Occupational risk of the acquired immunodeficiency syndrome among health care workers

In August 1983, we initiated nationwide prospective surveillance of health care workers with documented parenteral or mucous-membrane exposures to blood or other body fluids of patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related illnesses. The purpose of the surveillance project is to quantitate prospectively the risk to health care workers of acquiring the AIDS virus, human T-cell lymphotropic virus Type III/lymphadenopathy-associated virus (HTLV-III/LAV), as a result of occupational exposures. By December 31, 1985, 938 health care workers were being followed in the surveillance project. The mean length of follow-up was 15 months (range, 0 to 56) and 531 health care workers (57 percent) had been followed for more than one year. Needlestick injuries and cuts with sharp instruments accounted for 76 percent of the exposures. Over 85 percent of all exposures were to blood or serum. None of the health care workers have acquired signs or symptoms of AIDS. Analyses of T-lymphocyte subsets were performed for 341 (36 percent) of the exposed health care workers, and tests for antibody to HTLV-III/LAV were performed for 451 (48 percent). Seven health care workers who had low helper/suppressor T-lymphocyte ratios on initial testing were retested; only three had persistently low ratios. Only two health care workers tested were seropositive for antibody to HTLV-III/LAV. The results of this surveillance project, thus far, suggest that the risk to health care workers of occupational transmission of HTLV-III/LAV is low (the upper bound of the 95 percent confidence interval for the seroprevalence rate among workers with greater than or equal to 3 months of follow-up with HTLV-III/LAV antibody testing is 1.65 percent) and appears to be related to parenteral exposure to blood.     

Risk and management of blood-borne infections in health care workers

Exposure to blood-borne pathogens poses a serious risk to health care workers (HCWs). We review the risk and management of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections in HCWs and also discuss current methods for preventing exposures and recommendations for postexposure prophylaxis. In the health care setting, blood-borne pathogen transmission occurs predominantly by percutaneous or mucosal exposure of workers to the blood or body fluids of infected patients. Prospective studies of HCWs have estimated that the average risk for HIV transmission after a percutaneous exposure is approximately 0.3%, the risk of HBV transmission is 6 to 30%, and the risk of HCV transmission is approximately 1.8%. To minimize the risk of blood-borne pathogen transmission from HCWs to patients, all HCWs should adhere to standard precautions, including the appropriate use of hand washing, protective barriers, and care in the use and disposal of needles and other sharp instruments. Employers should have in place a system that includes written protocols for prompt reporting, evaluation, counseling, treatment, and follow-up of occupational exposures that may place a worker at risk of blood-borne pathogen infection. A sustained commitment to the occupational health of all HCWs will ensure maximum protection for HCWs and patients and the availability of optimal medical care for all who need it.     

Risk of needle stick injuries in health care workers - a report

Health care workers (HCW) are at a risk of occupational acquisition of Human Immunodeficiency Virus (HIV) infection, primarily due to accidental exposure to infected blood and body fluids. In our general public hospital, over a period of one year (June 2000 - 2001) a total number of 38 self reported incidences of needlestick injuries and other exposures to patient's blood and body fluids were reported by HCWs. A greater incidence of occupational exposure was seen in surgery residents as compared to medicine residents. Till date, i.e. in one and a half-year follow up period, no seroconversion was seen in any of the reported accidental injury cases. This data emphasizes, that needle stick injuries present the single greatest risk to medical personnel and the importance of increased awareness and training in universal safety precautions (USP), for prevention of nosocomial infection.     

Knowledge,attitude and practices of health personnel with regard to HIV/AIDS in Tamatave (Madagascar)

BACKGROUND: Health care workers are key players in the prevention and management of HIV-infection. We surveyed HIV/AIDS-related knowledge, attitudes and practices of health care workers in Tamatave (Madagascar), to assess the feasibility of voluntary counselling and testing for HIV infection in antenatal care. MATERIALS AND METHOD: A Knowledge Attitude and Practice study was conducted during July 2000 in the antenatal health care centres and the hospital of Tamatave. The health workers completed a self-administrated questionnaire on HIV transmission, attitudes and practices regarding AIDS testing and counselling, HIV risk perception and attitudes regarding patients with HIV disease. RESULTS: A 90% response rate was obtained, with completed questionnaires from 45 health care workers. The sample included physicians, midwives, nurses, medical students and nursing auxiliaries. Scientific knowledge about transmissibility of HIV infection was poor: transmission was believed possible by living together without having sex (7%), by breastfeeding a HIV-positive child (9%), by using toilets after a HIV-positive patient (13%) and by blood donation (76%). 73% of the health staff believed a child born of an HIV-positive woman would systematically be infected and interventions to reduce this risk were unknown. Sixty one per cent of the health-workers reported never having advised patients to be tested and less then 10% mentioned correct counselling precautions. Seventy nine percent believed that they were at risk of acquiring AIDS, mainly through occupational exposure. Negative attitudes towards HIV-positive patients were also noted: twenty per cent of the health workers mentioned that AIDS patients should be isolated in quarantine. Physicians and paramedical staff differed only in their better knowledge about transmissibility of HIV. Physicians had the same restrictive attitude towards patients with HIV as paramedical health workers and did not differ by their counselling practice. CONCLUSIONS: Our study revealed gaps in the knowledge of health care workers about HIV infection. Before implementing voluntary counselling and testing in antenatal care, additional HIV/AIDS training for health staff seems necessary.     

Recommended infection-control policies for patients with human immunodeficiency virus infection. An update

HIV is not readily transmitted to health care workers, even after accidental parenteral exposure to infected blood. Existing guidelines for reducing exposure to blood and other body fluids will protect workers who care for patients infected with this pathogen. New infection-control guidelines for patients with AIDS are therefore not required. Awareness of the potential for nosocomial transmission of HIV has resulted in a renewed respect for the principles and practice of infection control. The procedures that the task force recommended to prevent contact with body fluids will reduce exposure not only to HIV but also to other potentially contagious pathogens in the health care environment. Implementation and enforcement of these guidelines for all patients could greatly reduce the incidence of nosocomial and occupationally acquired infections.     

Human parvovirus B19 infection among hospital staff members after contact with infected patients

In the spring and summer of 1988, two separate outbreaks of an illness with a rash resembling erythema infectiosum occurred among members of the nursing staff of the Children's Hospital of Philadelphia. The sources were two adolescent patients with sickle cell disease and aplastic crisis who had unsuspected parvovirus infection. Tests for IgM and IgG antibodies to parvovirus B19 were positive in both patients, and electron microscopical examination showed parvovirus-like particles in the early serum samples. Of 40 health care workers exposed to infected patients, 12 (30 percent) were infected, 2 (5 percent) were possibly infected, 8 (20 percent) had evidence of a past infection with B19, and 18 (45 percent) remained seronegative. Attack rates among the susceptible contacts were 36 percent in the first outbreak and at least 38 percent in the second. Clinical symptoms began a mean of 12.6 days after exposure and included malaise, rash, and joint pain. We conclude that hospital workers are at risk of contracting nosocomial erythema infectiosum from patients with parvovirus-associated aplastic crisis. We recommend that all patients with hereditary hemolytic anemias who are admitted with a febrile illness be evaluated for aplasia and promptly placed in respiratory and contact isolation if aplastic crisis is suspected.     

Incidence of visits for health care worker blood or body fluid exposures and HIV postexposure prophylaxis provision at Rhode Island emergency departments

OBJECTIVES: To compare the incidence and types of emergency department (ED) visits for blood or body fluid exposures sustained by health care workers (HCWs) in Rhode Island and to identify factors predictive of HIV postexposure prophylaxis (PEP) utilization for these exposures. METHODS: A retrospective study of ED visits for blood or body fluid exposures to all Rhode Island EDs from January 1995 to June 2001 was conducted. Average incidence rates (IRs) of visits by HCW occupation and type of exposure were estimated and compared. Logistic regression models were created to determine which HCWs were more likely to be offered and to accept HIV PEP. RESULTS: Of 1551 HCW ED visits for occupational exposures, 72.5% sustained a percutaneous injury and only 2.5% were exposed to a source known to be HIV-infected. Hospital custodians had the highest IR of ED visits for percutaneous injuries (81 ED visits per year per 10,000 workers). Visits for all exposures increased over the study years and were most common during March, on weekends, and at 5:00 PM. Of all HCWs, 91.2% presented within 24 hours of their exposure and 98.2% presented within 72 hours. HIV PEP was offered to 469 HCWs and accepted 229 times. HCWs more likely to be offered HIV PEP were exposed to a known HIV-infected source (odds ratio [OR] = 6.38), sustained a significant exposure (OR = 4.98), presented to an academic hospital ED (OR = 2.60), were a member of the medical staff (OR = 2.02), and were exposed during the latter years of the study (OR = 1.23). HCWs were more likely to accept HIV PEP when it was offered if they were male (OR = 1.64) and presented to an academic hospital ED (OR = 2.72). CONCLUSIONS: The IRs of ED visits for exposures varied by occupation, and there were clear temporal trends for these visits. Despite the existence of federal guidelines for HIV PEP for occupational blood or body fluid exposures, factors other than characteristics of the exposure, such as type of hospital, occupation, and gender, may be influencing HIV PEP utilization.     

A look-back investigation of patients of an HIV-infected physician. Public health implications

BACKGROUND. Transmission of the human immunodeficiency virus (HIV) to five patients receiving care from an HIV-infected dentist in Florida has recently been reported. Current data indicate that the risk of HIV transmission from health care workers to patients is low. Despite this low risk, programs to notify patients of past exposure to an HIV-infected health care worker are being conducted with increasing frequency. METHODS. We recently conducted an investigation of all the patients cared for by an HIV-infected family physician during a period when he had severe dermatitis caused by Mycobacterium marinum on his hands and forearms. After reviewing the patients' records, we notified 336 patients who had undergone one or more procedures (digital examination of a body cavity or vaginal delivery) placing them at potentially increased risk of HIV infection. The patients were offered tests for HIV infection and counseling. RESULTS. Of the 336 patients, 325 (97 percent) had negative tests for HIV antibody, 3 (1 percent) refused testing, 1 (less than 1 percent) died of a cause unrelated to HIV infection before notification, and the HIV-antibody status of 7 (2 percent) remained unknown. The direct and indirect public health costs of this investigation were approximately $130,000. CONCLUSIONS. The results of this investigation raise important questions about the risk of HIV transmission from health care workers to patients and the usefulness of HIV look-back programs, particularly in the light of recently published recommendations from the Centers for Disease Control. We propose that before a look-back investigation is undertaken, there should be a clearly identifiable risk of transmission of the infection, substantially higher than the risk requiring limitation of an HIV-infected health care worker's practice prospectively.     

HIV‐1 seroconversion promotes rapid changes in cervical human papillomavirus (HPV) prevalence and HPV‐16 antibodies in female sex workers

The extent to which human immunodeficiency virus (HIV‐1) infection impacts on the ability to mount an effective immune response to HPV is unknown, but is relevant in planning HPV vaccine strategies for HIV‐1 infected individuals. This longitudinal study investigated changes shortly after HIV‐1 seroconversion on cervical HPV types and HPV‐16 antibody responses in serum and at the cervix of female sex workers. Typing of HPV DNA from cervical cells was done prior to HIV‐1 seroconversion and within 1 year and greater than 2 years after HIV‐1 seroconversion. Antibody determinations on serum and cervico‐vaginal rinse samples were by HPV‐16 virus‐like particle‐based, enzyme‐linked immunosorbent assay. Of 104 women tested, 40 (38.4%) became HIV‐1 seropositive (HIV‐positive) during the course of the study. Shortly after HIV‐1 seroconversion a significant increase in multiple (>1) HPV infection (OR 4.0, 95% CI 1.3–11.9) was observed compared with HIV‐1 seronegative (HIV‐negative) women and certain changes in HPV type infection. HIV‐1 seroconversion resulted in a reduced prevalence of serum HPV‐16 IgA and cervico‐vaginal IgA and IgG but an increased prevalence of serum HPV‐16 IgG. All HIV‐positive women had been exposed to HPV‐16 as all displayed serum HPV‐16 IgG. Serum HPV‐16 responses were maintained at a high magnitude in the presence of HPV‐16 infection irrespective of HIV infection, but decreased in the absence of HPV‐16 infection. In conclusion, HIV‐1 seroconversion in sex workers rapidly increased cervical HPV infection and caused a reduced ability to produce cervical HPV‐16 antibodies but a continued ability to generate serum IgG antibodies. J. Med. Virol. 81:203–210, 2009. © 2008 Wiley‐Liss, Inc.     

Occupational risk of exposure to blood in nurses. Results of a one-year monitoring of the risk for nurses in 17 hospitals]

To evaluate the incidence of risk factors for exposure of health care providers to patients' blood, a prospective multicenter study was carried out in 1990 in 17 hospitals in continental France. 521 nurses from 20 departments of medicine and 9 intensive care nurses participated in the study. Trained investigators documented exposures to blood using a standardized questionnaire and carried out monthly 24 hours cross-sectional surveys to determine the number of high risk procedures performed on a given day. One hundred and eighty-three exposures to blood were documented, for an incidence of 0.35/nurse/year. Needle-stick injuries were the most common events (75%). Exposure to blood occurred during a sampling procedure in 48% of cases, an infusion-related procedure in 20% of cases, and an injection in 17% of cases. Comparisons of rates of procedures associated with needle-stick injuries and of procedures performed during a typical day demonstrated differences in the magnitude of the risk associated with each procedure: infusion-related procedures carried the greatest risk, followed by venous blood sampling procedures. Sixty-four percent of exposures to blood occurred after completion of the procedure. Forty-nine percent of documented exposures to blood would probably not have occurred if universal infection control recommendations (CDC, DGS) had been implemented. Twenty-seven percent of exposures to blood involved HIV-positive patients, who accounted for only 7% of patients managed in the participating centers during the study period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Human immunodeficiency virus infection among employees in an African hospital

To define the prevalence and course of human immunodeficiency virus (HIV) infection, we examined prospectively a cohort of 2002 adult hospital workers in Kinshasa, Zaire. From 1984 to 1986 the prevalence of HIV infection increased from 6.4 percent to 8.7 percent. Over the two years there was a cumulative incidence of new HIV infection of 3.2 percent. The prevalence was higher among women (16.9 percent) and men (9.3 percent) under the age of 30 than among women (9.0 percent) and men (6.2 percent) over 30. Prevalence rates were similar among physicians (5.6 percent), laboratory workers (2.9 percent), and clerical workers (7.9 percent), but they were higher among female nurses (11.4 percent) and manual workers (11.8 percent). Despite marked differences in the intensity of nosocomial exposure, female nurses had similar infection rates on the female internal medicine ward (9.9 percent), in pediatrics (10.8 percent), and in the delivery room (10.7 percent). The attributable risk of HIV infection from a transfusion was 5.9 percent. Neither medical injections nor scarification was a risk factor for HIV infection. Of the 101 seropositive asymptomatic employees in the 1984 survey, 16 percent had AIDS-related complex, 3 percent had AIDS, and 12 percent had died of AIDS by 1986. Previous studies have revealed a seroprevalence of 8.4 percent among women attending an antenatal clinic near the hospital in 1984 and 1986, and of 5.8 percent (in 1984) and 6.5 percent (in 1986) among men donating blood at the hospital's blood bank. We conclude that there is a continuing high prevalence of HIV infection among hospital workers in Kinshasa, Zaire, which appears to be representative of that in the community and not nosocomial.     

Cytomegalovirus and child day care. Evidence for an increased infection rate among day-care workers

To determine whether day-care workers acquire cytomegalovirus infection from the children they care for, we studied 610 women employed at 34 day-care centers over two years. Forty-one percent of the caretakers were seropositive for cytomegalovirus. After adjustment for the effects of race, marital status, and age on seropositivity, the women who cared for children younger than two years of age had a significantly higher seropositivity rate (46 percent) than the women who cared for children older than two years of age (35 percent) (relative risk, 1.29; 95 percent confidence interval, 1.05 to 1.57; P less than 0.02). Of 202 initially seronegative caretakers (observed for an average of 305 days per woman), 19 seroconverted, for an annual seroconversion rate of 11 percent. This rate was significantly higher than the 2 percent annual rate of seroconversion among 229 seronegative women (11 of whom seroconverted) in a comparison group of female hospital employees observed for an average of 781 days per woman (relative risk, 5.0; 95 percent confidence interval, 2.4 to 10.5; P less than 0.001). At three day-care centers in which the children were also studied, seven of the nine women shed isolates of cytomegalovirus in their saliva or urine that had EcoRI and BamHI DNA-digestion patterns identical to the DNA patterns of isolates shed by one or more children in their care. We conclude that workers in day-care centers may acquire cytomegalovirus infection from the children in their care and that this risk is significantly greater among those who care for children less than two years of age.     

Reduction of Diagnostic Window by New Fourth-Generation Human Immunodeficiency Virus Screening Assays

In order to reduce the diagnostic window between the time of human immunodeficiency virus (HIV) infection and laboratory diagnosis, new screening enzyme-linked immunosorbent assays (ELISAs) which permit the simultaneous detection of HIV antigen and antibody have been developed. Two fourth-generation assays, HIV DUO (Biomérieux) and HIV Combi (Boehringer Mannheim), for the combined detection of HIV antigen and antibody, were compared with a third-generation assay (HIV-1/HIV-2 3rd Generation Plus enzyme immunoassay [EIA]; Abbott) and a p24 antigen test (HIV-1 Ag monoclonal; Abbott). A total of 17 seroconversion panels, 15 cell culture supernatants infected with different HIV type 1 (HIV-1) subtypes, and 255 potentially cross-reactive serum samples were tested. Ten seroconversions were detected an average of 8.1 days earlier with HIV DUO and 7.5 days earlier with HIV Combi than with the third-generation ELISA. Overall, in the 17 seroconversion panels tested, HIV DUO detected HIV-1 infection an average of 4.8 days and HIV Combi detected infection an average of 4.4 days earlier than HIV-1/HIV-2 3rd Generation Plus EIA. HIV antigen was detected with HIV DUO and HIV Combi in all of the 15 cell culture supernatants infected with different HIV-1 subtypes, including subtype O. With fourth-generation assays, considerably fewer false-positive results (n = 4 to 6) were obtained, in comparison with the third-generation EIA (n = 18). Fourth-generation assays permit an earlier diagnosis of HIV infection than third-generation antibody screening assays through the detection of p24 antigen, which may be present in serum samples from individuals with recent HIV infection prior to seroconversion.     

Low occupational risk of human immunodeficiency virus infection among dental professionals

We studied 1309 dental professionals (1132 dentists, 131 hygienists, and 46 assistants) without behavioral risk factors for the acquired immunodeficiency syndrome (AIDS) to determine their occupational risk for infection with human immunodeficiency virus (HIV). Subjects completed questionnaires on behavior; type, duration, and location of their dental practice; infection-control practices; and estimated numbers of potential occupational exposures to HIV. Serum samples were tested for antibodies to HIV and to hepatitis B surface antigen (unvaccinated subjects). Fifty-one percent of the subjects practiced in locations where many cases of AIDS have been reported. Seventy-two percent treated patients who had AIDS or were at increased risk for it. Ninety-four percent reported accidental puncturing of the skin with instruments used in treating patients. Adherence to recommended infection-control practices was infrequent. Twenty-one percent of unvaccinated subjects had antibodies to hepatitis B surface antigen. Only one dentist without a history of behavioral risk factors for AIDS had serum antibodies to HIV. We conclude that despite infrequent compliance with recommended infection-control precautions, frequent occupational exposure to persons at increased risk for HIV infection, and frequent accidental puncturing of the skin with sharp instruments, dental professionals are at low occupational risk for HIV infection.     

The incubation period of acute retroviral syndrome as a multistep process: a parametric survival analysis

A long duration of acute retroviral syndrome (ARS) and a short incubation of ARS (IncARS) are independent predictors of a fast progression to AIDS. The first objective of this study was to validate previous estimates of IncARS by comparing durations between health care workers (HCWs) accidentally infected by HIV and individuals infected by other routes (non-health care workers [N-HCWs]). The second objective was to use parametric survival models to generate hypotheses on various steps occurring during the IncARS. Data from a prospective cohort of patients with documented ARS and from individuals with ARS as the result of accidental exposure to HIV were analyzed. Nonparametric and parametric survival models were used to describe the incubation of ARS. No differences were found for the median IncARS between 34 HCWs (21.5 days) and 70 N-HCWs (21.5 days) (log-rank test, P = 0.72). According to survival models, IncARS can be modeled with a gamma and/or lognormal model with means of 26.4 days and 26.7 days, respectively. The gamma model suggests that 3 sequential stages are present during the IncARS, which is compatible with basic science investigations identifying crossing of the epithelial barrier by the virus, the virus-host cell interactions, and the viral systemic dissemination.     

Unrecognized human immunodeficiency virus infection in emergency department patients

To determine the extent of unrecognized human immunodeficiency virus (HIV) infection, we examined blood samples drawn from patients presenting to an inner-city emergency department. We found 119 of 2302 consecutive adult patients (5.2 percent) to be seropositive for HIV. Although 27 patients presented with known symptomatic HIV infection, 92 of the remaining 2275 patients (4.0 percent) had unrecognized HIV infection. The highest seroprevalence rate (11.4 percent) was found among black men 30 to 34 years of age. Blacks, other nonwhites, and patients under the age of 45 had high rates of unrecognized infection. The clinical team established risk-factor status in only 29.0 percent of the patients. Of the 276 patients with identified risk factors, 13.0 percent were seropositive, whereas 3.1 percent of the 1616 patients with unknown risk-factor status were seropositive. None of the 102 patients who reported no risk factors were seropositive. Although penetrating trauma (seroprevalence, 13.6 percent) was the only clinical presentation associated with an increased seroprevalence rate independent of other known predictors of infection (P = 0.02), seropositive patients were found in all categories of clinical condition. These data, although based on observations in one emergency department setting, support the concept of universal blood and body-fluid precautions by all health care workers whether or not HIV infection is known.     

Intrahost genetic variability of human herpes virus‐8

Studies were conducted to determine whether HHV‐8 hyperactivity could be the consequence of the propensity of the host to multiple HHV‐8 infection. The aim of the present work was to investigate HHV‐8 intrahost genetic variability. HHV‐8 subgenomic DNA was amplified by PCR from patients infected with HIV, health care workers (HCW) and bone marrow transplant recipients (BMT), and from oral lesional tissues of AIDS‐Kaposi's sarcoma (KS) patients. As controls, blood from HIV‐negative health care workers, and the cell lines BC‐1, BC‐2, and BCP‐1 were used. Clones derived from amplicons originating from DNA fragments in open reading frame (ORF) 26 and ORF K1 were isolated. For each ORF, intra‐specimen nucleotide sequence differences were determined. The extent of HHV‐8 variation in clones derived from blood of patients infected with HIV was significantly higher than in blood from health care workers or post‐bone marrow transplantation patients or in AIDS‐KS tissue. Among the clones derived from the latter three categories of specimens, sequence variations were not significant. It is concluded that HIV‐infected individuals can have multiple of HHV‐8, but AIDS‐KS lesions are associated with infection by a single HHV‐8 variant or a small group of related variants. J. Med. Virol. 85:636–645, 2013. © 2013 Wiley Periodicals, Inc.     

Case report: risk of virus infection after accidental blood inoculation from a multi-infected AIDS patient

Infections caused by blood-borne viruses such as hepatitis B and C and the human immunodeficiency virus (HIV) are associated commonly with needlestick injuries, especially in a hospital setting. A prospective investigation was conducted on a medical doctor who suffered an accidental needlestick injury during blood collection from a patient with AIDS. The patient's blood contained 195,000 copies of HIV RNA, 1 × 10(6) IU hepatitis C virus (HCV) RNA, and >10(7) copies of parvovirus B19 DNA per 1 ml plasma. It was positive for cytomegalovirus virus and evidence of a resolved hepatitis B virus (HBV) infection was found. HCV viremia was detected in the physician 15 days later and was not resolved by seroconversion after 57 days. HIV infection was not transmitted, possibly because of the immediate use of anti-HIV prophylactic drugs after exposure. Parvovirus B19 infection was presumably prevented by pre-existing specific antibodies in the patient. Considering that many HIV carriers are coinfected with hepatitis B and C viruses, this case report support the knowledge that the risk of HCV transmission from a patient with AIDS is greater than that of HIV.     

Tuberculosis at the end of the twentieth century

Tuberculosis has once again emerged as a significant public health problem in Western countries. Much of the rise has been fueled by the growing numbers of persons infected with HIV. Co-infection withMycobacterium tuberculosis and HIV has been shown to result in high rates of active tuberculosis, and possibly in acceleration of progression to AIDS. Primary tuberculosis occurs at high rates among dually infected persons, further emphasizing the need for effective isolation of infectious cases. Recent preliminary studies have demonstrated that the survival of persons with multidrug-resistant tuberculosis can be six months and longer, far in excess of the 4 to 12 weeks reported previously. At least seven health care workers have died of occupationally-acquired multidrug-resistant tuberculosis, making control of the spread of tuberculosis in health care settings an urgent public health priority.