transmission and make the infection worse. Levels of protein D7 are more prevalent in salivary glands of dengue-infected mosquitoes compared to those uninfected ones. D7 is found in mosquito saliva and was thought to assist the process of blood feeding. Despite the prior assumptions, D7 can modulate the host cell and act against the virus to prevent viral infection. Unfortunately, D7 proteins provoke immune responses, which raise anti-D7 antibody levels. These antibodies inhibit the function of D7 proteins, which enhance transmission of dengue virus. Although immune responses against D7 proteins might impair their antiviral activity, a study showed that non-DENV subjects have slightly higher anti-D7 IgG levels than infected ones, although it was not statistically significant. Thus, more studies over D7 protein family are needed do elucidate its role on DENV infection and its applicability in medicine. Vaccine research Only one vaccine for dengue is currently approved in 11 countries (Mexico, the Philippines, Indonesia, Brazil, El Salvador, Costa Rica, Paraguay, Guatemala, Peru, Thailand, and Singapore). Several vaccines are under development by private and public researchers. Developing a vaccine against the disease is challenging. With four different serotypes of the virus that can cause the disease, the vaccine must immunize against all four types to be effective. Vaccination against only one serotype could possibly lead to severe dengue hemorrhagic shock when infected with another serotype due to antibody-dependent enhancement. When infected with dengue virus, the immune system produces cross-reactive antibodies that provide immunity to that particular serotype. However, these antibodies are incapable of neutralizing other serotypes upon reinfection and actually increase viral replication. When macrophages consume the 'neutralized' virus, the virus is able to replicate within the macrophage, causing disease. These cross-reactive, ineffective antibodies ease access of virus into macrophages, which induces more severe disease (dengue hemorrhagic fever, dengue shock syndrome). A common problem faced in dengue-endemic regions is when mothers become infected with dengue; after giving birth, offspring carry the immunity from their mother and are susceptible to hemorrhagic fever if infected with any of the other three serotypes. One vaccine was in phase III trials in 2012 and planning for vaccine usage and effectiveness surveillance had started. In 2009, Sanofi-Pasteur started building a new facility in ' (fr), a suburb of Lyon (France). This unit produces four-serotype vaccine for phase III trials. In September 2014, the Sanofi-Pasteur CEO gave early results of the phase III trial efficacy study in