Dengue and DNA vaccines

Context: Recent research announced that India’s first and only DNA vaccine for dengue has shown promising results.

About Dengue:

• Dengue is a vector-borne disease transmitted by the bite of an infected female Aedes Aegypti mosquito.
• The mosquito becomes infected when it feeds on the blood of a person infected with the virus.
• There are 4 serotypes of the virus that causes dengue. These are known as DEN-1, DEN-2, DEN-3, and DEN-4.
• Dengue cannot be spread directly from person to person.
• Most cases occur in tropical areas of the world, including the Indian subcontinent, Southeast Asia, Southern China, Taiwan, the Pacific Islands, the Caribbean, Mexico, Africa, and Central, and South America.

Symptoms include: High fever, Headache, Vomiting, Muscle and joint pains, Skin Rash

• The diagnosis of dengue infection is done with a blood test.
• WHO estimates 39 crore dengue virus infections per year, of which 9.6 crore show symptoms.

About DNA Vaccines :

• DNA vaccines are often referred to as third-generation vaccines.
• They use engineered DNA to induce an immunologic response in the host against bacteria, parasites, viruses, and potentially cancer.
• The vaccines that are currently available to the global population include those for measles, mumps, rubella, seasonal influenza virus, tetanus, polio, Hepatitis B, cervical cancer, diphtheria, pertussis as well as several other diseases that are endemic to certain regions of the world.

Working :

• DNA vaccines induce an adaptive immune response.
• The basic working principle behind any DNA vaccine involves the use of a DNA plasmid that encodes for a protein that originated from the pathogen in which the vaccine will be targeted.
• More specifically, these vaccines expose the immune system to the target pathogen elements, which allows the immune system to develop antibodies that can recognize and attack this infectious agent if the vaccinated host encounters this pathogen in the future.

DNA Vaccine and COVID-19:

• In September 2021, India gave emergency authorization to the world’s first DNA vaccine for human use called ZyCoV-D.
• The vaccine was developed by the Zydus Cadila pharmaceutical company.
• It was approved for emergency use in adults and in children 12 and older.

Advantages of DNA Vaccine:

• They can be developed quickly.
• They are easy to transport and store.
• It’s less expensive to make and purify large amounts of DNA from viruses or bacteria than to create traditional vaccines.

Disadvantages of DNA Vaccines:

• Limited approvals: as of 2021, the FDA had approved the DNA vaccine only for use in certain animal diseases, such as West Nile Virus in horses and melanoma in dogs.
• More research into the use of DNA vaccines against COVID-19 and other diseases caused by viruses or bacteria is required.
• Scientists still do not properly understand much of the immune response caused by DNA vaccines. Limited data is available on their safety, possible side effects, and effectiveness.

Source: DOWN TO EARTH

Previous Year Questions

Q.1) In the context of vaccines manufactured to prevent the COVID-19 pandemic, consider the following statements: (2022)

1. The Serum Institute of India produced a COVID-19 vaccine named Covishield using an mRNA platform.
2. The Sputnik V vaccine is manufactured using a vector-based platform.
3. COVAXIN is an inactivated pathogen-based vaccine.

Which of the statements given above is correct?

1. 1 and 2 only
2. 2 and 3 only
3. 1 and 3 only
4. 1, 2 and 3

Q.2) With reference to recent developments regarding ‘Recombinant vector Vaccines’, consider the following statements: (2021)

1. Genetic engineering is applied in the development of these vaccines.
2. Bacteria and viruses are used as vectors.

Which of the statements given above is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2