Seroepidemiological study of respiratory syncytial virus in São Paulo State, Brazil

Abstract

Transmission of respiratory syncytial virus is thought to be highly seasonal based on reported clinical cases, although transmission resulting in mild disease in all age groups has been little studied. This has been investigated in a seroepidemiological survey using sera from São Paulo, Brazil. Seroprevalence was found to increase rapidly with age, reaching over 90% by three years of age. This is typical of viral infections, which produce life-long immunity following primary infection. One-hundred percent seropositivity was attained by five years of age and maintained throughout adulthood, whereas mean antibody titers continued to increase with age. The mean duration of maternal antibodies was estimated to be 3.3 months with antibody decay demonstrated in paired samples from infants. The results are discussed in relation to possible mechanisms generating such a profile.

Immune response to respiratory syncytial virus in young Brazilian children

“…The decrease in RSV-specific antibodies detected in infants <1 month to 6 months of age is consistent with the loss of maternal antibodies, as reported previously (5,18). In the present study, examination of sera from RSV-infected children revealed that the total IgG levels were higher than IgG1 levels.…”

“…The components of the immune response to RSV, which lead to protection or pathology, are not well understood, and this has hindered vaccine development (1,2). There is a considerable amount of data about the humoral response to human RSV infection (3)(4)(5), but limited information about the cellular immune response (6)(7)(8). Studies on humans and animals have demonstrated that antibodies are important contributors to protective immunity (9)(10)(11)(12) and that cellular immunity is important for clearing the infection (13,14).…”

Lower Respiratory Tract Infection Caused by Respiratory Syncytial Virus in Infants: The Role Played by Specific Antibodies

“…Previous seroprevalence studies have shown that anti-RSV maternal antibodies remain in the infants' blood during this specific period of their lives, gradually decreasing until the sixth to seventh month of life. 8 An evaluation of antibodies during the convalescence phase was not performed in this study. This approach would certainly provide relevant information with regards to the infants' response to infection.…”

“…It is possible, however, to provide adequate protection against RSV-LTRI with the prophylactic use of immunoglobulins (RSVIg) or monoclonal antibodies in infants. [8][9][10][11] A reasonable explanation would be the lack of specificity of the maternal antibodies to the RSV genotype (subtype) infecting the infant, due to the known fact that circulating genotypes of RSV in a current season are substituted for others a few years later; therefore, the serum maternal antibodies at the time of infection would not correspond to the current infecting genotype, but rather to genotypes from previous years. 12,13 In order to test this hypothesis, the authors identified the type/genotype of the RSV detected in infants with LRTI, and evaluated the presence and amount of serum subtype-specific antibodies for the RSV genotype responsible for the infection.…”

The use of a formal sensitivity analysis on epidemic models with immune protection from maternally acquired antibodies

“…As a result MAb are short lived and following birth, concentrations of IgG in the newborn decay exponentially with a typical half life of around 35-40 days [4]. Many seroepidemiological surveys have shown that most infants become seronegative within 6-9 months of age (see the work by Cox et al [5] and Hacimustafaoglu et al [2] for hRSV, Williams et al [6] for measles and Nicoara et al [4] for measles, mumps and rubella (MMR)).…”