Further research published by The Centers for Disease Control and Prevention (CDC) on Jan. 7 reiterated that the COVID-19 vaccines protect recipients, while serious outcomes associated with the shots were seen in individuals who had risk factors.

Every vaccinated individual who suffered serious outcomes as part of a study of more than 1.2 million people had at least one risk factor that left them vulnerable, the CDC said in its Morbidity and Mortality Weekly Report (MMWR).

The study defined serious COVID-19 outcomes as hospitalization with a diagnosis of acute respiratory failure, the need for noninvasive ventilation (NIV), ICU admission, including requiring invasive mechanical ventilation, and death.