• Colin Powell, 84, died Monday morning due to complications from Covid-19.
• Powell was fully vaccinated against the virus, his family said in a statement.
• Powell was elderly, a known risk for severe Covid, and suffered from multiple myeloma, a blood cancer that studies show can make the shots less effective.
• A study published in late July found that only 45% of patients with active multiple myeloma developed an "adequate" immune response after getting vaccinated with either the Pfizer-BioNTech or Moderna vaccines.
• Just 22% of patients in the study had a "partial" response.

Colin Powell, 84, died Monday morning due to complications from Covid-19 even though he was fully vaccinated, his family said in a statement.

The former secretary of State's death has led some to ask why they should bother getting vaccinated when there is still a chance they could get severely ill or die.

Health experts say it's important to note that no vaccine is 100% effective. In addition, Powell was elderly, a known risk for severe Covid, and suffered from multiple myeloma, a blood cancer that studies show can make the shots less effective.

"The goal of the vaccine is to dramatically reduce your chance of suffering or being hospitalized or dying but it doesn't eliminate it," said Dr. Paul Offit, who advises the Food and Drug Administration on Covid vaccines.

In Powell's case, he was over 80 and had a cancer that put him at higher risk for severe Covid, Offit said.

People with weakened immune systems, including cancer and HIV patients or those who have had organ transplants, represent only about 2.7% of the U.S. adult population but make up about 44% of hospitalized Covid breakthrough cases, according to data presented by the Centers for Disease Control and Prevention in July. A breakthrough case is when a fully vaccinated individual becomes infected.

A study published in late July found that only 45% of patients with active multiple myeloma developed an "adequate" immune response after getting vaccinated with either the Pfizer-BioNTech or Moderna vaccines. Just 22% had a "partial" response.

Unfortunately, the same mechanisms that impede multiple myeloma patients' "ability to fend off infections also reduce their capability to generate immunity from vaccination," the researchers wrote.

U.S. regulators say a third vaccine dose can help such people generate a better immune response. The FDA in August authorized third shots for people with weakened immune systems who received the Pfizer or Moderna vaccines.

Regulators have also authorized Pfizer booster shots for people age 65 or older and other at-risk adults.

It's unclear based on the family statement whether Powell got an extra dose.

Offit said fully vaccinated people with weak immune systems should also continue to wear masks and social distance indoors.