U.S. Officials Say 50 Percent of American Adults Are Now Fully Vaccinated

Half of America's adults are now fully vaccinated against the new coronavirus, U.S. officials announced Tuesday.

"This is a major milestone in our country's vaccination efforts," White House senior COVID-19 adviser Andy Slavitt said during a White House media briefing, noting that only 1 percent of Americans were vaccinated when President Joe Biden entered office in January.

Biden has said there will be enough vaccines for every adult American by the end of this month, and all people aged 12 years and older are now eligible to receive a shot. At least 25 states, plus Washington, D.C., have now fully vaccinated at least half of their adult residents, CNN reported.

At least 70 to 85 percent of the U.S. population will need to have immunity to COVID-19 to reach the threshold of protection needed to limit the spread of the virus, health experts have said. Vaccinating children, teens, and young adults could help officials reach that percentage, while leaving the young unvaccinated could give the virus a chance to spread, mutate, and develop a strain resistant to existing vaccines, CNN reported. Vaccinating children and adolescents will also help schools reopen more safely in the fall.

As the promising vaccination numbers were released, CDC Director Rochelle Walensky, M.D., offered a mix of hope and caution as Americans prepare to celebrate Memorial Day weekend, the traditional beginning of summer with friends and family. "If you are vaccinated, you are protected, and you can enjoy your Memorial Day," Walensky said during the White House media briefing. "If you are not vaccinated, our guidance has not changed for you, you remain at risk of infection. You still need to mask and take other precautions."