Dengue Fever Saused By a Virus Named DENV

Background Information

Dengue fever is a disease caused by a virus named DENV which refer to Dengue virus. This virus is transmitted through the Aedes aegypti mosquito vector (Richard J.Kuhn et al). Dengue virus is ranked one of the most dangerous human viral pathogens which is transmitted by mosquitoes and causes 50 million or more cases of infection worldwide each year, resulting in around 24,000 deaths (World Health Organization, 1998). The characteristics of dengue fever disease are detected when fever and severe joint pain appear on the patient. In addition it could lead to more serious cases such as dengue hemorrhagic fever or dengue shock syndrome. Dengue fever consists of four serotypes which are the following DENV-1, DENV-2, DENV-3, and DENV-4(Jane P. Messina, 2014).

Symptoms starts first to appear in Chinese medical encyclopedia dating back to 265-420 AD and than the epidemic reached the West Indies and Central America.3.9 billion people among the world are at risk of dengue infection (WHO). Moreover, it has been shown that the global incidence due to the disease was increasing rapidly. In 2015, cases of dengue fever spread worldwide specially in Brazil, Malaysia, Philippines, India, Hawaii, and the Pacific Islands. The high spread of disease show the need for an intervention.

The Need for an Intervention

Regardless of the work done to control the diseases, both the costs and burden of disease were still an obstacle. And it was shown that during the past years, the expansion of having a safe and effective dengue vaccine faced a number of obstacles. During the previous years, the number of awareness campaigns and session regarding this topic increased due to its importance. Studies shows “A live-attenuated viral vaccine actively replicates in the host, resulting in an array of wild virus-like antigens, which could potentially provoke a response similar to natural immunity”( Jacqueline L. Deen, 2004). As the result of the previous research, CYD-TDV which is named Dengvaxia® was registered in 2015 as the first dengue vaccine (Jeffery Sauer, et al, 2018).The world health organization recommended the most varlanble society to take the Dengvaxia vaccine. They vaccine works on strengthens the immune system of people between 9 and 45 years old.

Vaccine Development and Implementation

• Phase 1 clinical trails: This trail was performed on a small scale to insure the that the vaccine doesn’t t hurts human beings.
• Phase 2 clinical trails: In this trail it was performed on a larger scale in which it assure that the vaccine effectiveness towards specific diseases. In addition it shows the disadvantages of this vaccine.
• Phase 3 clinical trails: This trail was directed on large scale in order to study the viability of the vaccine under normal illness conditions

After the 10 years passed the trails shows positive feedback about the vaccine. Its important to shed light on the idea that the study was done in 25 clinical studies around the world and it consist of 40,000 participant in which 29000 took the vaccine. The trails end up showing the following conclusion: 67% of the volunteers were safe after taking Dengaxia vaccine (Bruno Guy et al, 2015). CYD14 and CYD15 are two III trials that were performed in two different regions. The first on in Asia and the targeted population were between 2-14 years. And second one were in Central and South America in which it targeted teenagers between 9-16.The results shows that the trails were successful during the active phase and meets the required goals. Epidemics were identified in the two regions and the trials had shown to be effective. Moreover, its shown that among several immunization, Denagxia was the only vaccine that completed the Phase III trials in a successful way (Thomas J. Hladish et al 2016). Up until this point, the vaccine is endorsed in eleven nations: Mexico, The Philippines, Brazil, El Salvador, Costa Rica, Paraguay, Guatemala, Peru, Indonesia, Thailand, and Singapore (Sanofi Pasteur,2016)

Reasons for Success

Based on the WHO and U.S. military, the dengue fever is classified as the most spreading disease in the world and this leads to make the dengue fever a main global worry (Edelman R,2007).In 2010, Dengue Vaccine Initiative (DVI) was formed which aims to show the main aspects related to the dengue vaccine. This organization play an important role in the success of the vaccine (Jameson H,2016).

References

• Messina JP, Brady OJ, Scott TW, Zou C, Pigott DM, Duda KA, Bhatt S, Katzelnick L, Howes RE, Battle KE, Simmons CP. Global spread of dengue virus types: mapping the 70 year history. Trends in microbiology. 2014 Mar 31;22(3):138-46
• Guy B, Briand O, Lang J, Saville M, Jackson N. Development of the Sanofi Pasteur tetravalent dengue vaccine: One more step forward. Vaccine. 2015 Dec 10;33(50):7100-11World Health Organization. Dengue and Severe Dengue Fact Sheet. 2001 July
• Deen JL. Editorial: The challenge of dengue vaccine development and introduction. Tropical Medicine & International Health. 2004 Jan1;9(1):1-3.
• Sanofi Pasteur. (2016). First Dengue Vaccine Approved in More than 10 Countries | Sanofi Pasteur | Dengue Info. [online] Available at: http://Dengue.info/first-Dengue-vaccine-approvedin-more-than-10-countries/ [Accessed 01 Dec.2016].
• Hladish TJ, Pearson CA, Chao DL, Rojas DP, Rec-chia GL, Gómez-Dantés H, Halloran ME, PulliamJR, Longini IM. Projected impact of dengue vac-cination in Yucatán, Mexico. PLoS Negl Trop Dis.2016 May 26;10(5):e0004661.
• Dengue Vaccine Initiative (DVI). (2016). Why a Vaccine | Dengue Vaccine Initiative. [online]Available at: http://www.Denguevaccines.org/why-a-vaccine [Accessed 01 Dec. 2016].
• Edelman R. Dengue vaccines approach the finish line. Clinical Infectious Diseases. 2007 Jul 15;45(Supplement 1):S56-60..
• Jameson H. (2016). Case Study: Advancing the Dengue Vaccine. [online] Johns Hopkins Bloomberg School of Public Health. Available at:http://www.jhsph.edu/research/centers-and-in-stitutes/ivac/resources/case-studies/advanc-ing-Dengue-vaccine.html [Accessed 01 Dec.2016].