In its early studies, India’s sole DNA vaccine candidate for dengue showed encouraging results. The National Centre for Biological Sciences, Bangalore, is creating this vaccine. Learn more about the India-developed DNA vaccine for dengue in this article.
Concerning Dengue Vaccines
Sanofi, a French pharmaceutical firm, produces Dengvaxia. Nevertheless, it can only be used by individuals who have already experienced Dengue or who reside in a region where the bulk of the population has already had the disease. This vaccination may raise the chance of developing severe dengue in those who have never had the virus.
Qdenga: Made by the Japanese business Takeds, it is safe for use by those who have never had an illness.
Vaccine NCBS
The vaccination has excellent outcomes in mice. Both the B-cells (which produce antibodies) and the T-cells were produced as a result of it (protect from infection).A challenge investigation for the vaccine was also carried out, in which immunocompromised animals were given blood serum from the injected mice. As a result, these immunocompromised mice had a 50% higher survival rate than the unvaccinated animals.The vaccine will need to be tested on non-human primates after this breakthrough, and if effective there, it will go on to clinical trials.
What is a DNA Vaccine?
It is also known as the 3rd generation of vaccines. It relies on the in-situ production of the target antigen against which the response is sought. This is done by introducing the DNA sequence of the antigen into the cells of the person getting immunised. Once the plasmid DNA enters the nucleus of the person’s cell, it produces mRNA which travels to the cytoplasm and eventually gets copied to create the proteins responsible for generating the immune response. The traditional or the “whole virus” vaccines, since they contain the whole virus, also include those parts of it which can produce an adverse effect on human beings. The vaccines allow the researchers to pick only those parts of the virus which will help in generating the immune response. These vaccines are thus not only safer but also cost-effective and more stable than the “whole-virus” vaccines. World’s first DNA Vaccine “ZyCoV-D” was developed in India by Zydus Cadilla, for Covid, and was approved in 2021 for emergency use.
DNA Dengue Vaccines Issues
- They produce a weaker immune response in humans compared to mice, so more doses will be required.
- Antibody-Dependent Enhancement: Ordinarily, vaccines prompt the body to create antibodies that halt the virus from attaching to cells if it is encountered again in the future. Nevertheless, in the case of dengue, antibodies can promote the virus to duplicate and induce serious illness. This is due to the fact that antibodies formed after either receiving a vaccine or contracting the disease itself may be insufficient in both quality and quantity, which allows them to bind to the virus, forming a complex that fastens itself to immune cells. Once inside the cells, the virus can replicate, thereby increasing the viral load. The Antibody-Dependent Enhancement is the reason why Dengvaxia hasn’t been completely successful.
Advantages and disadvantages of DNA vaccines
This approach offers a number of potential advantages over traditional approaches: stimulation of both B- and T-cell responses, improved vaccine stability, cost-efficient, absence of any infectious agent (easier to handle than traditional vaccines) and relative ease of large-scale manufacture. A DNA platform allows researchers to pick certain regions that can provoke an effective response and eliminate those likely to cause harm. Further, this vaccine can be modified to target other viruses. Disadvantages of vaccines One caveat with DNA vaccines is that they generate weaker immune response in humans than in mice. This means humans must take high doses or multiple boosters. An mRNA vaccine is known to provoke better immune responses than DNA. Why developing an effective vaccine against dengue is tricky However, developing an effective vaccine against dengue is tricky because it is caused by four closely related viruses—DEN-1, DEN-2, DEN-3 and DEN-4—called 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. An ideal vaccine must target all serotypes. There is another concern with dengue viruses—antibody-dependent enhancement (ADE). Typically, vaccines trigger production of antibodies that prevent the virus from binding to cells at later exposure. But with dengue, antibodies help the virus replicate and cause severe disease. This happens because antibodies generated after vaccination or natural infection may be of low quality and quantity and bind to the virus, resulting in a virus-antibody complex that attaches itself to immune cells. Once inside the cells, the virus makes multiple copies, increasing the viral load. ADE may have contributed to the partial failure of Dengvaxia, the first and only approved dengue vaccine, which contains a live attenuated (weakened) virus. Do you know? The world’s first vaccine—ZyCoV-D, developed by Ahemdabad-based pharmaceutical firm Zydus Cadila—was approved in 2021 for emergency use against COVID-19.
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FAQ
Q: How do DNA vaccines work?
DNA vaccines work by introducing genetic material from a pathogen into the body, which is then taken up by cells. The cells use this genetic material to produce proteins from the pathogen, which are recognized by the immune system as foreign and trigger an immune response. This immune response can then protect the body from future infections with the pathogen.
Q: Are DNA vaccines safe?
DNA vaccines have been shown to be safe in numerous preclinical and clinical studies. They have not been associated with any serious adverse events, and have a favorable safety profile compared to other types of vaccines.
Q: How effective are DNA vaccines?
vaccines have shown promising results in preclinical and early clinical studies, but their efficacy in large-scale trials is still being evaluated. Some vaccines have been shown to induce strong immune responses in humans, but further research is needed to determine their long-term efficacy and potential for widespread use.