Covid-19Johnson & Johnson COVID-19 vaccine: What are the side effects?knowledgeisleApril 27, 2021April 27, 2021 by knowledgeisleApril 27, 2021April 27, 20210588 The Johnson & Johnson, or Janssen, COVID-19 vaccine is a single-dose vaccine to prevent COVID-19. This Snapshot feature addresses potential side effects and the controversies...