(CNN) The White House on Tuesday touted the US reaching a new milestone when it comes to vaccinations, with 50% of adults becoming fully vaccinated, according to White House senior Covid-19 adviser Andy Slavitt.
"This is a major milestone in our country's vaccination efforts," Slavitt said during a White House briefing, noting only 1% of Americans were vaccinated when President Joe Biden entered office in January.
More than 130.6 million Americans are fully vaccinated against Covid-19 as of Tuesday morning, according to the US Centers for Disease Control and Prevention.
Earlier this month, Biden said he wanted 160 million US adults fully vaccinated by July 4.
Slavitt made an appeal to Americans who remain on the fence about getting vaccinated against Covid-19.
"Find whatever reason you want to get vaccinated. For those not sure yet, do your homework, talk to your doctor or your pharmacist. All concerns are reasonable, but do yourself a favor: Don't let some guy on Facebook answer your question when good answers are available," Slavitt said.
Overall, 49.4% of the US population age 12 and above has received at least one shot and 39.3% of the US population age 12 and above is fully vaccinated.
The Pfizer vaccine for Covid-19 was only authorized for younger teens earlier this month and Moderna said Tuesday morning that its Covid-19 vaccine is safe and appears to be effective in adolescents. The Moderna vaccine is not yet authorized for use in people younger than 18; the company says it plans to submit the results to the US Food and Drug Administration in early June along with a request for authorization to use the vaccine in adolescents.
White House officials have been focused on increasing accessibility to the vaccines, combating misinformation and assisting those without the resources to get vaccinated as they race to get shots in arms across the country.
Biden has said there will be enough vaccine for every adult American by the end of this month and all people age 12 and up are eligible to receive a shot.
At least 25 states, plus Washington, DC, have now fully vaccinated at least half of their adult residents, CDC data shows.
The federal health agency defines fully vaccinated as two weeks after the second dose of a Pfizer/BioNTech or Moderna vaccine or two weeks after the single shot of the Johnson & Johnson vaccine.
At least 70% to 85% of the US population will need to be immunized through vaccines or infection in order to reach the threshold of protection needed to limit the virus' spread, according to health experts. Focusing on vaccinating children, teens and young adults could help reach that percentage, and furthermore, leaving them unvaccinated could give the virus a chance to spread, mutate and develop a strain resistant to existing vaccines.
In addition, vaccinating children and adolescents has been an increasing focus as officials look ahead to the new school year starting in the fall.
The Biden administration more than doubled its initial goal of 100 million Covid-19 vaccine doses administered in its first 100 days, reaching the 200 million benchmark on April 21. The administration has been ramping up efforts to get the rest of the population vaccinated as variants spread throughout the country and threaten to derail the progress the nation has made in combating the pandemic.
Some Americans are resisting getting vaccinated, and in response the White House has poured resources into educating the American public about the safety and efficacy of the three Covid-19 vaccines available in the US.
This story has been updated with additional information.