Persistence of Immunogenicity of a Purified Inactivated Zika Virus Vaccine Candidate in Healthy Adults: 2 Years of Follow-up Compared With Natural Infection.

Background: We report 2-year persistence of immune response to Takeda's prophylactic purified formalin-inactivated whole Zika virus vaccine candidate (TAK-426) compared with that observed after natural infection.

Methods: A randomized, observer-blind, placebo-controlled, dose-selection, phase 1 trial was conducted in 18-49-year-old adults at 9 centers (7 in the United States, 2 in Puerto Rico) from 13 November 2017 to 24 November 2020. Primary objectives were safety, tolerability, and immunogenicity of 3 increasing doses of TAK-426 administered as 2 doses 28 days apart to flavivirus (FV)-naive and FV-primed adults.

Specificity and Breadth of the Neutralizing Antibody Response to a Live-Attenuated Tetravalent Dengue Vaccine.

Background: An effective dengue vaccine should ideally induce broadly neutralizing antibody (nAb) responses against all 4 dengue virus (DENV) serotypes.

Methods: We characterized the specificity and breadth of the nAb response to TAK-003, a live-attenuated tetravalent dengue vaccine, in serum samples from phase 2 and 3 clinical trials.

Results: Microneutralization tests using postvaccination serum showed comparable neutralization against diverse DENV-1-4 genotypes.

Single dose of chimeric dengue-2/Zika vaccine candidate protects mice and non-human primates against Zika virus.

The development of a safe and effective Zika virus (ZIKV) vaccine has become a global health priority since the widespread epidemic in 2015-2016. Based on previous experience in using the well-characterized and clinically proven dengue virus serotype-2 (DENV-2) PDK-53 vaccine backbone for live-attenuated chimeric flavivirus vaccine development, we developed chimeric DENV-2/ZIKV vaccine candidates optimized for growth and genetic stability in Vero cells. These vaccine candidates retain all previously characterized attenuation phenotypes of the PDK-53 vaccine virus, including attenuation of neurovirulence for 1-day-old CD-1 mice, absence of virulence in interferon receptor-deficient mice, and lack of transmissibility in the main mosquito vectors.

A high throughput reporter virus particle microneutralization assay for quantitation of Zika virus neutralizing antibodies in multiple species.

Zika virus is a Flavivirus, transmitted via Aedes mosquitos, that causes a range of symptoms including Zika congenital syndrome. Zika has posed a challenging situation for health, public and economic sectors of affected countries. To quantitate Zika virus neutralizing antibody titers in serum samples, we developed a high throughput plate based Zika virus reporter virus particle (RVP) assay that uses an infective, non-replicating particle encoding Zika virus surface proteins and capsid (CprME) and a reporter gene (Renilla luciferase).

Complete Protection in Macaques Conferred by Purified Inactivated Zika Vaccine: Defining a Correlate of Protection.

A critical global health need exists for a Zika vaccine capable of mitigating the effects of future Zika epidemics. In this study we evaluated the antibody responses and efficacy of an aluminum hydroxide adjuvanted purified inactivated Zika vaccine (PIZV) against challenge with Zika virus (ZIKV) strain PRVABC59. Indian rhesus macaques received two doses of PIZV at varying concentrations ranging from 0.