The expansion of COVID-19 vaccination requirements across the United States has not had the desired effect, with the number of Americans receiving their first shots falling in recent weeks. Some experts are concerned that the move to dispense boosters will exacerbate the situation.

The fear is that the introduction of booster shots will cause some people to doubt the vaccine’s efficacy in the first place.

According to the most recent federal data, the average daily count of Americans receiving their first dose of vaccine has been declining for six weeks, falling more than 50% from around 480,000 in early August to under 230,000 by the middle of last week. Despite a summer surge in infections, hospitalizations, and deaths caused by the delta variant, an estimated 70 million vaccine-eligible Americans have yet to begin vaccinations.

This is despite a growing number of companies, including Google, McDonald’s, Microsoft, and Disney, announcing vaccination requirements for their employees. In addition, major cities such as New York and San Francisco require people to be vaccinated in order to eat at restaurants or enter certain other businesses.

Separately, on September 9, President Joe Biden announced broad new vaccine requirements for up to 100 million Americans. Employees at companies with more than 100 employees will be required to be vaccinated or subjected to weekly testing. However, the mandates have yet to take effect, and the necessary regulations are still being drafted.

Allie French of Omaha, Nebraska, said the move toward booster shots only reinforced her firm belief that vaccinations are unnecessary, especially for people who take care of themselves.

Scientists have emphasized that the vaccine is still highly effective against serious illness and death caused by COVID-19, noting that the unvaccinated account for the vast majority of those who have died or been hospitalized recently. However, experts have noticed signs that the vaccine’s protection is eroding, and they want to get ahead of the problem.

Experts have long stated that vaccinating the vast majority of the American public — possibly as much as 90 percent — is the key to ending the epidemic in the United States. However, according to data from the Centers for Disease Control and Prevention, only about 65 percent — 184 million — of the more than 283 million Americans aged 12 and older who are eligible for shots are fully vaccinated. Children under the age of 12 are not yet eligible for vaccination, so only about 55 percent of the general public in the United States is fully protected.

Officials at the White House said they doubt the need for boosters is a real concern among the vast majority of the unvaccinated, who have resisted getting their shots for a variety of reasons, including misinformation, despite nearly a year’s worth of data showing their lifesaving potential.

They also argue that as the pool of unvaccinated Americans shrinks, so will the number of new people receiving vaccinations. They argue that the latest figures should not be interpreted as evidence that mandates are ineffective, noting that most businesses have yet to implement the Biden administration’s vaccinate-or-test policy.

Indeed, despite the CDC’s data showing a decline in vaccination rates, they claim there is evidence that employer mandates are already working. A number of success stories were cited by White House officials, including significant increases in the percentage of vaccinated employees at the Henry Ford Health System in Detroit, United Airlines, and the Defense Department.

Last week, the Food and Drug Administration and the Centers for Disease Control and Prevention (CDC) approved booster doses of Pfizer’s vaccine for tens of millions of Americans who are 65 or older, have underlying health conditions, or work in high-risk jobs. The additional dose would be administered six months after the two-shot regimen.

However, some members of an expert panel that advises the CDC expressed concern last week that the booster debate was diverting attention away from the more pressing need to get more Americans vaccinated.

At the meeting, a CDC official presented previously unpublished data from a recent 1,000-person survey, which suggested that offering boosters would make 25 percent of unvaccinated Americans much less likely to get vaccinated. A Kaiser Family Foundation poll of more than 1,500 adults conducted this week found that 71% of the unvaccinated believe the recent news about boosters is evidence that the vaccines aren’t working.