Austrian scientists have recently expressed the first recombinant live vaccine that can prevent infection of Chikungunya virus, through modifying the measles vaccine virogene. The Vaccine, as shown by the research result, has good safety, and can induce the specific immunity response in the healthy subjects. As expressed by a member of the research team, they expected that the Vaccine will be used for the adults and children in the following 4-6 years.
According to information, as one virus infection spread by mosquitoes, Chikungunya fever manifests as chronic weak arthritis symptom. Such infection originally broke out in tropical countries, and has been gradually becoming one global infection threat with the rise of tourism and global warming. There has been no effective therapeutic method and prophylactic vaccine available for such infection so far.
In the research mentioned at beginning of this article, the Austrian researchers conducted expression through transferring Chikungunya virogene into Schwartz virus strain which generates measles vaccine, to obtain the Vaccine. The selection of Schwartz measles vaccine virus strain as the carrier is because it is one human vaccine proven to be safest and most effective, and easy for conducting transgenosis operation.
42 healthy adults aged 18 to 45 were recruited in Vienna by the researchers from November 2, 2013 to February 5, 2014. At the beginning, 12 subjects were separately conducted low-dose, mid-dose and high-dose test vaccine inoculation immunity test, and the rest 6 subjects were conducted measles, mumps and rubella vaccination as a control. Booster vaccination of the same dose was given after 28 days or 90 days; meanwhile, subjects receiving vaccination on the 28th day would be conducted placebo injection on the 90th day, and similarly, subjects receiving placebo injection at the 28th day would receive vaccination on the 90th day. Normal saline was used as placebo in the test. Blood samples of the subjects were taken on the 56th day and 120th day for antibody titer testing.
When the geometric mean titer (GMT) was or greater than 10, it was determined that the vaccination could have the specific immune reaction to Chikungunya virus infection. Meanwhile, researchers also determined the measles antibody titer, to evaluate the immunity of the in vivo anti-measles virus antibody on Chikungunya virus. All adverse reactions were recorded in two weeks after vaccination.
The seroconversion rate of the low-dose, mid-dose and high-dose groups after the first vaccination was separately 44%, 92% and 90%; the rate of those three test groups after booster vaccination all increased to 100%. The GMT of the mid-dose and high-dose groups was obviously increased, as compared to that of the low-dose group. Totally 6 subjects occurred with serious adverse reactions during the test, including headache, musculoskeletal pain and nasopharyngitis, etc. The intensity of the adverse reactions took on a certain correlation with the vaccine dose.
Chikungunya fever has high morbidity and quick spread. Children, old people and travelers to the epidemic areas are especially easy to be infected with such virus, therefore the demand for such Vaccine is very urgent at present. Chikungunya virus, similar to influenza virus, has a very high variation frequency, which is almost the largest problem faced by the current R&D work for such Vaccine. In light of this, development of such Vaccine requires participation of various forces like biotechnology companies; and more pointed research tests shall be conducted on the test target population who had better be people living in the epidemic areas to obtain an effective result with more applicability.
