Hospitals weigh costs and benefits of varicella vaccination programs
Hospitals weigh costs and benefits of varicella vaccination programs
Troubling questions, such as the need for furloughs, cause concern
A live, attenuated varicella vaccine became available in the United States in 1995 and was recommended for health care workers in 1996,1,2 but until now there have been no cost/benefit analyses of varicella vaccination programs for hospital employees. Two recent studies show that varicella vaccination for susceptible HCWs can result in financial savings and improved patient care.
Exposure to varicella is common in health care settings, and problematic for employee health and infection control practitioners. Identifying exposed, susceptible workers can be expensive and time-consuming.3,4 In 1984, exposure to a single infected patient forced one hospital to furlough 25 susceptible employees, and two nurses developed varicella.4 More recently, an outbreak in the United Kingdom included 88 exposed patients and two HCWs who contracted varicella.5 Another study showed that four of 45 nonimmune, exposed HCWs developed clinical varicella.6
The costs of varicella infection in terms of health and money are significant. Among adults and the immunocompromised, the disease is associated with serious complications such as encephalitis, pneumonia, and death.7,8 Mortality rates in adults are estimated to be 30.9 per 100,000 infected adults, almost 30 times that in healthy children.9
Approximately 1.6% of infected adults are hospitalized. The cost of one case of varicella is estimated to be $2,056, including outpatient care, time lost from work (two weeks), and hospitalization.9 Varicella-associated illness costs about $529 million each year nationally, with $439 million (83%) attributed to work-related losses.10
Controlling and preventing varicella in hospitals can also be costly. In the 1984 outbreak, investigation and containment cost $19,000.4 One year of varicella zoster virus control including work furloughs, serologies, patient isolation, epidemiological investigation, and varicella zoster immune globulin cost $41,500 according to one report11 and $56,000 according to another.3
However, as one recent cost-effectiveness study notes, the advent of the recently licensed varicella zoster vaccine (Varivax, Merck & Co., West Point, PA) can "substantially" cut the cost of varicella control in hospitals.12
"We knew we were spending an awful lot of money on special paid absences [furloughs], and we were curious to see exactly how much," says Juanita E. Brassard, RN, MS, nurse manager of the occupational health service at New York and Presbyterian Hospitals Inc., in New York City and a co-author of the varicella vaccine program study. "We looked, and out of that and considering the cost of the vaccine and the number of people who needed to get it we decided [a vaccination program] was worthwhile."
What Brassard and the other investigators found was that in 1994, of the more than 6,600 HCWs on staff, 224 (3.4%) were not immune to the varicella zoster virus, according to information gleaned from the employee database. In that year, 40 special paid absences resulted from 29 susceptible workers being exposed to varicella or herpes zoster, for a total of $38,463.93 in salaries to those furloughed. An additional $24,748.74 was paid to workers who replaced the furloughed employees. Three of the 29 susceptible workers had two absences each, and four had three absences each. Nine of the 29 had additional varicella exposures during 1995 and were furloughed a total of 12 more times.
Nine absences in four years
"Review of these 29 employees’ medical records from the date of hiring through 1995 revealed 86 varicella-zoster-related special paid absences among them," the study states. "Seventeen employees (58.6%) had multiple exposures and furloughs. Most remarkably, one healthcare worker went on nine special paid absences in four years of employment, and another was furloughed at least 15 times in 11 years on staff."
The study also points out that only nine (31%) of the 29 exposed workers who were sent on furlough in 1994 developed natural immunity to the varicella zoster virus. Seven contracted varicella, and two became seropositive without clinical disease.
Brassard and the others also computed the cost of initiating a vaccine program. At about $40 for each of the two vaccines recommended for adults, the total cost of vaccine for 224 workers was $17,920. The cost of vaccine for new susceptible employees would be minimal, given the low seronegativity rate among adults. Another one-time cost of $2,300 for a storage unit was necessary to keep the vaccine at an average temperature of -15 degrees C or below, per the manufacturer’s recommendations.
The varicella vaccination program was launched in March 1996, with occupational health personnel vaccinating and counseling employees. No new staff were needed.
Get vaccinated or forfeit free furlough
Initiating the program "took a lot of reinforcement from the departments and from human resources," Brassard tells Hospital Employee Health. "We sent out a letter to everyone who was [antibody-] negative and gave them the option to come and be evaluated and get the vaccine, or to sign a declination. If they signed a declination, they would forfeit free furlough if they were exposed and would not be able to use sick time. So if they were on a unit where someone had chickenpox, they would have to use their holiday or vacation time, or be unpaid. So people came [to be vaccinated]. The deal was that if they came and got assessed and for some medical reason could not have the vaccine, they would still have their paid furlough. But when we first sent out the letter, a lot of people paid no attention. They didn’t sign the declination or come in. Human resources hand-delivered the letter to each employee, made them read the information, and sign that they had received it."
Although some authorities recommend assuming that an individual who offers a history of varicella is immune,2,13 Brassard says self-reporting can be unreliable. She does not accept physicians’ notes as proof, either.
"We accept only lab titers from a certified lab, and we do them preplacement on everyone unless someone has them done currently by their own physician," she states.
Routine post-vaccination testing is not recommended by either the federal Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices or the CDC’s Hospital Infection Control Practices Advisory Committee (see related story, p. 113), but New York and Presbyterian Hospitals confirm serologic immunity one month after immunization completion.
"We realize that this will increase the initial cost of the program, but it will reduce the likelihood that healthcare workers who remain serologically naive despite vaccination will become inadvertent vectors for nosocomial transmission of varicella to highly susceptible patients," the study notes.
Brassard uses a varicella immunization and exposure algorithm for HCWs. (See algorithm, p. 112.)
One troublesome question affecting the costs and benefits of varicella vaccination programs relates to furloughs following vaccination. According to information from the manufacturer, in clinical vaccine trials that followed adult vaccinees for 42 days post-vaccination, a varicella-like rash at the injection site developed in 3% of subjects post-dose one (median number of lesions: 2), and in 1% of subjects post-dose two (median number of lesions: 2). A generalized rash developed in 5.5% of subjects post-dose one (median number of lesions: 5) and in 0.9% of subjects post-dose two (median number of lesions: 5.5).
No data exist on the need to furlough all vaccine recipients to protect susceptible patients. Such a practice is not advocated and would make vaccination extremely expensive.1,2 Brassard says if a vaccine-associated rash develops, workers are furloughed until the lesions are fully dried and crusted.
Furloughs would have ripple-down effect’
The furlough issue was problematic at the University of Iowa Hospitals and Clinics in Iowa City, where the second cost/benefit study was conducted in 1995.14 The study concludes that varicella vaccination of potentially susceptible HCWs can reduce costs and decrease morbidity, but infection control policy regarding work restrictions for vaccine recipients plays a key role in vaccination feasibility.
Despite the study’s conclusions, concerns about the need to furlough recipients kept administrators from initiating a vaccine program, says Marlene Schmid, RN, PhD, a former senior nurse epidemiologist there and co-author of the study. About 700 of the institution’s 10,000 employees (7%) were identified as nonimmune, so administrators thought furloughs for those who developed rash could amount to a significant expense.
"The very first employee who chose to get the vaccine on her own had the breakthrough rash, and we had to exclude her from work," recalls Schmid. "The problem we had was that [HCWs] who were nonimmune and repeatedly exposed often were physicians and others in key positions, and that would have a real ripple-down effect on the organization if we had to exclude them."
Nevertheless, the study points out that vaccinating all potentially susceptible workers would have resulted in a net cost savings for the institution of $41,000 over the lifetime of those workers, or approximately $59 per person. Serologic testing before vaccination was less cost-effective, but still resulted in a savings of $15,000, or $22 per recipient. If no vaccine was given, 24 cases of varicella would be expected in employees.
The authors note that cost savings depend on infection control policy regarding post-vaccination work restrictions. If more than 3% of recipients had been furloughed for 14 days due to vaccine-induced rash, "vaccination would result in a net financial loss for the institution," the study states.
One strategy suggested is for vaccine doses to be scheduled prior to employment or vacation, keeping in mind that vaccine-associated rash is more commonly associated with the first dose than the second. Another alternative is to schedule doses when employees are not engaged in patient care activities when the rash might appear, such as vaccinating susceptible workers who are furloughed after exposure to natural varicella.
"I was excited when the vaccine came out on the market because I was so sick and tired of tracking the exposures, which is so labor-intensive, but I didn’t anticipate all of the hurdles with it. I think it’s cost-effective if you figure out some of these alternatives, but I’m not so sure hospitals will absorb the expense of employees being out for a couple of weeks during the breakthrough rash period. That was the biggest problem we had. It’s not a clear-cut issue," Schmid says. "There’s still a long haul ahead due to unanswered questions."
Raymond A. Strikas, MD, a medical epidemiologist in the CDC’s National Immunizations Program, agrees that the furlough issue is a difficult one. "We just say hospitals should be aware that it is an issue and make guidelines, but there is no recommendation at all, so it’s a tough situation."
The vaccine is not perfect’
Postvaccination serologic testing is another debatable issue, Strikas notes.
"You do see infections following vaccination; the vaccine is not perfect. Our guidelines say that because seroconversion following varicella vaccination does not always result in full protection, consider postvaccination testing at the time of exposure, or retesting after exposure five or six days later to see if there’s an anamnestic response, or furlough them, so we kind of beg the question," he says.
Consequently, it might just be simpler to test workers postvaccination "to avoid having to scurry around and test [them] if there’s an exposure. If they think that’s more economical in time and [human] resources, if not money, then that’s their decision. Someone would have to do a cost analysis to see which one is better, but I can see the logic on both sides," he says. "I’m not going to say it’s wrong; it’s simply a difference in the way of approaching this."
Strikas says that because the vaccine is new, several unresolved issues remain, such as who should be vaccinated, how to ensure that vaccinated workers are immune if exposed, "as well as the issues of vaccinated [HCWs] potentially carrying disease to susceptible people if they develop a rash, and a less important issue is people who might transmit without a rash, which we think is exceedingly rare. Only time will tell us what might be a better way to do this."
References
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2. Centers for Disease Control and Prevention. Prevention of varicella: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1996; 45(no. RR-11):1-36.
3. Weber DJ, Rutala WA, Parham C. Impact and costs of varicella prevention in a university hospital. Am J Public Health 1988; 78:19-23.
4. Hyams PJ, Stuewe MCS, Heitzer V. Herpes zoster causing varicella in hospital employees: Cost of a casual attitude. Am J Infect Control 1984; 12:2-5.
5. Lewis DA, Jenks P, Gent AEM, et al. Varicella-zoster vaccination for healthcare workers. Lancet 1994; 343:1362-1363.
6. Haiduven DJ, Hench CP, Stevens DA. Postexposure varicella management of nonimmune personnel: An alternative approach. Infect Control Hosp Epidemiol 1994; 15:329-334.
7. Fleisher G, Henry W, McSorley M, et al. Life-threatening complications of varicella. Am J Dis Child 1981; 135:896-899.
8. Choo PW, Donahue JG, Manson JE, et al. The epidemiology of varicella and its complications. J Infect Dis 1995; 172:706-712.
9. Preblud SR. Varicella: Complications and costs. Pediatrics 1986; 78(suppl):728-735.
10. Lieu TA, Cochi SL, Black SB, et al. Cost-effectiveness of a routine varicella vaccination program for U.S. children. JAMA 1994; 271:375-381.
11. Krasinski K, Holzman RS, LaCouture R, et al. Hospital experience with varicella-zoster virus. Infect Control 1986; 7:312-316.
12. Tennenberg AM, Brassard JE, Van Lieu J, et al. Varicella vaccination for healthcare workers at a university hospital: An analysis of costs and benefits. Infect Control Hosp Epidemiol 1997; 18:405-411.
13. McKinney WP, Horowitz MM. Battiola RJ. Susceptibi lity of hospital-based health care personnel to varicella-zoster virus infections. Am J Infect Control 1989; 17:26-30.
14. Nettleman MD, Schmid M. Controlling varicella in the healthcare setting: The cost effectiveness of using varicella vaccine in healthcare workers. Infect Control Hosp Epidemiol 1997; 18:504-508.
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