Sven Arne Silfverdal

The Transfer of Immunity from Mother to Child

Abstract: The newborns immune system grows fast from a small size at birth by exposure primarily to the intestinal microflora normally obtained from the mother at and after birth. While building up its immune system, the infant is supported by the transplacental IgG antibodies, which also contain anti‐idiotypic antibodies, possibly also actively priming the offspring. The second mode of transfer of immunity occurs via the milk. Numerous major protective components, including secretory IgA (SIgA) antibodies and lactoferrin, are present.

Mental health and psychosocial characteristics in adolescent obesity: a population-based case-control study

In this population‐based study we compared self‐esteem, social background, social and academic competence, behavioural problems and lifestyle in 58 obese adolescents (BMI ≥ 99.6th percentile or ≥ 30 kg/m2), aged 14—18 y, with 58 sex‐ and age‐matched controls of normal weight. The instruments used were: I Think I Am, Youth Self Report and a lifestyle questionnaire. The obese group was on average, 40 kg heavier than the controls. The obese individuals rated themselves significantly lower in physical characteristics, but in all other aspects of self‐esteem, mental health and social and academic competence there were no differences between the two groups. There were significant socioeconomic differences, with more obese adolescents living with only one parent and with the mothers in the obese group having, in general, lower education than those in the control group. This study confirms previous observations that obesity is associated with special socioeconomic conditions in youth, but that obese adolescents do not differ from their normal‐weight peers in other aspects of mental health. □Adolescents, obesity, self‐esteem, social behaviour

The Impact of Haemophilus influenzae Type b Vaccination in Sweden

The number of patients with meningitis and bacteremia due to Haemophilus influenzae was studied in Sweden over the period 1987-1994. Conjugated H. influenzae type b vaccines were introduced in Sweden in 1992, and all children born after December 31, 1992, were offered vaccination free of charge. A rapid decline of H. influenzae meningitis and bacteraemia was observed in the autumn of 1993, when the expected peak incidence failed to appear. In the prevaccination period 1987-1991, the average annual incidence (cases/100,000) was 34.4 in children aged 0-4 years. In 1994, the annual incidence fell to 3.5. No significant decline was observed in older children or adults. There was a 92% reduction in the number of meningitis cases and an 83% reduction in cases of bacteraemia. A similar decline was noted in 2 regions which followed different strategies for the introduction of the vaccination programme.

Immunogenicity of a 2-dose priming and booster vaccination with the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine

Background: The immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was determined following a simplified 2-dose priming and the more commonly employed 3-dose priming both followed by a booster dose. Methods: A total of 351 healthy subjects were primed with PHiD-CV at either 3 and 5 or 3, 4 and 5 months of age followed in all subjects by a booster dose at 11 to 12 months of age. Serotype-specific pneumococcal responses were measured by 22F-inhibition ELISA and opsonophagocytic assays 1 month following primary and booster vaccinations. Results: Depending on the serotype, the percentages of subjects reaching the ELISA antibody threshold of 0.2 &mgr;g/mL were 92.8% to 98.0% following 2 primary doses and 96.1% to 100% following 3 primary doses except for serotype 6B (55.7% and 63.1%, respectively) and serotype 23F (69.3% and 77.6%, respectively). Opsonophagocytic activity (OPA) could be measured in 74.4% to 100% and 88.9% to 100% of the subjects after the 2-dose or 3-dose priming, respectively, except for serotype 1 (60.8% and 62.9%, respectively). In both groups, robust increases in ELISA antibodies and OPA titers were observed for all serotypes after the booster dose. Higher postprimary and postbooster ELISA antibody levels and OPA titers were observed for most serotypes following the 3+1 schedule. Conclusion: PHiD-CV was immunogenic in both schedules, but further effectiveness data are needed to fully understand the public health benefit to be expected from these schedules in terms of prevention against invasive and mucosal infections.

The immunological role of breast feeding

Hanson LÅ, Silfverdal S-A, Strömbäck L, Erling V, Zaman S, Olcén P, Telemo E. The immunological role of breast feeding. Pediatr Allergy Immunol 2001: 12(suppl 14): 15–19. # Munksgaard 2001. L. Å. Hanson, S.-A. Silfverdal, L. Strömbäck, V. Erling, S. Zaman, P. Olcén, E. Telemo Department of Clinical Immunology, Göteborg University, Göteborg, Sweden, Departments of Paediatrics, Microbiology and Immunology, Örebro Medical Centre Hospital, Örebro, Sweden and Department of Social and Preventive Pediatrics, King Edward Medical College, Lahore, Pakistan

A fourth dose of DTPa-IPV vaccine given to 4-6 year old children in Italy and Sweden following primary vaccination at 3, 5 and 11-12 months of age

Healthy 4–6 y old children from Italy and Sweden immunized with DTPa and inactivated or oral polio vaccines at 3, 5 and 11–12 months of age, received 1 dose of combined DTPa-IPV (n=211) or DTPa+IPV as separate doses (n=205) in a randomized trial. The pre-booster seroprotection rates were similar in each group and were above 60% against all antigens except diphtheria (31.3% and 37.0%) and PT (21.5% and 25.9%) in the DTPa-IPV and DTPa+IPV groups, respectively. At least 99.5% of subjects had seroprotective antibody levels against diphtheria, tetanus and polioviruses and ≥96% showed a vaccine response to each pertussis antigen after vaccination. Post-booster antibody levels increased at least 51-fold for anti-diphtheria and anti-tetanus, at least 18-fold for anti-pertussis antibodies and at least 32-fold for antibodies against all 3 poliovirus types, compared to prior levels. DTPa-IPV was comparable to DTPa+IPV in terms of seroprotection rates and mean antibody levels against each vaccine antigen. Similar reactogenicity profiles were observed between groups including swelling >50 mm [13% (9.1, 18.7) vs 17% (12.4, 23.4)] or involving an adjacent joint [0% (-,-) vs 1.5% (0.3, 4.3)] and were consistent with previous reports. The combined DTPa-IPV vaccine could be used to add DTP valences to the IPV vaccine currently given to children in Scandinavia and Italy at 4–6 y of age and reinforce protection against 4 diseases.

Incidence and clinical presentation of acute otitis media in children aged <6 years in European medical practices.

SUMMARY We conducted an epidemiological, observational cohort study to determine the incidence and complications of acute otitis media (AOM) in children aged <6 years. Data on physician-diagnosed AOM were collected from retrospective review of medical charts for the year preceding enrolment and then prospectively in the year following enrolment. The study included 5776 children in Germany, Italy, Spain, Sweden, and the UK. AOM incidence was 256/1000 person-years [95% confidence interval (CI) 243–270] in the prospective study period. Incidence was lowest in Italy (195, 95% CI 171–222) and highest in Spain (328, 95% CI 296–363). Complications were documented in <1% of episodes. Spontaneous tympanic membrane perforation was documented in 7% of episodes. Both retrospective and prospective study results were similar and show the high incidence during childhood in these five European countries. Differences by country may reflect true differences and differences in social structure and diagnostic procedures.

Invasive Haemophilus influenzae Disease: Epidemiology and Clinical Spectrum Before Large-scale H. influenzae Type b Vaccination

In a prospective study between January 1987 and December 1992, 103 patients with invasive Haemophilus influenzae (Hi) infection were identified in a well-defined population before large-scale Haemophilus influenzae type b (Hib) vaccination was introduced. The incidence (case/100,000/year) of invasive Hi infection was 5.9 for the whole population, 55 for children 0-4 years old and as high as 2.8 for adults. Hib was the predominant cause of the infection (83 cases) in children but, in adults, 13/39 (30%) cases were caused by non-typable Hi and 6/39 (19%) by Hi serotype f. Three patients (3%) died and 6 (5.8%) suffered a permanent sequel from the infection. All patients with such a sequel had invasive Hib infection. No significant difference between patients 0-6 years old and matched controls regarding the frequency of subnormal serum levels of immunoglobulins was found.

Economic Evaluation of General Childhood Vaccination against Haemophilus influenzae Type b in Sweden

The objective of the study was to evaluate the economic consequences of a general childhood vaccination programme against Haemophilus influenzae type b (Hib) in Sweden. A retrospective pre-vaccination annual cohort of 0-4-y-old children was compared with an annual cohort of the same age group after a complete implemented vaccination program against Hib. The cost analysis shows that vaccination against Hib is cost saving when indirect costs are included in the analysis. In the cost-benefit analysis it is shown that society will gain approximately 88 million Swedish Crowns (SEK) annually when Hib vaccination is totally implemented. In conclusion, general childhood Hib vaccination is a cost-effective public health intervention in Swedish society.

Immune System Modulation by Human Milk

The mother’s immune system seems to have a much more active role for the development and protection of her fetus and newborn than previously realized. We have recently learned that various cytokines of the mother’s immune response to her fetus play a major role in actively monitoring pregnancy, such as mediating the implantation in the decidua of the fertilized egg and the growth of the placenta. Breastfeeding we have mainly thought of as a process providing passive protection of the infant by transferring various ready made protective factors like secretory IgA antibodies, lactoferrin, oligosaccharides functioning as receptor analogues etc. Such protection is well proven against numerous infections. Now we realize that breastfeeding also brings various active stimuli for the immune system of the infant providing possibilities for enhanced protection against infections also after the termination of breastfeeding.