A healthcare worker prepares a vaccine at a pop-up vaccine site in New York City during the COVID-19 vaccine outbreak.
The waiting period for a booster shot for Moderna vaccine can be shortened by a month if you are 18 and older.
The FDA allowed people who received the Pfizer and BioNTech vaccine to get a booster dose at least five months after their second dose, down from six.
Moderna boosters were recommended by the Centers for Disease Control and Prevention. Eligibility for Pfizer boosters was lowered by the CDC.
Moderna and Pfizer are the most popular vaccines in the U.S., and the waiting period for boosters has been shortened due to the fact that two doses do not provide strong protection against omicron, the dominant variant in the U.S.
The U.K. Health Security Agency published a report last week showing that boosters are up to 75% effective at preventing infections from omicron two weeks after receiving the shot.
Dr. Peter Marks, head of the FDA group responsible for vaccine safety, said that vaccine is the best defense against COVID-19, including the circulating variant, and shortening the length of time between completion of a primary series and a booster dose may help reduce waning immunity.
Stephane Bancel, CEO of Moderna, said in an interview that fourth doses may be necessary at some point because the protection provided by boosters is likely to decline over time.
Bancel said that he would be surprised when the data came in that it was holding well over time.
Booster protection starts to decline after four weeks. Boosters were 50% to 70% effective at preventing infections after 10 weeks, and 45% to 70% effective at preventing infections after five weeks.
Albert Bourla, the CEO of Pfizer, told CNBC last month that people will probably need a fourth dose and the shot may be needed sooner than expected.
The U.S. is facing an unprecedented wave of Covid infections, with a seven-day average of more than 600,000 new cases daily, according to a CNBC analysis. That is a 72 percent increase from the previous week.
