ZPIV Zika Vaccine 2023

The U.S. National Institute of Allergy and Infectious Diseases (NIAID)'s ZPIV is a Zika virus candidate consisting of a purified formalin-inactivated Zika virus. The development of a safe and efficacious Zika virus vaccine is a global health priority, says the U.S. Centers for Disease Control and Prevention (CDC).

A phase 1, placebo-controlled, double-blind clinical trial was done at the Walter Reed Army Institute of Research Clinical Trials Center in Silver Spring, MD, USA. Eligible participants were healthy adults aged 18–49 years, with no detectable evidence of previous flavivirus exposure (by infection or vaccination), as measured by a microneutralization assay. According to The Lancet Infectious Diseases, these researchers found ZPIV well tolerated in flavivirus-naive and primed adults. Still, that immunogenicity varied significantly according to antecedent flavivirus vaccination status. Immune bias towards the flavivirus antigen of initial exposure and the timing of vaccination may have impacted responses. A third ZPIV dose overcame much, but not all, of the discrepancy in immunogenicity. The results of this phase 1 clinical trial have implications for further evaluation of ZPIV's immunization schedule and use of concomitant vaccinations. This study was funded by the U.S. Department of Defense, Defense Health Agency; National Institute of Allergy and Infectious Diseases; and Division of Microbiology and Infectious Disease.

ZPIV Indication

According to the NIAID, ZPIV is indicated to prevent Zika virus infections in people.

ZPIV Dosage

ZPIV in the clinical trials was given as intramuscular injections on days 1 and 29. Healthy adults were randomly assigned by a computer-generated list to receive 5 μg ZPIV or saline placebo, in a ratio of 4:1 at Walter Reed Army Institute of Research, Silver Spring, MD, USA, or of 5:1 at Saint Louis University, Saint Louis, MO, USA, and Beth Israel Deaconess Medical Center, Boston, MA, USA.

ZPIV Clinical Trials

ZPIV ZIKA vaccine has completed 4fourclinical trials. The Lancet published results in February 2018, aggregating three clinical trials. These trials are registered at ClinicalTrials.gov, NCT02963909, NCT02952833, and NCT02937233. Findings: 68 participants were enrolled between Nov 7, 2016, and Jan 25, 2017. One was excluded, and 67 participants received two injections of Zika vaccine (n=55) or placebo (n=12). The vaccine caused only mild to moderate adverse events. The most frequent local effects were pain (n=40 [60%]), or tenderness (n=32 [47%]) at the injection site, and the most frequent systemic reactogenic events were fatigue (29 [43%]), headache (26 [39%]), and malaise (15 [22%]). By day 57, 52 (92%) of vaccine recipients had seroconverted (microneutralization titre ≥1:10), with peak geometric mean titres seen at day 43 and exceeding protective thresholds seen in animal studies. Interpretation: The ZPIV candidate was well tolerated, and robust neutralizing antibody titers were elicited n healthy adults.