CNN  — 

Mark Warschauer, a professor of education at the University of California, Irvine, was “tremendously excited” about the authorization of Covid-19 vaccines, and happy when he became eligible to get his first doses.

And he was at the front of the line to get a booster, too.

“We were very concerned about Covid,” he told CNN. “I’m not elderly, but at the age of 67 I knew there was a substantial risk of hospitalization and even death from Covid. So I got my vaccine at the earliest possible date.”

Warschauer is leading a trend.

According to most recent data from the US Centers for Disease Control and Prevention, more people are receiving a booster dose of a Covid-19 vaccine each day than are getting their first shot or are becoming fully vaccinated each day.

CDC data now shows more than six million fully vaccinated Americans have received a booster dose of a Covid-19 vaccine. An average of 390,444 people are getting a booster shot each day, while only 288,105 people are starting their vaccination series each day and 276,539 people are becoming fully vaccinated each day.

Current recommendations from the CDC are that people over 65, people who have a health condition putting them at greater risk of severe disease if they do get a breakthrough infection or people who face a greater risk of contracting Covid-19 while at work or in their living circumstances can receive a booster dose. A booster dose is currently only authorized for those who received a full series of Pfizer’s Covid-19 vaccination.

Plus, certain people who are immune compromised are authorized for a third dose, although it’s not technically considered a booster because it’s likely they did not fully respond to the first two doses.

While Biden administration officials have stressed that booster doses are important in addition to increasing the number of Americans vaccinated with the initial series of shots, booster dose administration rates have outpaced the number of people starting vaccination since October 1.

“Vaccinating the unvaccinated remains the top priority, including through vaccination requirements,” White House Covid-19 Response Coordinator Jeff Zients said Wednesday in a White House Covid-19 Response Team briefing.

Getting boosters to protect themselves, others

Lindsay Adams, a 27-year-old attorney in Hamilton County, Indiana who is 18 weeks pregnant, said she got an additional dose in the hope of keeping her baby safe, as well as herself.

She was following news stories about studies done on women who got vaccinated while pregnant, which showed babies were born with high levels of antibodies from their mothers’ vaccination, she told CNN in an email.

As soon as her employer offered boosters, and after checking that her obstetrician approved, Adams got her booster shot.

“I was happy to be able to have a chance to get a booster while I’m pregnant in the hopes that it will help keep my baby safe, too,” she said.

“For me it has always been an easy decision,” she added, saying she’s grateful that she has been able to get all three shots.

According to CDC data, more than 64% of booster doses administered so far have been given to people 65 or older. Nearly 9% of all fully vaccinated people 65 or older have received a booster dose.

As someone who says he tries to follow the science carefully, Warschauer said he felt the same about boosters.