title: Humoral Immunity to Primary Smallpox Vaccination: Impact of Childhood versus Adult Immunization on Vaccinia Vector Vaccine Development in Military Populations.
abstract: Modified Vaccinia virus has been shown to be a safe and immunogenic vector platform for delivery of HIV vaccines. Use of this vector is of particular importance to the military, with the implementation of a large scale smallpox vaccination campaign in 2002 in active duty and key civilian personnel in response to potential bioterrorist activities. Humoral immunity to smallpox vaccination was previously shown to be long lasting (up to 75 years) and protective. However, using vaccinia-vectored vaccine delivery for other diseases on a background of anti-vector antibodies (i.e. pre-existing immunity) may limit their use as a vaccine platform, especially in the military. In this pilot study, we examined the durability of vaccinia antibody responses in adult primary vaccinees in a healthy military population using a standard ELISA assay and a novel dendritic cell neutralization assay. We found binding and neutralizing antibody (NAb) responses to vaccinia waned after 5-10 years in a group of 475 active duty military, born after 1972, who were vaccinated as adults with Dryvax®. These responses decreased from a geometric mean titer (GMT) of 250 to baseline (<20) after 10-20 years post vaccination. This contrasted with a comparator group of adults, ages 35-49, who were vaccinated with Dryvax® as children. In the childhood vaccinees, titers persisted for >30 years with a GMT of 210 (range 112-3234). This data suggests limited durability of antibody responses in adult vaccinees compared to those vaccinated in childhood and further that adult vaccinia recipients may benefit similarly from receipt of a vaccinia based vaccine as those who are vaccinia naïve. Our findings may have implications for the smallpox vaccination schedule and support the ongoing development of this promising viral vector in a military vaccination program.
authors.affiliation: U.S. Military HIV Research Program, Silver Spring, Maryland, United States of America.|The Henry M. Jackson for the Advancement of Military Medicine, Bethesda, Maryland, United States of America.
authors.forename: Bonnie M
authors.initials: BM
authors.lastname: Slike
authors.affiliation: U.S. Military HIV Research Program, Silver Spring, Maryland, United States of America.|The Henry M. Jackson for the Advancement of Military Medicine, Bethesda, Maryland, United States of America.
authors.forename: Matthew
authors.initials: M
authors.lastname: Creegan
authors.affiliation: Division of AIDS, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America.
authors.forename: Mary
authors.initials: M
authors.lastname: Marovich
authors.affiliation: Tripler Army Medical Center, Honolulu, Hawaii, United States of America.
authors.forename: Viseth
authors.initials: V
authors.lastname: Ngauy
mesh_terms: D000328:Adult; D002648:Child; D003713:Dendritic Cells / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006678:HIV / Q000235:genetics; D006801:Humans; D056724:Immunity, Humoral; D007114:Immunization; D008889:Military Personnel; D009500:Neutralization Tests; D012899:Smallpox / Q000276:immunology*; D012900:Smallpox Vaccine / Q000276:immunology*; D019076:Transgenes; D014611:Vaccination; D014616:Vaccinia virus / Q000276:immunology*
chemical_list: D012900:Smallpox Vaccine; D049452:Green Fluorescent Proteins