Clinical Trials of a Zika Vaccine to Begin
Posted: Nov 30th, 2016 at 12:00AM
The Mechanism
The mechanism used by scientists is similar to that which was used to develop the successful Japanese encephalitis vaccine. The vaccine consists of inactive, but whole, pieces of the Zika virus which have been altered in order to ensure that they cannot cause disease or replicate while within the human body.
The vaccine is known as the Zika Purified Inactive Virus (ZPIV) vaccine.
The vaccine has already been successful in non-human primates, so the outlook is quite promising as a means to help prevent the disease from spreading.
The Zika virus has been noted recently particularly for its effects on pregnant women and their children. Since the disease is transmitted primarily by mosquitos it has spread out of control in the areas where it is endemic, and this makes the development of a vaccine an urgent matter.
The Clinical Trials
The first phase of the study is going to induct 75 people between the ages of 18 and 49 who have had no prior flavivirus infection. This class of diseases includes yellow fever, dengue, West Nile virus, and Japanese encephalitis.
The trial is spread across three groups of twenty-five. The first group will receive one dose of the proposed Zika virus or a placebo, then another dose twenty-eight days later. The other two groups will receive a two-dose regimen for Japanese encephalitis or one dose of yellow fever vaccine respectively, followed by the two doses of the proposed Zika vaccine.
A group of thirty of the individuals involved in the first trial will receive a third dose a year later.
The reasoning behind the additional flavivirus vaccine has to do with travelers and military personnel often receiving these vaccines before being deployed into the areas where the Zika virus is found and to test for possible interactions.
This will be followed by four more trials to help determine different aspects of the vaccine.
- The second vaccine study will consist of injections of the newly-developed vaccine or a placebo control across twenty-eight The participants will also be randomly selected for a low, moderate, or high dosage in order to help determine the ideal dosage for further studies in the future.
- The third trial will be done on those who have already been exposed to dengue fever in order to determine if the vaccine will be safe in these circumstances. The group will be given a high, medium, or low dose of the vaccine at random.
- The fourth trial will be done in order to determine if it is effective to combine the vaccine with another investigational vaccine. They will receive the Zika investigational DNA vaccine first, followed by a booster dose of the ZIPV vaccine four weeks later.
- The final trial will involve one group receiving a single dose of the ZIPV vaccine and the other receiving two doses at varying intervals in order to determine the ideal amount of time between doses.
Overall, it looks to be a very thorough trial, and the results look hopeful considering the high-profile scientists and organizations involved in this endeavor.
The Need for a Vaccine
Thankfully, modern science is responding quickly to the urgent need for this vaccination to be made available. Zika has caused quite a bit of commotion in the news within the last year despite originally being discovered and isolated in 1947.
While the disease was previously confined to infection via mosquitos, it has mutated recently in order to be sexually transmitted. This has the potential to spread the disease far outside of its endemic range. This was first documented in 2015.
The virus itself is actually largely asymptomatic, meaning there is no outward sign of its infection. There are some cases of Zika fever occurring, which is usually a relatively minor illness with symptoms similar to dengue fever.
The real complications, however, occur in pregnant women. When the disease is spread from a pregnant woman to her unborn child there are a number of problems which can occur with the baby.
The most dramatic of these, and the most eye-catching is certainly microcephaly. This abnormality will cause the child to be born with a greatly reduced cranial size. This can cause all manner of problems, and those who suffer from the deformity often have a lessened lifespan and are likely to be mentally handicapped in some way. Microcephaly is estimated to occur in 1% of the cases where the virus has been transmitted.
There is no complete listing of the deformities and abnormalities caused, but some of them are just as dramatic in effect. These can include brain abnormalities, which may cause problems with hearing or vision, as well as seizures.
Overall, the disease is a threat to the unborn wherever it may be present, which makes it imperative to take immediate measures against it.
There are several flavivirus vaccines already available. This means the chances of the same methods working in order to allow for people to be inoculated is quite high. If all goes well with this trial, we may have an effective weapon against the disease before it becomes a serious threat to public health.
This clinical trial represents the hope that the disease may be controlled while in its early stages before the current epidemic spreads any further than it already has. The fact that the disease has mutated to become sexually transmittable, and the fact that it's largely asymptomatic, makes it a particularly insidious problem.
Even in the event that the vaccine proves to be ineffective, it's good to know that our doctors and scientists are already beginning to take the appropriate measures against it to ensure the survival and prevention of deformities in those unborn.
