VACCINES – Types & Uses
COVID-19, Monkeypox and now Polio outbreaks have created some sort of awareness among people about the present situation of medical microbiology. People have become aware of vaccines, their side effects, uses and efficiencies. Not all vaccines are made in a similar way and not all show the same efficiency rate, as we have seen with the COVID-19 vaccines. Here in this article, we shall have a quick look at what are vaccines and how they differ from each other, be it in uses or their efficiency.
Vaccines function in a way to teach our immune system to identify and generate antibodies thus providing our body with a capacity to defend itself against harmful viruses or bacteria. These vaccines can be taken via,
- Injections – Covid-19 vaccines.
- Pills – Vivotif.
- Liquids / drops – Polio.
- Nasal sprays – Nasovac.
As suggested earlier all vaccines are not made from a similar source or the process of making them is different and thus their role efficacy vary accordingly. Vaccines are classified as,
- Live attenuated vaccines – Where a weakened form of the virus is used. Example – Mumps, Measles, Rotavirus, etc.
- Inactive vaccines – Where an inactive form of the microbe is used. Examples – Hepatitis A and Rabies.
- Subunit vaccines – Where only a part of the microbe is used. Example – Novavax for Covid-19.
- Toxoid vaccines – Where a harmful toxin produced by the microbe is used. Example – Diphtheria and Tetanus.
- mRNA vaccines – Where a genetically engineered mRNA is used that carries the information related to production of antibodies. Examples – Moderna vaccine and GEMCOVAC-19.
- Viral vector vaccines – Where the genetic material is used that gives cells direction to produce antibodies. Examples – rVSV-ZEBOV against Ebola.
Once we take a vaccine a person may feel fever followed by other regular illness symptoms as the body gets used to the foreign substance and accordingly acts to a response that is generated. Even though these vaccines are formed through different pathways and processes, their role in generating an immune response remains constant. Though most people have a conservative attitude towards vaccines and their uses, the consequences of attaining immunity naturally by getting infected by a pathogen are far more serious than that of getting immunity through a vaccine. This is due to the fact a vaccine is always a reduced form of a microbe and doesn’t have the potency that a raw pathogen has.
The vaccine world is only going to grow with the emergence of superbugs and other unknown viruses and bacteria and their mutations. The development of some vaccines has hit many roadblocks due to the potency and mutations of viruses. A vaccine usually targets a virus in a particular form but in cases like HIV, the virus continuously mutates making it very difficult if not impossible to develop a vaccine that targets it.
