RELATED: If You Got This Vaccine, You May Never Need a Booster, New Study Says. The policy change, which is expected to be announced sometime on Aug. 12, comes after weeks of debate that many with weakened immune systems would require a booster to shore up protection against COVID-19, especially in the face of the highly transmissible Delta variant that is currently believed to be responsible for 93 percent of all cases in the U.S. Data from the Centers for Disease Control and Prevention (CDC) estimates that 2.7 percent of the American population—or roughly 9 million people—can be classified as immunocompromised, including patients undergoing cancer treatment, people with HIV, and those who’ve received an organ transplant. However, it’s not yet clear which exact groups would be affected by the FDA’s announcement. The expected change comes after other countries have begun offering third shots to those with weak immune responses, including France, Germany, and Hungary. It also caps weeks of speculation from top American officials that certain members of the population would soon be offered a booster shot. “When you look at immune-compromised people, namely those with cancers, those on chemotherapy for a variety of diseases, those who have immune depression of some sort of another, they likely never got a good immune response to begin,” Anthony Fauci, MD, chief White House COVID adviser, said during a recent interview with CNN. “We think they should get that additional boost sooner rather than later. Very soon,” he added. RELATED: Pfizer Executive Says This Is Who Will Get COVID Booster Shots First. Mounting research has shown that those with compromised immune systems may require additional shots to generate an adequate immune response that will keep them protected. One large study published in the medical journal Cancer Cell on June 5 found that while most of the 200 cancer patients included in the study responded well to COVID-19 vaccines, 30 percent of those taking immunosuppressant medications showed no signs of seroconversion, which is the medical term for the production of antibodies in response to a virus. And another recent randomized, placebo-controlled study from Canada found that booster shots of the Moderna vaccine generated an improved immune response in those it was given to, The New York Times reports.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: For more up-to-date information, sign up for our daily newsletter. The change in the FDA’s authorization also comes at a time when some non-immunocompromised people have begun seeking out third shots of their own. But officials have both cautioned that more data was needed before boosters would be recommended for the general population and assured that recent research has found the shots are still highly effective, even against new variants. As a result, some speculated that it might be months before additional shots become available to those who aren’t immunocompromised, CBS News reports. “I suspect, again, by sometime in September, we’ll be able to make some more coherent statement about what the recommendation will be here,” Peter Marks, MD, a top FDA official overseeing the vaccine approvals, said during a webinar in July. RELATED: If You Got Moderna, This Is When a Booster Will “Be Necessary”.