Do you know how different types of Covid vaccines work?

Many vaccines against the coronavirus have been approved worldwide for emergency and general use over the past year. People were initially skeptical about how effective the vaccine was, but now they are gradually beginning to trust vaccines that help eradicate pandemics.

Given the size of the pandemic and the urgent need for vaccination, it is often difficult to choose a vaccine. However, it is important to understand how the different types of approved vaccines work and what their composition is.

Most vaccines work by exposing the body to particles and molecules that trigger an immune response, protecting the body from future infections. The same applies to the COVID-19 vaccine.

COVID-19 vaccines can be divided into four main types. They only differ in the exposure method used. they are:

• All viruses
• Viral vector
• RNA / mRNA
• Protein subunit

All virus vaccine

Approved vaccines: Covaxin, Sinopharm, Sinovac, Coronavac, Covivac, Minhai, Qazvac

Required dose: 2 intramuscular doses

This vaccine uses a weakened or inactivated virus that, when injected, causes an immunogenic reaction in the body. These infused pathogens cannot infect our cells or replicate themselves. These come in two forms.

• A living but weakened virus that can replicate but does not get sick
• Alternatively, an inactivated virus that cannot replicate due to the destruction of genetic material but causes an immune response.

This technology is not new and has been used in the past for vaccines against hepatitis A, polio and rabies. Because this is a trial and tested method, it is relatively easy to manufacture and can be used by people with a weakened immune system. However, this vaccine may require a booster dose.

RNA or mRNA vaccine

Approved vaccines: Pfizer-BioNTech, Moderna

Required dose: 2 intramuscular doses

This is a new vaccine technology that has never been used before. However, they have been extensively studied in the past for various other viruses such as Zika and rabies.

According to the US Centers for Disease Control and Prevention, “Researchers have been researching and working on mRNA vaccines for decades. These vaccines can be developed in the laboratory using readily available materials. As a result, there is growing interest in these vaccines. They have been standardized, scaled up, and vaccines have been developed faster than traditional vaccine production methods. “

These vaccines use genetic material, such as RNA and DNA, to provide cells with a set of instructions for producing antigens. For the COVID-19 vaccine, it is a viral spike protein.

When it enters our body, it uses cellular protein factors to make antigens. It is detected by our immune cells and causes lymphocytes in our body. The body recognizes this virus and will automatically repel the infection no matter what virus it is exposed to in the future.

Because this vaccine does not contain any production, the virus is non-diseasing and safe. However, this vaccine can be storage-prone.

Viral vector vaccine

Approved vaccines: Sputnik V, Oxford AstraZeneca, Convidecia, Johnson, Johnson

Required dose: 2 intramuscular doses

This vaccine introduces a safe and modified version of the virus, called a vector, to transmit the genetic code to our immunogenic response. These vaccines also work by giving our cells specific genetic instructions to produce antigens.

However, they do that by introducing another set of harmless viruses and transmitting these instructions to the cells. The most commonly used is adenovirus. These vaccines mimic natural viral infections and thus provoke a strong immune response.

This is an established technique that has been used in the past for Ebola to provoke a strong immune response involving both B and T cells. However, exposure to vectors in the past can reduce their effectiveness.

Protein subunit

Approved vaccines: Epivaccorona, Zifivax, Novavax

Required dose: 2 intramuscular doses

These vaccines use the subunits of the pathogen (often fragments of proteins) to generate an immune response. Coronavirus vaccines use a purified portion of the pathogen, limiting the immune system to the entire pathogen and minimizing side effects, but causing an immune response.

This vaccination technique was previously used in hepatitis B, meningococcal disease, pneumococcal disease, and herpes zoster, and can also be used in people with a weakened immune system.

However, these vaccines are a bit more complicated to manufacture and may require booster vaccinations.

Last updated June 10, 2021 10:19 AM IST