The United States has a "very serious" problem with Covid-19 vaccination uptake, a top health official has warned. 

Vaccines are by far the most powerful tool available against the coronavirus, protecting people from getting seriously ill, being hospitalized, and dying from the virus. 

Unlike many less developed countries, the US has enough doses to vaccinate everyone as well as the necessary infrastructure to support the rollout. 

The problem: not everyone wants the shot.

"We do have a problem with vaccine uptake that is very serious in the United States and anything we can do to get people more comfortable to be able to accept these potentially life-saving medical products is something that we feel we are compelled to do," said Dr. Peter Marks, director of the Center for Biologics Evaluation and Research. 

According to the US Centers for Disease Control and Prevention, 48.7% of people over the age of 12 have been fully vaccinated and received at least one booster dose in the US.