People.com Lifestyle Health One in 4 U.S. Adults Are Now Fully Vaccinated Against COVID With all adults aged 16 and up now eligible for a COVID-19 vaccine in 39 states, the vaccination rate has jumped significantly By Julie Mazziotta Julie Mazziotta Twitter Associate Editor, PEOPLE Health People Editorial Guidelines Updated on April 8, 2021 03:35 PM Share Tweet Pin Email Photo: Martin Schwartz/PEOPLE One in four U.S. adults are now fully vaccinated against COVID-19, as more states open up their vaccine eligibility to anyone aged 16 and up. According to data from the Centers for Disease Control, 25% of the adult population has either received both doses of Pfizer or Moderna's two-dose regimen or the single-shot Johnson & Johnson vaccine. Around 75% of seniors are also now vaccinated. That number is a sign of continuing progress with COVID-19 vaccine distribution, with 39 states now allowing any adults to get vaccinated after months of restricting access to seniors, health care workers and other high-risk groups. As of April 8, over a third of the U.S. population, or 109,995,734, have received at least one dose of a vaccine. Within that group, 64,422,618 are now fully vaccinated. The vaccination rate has gone up significantly in the last two and a half months, with the U.S. now administering an average of more than 3 million doses a day. See Which States Have Opened Up COVID Vaccine Eligibility to All Residents Over Age 16 When the Biden administration took office, they discovered that there was no reserve of vaccine doses left from the Trump administration. In the weeks since, they have been working with Pfizer, Moderna and Johnson & Johnson to secure more doses, and on March 10 President Joe Biden announced that they had purchased another 400 doses of Johnson & Johnson, putting the U.S.'s total vaccine supply at 400 million. However, health experts are warning that more people need to get vaccinated with COVID-19 cases again on the rise. U.S. infections have increased by 14% in the last two weeks, particularly in Florida, Michigan, New Jersey, New York and Pennsylvania. Those five states currently account for 43% of all new cases in the last week, despite being home to just 22% of the U.S. population. The rise in cases is due in part to the faster-spreading B.1.1.7 virus variant, which is now the dominant strain in the U.S., CDC Director Rochelle P. Walensky said Wednesday. RELATED VIDEO: Martha Stewart Gets First Dose of COVID Vaccine, Says She 'Waited in Line with Others' Dr. Anthony Fauci, the nation's top infectious diseases expert, said that getting vaccinated is the best way to stop more COVID-19 mutations from emerging. "You need to get vaccinated when it becomes available as quickly and as expeditiously as possible throughout the country," he said in a press briefing on Monday. "And the reason for that is ... viruses cannot mutate if they don't replicate. And if you stop their replication by vaccinating widely and not giving the virus an open playing field to continue to respond to the pressures that you put on it, you will not get mutations." Fauci Says Not to Get 'Complacent' as COVID Cases Decline, Advises Double Masking for New Strain The makers of Pfizer and Moderna have said that their vaccines will be effective against the newly emerging COVID-19 strains, but the effectiveness may be slightly diminished, particularly with the strain that first emerged in South Africa. Johnson & Johnson has already tested their vaccine against both strains, and found that it was effective. Fauci also said that people who have already had COVID-19 still should get the vaccine, particularly with the South Africa strain. "If it becomes dominant, the experience of our colleagues in South Africa indicate that even if you've been infected with the original virus that there is a very high rate of reinfection to the point where previous infection does not seem to protect you against reinfection," Fauci said on CNN. As information about thecoronavirus 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 andlocal 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, clickhere.