May 24, 2024

A vaccine contains not just the antigen that will induce the production of antibodies but other components used for specific purposes. All these components are tested for safety before they are used.

1. The antigen is the main active component. It will stimulate the body’s immune system to produce antibodies against the infectious agent.

There are four types of Covid-19 antigens: live inactivated virus, portion or spike unit of the virus, nucleic acid or messenger RNA that provides instructions to our cells to produce antibodies against the spike of the virus, and viral vector vaccines. Viral vector antigens use a harmless virus, usually adenovirus, as the template for production of Covid-19 vaccine. The viral vector vaccine mimics SARS-CoV2 infection to stimulate antibody production against Covid.

2. Adjuvants like aluminum hydroxide and aluminum phosphate enhance immune response to the vaccine by making the vaccine stay at the site of injection for a longer time and stimulating the production of local immune cells. 

3. Antibiotics like Neomycin, Gentamicin, and Polymyxin B prevent bacterial contamination during the production of the vaccine. These are later removed in the final completed vaccine.

4. Preservatives prevent the contamination of a multi-dose vaccine once its container is opened. Examples are thimerosal and 2-phenoxyethanol. Some single-dose vaccines do not have preservatives.

5. Stabilizers prevent chemical reactions within the vaccine and prevent the components from sticking to the container. These can be lactose or sucrose, glycine, gelatin, or proteins like recombinant human albumin derived from yeast. 

6. Surfactants keep the components of the vaccine well-blended together and prevent clumping or settling in the vaccine solution.

7. Residuals are very small quantities of egg proteins, yeast or antibiotics and other residual elements used in the production of the vaccine and remain in the completed vaccine. These occur in very small amounts.

8. Diluent – most commonly sterile water – used to dilute a vaccine to the correct proportion before it is injected. 

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According to the Centers for Disease Control and the World Health Organization, there is still not enough information to evaluate the effect of the new strain of SARS-CoV2 on the efficacy of the current Covid vaccines.

The new strain first identified in the United Kingdom appears to spread more rapidly and may be up to 70 percent more transmissible. The behavior of the new strain is not completely known yet and data is still not sufficient to show that it will cause more severe disease or increased death rate.

The Coalition for Epidemic Preparedness, a foundation that funds the development of Covid-19 vaccines in the world, is monitoring if the new strain can evade the Covid vaccines.