Just days ago, the Centers for Disease Control and Prevention (CDC) issued an historic travel warning advising pregnant women and those thinking about becoming pregnant to avoid travel to a Miami, Florida neighborhood, which has seen over a dozen confirmed cases of locally transmitted Zika virus.
The Zika virus, originally discovered in Uganda in the late 1940s, is spread through mosquito bites and has rapidly expanded its reach in the Americas. According to the Centers for Disease Control and Prevention (CDC), common symptoms include fever, rash, joint pain and conjunctivitis. However, Zika infections can also be asymptomatic.
The virus is especially dangerous for pregnant women. Zika has been linked to birth defects, including a rare congenital condition called microcephaly in which infants are born with abnormally small heads and incomplete brain development.
With over 6,400 confirmed cases of Zika in the United States and its territories as of July 27, and with no vaccines or treatments to prevent the virus, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), announced onWednesday that it will begin testing an experimental Zika vaccine on humans.
Developed by scientists at NIAID’s Vaccine Research Center earlier this year, the vaccine will be tested on at least 80 healthy volunteers ages 18-35 to determine its safety and efficacy.
During the first phase of the clinical trial, volunteers receive a vaccination via a needle-free injector. Some participants receive an additional vaccine at eight weeks or 12 weeks later. They return within a 44-week time period for a follow-up visit where they are evaluated by health officials. Participants also return for two follow-up visits at 18 months and two years to determine durability of the immune response and monitor safety of the treatment.
“A safe and effective vaccine to prevent Zika virus infection and the devastating birth defects it causes is a public health imperative,” said NIAID Director Anthony S. Fauci, M.D. “NIAID worked expeditiously to ready a vaccine candidate, and results in animal testing have been very encouraging. We are pleased that we are now able to proceed with this initial study in people. Although it will take some time before a vaccine against Zika is commercially available, the launch of this study is an important step forward.”
According to NIAID, the vaccine uses a plasmid—a small, circular piece of DNA—engineered by scientists to make Zika virus proteins, which assemble themselves into virus-like particles once injected into a human. The body reacts by developing an immune response to the particles. The vaccine does not contain infectious material, so the individual cannot become infected with Zika through the treatment.
“A team of scientists here at NIAID worked tirelessly to rapidly develop this vaccine for clinical testing,” said John Mascola, M.D., director of NIAID’s VRC. “DNA or gene-based vaccines induce antibodies, but they also can activate the cell-mediated immune response, which ultimately could yield strong and durable protection against disease.”
The vaccine will be tested at three locations: the NIH Clinical Center in Bethesda, Md.; the Center for Vaccine Development at the University of Maryland School of Medicine’s Institute for Global Health in Baltimore, and Emory University in Atlanta.