Scientists from the Perelman School of Medicine at the University of Pennsylvania have just developed a candidate for a single dose Zika vaccine. The vaccine has already been tested on both mice and monkeys, with promising results. The details are in a paper that was just published in the journal Nature.
The Zika virus is continuing to spread across the globe and has recently begun to pop up in parts of the United States. Although many of these cases are related to travel, the virus is now endemic to some parts of the south, including Florida and Texas. In a healthy adult, the virus may seem like a mild flu and some carriers don’t show any symptoms at all. In rarer cases, the virus can cause a serious form of paralysis called Guillain-Barré Syndrome. The main dangers of Zika affect pregnant women since an infection can lead to severe birth defects, including microcephaly and other congenital brain abnormalities. The virus is mainly spread by mosquitoes but can also be transmitted through sexual intercourse and blood transfusions. There is currently no cure or vaccine for the Zika virus.
Researchers collaborated with a number of other institutions, including the National Institutes of Health, to research a possible vaccine for Zika. The team utilized messenger RNA (mRNA), molecules that normally translate DNA into instructions for building specific proteins. The researchers created modified mRNA that aren’t naturally removed by the immune system; foreign DNA or RNA molecules are normally destroyed by the body’s immune response. These mRNA molecules instead prompted the cells to begin producing basic Zika viral proteins. This would expose the body to the virus in a harmless way, allowing an immunity to build up. This is similar to how live virus vaccines work but with less risks to immunocompromised patients. The researchers tested their new vaccine on mice and macaque monkeys. A single dose of the vaccine protected the animals for over a month and the team believes it could provide protection for years.
The new Zika vaccine shows great promise and would be a good option for people who may be harmed by live virus vaccines. The vaccine is a single dose and could potentially protect patients for over a year. The team hopes that the vaccine can quickly move to human trials before the Zika outbreak gets worse.
Pardi et al. Zika virus protection by a single low-dose nucleoside-modified mRNA vaccination. Nature (2017).