GALVESTON, Texas – An international group of vaccine experts from The University of Texas Medical Branch at Galveston, the Walter Reed Army Institute of Research and Sanofi Pasteur in France have come together to lay out what is needed to quickly develop a safe and effective vaccine in the new edition of the New England Journal of Medicine.
A safe and effective vaccine against Zika is needed to stem the tide of the ongoing Zika epidemic in the Americas and help to prevent Zika-related birth defects. There are promising studies with newly developed candidate vaccines that can provide animals with immunity to this disease. There are currently two Zika vaccine hopefuls in the first phase of testing in volunteers. While this is very promising, before any vaccines become available in doctor’s offices, they must first undergo much testing and scrutiny to insure safety, which can take time.
“Taken together, developing, licensing and distributing a vaccine capable of affecting the current epidemic will require seamless coordination among developers, regulatory agencies, the World Health Organization and national public health authorities, along with solid funding from governments and funding agencies,” said Alan Barrett, UTMB pathology professor and director of the UTMB Sealy Center for Vaccine Development.
Before trying out on people, a potential vaccine must be studied to determine that it is safe, to determine if it affects males and females differently, how it interacts with various bodily systems such as the brain, how exactly the immune system produces the desired protective response after vaccination and what impact, if any, the vaccine may have on a pregnancy.
Another important aspect is how a Zika vaccine may interact with other viruses. The Zika virus is part of a larger family of related viruses called flaviviruses, which includes dengue, West Nile, yellow fever and Japanese encephalitis. Being infected with both Zika and a related virus at the same time or already having immunity to another flavivirus may alter how well a Zika vaccine performs.
Developing a vaccine during an epidemic is more challenging because time is of the essence. It generally takes at least 10 years from the time a potential vaccine is first designed in a laboratory to reach the doctor’s office.
Further complicating the matter is the fact that mosquitoes tend to be most active during warm and humid months, so the window of time for determining how effectively a vaccine works in people is limited.