“In general, fully vaccinated healthcare personnel (HCP) should continue to wear source control while at work,” the CDC states.1 “However, fully vaccinated HCP could dine and socialize together in break rooms and conduct in-person meetings without source control or physical distancing. If unvaccinated HCP are present, everyone should wear source control and unvaccinated HCP should physically distance from others.”

According to anecdotal reports, these maskless interactions already were occurring before the vaccines were available, and some have speculated they could have been one of the primary sources of infection in healthcare workers. (See Hospital Infection Control & Prevention, January 2021.) Although the vaccines are proving extremely effective, sanctioning these practices now still raises questions because of issues such as breakthrough infections, variant strains that may elude immunization, and whether asymptomatic, vaccinated people can transmit the virus.

“A growing body of evidence suggests that fully vaccinated people are less likely to have asymptomatic infection and potentially less likely to transmit SARS-CoV-2 to others,” the CDC states.2 “However, further investigation is ongoing.”

Remember, these are CDC recommendations – not required regulations, says Ann Marie Pettis, RN, BSN, CIC, president of the Association for Professionals in Infection Control and Epidemiology (APIC).

“We know that one size is not going to fit all with these recommendations,” she says. “ So, it is up to each organization, community, and each state. Often the states make mandates that you have to follow. Sometimes they go along with the CDC, sometimes they do not. We’re still sort of sitting tight, as I am sure a lot of states are.” A key indicator for such a policy is the level of SARS-CoV-2 in the surrounding community, she says.

“As with so many things, the devil is in the details,” Pettis says. “So, IPs [infection preventionists] all over the country are looking at these guidelines, adjusting them, talking to their organization leaders, and interacting with their states. IPs are very good at implementation – that’s our wheelhouse – implementing recommendations, regulations, guidelines.”

Importantly, vaccine breakthrough infections are occurring at a lower rate than would be expected for the two RNA-messenger vaccines.

“The true numbers that we are seeing locally, and even nationally, are less than their 95% efficacy would indicate, where there would be a 5% breakthrough,” she says. “We are seeing about a 1% [breakthrough]. So that’s good news, and I think that may have influenced the CDC coming out with these guidelines.”

If breakthrough infections rose as a result of variants, the CDC likely would revert to their previous, more conservative guidelines. “I think the CDC and the WHO [World Health Organization] are trying very hard to stay on top of that,” she says.

Still, if these policies are enacted, it raises the immediate question of which healthcare workers have been vaccinated and which have declined. That sounds straightforward enough, but it may be easier for some IPs than others.

“In New York state, there is a regulation that keeps track of that, but I don’t think that every state has mandated that,” says Pettis, director of infection prevention at University of Rochester (NY) Medicine.

Human behavior comes into play, as well as the age-old unpopular role of being the infection control police.

“We have lists of who is and who isn’t vaccinated,” she says. “But when you think about 24/7 looking into the break rooms – which I will say is where most transmission has occurred in healthcare workers – how do you police who is vaccinated and who isn’t?”

Another issue goes back to COVID-19 vaccination, which was approved for emergency use as a choice.

“We have also already heard from our unvaccinated staff that they are feeling unfairly singled out,” Pettis says. “We have to be very conscious of that. Messaging is extremely important in terms of how you would implement that. We’re really examining it closely.”

Although seemingly straight-forward, the CDC recommendations could open a can of worms. No one can afford to be cavalier about it because, ultimately, patients’ lives are at stake. Cases of breakthrough infections in vaccinated healthcare workers that involve patient exposures can be very sensitive and time-consuming, she says.

“Even though it is only 1%, it does happen, and IPs do contact tracing,” Pettis says. “In infection prevention, we may be over-careful because we have seen the worst-case scenarios occur. We are the ones on the frontline dealing with these things, so you can be sure that we will be very careful about which [of these guidelines] we are able to implement. We all want to go there [and remove PPE], but we need to do it very carefully, with safety being our number one concern.”

Airborne Transmission

In another recent CDC update, the agency said emerging science shows transmission of SARS-CoV-2 airborne viral particles can occur beyond six feet, particularly in enclosed, poorly ventilated spaces. IPs may want to check whether any of their break rooms and patient areas meet these conditions and may present an increased risk.

This has been something of a contentious issue, but the CDC acknowledges that under certain circumstances, the coronavirus can linger in the air and travel beyond the traditional six-foot droplet range. According to the CDC, factors that increase this risk include:

  • enclosed spaces with inadequate ventilation or air handling within which the concentration of exhaled respiratory fluids, especially very fine droplets and aerosol particles, can build up in the air space;

  • increased exhalation of respiratory fluids if the infectious person is engaged in physical exertion or raises their voice (e.g., exercising, shouting, singing);

  • prolonged exposure to these conditions, typically more than 15 minutes.


  1. Centers for Disease Control and Prevention. Updated healthcare infection prevention and control recommendations in response to COVID-19 vaccination. Updated April 27, 2021. https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control-after-vaccination.html#:~:text=Healthcare%20Personnel,-In%20general,%20fully&text=However,%20fully%20vaccinated%20HCP%20could,should%20physically%20distance%20from%20others%202
  2. Centers for Disease Control and Prevention. Science brief: Background rationale and evidence for public health recommendations for fully vaccinated people. Updated April 2, 2021. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/fully-vaccinated-people.html
  3. Centers for Disease Control and Prevention. Scientific brief: SARS-CoV-2 transmission. Updated May 7, 2021. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/sars-cov-2-transmission.html