Developing vaccines for mosquito-borne viral diseases by Dan Stinchcomb

Dan Stinchcomb recently joined the Infectious Disease Research Institution that employs over a hundred of scientists (39 of them have PhD per Dan). Dan launched at least three different projects there already: vaccine against tuberculosis are being tested in phase 2 (checking if the reoccurrence of the disease will be prevented); working on West Nile vaccine; and developing RNA vaccines. West Nile virus was first discovered in 1937. Birds are the reservoir for this virus which can be transmitted to humans through a mosquito bite. In 2002, the West Nile disease was first registered on the territory of the United States in NY and spread with birds throughout the country in 2003-2004 with a peak in 2006 and 2012-2013, so the U.S. needs a vaccine against this disease.

Dan lectured the audience on Dengue fever, Chikungunya disease, Zika virus, and introduced to RNA vaccines potential.

Dengue fever affects about 390 million people per year. It is a mosquito-borne infection and cause by the virus that has 4 strains (DENV-1, DENV-2, DENV-3, DENV-4). This disease mostly occurs in urban communities in tropical climate. The challenge in creating a vaccine against this disease is in that this vaccine must protect against all four types of virus, otherwise, it will increase the chance of the individual to get the Dengue fever via other virus strains and the disease will be severe with a lot of complications. Currently, there is one vaccine Yellow Fever/Dengue chimera by NiAiD, Takeda in phase 3 testing. This vaccine protects equally against all four virus types but still a bit low on DENV-2; the vaccine provides a good protection to individual that was exposed to Dengue fever in the past. The vaccine is not so effective in individual that was never exposed to the disease; the danger is in getting secondary infection and increased risk of hospitalization.

Another vaccine against Dengue fever is TVD by Takeda: live-attenuated tetravalent Dengue vaccine (DENV-2 based and recombinant). Dan is currently working on the development of this vaccine as well. The vaccine is in second phase of its development. So far, this vaccine is well tolerated in multiple age groups in Dengue epidemic counties. Prior moving forward, this vaccine will have to go through second phase again and confirm all results achieved in earlier experiments.

Chikungunya disease is caused by a virus that has two transmission cycles and is spread between wild primates and arboreal Aedes mosquitoes (sylvanic cycle); second cycle (urban) involves transmission in human-mosquito-human and has a higher mortality. The development of a vaccine against this disease is taking a lot of time and needs candidates for this research process. The Chikungunya disease originated in Africa and was spreading around the world since 2005. The problem is in protein mutation and lead to higher transmission rates. In U.S., this disease is spread within Gulf states. The NiH VLP vaccine is just starting phase 2.

Zika virus first was isolated from a monkey in 1947 in Zika forest in Uganda. There were numerous cases reported in 2007; epidemic in French Polynesia in 2013-2014. This disease is transmitted by arthropods, and can have perinatal transmission, sexual transmission, and via blood transfusion.

RNA vaccines have several advantages such as rapid response to global epidemics and they are easier to deliver that DNA vaccines. There is a good potential but also several challenges such as vaccine being unstable, and it is difficult to introduce the vaccine to the cells.

It was a knowledgeable lecture. The information provided makes you concerned about safety and health in the world where the virus can be simply transferred by birds. The question I’ve asked was about tips on safety and vaccines required prior visiting Africa as there were a lot of summer programs for students available there. The students were advised to be cautious with water, have long-sleeve shirts available, and mosquito repellent. There is also vaccination available but vaccines requirenments differ depending on the country the student will be going to. But overall, the internship in Africa is a great opportunity for the career growth.