Immunocompromised may need a fourth Covid-19 shot, CDC says
By Jen Christensen, People with certain health conditions that make them moderately or severely immunocompromised may get a fourth mRNA Covid-19 shot, according to updated guidelines from the US Centers for Disease Control and Prevention. The CDC authorized a third dose for certain immunocompromised people 18 and older in August. It said a third dose, rather than a booster — the CDC makes a distinction between the two — was necessary because the immunocompromised may not have had a complete immune response from the first two doses. A study from Johns Hopkins University this summer showed that vaccinated immunocompromised people were 485 times more likely