Adverse reactions after diphtheria-tetanus booster in 10-year-old schoolchildren in relation to the type of vaccine given for the primary vaccination

This prospective open study investigated adverse reactions in 527 schoolchildren to a diphtheria-tetanus (DT) booster given within a national vaccination programme at 10 years of age. Evaluation was based on those whose immunization records showed that they had received either three doses of an adsorbed DT vaccine (n = 388) or a non-adsorbed DT-pertussis vaccine (DTP) (n = 69) for primary series vaccination. No differences in systemic reactions to the booster between the two groups were observed. Local reactions were significantly (p < 0.001) more common 1 day after vaccination in children who had received DT for primary series vaccination: redness, 73% compared with 23%; swelling, 56% versus 15%; and itching, 47% versus 21%. One and 2 weeks after the booster, itching was still more pronounced in the group who had received DT for primary series vaccination (p < 0.001 and 0.014, respectively). The study indicates that there was a real basis for the increase in spontaneous notifications of local side-effects to the school DT booster in Sweden. The most likely cause for the increase seems to be the aluminium adjuvant in the vaccine given for primary vaccination, a late and unexpected consequence of a change in the infant immunization programme.

The role of aluminium for adverse reactions and immunogenicity of diphtheria-tetanus booster vaccine

In a randomized, double-blind clinical trial, 235 schoolchildren aged 10 years received either a regular, aluminium-adsorbed diphtheria-tetanus vaccine or the same vaccine in fluid form, in order to investigate if local side effects could be diminished by exclusion of aluminium. System reactions were rare and local reactions frequent in both groups but larger local reactions were even more pronounced in the non-adsorbed vaccine group. Antibody responses to both vaccines were excellent and even slightly higher to the non-adsorbed diphtheria-tetanus vaccine (p = 0.0135 and 0.0014 for anti-diphtheria and anti-tetanus, respectively). This study has shown that fluid diphtheria-tetanus vaccine does not solve the problem of extensive local side effects induced by the diphtheria-tetanus school booster. Alternative strategies, such as changes in vaccine composition, dosage and spacing, will have to be considered.

New roles for quin2: powerful transition-metal ion chelator that inhibits copper-, but potentiates iron-driven, Fenton-type reactions

The objective of this study was to investigate whether quin2, through its metal chelating properties, could affect copper- or iron-driven Fenton reactions. Chelation of ferric ion with quin2 uniformly strongly enhanced the formation of oxidizing species, detected with the DMSO and deoxyribose assays, both by H2O2 and a mixture of superoxide/hydrogen peroxide produced by hypoxanthine/xanthine oxidase. Fe(3+)-EDTA gave the same effects, but lacked reactivity with bolus H2O2 as detected with the DMSO assay. Whereas the formation of oxidizing species with Fe(3+)-EDTA and ferric ions alone were strongly inhibited by superoxide dismutase both in the bolus H2O2 and hypoxanthine/xanthine oxidase systems, such formation in the presence of Fe(3+)-quin2 either did not decrease or decreased only moderately. Fe(3+)-quin2 also strongly enhanced plasmid DNA strand breakage in the presence of H2O2. Our findings suggest that quin2 as chelator of ferric ion may be a more powerful enhancer of oxidant formation than other chelators so far tested. The formation of oxidizing species from copper ions and bolus H2O2 was found to be fundamentally dependent on the choice of buffer system. We could only detect significant amounts of oxidants in both assays in Hepes buffer, but not in the phosphate, cacodylate or unbuffered systems, which all gave low reactivity in the DMSO assay compared to the deoxyribose assay. Quin2 chelation of cupric ion effectively inhibited the formation of oxidants as well as plasmid DNA strand breakage.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of erythromycin treatment on antibody responses in pertussis

The effect of erythromycin treatment on antibody responses to Bordetella pertussis filamentous haemagglutinin (FHA) and pertussis toxin (PT) was investigated in convalescent blood samples from 105 children with pertussis. Erythromycin had been given to 59 children, median age 3.2 years (range 0.3-9.9) on median day 7 (range 11-14) after onset of disease while the remaining 46 children, age 3.45 (0.6-8.1) were untreated. No significant differences in IgG antibody concentration were noted to FHA by ELISA and to PT, neither by NT nor by ELISA, but a tendency towards lower median titers was seen to both antigens and by both type of assays in the erythromycin-treated group. Similarly, early erythromycin treatment i.e. within 7 days of onset of symptoms, did not influence significantly of the development of the antibody responses but tended to lead to lower titer levels. A significant response to PT and FHA was found in about 90% of blood samples, irrespective of treatment. All 56 children with culture-confirmed B. pertussis infection had a significant response to PT. The study has thus shown a slight but not significant effect of erythromycin treatment on antibody responses in pertussis.

Immune status and booster effects of low doses of tetanus toxoid in Swedish medical personnel

Of 102 medical staff at a Swedish hospital, 81% had tetanus antitoxin titres > or = 0.01 IU/ml in 1984-85. The unprotected individuals (antitoxin titre < 0.01 IU/ml) were all > 30 years of age. Of this group, one-third lacked a protective antibody level against tetanus toxin. Low booster doses of tetanus toxoid (0.75 or 1.9 Lf) were given to 66 vaccinees with a history of previous basic vaccination and no history of booster vaccination within the previous 5 years. The median titre increased from 0.26 IU/ml before to 3.3 IU/ml after vaccination. Low doses of tetanus toxoid may thus still provide an adequate immune response when given as a booster vaccination to individuals with a reliable history of basic immunization.

Immunoglobulin G antibodies to Pseudomonas aeruginosa lipopolysaccharides and exotoxin A in patients with cystic fibrosis or bacteremia

IgG antibodies to nine Pseudomonas aeruginosa lipopolysaccharides (LPS) and exotoxin A in sera from 11 patients with bacteremia and 51 patients with cystic fibrosis (CF) were analyzed. The methods used were enzyme immunoassay (EIA) and immunoblotting. Nine of the 11 bacteremic patients were infected with strains expressing an LPS serotype identical to one of the test antigens. In sera from six of these nine patients, antibody homologous to the serotype of the infecting strain was observed. An antibody response to heterologous Pseudomonas aeruginosa LPS antigens was observed in nine patients. Eight of the bacteremic patients mounted an antibody response to exotoxin A. Thirty-five CF patients chronically colonized with Pseudomonas aeruginosa possessed significantly higher levels of antibody to all of the test antigens than 16 patients with intermittent or no colonization (p < 0.001). For exotoxin A and serotype 3 the sensitivity was 91% and 94%, and the specificity 94% and 88% respectively. When the results for exotoxin A and serotype 3 were combined, the sensitivity was 91% while the specificity was 81%. The pronounced antibody response to heterologous LPS antigens, as measured by the EIA and immunoblot, suggests expression of a common antigen determinant. A simplified serological assay utilizing exotoxin A and serotype 3 as test antigens may be useful for detecting Pseudomonas aeruginosa infections in patients with CF and chronic colonization and in bacteremic patients from whom cultures are not available.

Helicobacter pylori in 205 consecutive endoscopy patients

The presence of Helicobacter pylori in the gastric, antral mucosa of 205 consecutive, unselected gastroscopy patients was investigated by 1-3 biopsies for urea broth test and culture, 1 biopsy for histological examination and 1 blood sample for serology by ELISA. Overall, 41% were positive for H. pylori by culture, 32% by urea broth test, 24% by histological staining and 67%, 56% and 49% for the 3 cut-off limits applied to serology. Culture and serology indicated the presence of H. pylori in 79-92% of the 14 cases with duodenal ulcer, in 59-82% of the 28 cases with gastric ulcers, in 45-71% of the 51 cases with endoscopic gastritis and in 33-69% of 13 cases with oesophagitis. In patients with histological antritis, H. pylori was identified by culture in 71% (60/84), by serology in 95%, 88% and 81% with the different cut-off limits. The sensitivity of serology ranged from 99-78% depending on the cut-off limits and the specificity from 78-100% against all parameters combined. These results suggest that serology is a useful screening method for the presence of H. pylori. Future antibiotic treatment studies are required to evaluate the clinical relevance of H. pylori in gastrointestinal disease and to investigate the possibility to monitor eradication by serology.

Serological correlates in whooping cough

Antibody concentrations to three Bordetella pertussis antigens in 94 predisease samples from women who, within a median of 220 days, developed culture-confirmed whooping cough were compared to antibodies in samples from matched controls. The median IgG antibody levels were significantly lower to all three antigens, pertussis toxin, filamentous haemagglutinin and lipopolysaccharide, in the predisease samples of cases as compared to non-cases (p values ranging from 0.0001 to 0.01). A significant difference in antibody distribution was, however, found only to pertussis toxin, measured either by ELISA or by a neutralization test (p values of 0.0004 and 0.007, respectively). The results could be interpreted as meaning that antibodies to the different antigens all participate in protection against disease but that antibodies to pertussis toxin play a major role.

Antibody prevalence and clinical manifestations of Lyme borreliosis and tick-borne encephalitis in Swedish orienteers

Antibody prevalence and clinical manifestations of Lyme borreliosis (LB) and tick-borne encephalitis (TBE) were studied in 362 orienteers from the county of Stockholm during a large relay race in October 1990. From all participating orienteers, a blood sample was collected and a questionnaire completed. Antibody activity to Borrelia burgdorferi was measured using a sonicated whole spirochete antigen in an ELISA, and to TBE virus (TBEV) by ELISA and haemagglutination inhibition (HI) test. A past history of LB was reported by 6% of the orienteers and antibodies to B. burgdorferi were found in 9%. Antibody reactivity to B. burgdorferi was found in 1-2% of the sera from 3 different control groups comprising 502 persons living in non-endemic areas. The corresponding value was 9% in sera from a fourth control group consisting of 150 persons living in the city of Stockholm. A past history of TBE was reported by 1 orienteer (0.3%) and detectable antibodies to TBEV in non-immunized individuals were found in 1%. No antibody activity to TBEV could be detected in sera from the control individuals living in the 3 non-endemic areas, but in 5% of the controls from Stockholm. In this study, there was no indication that frequent or severe manifestations of LB or TBE are common among orienteers in Sweden.

Clinical manifestations and antibody prevalence of Lyme borreliosis and tick-borne encephalitis in Sweden: a study in five endemic areas close to Stockholm

Five populations, including 903 individuals living in 5 different areas close to Stockholm, were studied with regard to clinical manifestations and antibody prevalence of Lyme borreliosis (LB) and tick-borne encephalitis (TBE). The study areas involved 4 groups of islands in the Baltic Sea and 1 island in Lake Mälaren. Serum samples from each individual were tested for antibody activity to Borrelia burgdorferi using a sonicated whole spirochete antigen in an ELISA, and to TBE-virus (TBEV) by ELISA and haemagglutination inhibition. A history of LB was reported by 1-21% and antibodies to Borrelia burgdorferi were found in 7-29% of the participants from the various areas. An increasing seroprevalence with age was seen. In sera from 3 different control groups, including 502 individuals living in non-endemic areas, antibodies to Borrelia burgdorferi were detected in 1-2% and from 1 control group including 150 individuals living in the city of Stockholm, in 9%. A history of TBE was reported by 0-6% of the individuals and in non-immunized individuals seropositivity was seen in 4-22%, depending on the area investigated. No antibody activity to TBEV could be detected in sera from persons in the 3 control groups living in non-endemic areas, whereas 5% of the controls from Stockholm were found to be positive. The prevalence rates of antibodies to TBEV in persons vaccinated against TBE were 40%, 53% and 79% after 1, 2 and 3 injections, respectively.

Mutagenic analysis of the promoter of the Streptomyces fradiae beta-lactamase-encoding gene

The Streptomyces fradiae beta-lactamase promoter (PblaF) was sequenced and characterized by promoter probing, primer extension, and exonuclease III-mediated deletions. The transcription start point (tsp) was the same in both S. lividans and S. fradiae. Oligodeoxyribonucleotide-directed random mutations and site-specific mutations were introduced in the promoter region. The effects of these mutations on transcription were assayed by an RNA colony hybridization method. This analysis identified cis-acting sequence determinants located similarly to the -10 and -35 regions of a typical Escherichia coli promoter. Also, a change in the distance between these regions from 19 to 17 bp drastically reduced promoter activity. PblaF was shown not to be recognized by sigma-whiG or by sigma-hrdA, hrdC, or hrdD. Sequence alignment of PblaF to sigma factor-classified Streptomyces promoters revealed little homology. Thus, PblaF is probably recognized by an as yet unidentified sigma factor.

Two-year survey of the incidence of Lyme borreliosis and tick-borne encephalitis in a high-risk population in Sweden

A survey was made over a two-year period (September 1987 to August 1989) of a population living in an area endemic for Lyme borreliosis and tick-borne encephalitis in Sweden. For each patient a blood sample was collected and a questionnaire completed annually. All sera were tested for an antibody response to Borrelia burgdorferi in an EIA using sonicated antigen and for an antibody response to the tick-borne encephalitis virus using an EIA and a haemagglutination inhibition test. Antibodies to Borrelia burgdorferi and tick-borne encephalitis virus were detected in 89 (25.7%) and 40 (11.6%) respectively of 346 samples collected in August 1987. In the first year of the study 14 of 303 subjects (4.6%) developed Lyme borreliosis and in the second year 9 of 277 subjects (3.2%). A significant increase in the antibody titre for Borrelia burgdorferi was seen in 14 of 303 (4.6%) subjects in the first year and 8 of 277 (2.9%) subjects in the second year. An earlier episode of Lyme borreliosis or an elevated antibody titre did not seem to protect against reinfection. One case of tick-borne encephalitis was seen each year. Seroconversion for tick-borne encephalitis virus was found in 3 of 258 (1.2%) subjects in the first year and 5 of 211 (2.4%) in the second year, excluding subjects who had undergone successful immunisation or had earlier been hospitalised for tick-borne encephalitis. The study thus demonstrated a high yearly incidence of tick-borne infections in a population at risk.

Evaluation of an improved DNA probe for diagnosis of pertussis

A Bordetella pertussis specific subclone, pRZ61, of a Bordetella genus-specific clone, pB23, was evaluated on nasopharyngeal aspirates of 179 patients with suspected pertussis. Hybridization was performed directly after spotting or after 1-3 days of preculture of the nylon membranes on solid culture medium. A direct comparison of the two probes was obtained by reprobing with the subclone the same membranes that had been hybridized with the parent probe. pRZ61 detected 50% of the serologically defined cases of pertussis, that is, had the same sensitivity as standard culture. Specificity as compared with serology was close to 100%. The increasing sensitivity and the corresponding decreasing specificity after preculture noted for pB23 was not seen with the subclone. The study showed that the improved probe represents a rapid diagnostic method in pertussis.

Impact of pertussis on the afflicted child and family

The effects of pertussis in an unimmunized population were investigated in 61 children consecutively identified by positive culture for Bordetella pertussis. Parents were interviewed twice, at a mean of 3 and 11 weeks after onset of symptoms. All children had a disease duration of more than 3 weeks. Behavioral changes were reported for 84% of the study children. Parents reported negative effects for themselves in 95% and for siblings in 63% of the families. The main problems were disturbance of night sleep, staying home from work and isolation of the family. Parental knowledge of the disease was generally good; a majority had few contacts with the medical services and coped with the disease themselves. Serious concerns for the child were reported by 51% of parents and fears for permanent sequelae by 10%. The attitude to pertussis vaccination was positive in 89% of cases at both interviews. The study has thus shown that pertussis in an unimmunized child population represents a heavy burden.

Specific immunoglobulin for treatment of whooping cough

Immunoglobulin treatment for whooping cough (pertussis) is widely believed to be ineffective although there are sound reasons for regarding the condition as a toxin-induced disease. We wondered whether the lack of success with pertussis immunoglobulins might be attributable to inadequate dose, so we designed a randomised, double-blind, placebo-controlled trial of two immunoglobulin preparations. The study was conducted at three Swedish hospitals. We enrolled 73 children aged less than 36 months who were admitted with a clinical diagnosis of whooping cough. On admission they were assigned to one of three groups: (a) monocomponent pertussis toxoid vaccine; (b) two-component acellular vaccine also containing filamentous haemagglutinin; or (c) 20% albumin solution (placebo). The immunoglobulins had a high antitoxin content and had been raised with acellular pertussis vaccines. Diagnosis of pertussis was confirmed by laboratory tests and the follow-up was completed in 67 children. The main study group consisted of 47 children with less than or equal to 14 days of disease before therapy. Duration of whoops post-treatment was 8.7 days (95% Cl 4.8, 12.6) in the 33 children receiving immunoglobulin vs 20.6 (95% Cl 11.9, 29.3) in the 14 receiving placebo (p = 0.0041). Mean number of whoops during the first week of follow-up was also significantly reduced (p = 0.0196). We found that early treatment was important, since the effect on duration of whoops was most pronounced when disease duration before treatment was less than or equal to 7 days. There were no significant differences between the two immunoglobulin preparations. High-dose specific pertussis immunoglobulin with a high antitoxin concentration has a beneficial effect in the treatment of whooping cough.

The melanophore aggregating response of isolated fish scales: a very rapid and sensitive diagnosis of whooping cough

Pertussis toxin (PT) has been found to block noradrenaline-induced pigment aggregation in fish melanophores, and, based on this, a rapid and highly sensitive assay for PT was developed. Some preliminary results have also indicated that it may be possible to detect PT-like activity in saliva samples from patients with clinically suspected pertussis. In the present study the diagnostic value of the fish melanophore method was evaluated in 70 patients suspected of having pertussis; culture, serology and physician diagnosis were used as reference methods. In 60 of the patients, pertussis was verified by at least one of the reference methods. The melanophore test showed PT-like activity in saliva samples from 58 of the patients. Three patients with reference-verified pertussis showed no PT-like activity in the test; among these, one patient had been immunized and had also been treated with erythromycin during 3 days immediately prior to visiting the hospital. The melanophore test has three major advantages: it allows detection of pertussis in the early and curable stage of the disease; it takes only 2 h to perform; and it requires no sophisticated equipment.

Lipase versus teichoic acid and alpha-toxin as antigen in an enzyme immunoassay for serological diagnosis of Staphylococcus aureus infections

Titres of IgG antibodies to Staphylococcus aureus lipase were analysed in 448 sera from patients suspected of having Staphylococcus aureus infections and the results compared to those for the routinely used staphylococcal antigens teichoic acid and alpha-toxin. The results indicated that determination of serum antibodies to lipase is a sensitive assay for serological diagnosis of staphylococcal infections and increased sensitivity may be achieved by selection of optimal antigen combinations.

Cumulative incidence of pertussis in an unvaccinated preschool cohort based on notifications, interview and serology

The cumulative incidence of pertussis at six years of age in the first unvaccinated cohort after cessation of immunisation in Sweden was investigated by serological methods and by a validation of the national epidemiological surveillance system by reports from the Child Health Centres (CHCs). In 312/385 (81%) eligible children, both an interview with the parents and a blood sample from the child could be obtained. The CHC reports yielded a cumulative incidence of 31%, whereas the serological assays found 54%. Of the cases reported by the parents to the CHCs, 89% were seropositives. In the additional cases of pertussis reported at the study interview, only 61% could be confirmed (p less than 0.001). Among children with reported severe cough not suspected to be pertussis, 46% were seropositive, distributed as 33% seropositives in cases with cough duration of less than 4 weeks and 69% for longer coughs (p less than 0.01). In the CHC reports, the parental diagnosis was found to have been confirmed in three-quarters of cases by medical personnel. The CHC reporting system was thus found to be reliable with an observed specificity of 93%, but sensitivity of only 52%. Thus, even this surveillance system, which yields the highest incidence rates, underestimates the incidence of the disease.

Bordetella pertussis adenylate cyclase activity in nasopharyngeal aspirates for rapid diagnosis of whooping cough in relation to culture and serology

Adenylate cyclase activity, measured in 201 nasopharyngeal aspirates from patients presenting with own or parental suspicion of whooping cough, was compared to diagnosis made by culture and by serology in the culture negative cases. The median amount of cyclic AMP in samples from culture negative patients (n = 145) was 0.60 pmoles which differed significantly (p less than 0.001) from the median value 3.28 in samples from culture positive patients (n = 56). The median value 0.70 pmoles of cyclic AMP in samples from culture negative patients who were positive by serology (n = 54) did not differ significantly from the value of 0.57 pmoles in samples from serology negative patients (n = 91). With a limit for positive cyclic AMP set at 2 pmoles, 45 samples were positive. The sensitivity of the assay was 66% (37/56) in culture positive patients while the specificity was 93% (85/91) in the serology negative patients. The positive predictive value for the c-AMP test was 82% (37/45) in relation to culture and 87% (39/45) in relation to culture and/or serology. The results confirmed that measurement of adenylate cyclase activity in nasopharyngeal aspirates by an 1-h incubation method can serve as an early and rapid diagnostic method of pertussis infection. The low sensitivity of the c-AMP assay in samples from serology positive but culture negative patients indicates however, that this assay will have to be supplemented by serology for a high diagnostic sensitivity in all cases of pertussis.

Diagnostic value of clinical and bacteriological findings in pertussis

Clinical and bacteriological findings in the diagnosis of pertussis were evaluated in 300 consecutive patients with parental or the patient's own suspicion of the disease. Serology was used as a reference method. Of the 285 (95%) patients fully sampled, 163 (57%) were diagnosed as having pertussis while the remaining 122 patients constituted the non-pertussis control group. The clinical and epidemiological data were collected at the first visit made on median day seven of illness. In this population of mainly unimmunised children, the highest predictive values were obtained for the physician's diagnosis of pertussis (100%) and for the physician's diagnosis of some other illness (93%). The only clinical symptom with a high predictive value for pertussis was the report of whoops (92%). Among epidemiological data the highest predictive value (90%) was obtained for reported household exposure in unimmunised children more than 1 year of age. Culture of Bordetella pertussis was found to have an overall 50% sensitivity. Isolation of other bacteria had no predictive value in the differential diagnosis of pertussis.

DNA hybridization for diagnosis of pertussis

The aim of the present study was to evaluate a mixed phase DNA hybridization assay for detection of Bordetella pertussis and Bordetella parapertussis in nasopharyngeal aspirates from patients with suspected pertussis. Among 179 consecutive patients with own or parental suspicion of pertussis, the diagnosis was confirmed in 103 patients by serology and in 52/103 (50%) cases also by culture. The remaining 76 patients served as nonpertussis controls. Direct hybridization was positive in 38% samples with serology as reference method, a non-significant difference to the 50% sensitivity for culture. Preculture of samples on membranes for 24, 48 and 72 h gave a significantly higher sensitivity only with 72 h preculture, 69% vs 50% (P = 0.007). The 72h preculture gave, however, also a significant decrease of specificity, 87% vs 100% for routine culture (P = 0.001) and is not a more rapid diagnostic method. The result shows that rapid diagnosis by DNA hybridization can be achieved in a large proportion of pertussis cases. The presence of smaller numbers of bacteria in samples only positive after preculture indicate that DNA hybridization could be a highly sensitive diagnostic method with further development of more rapid amplification systems.

Antistaphylococcal antibodies in cystic fibrosis

Chronic colonization with Staphylococcus aureus is found in 40-50% of the sputum producing patients with cystic fibrosis treated at Stockholm's Cystic Fibrosis Center, Huddinge University Hospital. 30-40% of these patients had increased ELISA IgG antibody titres against teichoic acid and against alpha-toxin. About half of the number of patients showed increased antibody titres to either antigen during infection. Increased antibody titres against staphylococcal antigens were only found in less than or equal to 10% of patients not chronically colonized with S. aureus (no different from the normal population). The serum titres of antistaphylococcal antibodies were significantly higher in the chronically colonized patients (p less than 0.001). Patients who were also chronically harbouring Pseudomonas aeruginosa had the highest titres of both antibodies. The titres increased with clinical signs of infection and were normalized by antimicrobial chemotherapy. To conclude, the use of ELISA IgG antibodies may prove suitable for routine evaluation of the need for, and control of the efficacy of antistaphylococcal chemotherapy in cystic fibrosis.

Comparison of flagellum and sonicate antigens for serological diagnosis of Lyme borreliosis

A sonicate antigen and two concentrations of a purified flagellum antigen of Borrelia burgdorferi were compared for serological diagnosis of Lyme borreliosis by an enzyme immunoassay (EIA). Generally, the higher concentration of flagellum antigen was found to be superior to the lower concentration, which was diluted eight times compared to the higher concentration. The diagnostic sensitivity for IgG antibody detection increased from 13% in the sonicate EIA to 31% in the best flagellum EIA assay (p = 0.01) in sera from patients with erythema migrans (n = 70), and from 34% to 55% (p = 0.01) in sera from patients with neuroborreliosis (n = 77). However, the sensitivity for IgG in sera from patients with acrodermatitis chronica atrophicans (n = 20) was high in both assays: 90% in the sonicate EIA compared to 95% in the flagellum EIA. Regarding IgM, there was no significant difference between the sensitivity of the assays in sera from any of the patient groups. The sensitivity values for IgM and IgG in cerebrospinal fluid (CSF) from patients with neuroborreliosis were also without significant differences. Sera and CSF from patients with meningitis/encephalitis of non-Borrelia etiology (n = 35), multiple sclerosis (n = 9) or syphilis (n = 24), served as controls. The flagellum EIA showed a significantly improved specificity for IgG in CSF from controls with syphilis (p less than 0.01). It is concluded that purified Borrelia burgdorferi flagellum antigen is superior to a sonicate antigen, especially for serodiagnosis of the early stages of Lyme borreliosis.

Long term serologic follow-up after pertussis immunization

Neutralizing antibodies to pertussis toxin (antitoxin) were determined in 201 blood samples from 4-year-old children. They had received primary immunization at 6 to 8 months of age with an acellular (n = 149) or a whole cell (n = 52) pertussis vaccine and 195 of them had received a booster dose of the acellular vaccine 9 to 16 months later. Data on exposure to pertussis and occurrence of pertussis were also collected. There was a rapid decrease of antitoxin between immediate postbooster titers and those measured 24 months later. This decrease per month was significantly greater than that after the primary immunization series (P less than 0.001). Neither the number nor the spacing of acellular vaccine doses given for primary series influenced the titers found 24 months after the booster. An antitoxin response was still measurable in 86% of the 196 four-year-old children. None of 19 exposed children developed whooping cough, which suggested that the antibody concentrations during the follow-up period were sufficient for protection. The results indicate a need for long term follow-up studies in the evaluation of new vaccines and immunization schedules.

Etiology of community-acquired pneumonia in children based on antibody responses to bacterial and viral antigens

The serologic responses to bacterial and viral antigens were determined in paired serum samples from 336 children, ages 1 month to 15 years, with roentgenographically verified community-acquired pneumonia. Significant increases in antibodies against one agent were found in 40% and against two or more agents in 8% of the children. There were significant increases in antibodies against respiratory syncytial virus in 20%, viruses of the influenza-parainfluenza group in 6% and adenovirus in 3%. A serologic response to one or more of the pneumococcal antigens used (type-specific capsular polysaccharide, C-polysaccharide and pneumolysin) was demonstrated in 13% of the patients. Ten percent of the children had significant increases in antibodies against Mycoplasma pneumoniae. Only three patients had increases against Haemophilus influenzae type b and one each against Legionella pneumophila and Chlamydia. Respiratory syncytial virus was the predominant etiologic agent in young children whereas M. pneumoniae was more frequent in the older age group.

Sixteen-month follow-up of antibodies to pertussis toxin after primary immunization with acellular or whole cell vaccine

Antibodies to pertussis toxin (antitoxin) were measured in three blood samples drawn during a 16- to 17-month follow-up of infants immunized with adsorbed two component acellular pertussis vaccine (JNIH-6) or plain whole cell vaccine. A significant decrease of antitoxin concentration was noted between each follow-up in the acellular vaccine groups (P less than 0.005). The higher antitoxin titers induced by three doses or by two doses spaced by 2 months compared with two doses with 1-month interval disappeared with time. The antitoxin titers among high responders to three doses of whole cell vaccine paralleled those of the acellular vaccinees but at a significantly lower level. Reported exposure to pertussis did not significantly alter the decrease of antitoxin titers. The study also showed that acellular pertussis vaccine induced an antitoxin response still measurable in greater than or equal to 97 and greater than or equal to 91% of samples drawn 10 to 11 and 16 to 17 months after primary immunization, respectively.

Adverse reactions and antibody response to an acellular pertussis toxoid vaccine in adult volunteers

A monovalent pertussis toxoid vaccine (JNIH-7, Biken, Japan) was evaluated for reactogenicity and immunogenicity in 20 healthy adults (phase 1 study). Fever of greater than or equal to 38 degrees C was recorded in 2/20; local reactions started in 2/20 on day 1 (early onset) and in 3/20 on day 7 (late onset). All 15/15 subjects tested showed a significant antibody response to pertussis toxin by neutralization or enzyme-linked immunosorbent assay. Significantly elevated antibodies were still detected in 12/13 subjects 32 months after the single subcutaneous dose of vaccine.

Increased dosage of diphtheria toxoid for basic immunization of adults

Basic immunization of adults with increased dosages of a diphtheria toxoid vaccine (2100 flocculation units (Lf)/mg) was evaluated. Three injections of 7.5 Lf or 15 Lf diphtheria toxoid were given to 243 adults who had a history of no more than one previous vaccine injection. Systemic reactions were rare in both groups. Following the first two injections, local reactions (greater than 5 cm) were observed in 6-14% of the adults. After the third injection, 35% of adults in the 15 Lf group reported a local reaction (greater than 5 cm) compared to 11% in the 7.5 Lf group (p less than 0.001). The 15 Lf dose elicited a better antitoxin response than the 7.5 Lf dose. In a seronegative subgroup including 65 vaccinees who showed no booster response to the first vaccination, 79% had a postvaccination titer of greater than or equal to 0.1 IU/ml and 28% a titer of greater than or equal to IU/ml after the third injection of 7.5 Lf. The corresponding numbers in the 15 Lf group were 94% and 44%, respectively. The study demonstrates that 7.5 Lf and 15 Lf diphtheria toxoid of high purity can safely be given to adults for basic immunization. The higher dose is more immunogenic but local reactions increase after the third injection.

Adverse reactions and serologic response to a booster dose of acellular pertussis vaccine in children immunized with acellular or whole-cell vaccine as infants

Adverse reactions and antibody response to pertussis toxin, ie, antitoxin, after a booster injection of an acellular pertussis vaccine were studied in 2-year-old children. A majority (212/241) of the children had previously been immunized with either two or three doses of the acellular vaccine at the ages of 6, 7, and 8 months. The other 29/241 children had received three doses of a plain whole-cell pertussis vaccine at the same ages. In the children who received primary immunization with the acellular vaccine, two cases of more serious systemic reactions occurred in close temporal association with the booster injection. Less serious systemic reactions were few. Local reactions were more common in the children only immunized with the acellular vaccine. Large reactions (greater than 10 cm) were only seen in this group. A good antitoxin response was elicited in both groups. The geometric mean titer in the former whole-cell vaccine recipients was significantly higher than in the children who received only acellular vaccine. The study raised some questions concerning differences in reactogenicity and immune response after a booster injection of an acellular vaccine depending on the type of pertussis vaccine given to infants for the primary immunization.

Immunity and immunization of children against diphtheria in Sweden

The level of immunity to diphtheria and the effect of vaccination with different doses of diphtheria toxoid was investigated. The 457 study children, 6, 10 and 16 years of age, had as infants received routine primary vaccination with three doses of diphtheria-tetanus-toxoid or diphtheria-tetanus-pertussis vaccine, and the 16 year-olds also had received a booster dose of tetanus with a small dose of diphtheria at the age of ten. Prior to the study booster, 15% of the 6-year-olds had antitoxin levels against diphtheria less than 0.01 IU/ml, the given minimum level for protection. Of the 10-year-olds, 48% had titres less than 0.01 IU/ml, while the corresponding figure for the 16-year-olds was 24%. After a booster injection of 0.1, 0.25 or 0.5 ml of diphtheria-tetanus vaccine, more than 97% of the children showed titre levels greater than or equal to 0.1 IU/ml, while levels of greater than or equal to 1 IU/ml, indicating titres sufficient for long-term protection, were attained by 23-96%. Systemic reactions were few and moderate. Local reactions were of little clinical significance. In a group of 5-years-olds given diphtheria-tetanus primary vaccinations over wider intervals, only 1.4% had antitoxin titres less than 0.01 IU/ml. The results show a need for serologic monitoring of vaccination programmes.

Immunoglobulin E response to pertussis toxin in whooping cough and after immunization with a whole-cell and an acellular pertussis vaccine

Immunoglobulin E antibodies to pertussis toxin (PT-IgE) were demonstrated in 15 of 23 (65%) patients with culture-confirmed pertussis. In 6 individuals there was a low-grade PT-IgE response after 6-9 weeks of disease and in 9 a rapid PT-IgE response, appearing 1-3 weeks after onset of symptoms. The PT-IgE antibody levels in immunized individuals were higher than in the non immunized. Following primary immunization of 23 children with a monovalent whole-cell pertussis vaccine (Burroughs-Wellcome, UK) or with an acellular pertussis vaccine (JNIH-6, Biken, Japan) a late low-grade PT-IgE response was found in 8 (35%). In 7/10 children previously immunized with the JNIH-6, a booster injection 16 months later with the same vaccine resulted in a rapidly appearing PT-IgE antibody response. In contrast, none of 13 children initially immunized with the monovalent whole-cell vaccine and then boostered with either this vaccine or JNIH-6 had detectable PT-IgE antibodies after the booster injection. The study shows that IgE-antibodies to pertussis toxin commonly appear in patients with whooping cough and that the kinetics and the magnitude of the response is influenced by previous exposure to the antigen. A PT-IgE response may also follow pertussis immunization.

Immune status and booster effects of low doses of diphtheria toxoid in Swedish medical personnel

During a diphtheria outbreak among Swedish alcoholics in 1984-1985, only 60% of 328 medical staff at risk for exposure had diphtheria antitoxin titers greater than or equal to 0.01 IU/ml, which is usually considered to give relative protection. 21% had levels between 0.01-0.09 IU/ml and the remaining 39% had titers greater than or equal to 0.1 IU/ml. Booster doses of 0.5 Lf-12.5 Lf of diphtheria toxoid were given to 450 vaccinees. Of 72 individuals with low pre-immunization titers, who were immunized with less than or equal to 2.5 Lf diphtheria toxoid, 40% failed to reach greater than or equal to 0.1 IU/ml when analyzed 4 weeks after vaccination. Local tenderness and swelling greater than 5 cm at the site of injection or general discomfort was found in 11% of those immunized with low dose diphtheria toxoid (less than or equal to 2.5 Lf). When the dose 0.5 Lf of diphtheria toxoid was combined with tetanus toxoid (3.75 Lf) the frequency of adverse reactions increased to 34% (p less than 0.001). The study shows that vaccination status in medical personnel must also be continuously examined in countries where diphtheria is rare and that low booster doses of diphtheria toxoid may not achieve an adequate immune response.

Enzyme-linked immunosorbent assay to evaluate the immunogenicity of a polyvalent Klebsiella capsular polysaccharide vaccine in humans

A highly sensitive enzyme-linked immunosorbent assay was developed for Klebsiella capsular polysaccharide (CPS) and used to evaluate the immunoglobulin G (IgG) antibody response to a 24-valent CPS vaccine in seven adult volunteers. The median rise in titer to all vaccine antigens in samples from the volunteers was significant (twofold or greater). Significant IgG responses to 11 immunologically related serotypes not included in the vaccine were also noted. The mean cross-reacting IgG titer of 127.2 was only slightly lower than the mean titer of 175.7 to the serotypes in the vaccine (P less than 0.05). The mean 29.9-fold increase in titer to the serotypes in the vaccine was significantly higher than the mean 13.5-fold increase in titer to the additional antigens (P less than 0.001). The difference was partly because of the significantly lower (P less than 0.01) natural antibody titers in the preimmune sera to the serotypes in the vaccine, compared with those to serotypes not included in the vaccine. The selection of vaccine serotypes was based on the frequency of serotype isolation from cases of Klebsiella bacteremia. The above findings, which show low levels of natural antibody to these serotypes, support the hypothesis that anti-CPS antibody is protective against bacteremic disease.

Primary immunization of infants with an acellular pertussis vaccine in a double-blind randomized clinical trial

The rate of adverse reactions and the immunogenicity of a two-component acellular pertussis vaccine as compared with a plain whole-cell vaccine and a placebo were evaluated for primary immunization in 319 6-month-old infants in a double-blind randomized clinical trial. The acellular vaccine produced few and mild systemic and local reactions. Fever (greater than or equal to 38 degrees C) occurred in 6% to 8% of acellular vaccinees as opposed to 25% to 37% of whole-cell vaccinees. Redness (greater than or equal to 1 cm) appeared in 2% to 13% of the acellular vaccine and 24% to 32% of the whole-cell vaccine recipients. Antibody response to pertussis toxin measured in a neutralization test was obtained in 97% to 100% of the infants receiving either two or three doses of the acellular vaccine as compared to 59% after three doses of whole-cell vaccine.

Evaluation of serologic assays for diagnosis of whooping cough

An enzyme-linked immunosorbent assay (ELISA) for the immunoglobulin G (IgG), IgM, and IgA response to Bordetella pertussis filamentous hemagglutinin (FHA) and pertussis toxin (PT) and a neutralization test (NT) in a microplate tissue culture assay for neutralizing antibodies to PT were evaluated in paired sera from 90 patients with culture-confirmed pertussis. Eighty patients were children (age, less than 15 years), and 6 of 80 children had been immunized with three doses of diphtheria-tetanus-pertussis vaccine as infants. A significant titer rise (greater than or equal to twofold), determined by ELISA, of IgG, IgM, and IgA to FHA was recorded in 75 (83%), 28 (31%), and 47 (52%) of the patients, respectively. A significant titer rise to PT in IgG was found in 83 (92%), IgM in 29 (32%), and IgA in 44 (49%) of the patients. A significant titer rise to FHA or PT in IgG was found in 88 (98%) of the patients, in combination with a significant rise in the titer of IgA to FHA. These data were obtained in a single serum dilution of 1:500. Titrations performed later showed that the titer rise to FHA in IgG was a mean of 6.5-fold, which was significantly lower than the mean 67.0-fold rise in IgG to PT (P less than 0.001). The mean titer of IgG to FHA in convalescent-phase serum was 270, which was also significantly lower than the mean PT titer of 2,943 (P less than 0.001). A significant rise (greater than or equal to fourfold) in PT titer by NT was found in 58 of 83 (70%) of the patients. The NT was significantly less sensitive than the ELISA for the determination of the IgG titer to PT ( P< 0.001). Results showed that a 100% (90 of 90) sensitivity in terms of titer rises was achieved in the serologic diagnosis of pertussis by ELISA in a single-point determination of the IgG and IgA responses to FHA and of the IgG response to PT.

Protective efficacy of a whole cell pertussis vaccine

A trial of the efficacy of a plain whole cell pertussis vaccine was conducted in Sweden. In this non-blinded trial 525 infants aged 2 months who were born on days with an even number received three doses of vaccine one month apart and 615 infants of the same age who were born on days with an odd number were enrolled as controls. During the 18 months of follow up there were 55 cases of pertussis. The attack rate was 1.5% (8/525) among the vaccinated children and 7.6% (47/615) among the unvaccinated children (p less than 0.001). The estimated efficacy of the vaccine was 80% (95% confidence interval 58 to 90). The estimated efficacy of pertussis vaccine was similar to that observed in British trials over 30 years ago.

Protective effect of acellular pertussis vaccines

Two acellular pertussis vaccines, a mono-component toxoid of pertussis toxin and a two-component vaccine containing both the toxoid and filamentous haemagglutinin, were used for primary immunization of infants 5 1/2 to 10 months of age in two clinical trials in Sweden. Over a follow-up period of 12 to 17 months, 37 children were exposed to pertussis in the household or a daycare centre. Only one child developed mild, culture-confirmed pertussis as opposed to the expected number of 30 to 33 cases based on an assumed attack rate of 80-90% in non-immunized children. These preliminary findings indicate that, given as primary immunization to infants, the vaccines provide protection against pertussis.

Specific immunoglobulin A to Bordetella pertussis antigens in mucosal secretion for rapid diagnosis of whooping cough

Specific immunoglobulin A (IgA) to Bordetella pertussis filamentous hemagglutinin (FHA) and pertussis toxin (PT) was determined in mucosal secretions by an enzyme-linked immunosorbent assay (ELISA). It took 3 to 4 h to complete the ELISA. The upper limits of normal values for age were determined in nasopharyngeal (NPH) secretions from 23 patients with viral infections and in 10 healthy adults working with pertussis patients or cultures. A significant IgA response to FHA was found in 38 of 54 (70%) and to PT in 28 of 54 (52%) NPH secretions from patients with pertussis confirmed by culture, serology, or both. The rate of positive responses to either antigen (44 of 54 [81%]) was significantly higher than that by culture alone (29 of 54 [54%]; P less than 0.01). The rate of positive responses increased from 65% in patients with symptoms for 1 week or less to 87 to 92% in patients with symptoms for 2 or more weeks. The specific IgA response to PT was found in 100% of NPH samples from 17 unimmunized children less than 3 years of age and in only 30% of adults and immunized children greater than 3 years of age. A response to FHA was found in 65 to 73% of the NPH secretions in all age groups. Saliva samples were found to contain specific IgA to FHA and PT in all age groups, but these were of diagnostic value in 50% (11 of 22) of the adult patients. The specificity of the ELISA was 100% (10 of 10 negatives) in NPH secretions from patients with pertussis-like cough who had negative cultures and serology. The results indicate that determination of specific IgA to PT and FHA in NPH aspirates represents a sensitive and rapid diagnostic method for the detection of pertussis.

A longterm follow-up study of children born to women with contagious diseases at delivery

Data are presented from a long-term follow-up study of 308 live born children to women admitted post partum to the Department of Infectious Diseases (DID), Danderyd Hospital, Sweden, during a 10-year period (1975-1984) for avoiding nosocomial transmission of infections in the obstetrical wards. The rate of stillbirths (1/309 deliveries) was not higher than reported for all births in Stockholm. 20% of the live born children were transferred within 24 h after birth to the pediatric department for observation, but half of them could return to their mothers at the DID within 6 days (generally 3 days). Four newborns were treated at an intensive care unit. Only 3 fatalities occurred, all of them among newborns to mothers with an overt infection at delivery. The fatality rate (1.8%) was significantly higher among the newborns of these mothers than normally (0.3%) noted among all children born in Stockholm county during the period studied. Two of the 3 newborns, who all died within 3 days of life, had a low birth weight (600 and 1,000 g). The total number of newborns with low birth weights (less than 2,500 g) was, however, not higher in the above-mentioned group of newborns than for all children born in Stockholm county 1980. None of the 3 fatalities was caused by infection transmitted from the mother. No further deaths occurred. Infections in pregnancy at term, at birth or post partum were transmitted from the women to 41 (13%) of their newborns.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of pregnant women with contagious infections at delivery

Since 1970 pregnant women with contagious infections in the country of Stockholm have been delivered at the Danderyd Hospital, the only hospital in the area which has departments of obstetrics and pediatrics as well as infectious diseases. This paper presents data from a prospective study carried out during a period of 10 years (1975-1984). The study includes 303 women and their newborns who for various reasons were transferred to the Department of Infectious Diseases (DID) before or after delivery. A comprehensive microbiological investigation was made in order to establish an etiological diagnosis in all women included in the study. A possible transmission of the infection from the mother to her fetus/child before or after delivery was also investigated. Only 0.17% of the pregnant women in the area needed care at the DID at delivery or in the puerperal period. 9% of the deliveries occurred at another hospital, 32% at the DID and the remaining at the obstetrical department, Danderyd Hospital. The rate of complications, including cesarean sections, was 12%. Of the 165 women suffering from an infectious disease at the time of delivery, 40% had a verified viral disease--in most cases varicella or mumps, 28% had a bacterial infection and for 32% no etiology of the disease could be established. The study population also includes women suspected either to be incubated with a contagious disease or to be carriers of infectious agents, as well as healthy mothers whose newborns were expected to be carriers of infectious agents such as rubella and varicella. None of the women died during the study period but 5 were seriously ill and 3 needed intensive care. The rate of stillbirths was the same as reported among all births in the country of Stockholm but the perinatal mortality rate was significantly higher (see also a following article, ref. 27). Our routines prove the necessity to take special care of pregnant women carrying a contagious infectious agent at term.

Serum antibodies to pneumolysin in patients with pneumonia

Serum antibodies to purified pneumolysin were determined by enzyme-linked immunosorbent assay (ELISA) in paired samples from 406 adult patients with community-acquired pneumonia and in samples from 184 healthy controls. A high sensitivity (83%) was obtained in patients with blood culture-confirmed pneumococcal pneumonia. In patients with a tentative pneumococcal diagnosis based on culture of samples from the sputum or the nasopharynx, 45% were positive by ELISA. The difference likely reflected the different relevance of cultural findings for the diagnosis of pneumococcal pneumonia. A significant rise in ELISA titer was found in 17% of the patients. When the diagnosis was also based on high titers, 25% were positive. Pneumococcal pneumonia diagnosed by the pneumolysin ELISA was significantly more common in the patients with a more severe disease and who required hospitalization (21 versus 5% for outpatients). Younger patients were more often positive for pneumococci as determined by high titers, while older patients showed titer rises. Mixed infections with other infectious agents were not uncommon. The finding of low titers in acute-phase samples from positive patients and in the youngest and oldest age groups of healthy controls were unexpected, indicating that further studies on the role of pneumolysin in pneumococcal disease are warranted.

Adverse reactions and immunogenicity in adults to regular and increased dosage of diphtheria vaccine

Booster doses of 3 Lf or 7.5 Lf of a regular diphtheria vaccine were given to 200 previously immunized adult volunteers. The toxoid was prepared from toxin with a purity of 2100 Lf/mg protein nitrogen and adsorbed to aluminium phosphate. Systemic reactions were rare and no severe symptoms were observed. Local reactions occurred in 40-50% of the vaccinees, but in only 7.5% were they of clinical significance, i.e. an area of redness/swelling greater than 5 cm. The two doses did not cause significant differences in reaction rates, and the 7.5 Lf dose elicited a better antitoxin response. Thus, a dose of 7.5 Lf diphtheria toxoid of similar purity can safely be given to adults in vaccines.

Prospective study of serum antibodies to Pseudomonas aeruginosa exoproteins in cystic fibrosis

Serum immunoglobulin G to four purified antigens from Pseudomonas aeruginosa, phospholipase C, alkaline protease, exotoxin A, and elastase, were determined in 62 patients with cystic fibrosis by enzyme-linked immunosorbent assay. The patients were followed for 12 to 24 months in a prospective study. Increased titers, i.e., titers more than 2 standard deviations above those of normal controls, were exclusively found in patients chronically colonized with P. aeruginosa and not in patients harboring only Staphylococcus aureus. The frequencies of elevated titers of antibody to the different antigens varied from 100% (phospholipase C) to 58% (alkaline protease and exotoxin A) to 15% (elastase) in the chronically colonized patients. Mean serum titer levels, expressed as multiples of the age-correlated upper normal limit (=1), were significantly higher to phospholipase C in patients with dual colonization with P. aeruginosa and S. aureus than in those colonized only with P. aeruginosa (P less than 0.001). Conversely, the other three antigens showed significantly higher serum antibody titer levels in patients harboring only P. aeruginosa (P less than 0.001). In five patients who became colonized with P. aeruginosa during the study period, serum antibodies to phospholipase C and exotoxin A increased first. Exceptions to the general pattern of antibody responses were found in three patients chronically colonized with Escherichia coli. They showed a delayed enhancement of anti-phospholipase C titers after the chronic P. aeruginosa colonization. Serum titers were not influenced by exacerbations of pulmonary infection or by antimicrobial therapy. The determination of titers of serum antibody to phospholipase C seems to be a valuable indicator of a chronic colonization with P. aeruginosa. The results further suggest that bacterial metabolism and interactions may influence the antibody response.

Prospective study of serum staphylococcal antibodies in cystic fibrosis

Serum IgG antibodies to teichoic acid and alpha toxin from Staphylococcus aureus were measured in 62 patients with cystic fibrosis by enzyme linked immunosorbent assays. The patients were followed up for 12-24 months in a prospective study. Raised titres were found exclusively in patients chronically colonised with S aureus. Patients colonised with both S aureus and Pseudomonas aeruginosa had significantly higher titres against teichoic acid than those carrying S aureus alone. Titres were significantly higher when there were clinical signs of low grade infection in the patients chronically colonised with S aureus alone, and in those with both S aureus and P aeruginosa. Significant reduction in titres occurred after antimicrobial treatment given either orally or intravenously in patients with normal erythrocyte sedimentation rates and white cell counts. Measurement of staphylococcal antibody titres may be valuable in monitoring pulmonary infection and antimicrobial treatment in patients with cystic fibrosis.

Immunoglobulin class and immunoglobulin G subclass enzyme-linked immunosorbent assays compared with microneutralization assay for serodiagnosis of mumps infection and determination of immunity

Total immunoglobulin G (IgG) and IgG subclass reactivities with purified mumps glycoproteins (GP) and nucleoprotein (NP), measured in enzyme-linked immunosorbent assays (ELISAs), were compared with titers in a mumps microneutralization assay (NT). For determination of mumps immunity, the sensitivity of both ELISAs was 100% in comparison with the NT and the specificity was 90%. IgG1 was the dominant subclass against the two antigens found in seropositive healthy individuals. In samples from patients with clinical mumps infections and positive mumps IgM, titer rises of total IgG against NP were invariably seen before GP titer rises. Significant but often late titers rises in NT were found in all patients. Changes of IgG1 levels against both antigens followed the changes of total specific IgG. High levels of IgG3 against NP were diagnostic for mumps infection. In parainfluenza infections, titer rises in the mumps ELISAs and NT were found, but mumps IgM, NP IgG3, and the high ratio between the NP and GP titers found in early samples from patients with mumps infection were not observed.

A clinical trial of a monocomponent pertussis toxoid vaccine

We compared a monocomponent pertussis toxoid vaccine preparation (JNIH-7) in a double-blind, randomized study with another component vaccine (JNIH-6) containing pertussis toxoid and filamentous hemagglutinin in equal proportions. Monocomponent pertussis toxoid vaccines have not been tested previously in children. This trial comprised 255 previously nonimmunized children 6 to 10 months old who were given two 0.5-mL subcutaneous injections of either vaccine four to five weeks apart. Prevaccination and postvaccination serum samples from 235 infants showed an antitoxin seroconversion rate of 100% in both groups. Adverse reactions were few and mild, with local reactions occurring more often after administration of the second dose and among recipients of the two-component vaccine (P less than .05).

Immunological relation between serum antibodies against pneumolysin and against streptolysin O

The immunological relation between serum antibodies to pneumolysin and to streptolysin O was studied in patients with pneumococcal pneumonia (n = 40), patients with infections due to beta-haemolytic streptococci (n = 35), healthy human controls (n = 60) and in rabbits immunized with pneumolysin. There was no correlation between anti-pneumolysin and anti-streptolysin O titers (r = -0.279). The distribution of anti-pneumolysin titers in patients with high anti-streptolysin O titers did not differ from healthy controls. However, there was a tendency to increased or rising anti-streptolysin O titers in patients with pneumococcal infection. Antibodies obtained during pneumococcal infection might thus give false-positive reactions in the streptolysin O neutralization test. Serum antibodies to streptolysin O do not cross-react with pneumolysin in an ELISA. The pneumolysin ELISA for detection of pneumococcal disease will therefore not be disturbed by false-positive reactions due to antibodies directed against beta-haemolytic streptococci.

A sandwich ELISA for bovine serum in viral vaccines

A double antibody sandwich ELISA for the detection of bovine serum in viral vaccines was developed and standardized with commercially available reagents. The detection limit by ELISA was 0.5 ng ml-1. ELISA was found to be 50-400 times more sensitive than the currently used assays. It was concluded that ELISA is a specific, sensitive and reproducible method for the determination of residual amounts of bovine serum in viral vaccines.

Use of erythromycin to prevent pertussis in newborns of mothers with pertussis

During the period 1975-1985, 35 women with serology- or culture-confirmed pertussis at the time of labor were admitted to the Danderyd Hospital (Danderyd, Sweden). In 32 cases, the mothers were allowed to nurse their newborns while receiving erythromycin therapy. Erythromycin prophylaxis was given to 28 newborns. None of the newborns developed clinical or laboratory signs of whooping cough. The therapy was well tolerated by the newborns and did not affect the microflora in the gut. Maternal antibodies to pertussis toxin and to the filamentous hemagglutinin were found in cord blood, and levels decreased during the follow-up period. The study demonstrated that mothers with pertussis can safely be allowed to nurse their infants if both receive erythromycin.

Diagnosis of pneumococcal pneumonia by enzyme-linked immunosorbent assay of antibodies to pneumococcal hemolysin (pneumolysin)

An enzyme-linked immunosorbent assay (ELISA) with a highly purified pneumolysin as the antigen was evaluated for serological diagnosis of pneumococcal pneumonia. One hundred four healthy controls were tested, and the specificity of the test was set to 95%. In samples from patients with bacteremic pneumococcal pneumonia, 82% (18 of 22) were positive, i.e., at least one serum sample had a titer above the upper normal limit or at least a twofold rise in antibody titers was noted. In nonbacteremic pneumococcal pneumonia, 45% (21 of 47) of samples were positive. All sera were negative for patients with pneumonia caused by Haemophilus influenzae, Legionella pneumophila, Chlamydia psittaci, and influenza A virus. However, in patients with a diagnosis of Mycoplasma pneumoniae infection, 8 of 25 (32%) samples were positive for antibodies to pneumolysin. All sera, including those from patients with mycoplasma infection, were negative to a protein control antigen by ELISA. Serum immunoglobulin G response to pneumolysin as measured by ELISA might thus be an aid in the laboratory diagnosis of pneumococcal pneumonia. This assay may also help to further elucidate the occurrence of dual infections with pneumococci.