Dengue vaccine

Dengue is a viral infection caused by four types of viruses (DENV-1, DENV-2, DENV-3, DENV-4) belonging to the Flaviviridae family. The viruses are transmitted through the bite of infected Aedes aegypti and Aedes albopictus female mosquitoes that feed both indoors and outdoors during the daytime (from dawn to dusk). The 4 dengue viruses have spread worldwide and are endemic in Asia, Central and South America, the Caribbean, the Pacific Islands, parts of Australia, and parts of Africa. An estimated 50 - 100 million cases of dengue fever occur annually, which results in around 500,000 cases of dengue haemorrhagic fever (DHF) and an estimated 22,000 deaths, primarily in children. It is estimated that 2.5 billion people (40% of the world’s population) live in areas at risk of dengue virus transmission.

Dengue is an epidemic of national proportion in Sri Lanka. It is a tropical country with two monsoon seasons. Each monsoon brings in two peaks of dengue fever making it an endemic disease in Sri Lanka. However, 2017 started with an exceptionally high number of dengue cases which shot up to an outbreak in May-June 2017, creating the largest dengue outbreak experienced by the country for the last three decades. During the year 2017, a total of 186,101 suspected dengue cases were reported and as of May 24, 2018, a total of 19,459 suspected dengue cases were reported to the Epidemiology Unit of the Ministry Of Health (MOH) in Sri Lanka with over 320 deaths in 2017 and 202 deaths in 2018. Over 40% of dengue cases were reported from the Western province.

No effective licensed dengue vaccine is available at the moment nor is there any antiviral therapy for dengue virus infection. Treatment of dengue fever is based solely on symptoms and signs, with fluid replacement required for haemorrhagic or shock cases. Preventive measures rely on mosquito control and individual protection, are of limited efficacy, complex to implement and questionable in terms of cost-effectiveness. There is a great unmet global public health need for a safe and effective vaccine that will protect against all serotypes of dengue infection, and thereby reduce the morbidity and mortality associated with dengue disease.

Given the unprecedented spread of dengue throughout Sri Lanka, there is an urgent need for a foolproof and solid prevention mechanism for the spread of dengue fever. It was at such a time that RemediumOne brought a dengue vaccine trial into the country. The trial involved coordination between various stakeholders, including the National Epidemiology Unit, in charge of providing strategic oversight in the project implementation in Sri Lanka. The recruitment target was a massive one of 2,100 healthy children aged 4 to 16.

Retaining 2,100 children and their parents in a 5-year-long study is a great challenge. RemediumOne, together with the principal investigators, arrange various retention strategies such as weekly telephone calls to capture adverse events, seminars on child nutrition and dengue and workshops for children to retain these subjects in the study.

RemediumOne believes in finding solutions to problems that affect Sri Lanka and the dengue epidemic is one such problem. There is a need of the hour to find an effective prevention mechanism for this disease that has claimed many lives. This vaccine, if proven effective, would be one of the best solutions to the dengue epidemic and would be a giant step towards eradication of dengue in Sri Lanka.