An increasing number of employers are dropping their COVID-19 vaccination requirement for hiring new workers as part of a drive to fill gaps in their labor force, says a new study by job site Indeed.

Last week, an analysis of job postings on the site by Indeed economist AnnElizabeth Konkel found that the number of positions that required proof of vaccination fell from a peak of 7.1% as of March 12 to 6.7% by April 29.

In a comment to CNBC on Tuesday, Konkel noted that the jobs did not single out removing the COVID-19 vaccination specifically but added that was the implication because there were not many jobs requiring any vaccination prior to the pandemic.

The other implication of the study is that employers are leaning away from vaccine requirements as part of their effort to fill gaps in their workforce at a time of a national labor shortage.

“Employers may be hypothesizing that if the pandemic isn’t at the forefront of workers’ minds, advertising required vaccination isn’t going to appeal in the same way it did a few months ago,” Konkel told CNBC.

According to the Centers for Disease Control and Prevention (CDC), 89.2% of American adults received at least a dose of a COVID-19 vaccination and 76.2% are fully vaccinated against the virus. The number of deaths from the virus have dropped, but case numbers and hospitalizations have both trended upwards in recent weeks.

The pandemic has also contributed to a wider labor shortage across the U.S. economy. Last week, the Labor Department found that 4.5 million Americans had quit their job in March while there were 205,000 new job openings recorded.

In a thread on Twitter, Konkel explained that the downward trend has certain caveats attached to it. that show the decline in vaccination requirements is not linear.

For example, a trend in remote jobs requiring vaccination was found to have grown by about 10.5% compared to 3.5% for those with few to no remote working options.

Another variation was found to be geographic. Oregon was found to have the highest number of job postings that required vaccination with 12.4% of all postings advertising it. In contrast, Montana had the lowest with only 2.4% of jobs in the state requiring vaccination.