = 38 degrees C). Persistent crying was associated with painful local reactions. Effects that may have been due to vaccine pertussis toxin were not found. Lymphocytosis did not occur, nor did hypoglycemia. Some relatively elevated insulin values were noted; however, this finding was also noted in the comparison group of children experiencing febrile seizures unrelated to immunization. No biologically active pertussis toxin was found in the acute sera of children experiencing severe DTP vaccine reactions. CONCLUSIONS: Seizures associated with DTP vaccine have similar clinical characteristics as febrile seizures, and persistent crying is initiated by painful local reactions. Vaccine endotoxin is a cause of febrile DTP vaccine reactions. We found no evidence that DTP vaccine pertussis toxin plays a role in severe DTP vaccine reactions.

Detection of antibodies inhibiting the ADP-ribosyltransferase activity of pertussis toxin in human serum.

Bordetella pertussis produces a protein virulence factor termed pertussis toxin. Many candidate pertussis vaccines are based on the rationale that an immune response that neutralizes the virulence activities of this toxin, which are thought to arise from its catalytic ADP-ribosyltransferase activity, would be beneficial. The report describes two methods that quantify the inhibition of this activity by human serum. One, termed a direct assay, involves an initial incubation of toxin with serum, a second incubation that activates the toxin, and a third incubation that measures the ADP-ribosyltransferase activity of the mixture. The other assay, termed a plate assay, involves immobilization of the toxin, exposure of the immobilized toxin to serum and washing of the plate, and then activation and assay of the toxin's ADP-ribosyltransferase activity. The plate assay may be more selective than the direct assay in terms of identifying antibodies that neutralize the toxin in vivo. Sera from controls, selected patients presenting with cough, and vaccinated infants were first analyzed by the direct assay. In contrast to sera from controls, sera from several of the patients and vaccinated infants strongly inhibited activity. Dose-response curves of inhibition were determined for samples from three vaccinated infants by both the direct and plate assays. One of the samples had a dose-response curve of a different shape and thus differed not only in titer but also in functional characteristics. A comparison of inhibition of ADP-ribosyltransferase activity and neutralization in a CHO cell assay indicated that there was incomplete agreement between the two assays. Taken together, these results indicate that measurement of inhibition of ADP-ribosyltransferase activity by human serum is practical and may be useful in the evaluation of responses to pertussis vaccines.

Pathophysiology of reactions associated with pertussis vaccine.

Many adverse clinical events occur after pertussis immunization in children, but the pathophysiology is not well understood. It has been suggested that some of these adverse events may be due to biologically-active LPF and endotoxin present in DTP vaccines. Fifty-six children were studied who experienced severe reactions (fever greater than or equal to 40.5 degrees C, seizures, persistent crying greater than or equal to 3 hours or hypotonic-hyporesponsive episodes) within 48 hr of DTP immunization. Leukocytosis with neutrophilia was noted acutely (after vaccination) compared to follow-up (approximately one month later). No changes in insulin or glucose values were noted. Utilizing the CHO cell assay, no biologically-active LPF was found in the acute sera of children who had DTP-associated seizures. We found no evidence that biologically-active LPF or altered insulin/glucose metabolism were related to severe DTP-associated reactions.

GTP-binding proteins in human platelet membranes serving as the specific substrate of islet-activating protein, pertussis toxin.

Two GTP-binding proteins serving as the specific substrate of islet-activating protein (IAP), pertussis toxin, were purified from human platelet membranes as heterotrimers with an alpha beta gamma-subunit structure. The alpha of the major IAP substrate had a molecular mass of 40 kDa and differed from that of Gi 1 or Go previously purified from brain membranes. The partial amino acid sequences of the 40 kDa alpha completely matched with the sequences which were deduced from the nucleotide sequences of the human Gi 2 alpha gene. On the other hand, the alpha of the minor IAP substrate purified from human platelets was about 41 kDa and cross-reacted with an antibody raised against alpha of brain Gi 1 (Gi 1 alpha). These results indicate that the major IAP substrate present in human platelet membranes is a product of the Gi 2 alpha gene.