International experts warn of the danger of dengue fever

International experts presented the information at the 7th Asian Dengue Summit in Malaysia on June 5. The event was attended by more than 500 doctors and medical staff from 20 countries and territories. 13 reports highlighted strategies to fight the disease, aiming for zero deaths.

At the beginning of the conference, the chair reiterated the WHO’s warning that the global burden of dengue fever is being underestimated. From 2000 to 2019, the number of people infected with the disease increased 10-fold, from 500,000 to 5.2 million cases, spreading to 129 countries.

As of April 30, there were more than 7.6 million cases of dengue fever recorded. Over the past five years, cases have increased significantly in the United States – a place where it was not common before – surpassing 7 million cases at the end of April. As a result, in 2019, WHO ranked dengue fever as one of the top 10 global health threats.

Experts also emphasized the danger of the Dengue virus and the figure of 70% of the dengue fever burden in Asia. The rapid spread of the disease is due to changes in distribution and increased diversity of disease vectors (Aedes mosquitoes). The El Nino phenomenon and climate change cause increased temperatures, high rainfall and humidity, creating favorable conditions for Aedes mosquitoes to develop. In addition, another cause is the change in the circulating serotype in a country, affecting the community’s immunity.

With population growth and rapid urbanization, the risk of dengue fever is predicted to increase. Faced with that situation, WHO proposed the “Zero death” strategy, aiming to reduce the death rate to zero by 2030.

At the conference, experts in turn proposed solutions to control mosquitoes, dengue vaccines, and new antiviral drugs, while also providing a platform to help policymakers connect and learn epidemiological strategies. from countries that have succeeded, thereby meeting the “Zero death” goal.

Professor Datuk Dr Zulkifli Ismail – Chairman of the Asian Dengue Voice and Action group (ADVA) – said that the most important thing is to strengthen early detection and clinical management.

Professor Lee-Ching Ng, Dr Ami Syed Mohamed and Dr Eggi Arguni shared their experiences in using Aedes aegypti mosquitoes infected with Wolbachia bacteria to control dengue fever in Singapore, Malaysia and Indonesia respectively.

In addition, the Malaysian Ministry of Health launched the iDengue portal, which provides weekly updates on dengue cases, deaths and hotspots. At the same event last year, the conference launched the Young ADVA program, which encourages young people to prevent dengue.

Experts from many countries agree on the role of immunity in preventing the Dengue virus, because vaccination is one of the most effective disease prevention methods, moving towards achieving the goal of “Zero death”.

The conference also addressed the challenge of changing dengue epidemiology affecting vaccine development. Nearly a century ago, scientists began researching vaccines, but there are four types of dengue virus: Den-1, 2, 3 and 4. In theory, a person can get dengue four times in their life, each time with a different type, each time with a higher risk of being more severe.

Experts reveal that the antigenic evolution of this virus is a complex process, allowing it to evade the host’s immune response, modifying the risk of future disease and affecting vaccine effectiveness. This factor causes considerable difficulty in the vaccine research process.

After a long journey of finding a solution, in 2015, the world’s first dengue vaccine was licensed in Mexico. There are currently two types approved by WHO: Dengvaxia (manufactured by Sanofi), Qdenga (Takeda). In mid-May, Vietnam’s Ministry of Health agreed to circulate Qdenga.

WHO’s Immunization Strategy Advisory Group of Experts (SAGE) recommends that countries with a high dengue burden adopt additional vaccines.