More than 40 million doses of either the Pfizer or Moderna COVID-19 vaccines have been administered in the United States, mostly to seniors and healthcare workers, since the rollout began in mid-December.

With the growing number of immunizations comes a clearer picture of the negative side effects associated with the shots.

Recommended Stories

What you need to know about the Johnson & Johnson coronavirus vaccine headed toward approval

FDA authorizes extra dose of COVID-19 vaccine for immunocompromised people

Fevers, headaches, and muscle pain: Side effects to expect from the COVID-19 vaccine