Vaccines are a crucial component of global health, designed to protect individuals from infectious diseases. They work on the fundamental principle of exposing our immune system to an inactive, weaker or partial form of a particular virus or its traits, promoting the body to develop immunity against the disease.
Virus Strain and Mutation
Viruses have the ability to change their form through mutations, leading to new virus strains. These changes are significant as they can affect the virus’s transmissibility, severity, and responsiveness to previously effective vaccines, making it essential for researchers to continually monitor and develop updated vaccines.
Vaccines Varieties in the Spotlight: Corbevax and Covovax
India’s recent approval of two vaccines – Corbevax and Covovax – for treating COVID-19 patients has drawn attention to these medical inventions.
Corbevax, a protein subunit vaccine, works by using fragments of the virus rather than the whole virus to incite an immune response. Specifically, it employs a harmless Spike (S) protein, a critical factor in viral infections. Once recognized by the immune system, this protein induces the production of antibodies that can combat an actual infection. Published studies suggest Corbevax’s effectiveness at preventing symptomatic infections is over 80%.
Covovax, developed by the US-based Novavax and manufactured by Serum Institute of India (SII), employs Recombinant Nanoparticle Technology. It creates immunity against the virus using a spike protein grown in insect cells. This protein is then extracted, formulated into virus-like nanoparticles, and injected with an adjuvant to boost immune response. The efficacy of this vaccine is 96.4% against the original virus strain and 86.3% against Alpha.
Molnupiravir – A New Pill for COVID-19 Treatment
In addition to vaccines, novel treatments like Molnupiravir, an oral antiviral drug, have been approved for use. This drug works by introducing errors into the virus’s genetic code, inhibiting its replication. Its usage restrictions include a limit of five consecutive days of administration and its prescription to adults with high risks of disease progression.
Diving Deeper: Understanding the Types of Vaccines
There are several types of vaccines developed for various infectious diseases:
Inactivated Vaccines utilize a dead version of the disease-causing germ. While typically less potent than live vaccines, they can still effectively protect against diseases such as Hepatitis A, Flu, Polio, and Rabies.
Live-attenuated Vaccines involve a weakened form of the germ. These vaccines create a powerful and lasting immune response, but cannot be given to individuals with weakened immune systems. These are used to target diseases like Measles, Mumps, Rubella, Rotavirus, Smallpox, etc.
Messenger RNA (mRNA) Vaccines produce proteins to trigger an immune response. They offer several advantages including rapid production and the absence of live viruses, hence pose no risk of infecting the recipient. An example is the Covid-19 vaccine.
Subunit, Recombinant, Polysaccharide, and Conjugate Vaccines use specific pieces of a germ, yielding a strong immune response. They can also be administered to people with weakened immune systems and chronic health conditions. They protect against diseases like Haemophilus influenzae type b disease, Hepatitis B, Human papillomavirus, Pneumococcal disease, and more.
Toxoid Vaccines use a toxin made by the germ that causes a disease. Instead of combating the entire germ, these vaccines aim to create immunity against the parts of the germ that cause the disease, such as Diphtheria and Tetanus.
Viral Vector Vaccines use a modified version of a separate virus to deliver protection. Adenovirus, a common cold-causing virus, is one of the viral vectors used in some Covid-19 vaccines being studied in clinical trials.