Lifestyle Health COVID Booster Loses Potency After 4 Months, Fauci Says 'There May Be the Need' for Fourth Dose Although new CDC data finds that the COVID-19 booster loses much of its potency after about four months, Dr. Anthony Fauci says a fourth dose wouldn't be recommended "across the board for everyone" By Glenn Garner Glenn Garner Instagram Twitter Glenn Garner is a Writer/Reporter who works heavily with PEOPLE's Movies and TV verticals. Since graduating from Northern Arizona University with a dual major in journalism and photography, he got his professional start at OUT Magazine, The Advocate and Teen Vogue, and he's since consistently kept his finger on the pulse of the LGBTQ community. His first book The Guncle Guide was released in 2020 and was featured on Katie Couric's list of 100 recommended books of the year. People Editorial Guidelines Published on February 11, 2022 07:18PM EST Share Tweet Pin Email Dr. Anthony Fauci. Photo: Greg Nash-Pool/Getty Images A fourth dose of the COVID-19 vaccine might be necessary for some Americans. New data from the Centers for Disease Control and Prevention (CDC) finds that the mRNA shot's protection begins to decline after about four months, according to a study released Friday. Although vaccine effectiveness against COVID-related hospitalizations was at 91 percent during the first two months after a third dose, it decreased to 78 percent by the fourth month. The study, which was conducted during the Omicron-dominate phase of the pandemic, focused on those who sought medical treatment for COVID symptoms. It did not include a breakdown of age or whether their third dose was a booster or part of their primary inoculation series, which the CDC recommends for some immunocompromised people. "There may be the need for yet again another boost — in this case, a fourth-dose boost for an individual receiving the mRNA — that could be based on age, as well as underlying conditions," Dr. Anthony Fauci, the nation's top infectious disease expert, told reporters Tuesday. U.S. COVID Death Toll Surpasses 900,000: 'Another Tragic Milestone,' Says Biden Pfizer-BioNTech's COVID-19 vaccine. LUIS ACOSTA/AFP via Getty Fauci clarified that recommendations for a fourth dose will likely not be made "across the board for everyone," adding: "It very likely will take into account what subset of people have a diminished, or not, protection against the important parameters such as hospitalization." The CDC's update comes after the COVID-19 death toll in the U.S. surpassed 900,000 last week, less than two months after it reached 800,000. President Joe Biden urged Americans who hadn't gotten their shots yet to get vaccinated as he marked the tragic milestone. "Vaccines and boosters have proven incredibly effective, and offer the highest level of protection," he said. "Two hundred and fifty million Americans have stepped up to protect themselves, their families, and their communities by getting at least one shot — and we have saved more than one million American lives as a result." RELATED VIDEO: Doctor Says Fully Vaccinated People Are Going to Test Positive with Omicron: 'Our New Normal' As of Feb. 11, about 75.8 percent of Americans have received at least one dose of a COVID-19 vaccine, and 64.3 percent are fully vaccinated, according to the CDC's COVID Data Tracker. Just 42.7 percent of fully vaccinated people have gotten a booster dose, for which 50.2 percent are eligible. A recent report from the Centers for Disease Control showed that unvaccinated people in the U.S. were 53 times more likely to die of COVID-19 compared to those who are vaccinated and boosted. "We can save even more lives — and spare countless families from the deepest pain imaginable — if everybody does their part," Biden said. As information about the coronavirus pandemic rapidly changes, PEOPLE is committed to providing the most recent data in our coverage. Some of the information in this story may have changed after publication. For the latest on COVID-19, readers are encouraged to use online resources from the CDC, WHO and local public health departments. PEOPLE has partnered with GoFundMe to raise money for the COVID-19 Relief Fund, a GoFundMe.org fundraiser to support everything from frontline responders to families in need, as well as organizations helping communities. For more information or to donate, click here.