Covid-19 vaccine: Tens of millions of Americans might not have had an adequate response to shot

Tatelman had recently received her second dose of Pfizer’s Covid-19 vaccine, and the end of the pandemic was finally in sight. Maybe soon she could play with her grandchildren and return to her volunteer work helping children in foster care. Maybe in a few months, when her husband turned 75, they could go out to a restaurant to celebrate.

As she walked, she ran into her family physician — who killed her buzz very quickly.

To treat inflamed blood vessels in her lungs, Tatelman, 73, takes a drug that suppresses her immune system. Her doctor had been reading recent medical studies…