Covid-19 vaccines are biological preparations designed to provide immunity against the SARS-CoV-2 virus. These vaccines work by stimulating the immune system to recognize and fight the virus, thereby preventing illness or reducing its severity. Several types of vaccines have been developed, including mRNA vaccines (e.g., Pfizer-BioNTech, Moderna), viral vector vaccines (e.g., AstraZeneca, Johnson & Johnson), and protein subunit vaccines.
