An enveloped virus-like particle alum-adjuvanted cytomegalovirus vaccine is safe and immunogenic: A first-in-humans Canadian Immunization Research Network (CIRN) study.

INTRODUCTION: Cytomegalovirus (CMV) is the most common cause of congenital infection and affected children often have permanent neurodevelopmental sequelae, including hearing loss and intellectual disability. Vaccines to prevent transmission of CMV during pregnancy are a public health priority. This first-in-humans dose-ranging, randomized, placebo-controlled, observer-blinded study evaluated the safety and immunogenicity of an enveloped virus-like particle (eVLP) vaccine expressing a modified form of the CMV glycoprotein B (gB). METHODS: Healthy CMV-seronegative 18 to 40-year-olds at 3 Canadian study sites were randomized to one of 4 dose formulations (0.5 µg, 1 µg, or 2 µg gB content with alum) or 1 µg gB without alum, or placebo, given intramuscularly on days 0, 56 and 168. Outcome measures were solicited and unsolicited adverse events (AE), severe AE, gB and AD-2 epitope binding antibody titers and avidity, and neutralizing antibody (nAb) titers to CMV measured in fibroblast and epithelial cell infection assays. RESULTS: Among 125 participants, the most common solicited local and general AEs were pain and headache, respectively. A dose-dependent increase in gB binding, avidity and nAb titers was observed after doses 2 and 3, with the highest titers in the alum-adjuvanted 2.0 µg dose recipients after the third dose; in the latter 24 % had responses to the broadly neutralizing AD-2 epitope. Neutralizing activity to CMV infection of fibroblasts was seen in 100 % of 2.0 µg alum-adjuvanted dose recipients, and to epithelial cell infection in 31 %. Epithelial cell nAb titers were positively correlated with higher geometric mean CMV gB binding titers. CONCLUSIONS: An eVLP CMV vaccine was immunogenic in healthy CMV-seronegative adults and no safety signals were seen. Alum adjuvantation increased immunogenicity as did higher antigen content and a three dose schedule. This phase 1 trial supports further development of this eVLP CMV vaccine candidate.

Genetic characterization of respiratory syncytial viruses isolated from consecutive acute respiratory infections in a HIV infected child.

BACKGROUND: Human respiratory syncytial virus (HRSV) was isolated from a 2-year-old child suffering from perinatally transmitted AIDS in the course of three distinct episodes of respiratory infections. The first episode occurred in the winter of 1994, the following two episodes of cough and fever occurred two and 4 months after the initial episode. OBJECTIVE: To analyze the genetic variability of the child's HRSV strains, and with contemporary circulating HRSV isolates. RESULTS: The three child's HRSV isolates belonged to group B. Sequence analysis of the attachment (G) protein gene (which has the highest degree of antigenic and genetic diversity in HRSV), demonstrated no difference in the sequence obtained from the three isolates recovered from the child. Comparison of the child's HRSV strain with contemporary circulating group B HRSV isolates showed a close sequence similarity with one of them. CONCLUSIONS: The immunodeficiency in an HIV-positive child may have resulted in the recurrent isolation of one HRSV strain. Although it cannot be discarded the possibility that the recurrent episodes might be re-infections, it is unlikely in view of the lack of change in the HRSV glycoprotein G. This is the first study that analyzes the genetic variation in HRSV isolates from consecutive respiratory disease episodes in an immunosuppressed patient.