Journal Reviews
June 1, 1998 5 minutes read
Journal Reviews
Alimonos K, Nafziger AN, Murray J, et al. Prediction of response to hepatitis B vaccine in health care workers: Whose titers of antibody to hepatitis B surface antigen should be determined after a three-dose series, and what are the implications in terms of cost-effectiveness? Clin Infect Dis 1998; 26:566-571.
It is possible to predict which health care workers will have a high probability of developing a protective response to hepatitis B vaccine. For those workers - i.e., nonsmokers who are not overweight - determining post-immunization antibodies to hepatitis B surface antigen (anti-HBs) is neither necessary nor cost-effective, the authors report.
Recommendations currently call for a three-dose series of HBV vaccine followed by assessment of the anti-HBs titer to document response in health care workers. The authors studied the demographics of 385 health care workers to identify those whose chance of developing a protective response to a standard primary hepatitis B immunization series was so high that the need for testing for would be obviated following immunization.
Assessing such criteria as age, height, weight, and whether the person smoked, the authors developed a predictive model for vaccine response.
"Our data suggest that the main risk factor in nonresponse to HBV vaccine is smoking status," the authors conclude. "Age of 50 years [or older], male sex, and increasing body size are also predictive but less so."
However, to avoid the confusion of a two-tiered approach for checking anti-HBs titers, the authors suggest conducting post-exposure testing of the patient and the exposed worker following a blood exposure such as a needlestick. If the patient is HBV-positive, they determined it was cost-effective to treat the worker with immune globulin and one additional dose of HBV vaccine. That approach may be preferable to routinely assessing vaccine response in immunized workers.
"This cost-effective strategy would eliminate any confusion from a two-tiered approach in recommending the checking of anti-HBs titers in only those health care workers who are at risk of nonresponse to hepatitis B vaccine, and it should reduce overall cost of immunization,"the authors report.
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Henderson, DK. Editorial response: Occupa-tional infection with hepatitis B virus - waging war against an insidious, intractable, intolerable foe. Clin Infect Dis 1998; 26:572-574.
While the authors of the above study on hepatitis B vaccine may have found "a reasonable, cost-effective approach to managing reported parenteral exposures in their institution," the study has limitations and should not necessarily be generalized to all institutions, the author of this accompanying editorial notes.
For example, health care workers are notorious for not reporting needlesticks, and workers who assume they are immune to HBV because they have been vaccinated may be less likely to report an exposure, he reminds.
". . . Employees who do not recall such exposures and those who do not report them would reap no benefit of [the author's] immunoglobulin/booster vaccination approach," the author notes. ". . . Whether these results will be generalizable to other institutions and whether this strategy will permit hepatitis B to re-establish a beachhead among health care workers who either experience undetected exposures or fail to report their exposures remain to be determined."
Despite available vaccine and a federal mandate for its use against the bloodborne pathogen, many perplexing questions remain concerning the management of occupational risk for HBV in health care workers.
"Each study that addresses one or more of these questions moves us one step closer to the optimal management of occupational exposures to bloodborne pathogens," the author notes, citing the following examples:
· Why are at-risk health care workers still reluctant to be immunized with the hepatitis B vaccines?
· What interventions are effective in improving health care worker compliance with hepatitis B immunization recommendations?
· How can we improve health care worker reporting of occupational exposures to bloodborne pathogens?
· Since only 90% to 94% of vaccine recipients acquire protective levels of antibody to HbsAg (anti-HBs), should health care institutions routinely determine post-vaccination antibody status for some or all employees?
· What, if anything, can be done to provide protection for vaccine nonresponders?
· Are vaccine nonresponders and hyporesponders at risk for hepatitis B infection? Should nonresponders' health care workplace duties be restricted in any way?
· What is the duration of immunity afforded by the routine series of three doses of recombinant hepatitis B vaccine?
· Should institutions test employees periodically to determine if they have maintained protective levels of anti-HBs? If so, which employees should be evaluated and at what intervals?
· Are booster doses of vaccine needed to protect health care workers whose levels of anti-HBs have declined? If so, at what interval, or at what level of declining antibody, should boosters be administered?
· What is the role of cellular immunity in protection against occupational infection with hepatitis B virus?
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Nivin B, Nicholas P, Gayer M, et al. A continuing outbreak of multidrug-resistant tuberculosis, with transmission in a hospital nursery. Clin Infect Dis 1998; 26:303-307.
The authors report an outbreak of multidrug-resistant tuberculosis in a nursery setting that was apparently a continuation of an earlier nosocomial TB outbreak at the same hospital in New York City.
Seven (29%) of 24 patients described in the investigation may have been exposed in the hospital nursery during an approximate two-week period that ended in January 1993. One possible source case for the nursery exposure was a health care worker with TB who may have been infected during the earlier nosocomial outbreak in 1991. The worker reported being in the nursery only intermittently to sign in for work assignments. The investigators also could not rule out transmission from a TB patient who was admitted to a floor below the nursery but was known to wander the hospital.
It is important to be vigilant in obtaining information about both patients and visitors with regard to symptoms and history of TB, the authors emphasize. The cases included four infants who had a relatively brief period of exposure - an average hospital stay of five days - before developing active disease. Newborn infants are thought to be particularly susceptible to infection with TB because of the paucity of alveolar macrophages in neonatal lungs. The diminished rates of phagocytosis and killing of bacteria by these cells may allow increased microbial replication by bacteria entering the respiratory tract.
The authors cited previous recommendations that an investigation be carried out among nursery personnel and frequent visitors when any child ages 5 months or younger develops active tuberculosis and for whom a source case cannot be found in the household. Employee health services personnel should include nursery staff in monitoring high-risk areas for TB exposure. That must apply to all levels of staff, including those who enter the nursery on an intermittent basis, they conclude.
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