Combatting Dengue Epidemics: Bridging Gaps with Vaccine Innovation

Dengue is an arthropod viral disease which poses a public health concern globally as well in Pakistan. Its virus called as dengue virus spreads through Aedes mosquito. The clinical spectrum varies from asymptomatic infections to life threatening complications like dengue hemorrhagic fever and dengue shock syndrome. Classic dengue fever, the symptomatic form, is characterized by high-grade fever, severe headache, retro-orbital pain, myalgia, arthralgia and rash. Only symptomatic treatment is required in these cases. Dengue Hemorrhagic fever is accompanied by decline in platelets and hemorrhagic tendencies. If untreated it can lead to dengue shock syndrome which causes circulatory collapse and organ dysfunction. Factors influencing the severity of disease include secondary infection with a different serotype, younger age, pregnancy, diabetes and hypertension. Since there is only symptomatic treatment available, it makes prevention and vaccines to control epidemics critical.1-3 In Pakistan, dengue is a public health concern with outbreaks affecting major urban cities.  Dengue epidemics started in 2011 in Pakistan; to address this threat Dengue Expert Advisory group was formed.4,5 The National Institute of Health in Pakistan has reported 20,057 confirmed dengue fever cases in 2024.6 There are a number of licensed vaccines and vaccines under development for dengue prevention including Dengvaxia, QDenga, InViragen’s TDV and GlaxoSmithKline’s tetravalent dengue vaccine and Takeda’s V180. Sanofi Pasteur, Dengvaxia was the first licensed dengue vaccine. It is approved for individuals aged 9-45 with prior dengue exposure and has demonstrated efficacy in preventing severe dengue and hospitalization.  Administering it to seronegative individuals has been associated with an increased risk of severe dengue upon subsequent infection. This is particularly concerning in resource limited settings like Pakistan where testing prior to vaccination becomes challenging. The Drug Regulatory Authority of Pakistan has approved Dengvaxia, but not for routine mass immunization. Moreover, its use is recommended under strict guidelines by the World Health Organization.7 The second licensed vaccine in several countries is QDenga, a tetravalent live attenuated vaccine developed by Takeda. However as per now this has not been approved for use in Pakistan. QDenga offers broader protection across all four dengue serotypes and is suitable for a more extensive population, including seronegative individuals. Mass administration makes it more suitable for developing countries.8,9