Vegans cannot take COVID-19 vaccines because they contain animal products.
COVID-19 Vaccines: My Message To Vegans [...] Are COVID-19 vaccines vegan? Whether or not COVID-19 vaccines are vegan depends on how you define veganism. If you define veganism as zero use of animals, or animal products, they are not vegan. If you define veganism as philosophy that excludes animal exploitation "as far as possible and practical", like the Vegan Society, then the answer is fuzzier.