Infection preventionists may one day be faced with a pandemic flu or the release of a bioterrorism agent that calls for mass vaccinations or post-exposure prophylaxis of healthcare workers. One novel way to prepare now is to stage annual flu vaccinations as an emergency drill. A healthcare system in Delaware did just that, vaccinating a staggering 8,035 employees in a single day.

Such an effort takes considerable planning and administrative support, but there are a multitude of positives — not the least of which is getting a large amount of facility staff ready for flu season before the annual virus starts circulating.

ChristianaCare healthcare system in Wilmington, DE, started its “#HitMeWithYourFluShot” campaign in the 2018-2019 influenza season, mass vaccinating 7,868 employees. In October 2019, they followed suit for the 2019-2020 season, topping the prior total in an 18-hour vaccine marathon from 3 a.m. to 9 p.m.

The one-day blitz included vaccinating onsite at two hospitals and sending out mobile vaccination units to affiliated institutions in neighboring states. Overall, the outreach included 100 nearby locations in Delaware, Pennsylvania, Maryland, and New Jersey. That included the two hospital campuses in Wilmington and in Newark, NJ. Mobile teams dropped off vaccination kits or administered vaccines, so caregivers in remote sites could be vaccinated quickly and easily. These locations included primary care, specialty care, medical aid units, imaging, laboratory, rehabilitation services, and nonclinical sites.

A novel addition this year was a drive-thru option, allowing workers who were not on shift to come by and be vaccinated without leaving their cars. Employees were encouraged to preregister for their flu shot in the weeks leading up to the drill, which improved the efficiency of the exercise. Those not vaccinated during the one-day campaign were slated for follow-up immunization.


Hospital Infection Control & Prevention asked for more detail about the mass immunization campaign in an interview with Marci Drees, MD, MS, FACP, DTMH, FSHEA, chief infection prevention officer and hospital epidemiologist.

HIC: Why did you decide to go to this mass vaccination approach for healthcare worker annual flu shots?

Drees: We have had a pretty intensive flu campaign prior to the last two years, but basically it was spread out over three weeks. We had put into place a tracking system so that we knew who was vaccinated [in-house and at affiliated sites and clinics]. We had that in place for five or six years prior to this event. There have been other hospitals that published similar plans to kind of dual-purpose your flu campaign into a vaccination drill. We took some lessons from what we read and put our own spin on it as well.

We are pretty geographically diverse. So, having everyone come to one spot to get vaccinated — which is what some of the other institutions have described — was not going to be very feasible for us. So we did it our own way by having several different locations plus a traveling team that went out to all of our outpatient and ancillary sites across four states. They brought vaccines if there were staff that were able to vaccinate at the location. We also had a traveling vaccination team that went around to the nonclinical sites, where there was no one physically there who could administer the vaccine. Most folks that were vaccinated got it on campus because that is where most of our staff are on any given day. Delaware is a pretty small state. We are right at the juxtaposition of the four states. It’s a complex system in terms having to get where you need to go, but it is not a huge [geographic area].

HIC: How do you set up the program for those that are going to be vaccinated within the hospital? Did you go around with vaccination carts?

Drees: For the two physical hospitals, we set two locations at the bigger one, and one at the smaller one, where staff could come down to get vaccinated. We have multiple tables and there were very few times throughout the day that there were lines — just because we had staffed up appropriately. For the outpatient sites, we had to know how many people needed vaccination, so that we could drop off a package — vaccine, syringes, alcohol swabs — everything they needed to vaccinate their own staff. Or the traveling vaccine team would come through [and immunize people]. We were able to find out ahead of time how many staff needed vaccine.

HIC: Does this one-day campaign generate a lot of enthusiasm that helps with staff participation?

Drees: I think it really does — we really talk it up a lot. [Marketing] did a great job in terms of publicity. You have to make it fun. A radio station came in, we had therapy dogs, and tons of stuff that people could do while they were waiting.

The other thing is we had a lot of nurses and pharmacists volunteer to give vaccines. We also had a lot of hospital leaders come down to help and that was nice. It’s fun — you get to see staff you don’t see every day.

HIC: For the drive-thru immunization, did staff have to get out of their car?

Drees: No, actually you just roll up your sleeve. We thought it might be a nice opportunity to get some of our people that were off they day. They might have their kids with them and they don’t want to park and come in. We put it in back of the employee parking lot, and we got a lot of positive feedback. The longest wait was like 25 minutes, but people were happy with that option. That was a big success for this year — that was something new.

HIC: Can you report this mass immunization effort as a drill for emergency preparedness to The Joint Commission?

Drees: Yes, exactly. It helps us with that regulatory accreditation, but we really did need to understand how we would do this on very short notice. We took six months to plan our first event, and the second time it got a little bit easier in some ways. There are a lot of lessons learned. For example, nobody had a true “master list” of where all our staff work. Different departments had different lists. From an emergency management perspective, you need to have a master list. That was a great lesson learned from the first go-around. We have primary care clinics with outpatient labs, outpatient radiology, and physical therapy. No one person at that physical location had a reporting system for all of those different types of clinical sites. So, you have to communicate four different times for four different clinics, even though they are all physically at the same place. That was a lesson learned last year. So, this year we made sure there was some kind of site contact that was responsible for communicating for all of the different services at a given physical site. That really streamlined things. It has been nice to partner with emergency management. It is a ton of work, so the fact that we have support from the very top is really essential. We never know when flu is going to hit — some years it hits earlier than others. But by the middle of October we have two-thirds or three-quarters of this done. It is nice to have a jumpstart on that.

HIC: Would this kind of drill be appropriate training for the next influenza pandemic or the kind of mass prophylaxis that would be necessary after a large exposure or bioterrorism incident?

Drees: I was here in 2009, when we had the last pandemic. I think the bigger issue then was we didn’t have vaccine. So, the question was how you prioritize [vaccine] to the patients, the staff, and to which staff. Who are the people at a higher risk of complications? It gets very tricky. So, this is slightly different, but I think we still learned things by having this drill. It doesn’t have to be a vaccine necessarily, it could be a mass prophylaxis with antibiotics. It would be the same process, so I think it is useful for other things.

HIC: Does your healthcare system mandate seasonal flu immunization for healthcare workers?

Drees: We do not. We allow people to decline. We have what I call a “mandatory declination” process. They are required to participate in the process. We typically have less than 5% decline. That is pretty good herd immunity for flu. I know facilities that mandate vaccine have about 99% [compliance] because they fire people. This is a little more lenient, but we still get the results that we need.

HIC: Do you conduct annual education to try overcoming antivaccine sentiment and myths?

Drees: We always do education. We put together web-based learning that we push out in September. For the last couple of years, we have done kind of a [basic] version for people who know they are going to be vaccinated and just wanted to know where and when. Or they can choose a longer version that goes into the type of vaccines out there and any safety concerns. We probably have 200 “frequently asked questions” — all grouped by category — based on questions we have received in the past. We make sure that is updated each year. For those people that do decline, we have them give a reason for declining. We also look at what department they are in. So, if there is a department that has a little lower vaccination rate, we target them for some advertising materials and try to get some of their own staff members to be models for the fliers. So, it really emphasizes that someone they know is really supportive of flu vaccination.

HIC: For those who decline vaccination, do you enforce mask requirements during flu season?

Drees: They must participate in the [vaccination] process and we give them a date of November 30 to complete that. We then push out to managers [which employees] are not vaccinated and they know that they have to wear a mask. Once flu starts circulating in the community, we will put out a notice saying now is the time to start masking for anyone who is unvaccinated for any reason. We typically get another rush at that time down to employee health, of people who want to get vaccinated. They don’t want to wear a mask, so they come down and get it, but we do have people who wear masks all winter long.