A SURVEY OF ANTIBODIES TO RESPIRATORY SYNCYTIAL VIRUS IN THE POPULATION

Clinical manifestations of respiratory tract infections due to respiratory syncytial virus and rhinoviruses in hospitalized children

From September 1984 to May 1986, nasopharyngeal secretions were obtained from 519 children with some form of respiratory tract infection. The nasal secretions were screened for respiratory syncytial virus (RSV), rhinoviruses, adenoviruses, parainfluenza virus types 1, 2, 3, influenza virus types A and B, and enteroviruses by tissue culture virus isolation technique and/or enzyme-linked immunosorbent assay. A uniform questionnaire gave information about age, sex, individual signs and symptoms, findings of the physical examination and clinical diagnosis of the patients. RSV was detected in 119 (23%) specimens and was thus the most frequent causative agent of respiratory infections. After RSV, rhinoviruses were the most frequently recovered pathogens accounting for 60 (12%) cases of acute respiratory disease. A comparison of the individual signs and symptoms, the findings of the physical examination and the clinical diagnosis of RSV and rhinovirus infected children revealed that there was no characteristic clinical pattern associated with either of the two viral respiratory pathogens. According to our results, rhinovirus infections were a major cause of lower respiratory tract infections in hospitalized children less than or equal to 3 years old.

Evaluation of clinical specimens for the presence of respiratory syncytial virus antigens using an enzyme immunoassay

An enzyme-linked immunoassay (EIA) was developed for the detection of respiratory syncytial virus (RSV) antigen in nasopharyngeal secretions. This assay, which employs goat and rabbit anti-RSV as the capture and detector antibodies respectively, was used in a retrospective evaluation of frozen clinical specimens from children. The EIA results were compared with those of virus isolation in cell culture and direct fluorescent antibody staining performed at the time of specimen collection. The sensitivity of the RSV EIA compared to cell culture was 91.3% (63/69) with a specificity of 96.8% (93/96). The predictive value of a positive EIA result was 95.4% and for a negative EIA result, 93.9%. The sensitivity of the RSV-EIA compared to direct FA was 91.5% (43/47) with a specificity of 96.5% (83/86). These data represent the preclinical evaluation of the Abbott RSV-EIA. This assay could prove to be a useful alternative to virus isolation or direct FA for the diagnosis of RSV infection.

Detection of RS-virus IgG-subclass-specific antibodies: variation according to age in infants and small children and diagnostic value in RS-virus-infected small infants

The variation according to age of RS-virus IgG-subclass specific antibodies was investigated by ELISA in 140 acute phase sera from 140 infants and children 1-47 mo of age who were hospitalized with acute respiratory disease. Sixty-nine of these serum samples were obtained from patients with RS-virus infections. Mean OD values of IgG-1 antibodies decreased corresponding to the decrease in maternal antibodies. In patients with RS-virus infections, the mean IgG-1 OD values increased in children who were 3 yr old, but in patients without RS-virus infections this increase was observed in children at 1 yr of age. RS-virus IgG-3 antibodies were detected only in children 1-3 yrs of age, and only in 18% of samples from children without RS-virus infections. The concept of the transient nature of RS-virus IgG-3 antibodies as compared with RS-virus IgG-1 antibodies is supported by these results. RS-virus subclass specific antibodies were studied in paired serum samples from 12 infants 1-5 mo of age with acute lower RS-virus disease. IgG-1 antibodies developed in six infants, but only in one of six infants aged 1-3 mo. IgG-3 antibodies developed in nine infants, including four of six infants who were 1-3 mo old. These results suggest that in small infants with RS-virus infections the detection of IgG-3 antibodies is of higher diagnostic value than the detection of IgG-1 antibodies.

Age-specific prevalence of complement-fixing antibodies to sixteen viral antigens: a computer analysis of 58,500 patients covering a period of eight years

The age-specific prevalence of CF antibodies against 16 viral antigens was determined by using the computerized data registry of the routine diagnostic laboratory of the authors' department. The material consisted of data based on serum specimens from about 58,500 patients. All ages from newborn infants to 90-year-olds were represented. The sera had been collected and tested with a CF screening test over a period of 8 years (1971-1978). Several different antibody prevalence patterns were distinguished in regard to the rapidity and timing of the initial increase of the prevalence, as well as to the mode of later changes in prevalence. For most respiratory viruses a rapid increase of the prevalence was seen through the childhood continuing, for some of them, up to the 30s (influenza A and coronavirus), while rather variable patterns were found in the older age groups. Herpes simplex and cytomegaloviruses showed, interestingly, another type of pattern: a slow increase of prevalence continuing through the whole age range. The frequency of herpes simplex antibodies reached 90% by the age of 80 years. Antibody levels against any antigen in infants less than one-month-old were equal to those in 20- to 40-year-old adults, and the expected rapid decrease of antibodies took place within the first 6 months of life. Possible influences of epidemics and repeated exposures to different viruses (external boosting), and of latent or chronic infections (internal boosting), as well as of technical variations, on the observed prevalence patterns are discussed.

Respiratory syncytial virus infection: admissions to hospital in industrial, urban, and rural areas. Report to the Medical Research Council Subcommittee on Respiratory Syncytial Virus Vaccines

A collaborative study of 10 centres during the winters of 1973-4 and 1974-5 showed that respiratory syncytial virus (RSV) was the major cause of admission to hospital for respiratory disease in children under 5 years of age in industrial, urban, and rural communities. In all areas the distribution of clinical symptoms and their severity was similar, but the rate of admission in relation to population was over twice as high in industrial as in other areas. The maximum yearly admission rate occurred among infants aged 1 to 3 months: 24.5 per 1000 of that age group were admitted to hospital. Two methods of diagnosing RSV infection--virus isolation and immunofluorescence from postnasal aspirates--were compared, and the two methods were found to agree in 91% of cases. The results of this study confirmed the importance of RSV as a respiratory pathogen in young children. Further studies are needed to determine how the virus produces its effects and to develop preventive measures.

Adenovirus, parainfluenza virus and respiratory syncytial virus antibodies in the sera of Jamaicans

Surveys for respiratory virus antibodies in the Jamaican population have shown that adenovirus, respiratory syncytial virus and parainfluenza types 1 and 3 virus antibodies are acquired early in life. The incidence of haemagglutination-inhibiting antibodies to parainfluenza viruses increases rapidly with age and almost all adults possess parainfluenza type 3 antibody, usually in high titre. Parainfluenza type 1 antibodies are only slightly less common. Complement-fixing antibodies to the adenovirus group were also observed to increase in incidence with age.Complement-fixing antibody to respiratory syncytial virus was less common in Jamaican sera than antibody to the other respiratory viruses described here. The highest titres were observed in the youngest age-group.

Virus infections and respiratory disease of childhood

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Anticorpos fixadores de complemento para o vírus respiratório sincicial e adenovírus e inibidores da hemaglutinação para os vírus parainfluenza 1, 2 e 3 numa população infantil brasileira

Apresentaram-se os resultados obtidos na pesquisa de anticorpos fixadores de complemento para o vírus respiratório sincicial e adenovírus, assim como de anticorpos inibidores da hemaglutinação para os vírus parainfluenza dos tipos 1, 2 e 3, num grupo de 972 crianças de idade compreendida entre 3 meses e 14 anos. A técnica de colheita de sangue foi a de embebição em papel de filtro. Do total de crianças examinadas, considerando o conjunto de todas as idades, 34,6% apresentavam anticorpos para o vírus respiratório sincicial; as porcentagens com anticorpos para adenovírus, parainfluenza 1, parainfluenza 2 e parainfluenza 3, foram respectivamente 47,7%, 46,8%, 54,1% e 66,6%. Foram estudadas as distribuições dos anticorpos em função da idade, do sexo e da localização do domicílio. Em relação aos dois últimos atributos obtiveram-se os seguintes resultados: dos indivíduos do sexo masculino, 32,3% apresentavam anticorpos contra o vírus respiratório sincicial, 49,2% contra adenovírus, 60,1%, 65,1% e 78,3%, respectivamente, contra os vírus parainfluenza 1, 2 e 3; nas crianças do sexo feminino as porcentagens de positividade encontradas foram, respectivamente, 37,4%, 45,9%, 31,1%, 41,2% e 52,9%; em relação à localização do domicílio, 44,8% do total de crianças da zona rural mostraram possuir anticorpos contra o vírus respiratório sincicial, 70,1% contra adenovírus, 43,8% contra vírus parainfluenza 1 e 46,8% e 65,4% contra os vírus parainfluenza dos tipos 2 e 3; as porcentagens de positividade na zona urbana foram, respectivamente, 30,5%, 38,7%, 47,9%, 57,1% e 67,1%.

Antibodies to respiratory syncytial virus in human sera from different regions of the world

Since it was first isolated in 1956, respiratory syncytial (RS) virus has been found in many parts of the world, generally in association with human respiratory illness, especially of young children. Previous studies have examined the frequency of serological evidence of infection in certain countries. The present study is a more general survey, dealing with the prevalence of RS virus antibody in sera from 14 different countries widely separated geographically. There was evidence of infection in all the populations studied, and the presence of antibody could not be accounted for by a relationship between RS virus and measles virus. It would therefore seem probable that RS virus is an agent of world-wide importance.