As Covid-19 boosters continue to roll out, some health care organizations—including University Hospital in New Jersey—have begun mandating boosters for certain employees. Here's what public health leaders say about what it means now, and could mean in the future, to be "fully vaccinated."

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NJ hospital mandates boosters for J&J recipients

For example, University Hospital in New Jersey, which employs 3,700 people, on Wednesday announced a Covid-19 booster mandate for all employees who received the Johnson & Johnson (J&J) single-dose vaccine. This requirement followed the hospital's general Covid-19 vaccine mandate for employees, which was originally implemented in June, Modern Healthcare reports.

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"Data and analysis indicate that a single dose of the [J&J] vaccine may no longer confer a level of effectiveness that prevents Covid-19 infection in enough of our employees if they are exposed, which has implications on our ability to keep vulnerable patients and families safe," said Shereef Elnahal, the hospital's president and CEO.

According to Elnahal, around 270 hospital employees were vaccinated with J&J's vaccine and are now required to receive an additional dose of any of three Covid-19 vaccines authorized in the United States. Affected workers will have until Dec. 24 to comply with the mandate or face discipline.

So far, University Hospital has not mandated boosters for recipients of Moderna's or Pfizer-BioNTech's vaccines, Becker's Hospital Review reports, but officials said they will continue to monitor data to determine whether additional mandates are necessary.

The definition of 'fully vaccinated' may change

Currently, individuals who have received two doses of Moderna's or Pfizer-BioNTech's vaccines or one dose of J&J's vaccine are considered fully vaccinated, but that may change as boosters continue to roll out, Business Insider reports.

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For instance, during last week's meeting of CDC's Advisory Committee on Immunization Practices (ACIP), some committee members raised the possibility of treating an additional dose of J&J's vaccine as the second dose of a two-dose regimen instead of as a "booster."

However, Doran Fink, FDA's liaison to ACIP, said that "[a]t this time," J&J's vaccine is a single-dose vaccine. That said, Fink added, "This is not determinative of what the vaccination regimen might ultimately be as we accrue additional data."

Separately, CDC Director Rochelle Walensky said the definition of being fully vaccinated has not yet changed since only certain groups are currently eligible for booster doses. However, she added that the definition may change in the future as more information becomes available.

"We have not yet changed the definition of 'fully vaccinated.' We will continue to look at this," Walensky said. "We may need to update our definition of 'fully vaccinated' in the future." (Devereaux, Modern Healthcare, 10/27; Gooch, Becker's Hospital Review, 10/27; Gonzalez, Axios, 10/22; Dzhanova, Business Insider, 10/23)