Context

• Researchers at India’s National Centre for Biological Sciences, in collaboration with nine other institutions, have developed India’s first and only DNA vaccine candidate for dengue fever.

Dengue

• • Dengue fever is a mosquito-borne tropical disease caused by dengue virus(Flavivirus).
  • It is transmitted by mosquito species in the genus Aedes and Aedes aegypti.
  • The virus that causes dengue has four distinct but closely related serotypes(DEN-1, DEN-2, DEN-3, and DEN-4).

• Serotypes refer to separate groups within a species of microorganisms that all share a similar characteristics.

• Symptoms include a high fever, severe headaches, muscle pain, etc

Findings

• In 2021, India reported 110,473 dengue cases, ranking fourth among the worst-affected nations.
• According to the study, Climate change will cause an expansion in the geographical range of Aedes aegypti to the hot arid regions of the Thar Desert and Aedes albopictus to the cold upper Himalayas.

Dengvaxia

• It is the first and only approved dengue vaccine, which contains a live attenuated (weakened) virus
• The US Food and Drug Administration recommends Dengvaxia for children above nine years and those with prior infection.
• India has not approved it.
• The World Health Organization revealed that Dengvaxia has increased disease severity among those who got their first natural infection after the shot.

DNA Vaccine

• The world’s first DNA vaccine—ZyCoV-D, was approved for emergency use against covid-19 in 2021.
• DNA vaccines contain DNA that codes for specific proteins (antigens) from a pathogen.
• They exhibit several advantages in terms of safety, stability, ease of manufacturing, and immunogenicity.
• Immunogenicity is the ability of a foreign substance to enter a person’s body and cause an immune response. Example: Vaccination. When a person gets vaccinated, they are injected with a very tiny amount of a specific disease.

Need for DNA Vaccine for dengue

• They are able to provide an effective immune response and improved survival rate after exposure to the disease.
• They have emerged as a safer alternative to standard live and inactivated vaccines for treating human and animal viral diseases.
• It allows researchers to pick regions in DNA that can provoke an effective immune response, thereby eliminating those regions that can cause harm.

Concerns

• Developing an effective vaccine against dengue is tricky because it is caused by four closely related virus serotypes.
• Each one interacts differently with antibodies in human blood. A person infected with DEN-1 is then protected against it for life, but not against the other three serotypes.

• Further, DNA vaccines generate a weaker immune response. This means that one must take high doses or multiple boosters.

Conclusion

• Countries should improve their reporting systems and capture the true burden of the disease.
• WHO should support countries in the development of dengue prevention and control strategies and ensure the adoption of Global Vector Control Response.