The US Centers for Disease Control and Prevention claims to have administered more than one million doses of COVID-19 vaccines by Wednesday.
The CDC also claims to have distributed more than 9.46 million doses across the country.
Currently, priority is being given to health professionals and nursing home residents in the initial phase of the vaccination program across the country. A private research institute claims that the number of people in these groups is over 17 million.
The CDC plans to expand the scope of the phased vaccination program. Next in line for the vaccine will include police, firefighters, people aged 75 and over, teachers and grocery workers.
Meanwhile, the CDC said it had received a report that six people who received the injection developed severe allergic reactions.
Officials from the CDC and the US Food and Drug Administration are investigating the cases. Employees published guidelines for safe vaccinations. They called for a system in which recipients are observed after vaccination and treated immediately in case of any adverse reaction.
United States Secretary of Health and Human Services Alex Azar said he expects a total of 100 million doses of the Pfizer and Moderna vaccines to be distributed by the end of February.
He added that more doses should be available if vaccines from Johnson & Johnson and AstraZeneca are approved.