A vaccine is a preparation intended to generate immunity against a disease by stimulating the production of antibodies, which are the body's natural defense system. There are currently three types of COVID-19 vaccines that are licensed:

1. MRNA vaccines

2. Vector vaccines

3. Protein subunit vaccines

How do these vaccines work?

• MRNA vaccines

They contain material from the virus that causes COVID-19, which instructs our cells to create a harmless protein that is unique to the virus, in this way the body recognizes that this protein should not be present and creates T and B lymphocytes that will remember how defend against the virus that causes COVID-19 in case of infection.

• Vector vaccines

They contain a modified version of a different virus, which in its envelope contains a viral vector (contains material from the virus that causes COVID-19). Once the viral vector enters the cells, the genetic material instructs the production of a protein that is unique to the virus that causes COVID-19, in this way our cells make copies of the protein. T and B lymphocytes are produced that will remember how to defend against the virus that causes COVID-19 in case of infection.

• Protein subunit vaccines

They contain harmless portions of the proteins of the virus that causes COVID-19. Upon receiving the vaccine, our body recognizes that this protein should not be present and creates T lymphocytes and antibodies that will remember how to defend itself against the virus that causes COVID-19 in case of infection.

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Pfizer-BioNTech

• Vaccine type: mRNA
• Dosage: 2 doses with 21 days between each
• Mode of administration: intramuscular
• Indications: it is recommended in people over 16 years old
• Effectiveness: 95%

Modern

• Vaccine type: mRNA
• Dosage: 2 doses with 28 days between each
• Mode of administration: intramuscular
• Indications: recommended in people over 18 years of age
• Effectiveness: 94,1%

Janssen of Johnson & Johnson

• Vaccine type: viral vector
• Dosage: 1 injection
• Mode of administration: intramuscular
• Indications: it is recommended in people over 18 years of age
• Effectiveness: 66.3%

AstraZeneca

• Vaccine type: Viral vector
• Dosage: 2 doses in an interval of 8 and 12 weeks
• Mode of administration: intramuscular
• Indications: it is recommended in people over 18 years of age
• Effectiveness: 63,09%

Sinovac

• Vaccine type: inactivated virus
• Dosage: 2 doses with an interval of 28 to 35 days
• Mode of administration: intramuscular
• Indications: it is recommended in people over 18 years of age
• Effectiveness: 91,25%

Vaccination safety

All available vaccines against COVID-19 have been exhaustively evaluated in the different phases of clinical trials where their safety and efficacy are demonstrated. The vaccine not only provides protection against oneself, but also protects the people around us by reducing the risk of being infected by us, especially people with risk factors and the immunocompromised. It is important to follow the prevention and hygiene instructions, even after having been vaccinated.

Bibliography

How vaccines work. (2021). Centers for Disease Control and Prevention. https://espanol.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html

COVID vaccination. Government of Mexico. (2021). https://coronavirus.gob.mx/vacunacion-covid/