An influenza B epidemic among children in day-care.

An outbreak of influenza virus type B infections occurred in the Frank Porter Graham Day Care Center from February to April, 1974. During the epidemic there were 27 isolations of influenza B virus from 20 children. One half of these were obtained from children who were well at the time of culturing. Attack rates as determined by virus isolation and seroconversion for most age groups approximated the 40% rate for the entire population. Clinical and microbiological data from this study were compared to those obtained in the center during the same three months in 1973. Increases in the incidence of otitis media and temperatures over 38 C were seen during the 1974 study. Intensive continuous microbiological surveillance for bacteria, viruses, and mycoplasmas failed to reveal predominance of any other potential pathogen to account for these clinical findings. The analysis permitted by the nature of this study design in a day-care setting revealed several unexpected findings: high attack rates unrelated to age; common inapparent infections; and frequent association with otitis media.

Breast-feeding and respiratory virus infection.

Thirty-nine breast-fed and 42 bottle-fed infants were followed up from birth over a four-year period. Virus infection was documented by culture and serologic testing, and history and physical examination were recorded for all episodes of respiratory illness. There were no statistically significant differences in rates or distributions of infection with individual viruses or with all viruses over the first three or six months or during the second six months of life in the two groups, nor were there statistically significant differences in rates or distributions of disease of the upper and lower respiratory tract or total respiratory disease, except for decreased disease of the lower respiratory tract in bottle-fed infants in the second six months. There were trends to decreased morbidity in breast-fed infants in the first three and six months and more episodes of pneumonia and bronchiolitis in bottle-fed infants in the first six months (P less than .05) but similar use of medical care by both groups. High cord blood titers to two viruses were not associated with evidence of breast-feeding protection from infection with those two agents. Breast-fed babies do not have fewer respiratory virus infections or illnesses but may experience less severe illness.

Relation of serum antibody to glycoproteins of respiratory syncytial virus with immunity to infection in children.

Immunity in relation to passively transferred maternal and naturally-induced serum antibody to the viral proteins was determined in 34 children who were followed from birth through three years of age for respiratory syncytial virus infection (RSV). Sera were tested by immunoglobulin class-specific enzyme-linked immunosorbent assay using the attachment and fusion proteins of the Long strain. The basis for immunity for maternal antibody in primary infection was assessed by a comparison of the distribution of antibody titers in a) 7 children who had an upper respiratory illness to 12 whose illness was accompanied by lower respiratory disease and of b) 13 children with an RSV-associated illness in the first 6 months of life who were age-matched as to month and approximate day of birth with 11 not infected in the same period. Infection induced immunity was evaluated by a comparison of antibody titers in 19 children who were reinfected with RSV in the year following their primary infection to 15 in whom reinfection was not documented. A statistical analysis of titers revealed that antibody to the fusion protein is an important correlate of immunity. In all three comparisons, the children with less RSV disease had significantly higher IgG anti-F titers prior to infection. No differences were observed between IgA anti-F or IgG and IgA anti-G titers.

A computerized reminder strategy is effective for annual influenza immunization of children with asthma or reactive airway disease.

BACKGROUND: Influenza virus infection frequently triggers asthma exacerbation and hospitalization. Annual influenza immunization is recommended for children with chronic conditions, including those with asthma or reactive airway disease (RAD); however, <10% receive it each year. METHODS: In September, 1997, we instituted a computerized staged reminder strategy for annual influenza immunization of children with asthma/RAD at the Scott and White Pediatric Clinic in Temple. A reminder letter, followed six weeks later by an autodial recall telephone message, was sent to the parent/guardian of children with asthma/RAD using the Shared Medical Systems to identify children with asthma/RAD and the Integrated Client Encounter System to record immunizations. The effect of this computerized reminder system on the influenza immunization rate of a cohort of 925 Scott and White Pediatric Clinic children with asthma/RAD was examined for the 1996 to 1997 and 1997 to 1998 influenza seasons, before and after intervention. RESULTS: A significant increase in influenza immunization rate from 5.4% to 32.1% occurred in all age groups, regardless of the insurance status. The medically attended acute respiratory illness rate per 100 subjects was significantly higher in vaccinated than in unvaccinated children for each of the two influenza epidemics and in the period between the two epidemics. CONCLUSION: A computerized reminder letter followed by an autodial recall telephone message is effective in increasing the influenza immunization rate of children with asthma/RAD. Children with significantly higher respiratory morbidity during and in between two influenza epidemics were more likely to be immunized after receiving written and telephone autodial reminders.

Influenza virus infections in infants.

BACKGROUND: Universal immunization of children with live attenuated cold recombinant vaccine has been proposed. The renewed recommendation for maternal immunization with influenza vaccine should increase the amount of antibody transmitted to the infant and postpone the need for active immunization. This study examines the risk of influenza during the first year of life to provide information about the time to initiate active immunization. METHODS: Infants followed from birth to 1 year of age in the Houston Family Study were monitored weekly for influenza virus infection. Serum specimens were tested for evidence of infection at 4-month intervals. RESULTS: One-third of 209 infants were infected during the first year; most of the infections occurred during the second 6 months of life. Only 26 of 69 infections were detected before 6 months of age compared with 43 afterward. More striking was the concentration of serious illnesses in the latter half of the first year; 8 of 9 otitis media episodes and 9 of 11 lower respiratory tract illnesses occurred in the older infants. CONCLUSIONS: The combination of increased maternal antibody titers that should result from influenza immunization and the lesser risk of influenza in the first 6 months of life allows initiation of active immunization of children after 6 months of age.

Haemophilus influenzae type b-specific antibody in infants after maternal immunization.

OBJECTIVE: To study the kinetics of Haemophilus influenzae type b (Hib)-specific antibody in infants born to mothers immunized with an Hib polysaccharide or one of two Hib conjugate vaccines. STUDY DESIGN: Serum antibody to the polyribosylribitol (PRP) moiety of Hib was measured by radioimmunoassay and enzyme-linked immunosorbent assay at birth and at 2 and 6 months of age in infants born to women immunized with Hib polysaccharide or conjugate vaccine (PRP-D and HbOC). A subset of infants > or = 6 months of age was immunized with Hib conjugate vaccine after licensure of this vaccine for infants. A comparison group of 18 infants born to unimmunized women received the same Hib conjugate vaccine on a similar schedule. RESULTS: Total PRP antibody concentrations were 1.50, 14.4 and 20.4 microg/ml in 2-month-old infants born to mothers immunized with polysaccharide, PRP-D and HbOC vaccines, respectively, and 2.54, 1.35 and 2.46 microg/ml in 6-month-old infants. Infants born to mothers immunized with polysaccharide vaccine had significantly less PRP antibody at 2 months of age but similar antibody concentrations at 6 months of age. Persistence or increases in total PRP antibody during 6 months were noted in 21 of 47 (44.6%) study infants. A subset of study and comparison infants was immunized with a mean of 2.6 doses of Hib vaccines between 6 months and 2 years of age, and all infants had total PRP antibody concentrations > or = 0.15 microg/ml. CONCLUSION: Conjugate Hib vaccines administered during the last trimester of pregnancy resulted in significantly higher PRP antibody titers in infants at birth and 2 months of age than did polysaccharide vaccine. A subset of infants born to immunized mothers was subsequently immunized with Hib conjugate vaccine and had antibody concentrations similar to those in infants born to nonimmunized women.

Safety and antibody persistence following Haemophilus influenzae type b conjugate or pneumococcal polysaccharide vaccines given before pregnancy in women of childbearing age and their infants.

BACKGROUND: Immunization of healthy women before pregnancy is a potential approach to providing increased levels of maternal antibody to newborns to protect them from infections occurring during the perinatal period and first months of life. METHODS: Healthy nonpregnant Pima Indian women of childbearing age were randomized to receive one of two Haemophilus influenzae type b (Hib) conjugate vaccines [HbOC or Hib-meningococcal outer membrane protein complex (OMP)] or a 23-valent pneumococcal polysaccharide vaccine (PnPs). Infants received Hib-OMP vaccine at 2, 4 and 12 months of age. Vaccine safety and immunogenicity was evaluated in the women and their infants. RESULTS: Anti-polyribose ribitol phosphate antibody titers were significantly higher in women in both Hib conjugate vaccine groups than in the pneumococcal vaccine group throughout the 37-month observation period. Antibody responses to HbOC vaccine were significantly higher than those to Hib-OMP. A subsequent booster dose of each Hib conjugate vaccine induced reactions and antibody responses similar to those of the first dose. Infants born to mothers immunized with Hib vaccines compared with PnPs had significantly higher polyribose ribitol phosphate-specific IgG antibody titers at birth and 2 months of age but lower antibody responses to Hib-OMP at 6 months and similar titers before and after boosting with Hib-OMP at 1 year of age. By contrast women immunized with PnPs did not have significantly elevated concentrations of pneumococcal-specific antibody at delivery, and their infants had pneumococcal antibody titers similar to those of infants born to mothers who did not receive pneumococcal vaccine before pregnancy. CONCLUSION: Hib conjugate vaccine given to women before pregnancy significantly increased the proportion of infants who had protective Hib antibody levels at birth and 2 months of age.

Serological evidence of Hantaan virus infection in the United States.

We found low titers of fluorescent antibodies against Hantaan virus, the etiologic agent of Korean hemorrhagic fever, in sera from 7 of 1,035 patients with febrile illnesses of unknown origin and from 6 of 664 blood donors in the United States. All but 1 of these individuals possessed neutralizing antibodies against Hantaan virus. This was a 31-year-old research technician who had worked with laboratory rodents with virus-induced tumors, but had not traveled abroad, suggesting that infection with Hantaan virus or a closely related agent was locally acquired. However, the precise source of his infection remains unclear.

Reactive airway disorders in children. Role of respiratory virus infections.

The knowledge of pathogenetic mechanisms of reactive airway disorders of children has advanced to complex interactions that involve respiratory virus infection, both antigen-specific and nonspecific chemical mediation, and neurogenic bronchoconstriction. Most of the clinical correlations have been derived from fragmentary studies which involved groups of children defined by one or only a few variables. To progress beyond this point, longitudinal studies are needed of infants and children for whom all of the variables are defined so that the interrelationship of these factors can be unraveled. Essential components of these studies would be that the subjects be tested for evidence of atopy, that the etiology of lower respiratory infections be determined, and that methods to follow pulmonary function be employed. These studies would require that relatively large numbers of children be followed from early infancy through childhood and that noninvasive procedures be employed for testing the various parameters in order to maintain compliance. Some investigators have suggested that the T-lymphocyte regulation of the immune response to certain antigens is altered in persons with atopy. Further research is needed to determine the genetic basis of this response. Furthermore, patients with asthma appear to have altered function of the autonomic nervous system. More information is needed to determine if this altered response (beta adrenergic subsensitivity versus alpha adrenergic and cholinergic hypersensitivity) is a cause, or a coexistent defect, or a result of atopic asthma. Finally, does hyperresponsiveness of the airways to non-specific irritants exist without underlying atopy? Most of the data presented above indicate that in its severe forms it, at least, coexists with allergen-induced asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Diurnal variation in responses to influenza vaccine.

Data from two field trials of influenza vaccine were examined for an association between vaccination time and subject response. Both were conducted on adults and involved the same antigens and dose via intramuscular injection. In one study (Princeton) a diurnal pattern in antibody response to the antigen A/Philippines, but not to A/Chile or B/USSR, was detected after the first vaccination administered during summer 1984, but not after the second revaccination given during summer 1985. In a second study (Houston) conducted during autumn 1985, no diurnal pattern in antibody response was detected for any of the antigens assessed. No diurnal pattern in systemic reactions was observed. Previously vaccinated subjects of both studies more commonly experienced local reactions of arm redness, hardness, and soreness after afternoon versus morning (p < 0.05) injection upon revaccination, both before and after adjustment for possible confounders of age and gender.

Maternal vaccines.

Acute lower respiratory illness (LRI) is the leading cause of disease worldwide as measured by disability-adjusted life years. New strategies are necessary to decrease the disease burden that is largely borne by infants. Respiratory syncytial virus is the most important cause of LRI in infants. Lower respiratory illness can be prevented by endowing infants with high levels of neutralizing antibodies from mothers whose antibodies are boosted during pregnancy with a potent subunit vaccine. Another important cause of infant mortality is group B streptococcus sepsis in the neonatal period; maternal immunization with a group B conjugate vaccine could prevent this devastating infection.

Influenza surveillance in an urban area.

In Houston the yearly influenza epidemics have been defined virologically by community surveillance obtained by testing specimens submitted from patients with acute respiratory illnesses seen by sentinel physicians. Mortality attributed to influenza and pneumonia has increased regularly during the period of intense influenza virus activity, but the peak has lagged two weeks behind the peak of activity defined by the virological surveillance. Most of the deaths occurred in persons aged 65 years and older; the average annual rate has been 103.5 per 100,000 in that age group. Hospitalizations for pneumonia and other acute respiratory conditions also peaked during influenza epidemics; the highest rate occurred in the elderly, but children under five years of age also had high rates. Morbidity in the ambulatory setting was highest in children. The average visit rate for children under five years of age was 28%; the rate decreased to about 10% for persons aged 10 years and older. Improved coverage with more immunogenic vaccines is needed to protect the elderly. Young children would benefit from universal immunization with available live attenuated vaccines.

[Influence of influenza epidemics on the urban population]. / Vliianie épidemii grippa na gorodskoe naselenie.

The results of studies carried out in 1974-1979 according to the programme of epidemiological survey of influenza among the population of Houston (USA) developed by the Research Center for Influenza at the Baylor Medical College are reviewed. The data of selective virological and epidemiological surveys of the population were used for comparative analysis of several epidemic outbreaks caused by different antigenic variants of influenza virus. The analysis has been aimed at the detection of "high risk" groups of the population, investigation of the effect of influenza on the health of the population, determination of the factors conducive to virus spread, development of methods for the evaluation of the efficacy of influenza control measures, as well as determination of the earliest signs of activity of influenza viruses among the population and search for the best method of prediction of an epidemic virus for the following season.