Risk of cytomegalovirus infection in nurses and congenital infection in their offspring

Primary Cytomegalovirus Infection in Pediatric Nurses: A Meta-Analysis

A meta-analysis of six controlled studies was performed to evaluate the risk of cytomegalovirus (CMV) infection among pediatric nurses. The pooled risk ratio for CMV infection in pediatric nurses using cumulative incidence data was statistically significant (risk ratio [RR] 2.7; 95% confidence interval [CI] 1.33 - 5.52), but person-year analysis taking account of follow-up periods demonstrated a trend toward increased risk that failed to reach statistical significance (RR 1.8; 95% CI 0.88 - 3.55). Despite pooling, there was low statistical power for comparing person-year rates. The studies included in this analysis failed to provide data on several potential confounding variables. We conclude that studies published prior to the widespread adoption of universal precautions suggest that pediatric nurses may have been at increased risk for CMV infection due to occupational exposure, but inadequate design and sample size of the studies prevent a definitive conclusion. Well-designed, controlled studies are still needed to define the occupational risk of CMV infection.

Cytomegalovirus seroprevalence in exposed and unexposed populations of hospital employees

The objective of this work was to compare the seroprevalence of cytomegalovirus in an unexposed and exposed population, both working in a hospital, and to study the occupational risk factors related to seropositivity, while taking personal risk factors into account. We conducted a cross-sectional study in a French hospital over a period of 12 months. The overall seroprevalence among the 550 subjects was 49.5%. The multivariate analysis showed that seropositivity was significantly associated with age (36-43 years: odds ratio [OR] = 1.7; 95% confidence interval [CI]: [1.1-2.8]) and working as a pediatric nurse's aide (OR = 1.8; 95% CI: [1.1-2.8]). This study confirms the need to improve prevention procedures in the workplace, including screening, information, and hygiene rules.

[Review and guidelines on the prevention, diagnosis and treatment of post-natal cytomegalovirus infection]

Postnatal cytomegalovirus (CMV) infection in the newborn can occur from exposure to maternal cervical secretions during birth, ingestion of breast milk, transfusion of blood products or transmission by body fluids of infected people. Breast milk is the main source of infection, given the high rate of CMV-positive mothers excreting CMV in milk. Freezing reduces the risk of CMV transmission by breastfeeding, although it does not eliminate it completely. Pasteurisation prevents such transmission, but it can alter the immunological properties of breast milk. Postnatal CMV infection is usually asymptomatic, as it normally results from viral reactivation in the mother, and the neonate is born with protective antibodies. However, in the very low birth weight premature infant the amount of transferred antibodies is smaller and a symptomatic infection can occur. Symptomatic post-natal CMV infection in the newborn typically causes hepatitis, neutropenia, thrombocytopenia or sepsis-like syndrome. Pneumonitis and enteritis are less common, but very characteristic. Diagnosis is based on urine virus detection at the time of onset of symptoms. Postnatal CMV infection in the newborn generally resolves spontaneously without antiviral treatment. Ganciclovir should be reserved for severe cases. Unlike congenital CMV disease, post-natal CMV infection in the preterm infant does not seem to be associated with hearing loss or abnormal neuro-development in long term follow-up.

Primary cytomegalovirus infection in pediatric nurses: a meta-analysis

A meta-analysis of six controlled studies was performed to evaluate the risk of cytomegalovirus (CMV) infection among pediatric nurses. The pooled risk ratio for CMV infection in pediatric nurses using cumulative incidence data was statistically significant (risk ratio [RR] 2.7; 95% confidence interval [CI] 1.33 - 5.52), but person-year analysis taking account of follow-up periods demonstrated a trend toward increased risk that failed to reach statistical significance (RR 1.8; 95% CI 0.88 - 3.55). Despite pooling, there was low statistical power for comparing person-year rates. The studies included in this analysis failed to provide data on several potential confounding variables. We conclude that studies published prior to the widespread adoption of universal precautions suggest that pediatric nurses may have been at increased risk for CMV infection due to occupational exposure, but inadequate design and sample size of the studies prevent a definitive conclusion. Well-designed, controlled studies are still needed to define the occupational risk of CMV infection.

Cytomegalovirus infection in day care centers in Rome, Italy: viral excretion in children and occupational risk among workers

From nine day care centers in Rome, Italy, 253 children of middle to low socioeconomic classes were examined for cytomegalovirus (CMV) excretion in saliva. The overall excretion rate was 13%, with no marked differences between centers. Socioeconomic level, age of enrollment, chronological age, length of attendance, and number of siblings did not have any discernible influence on viral shedding. The most notable result is that during the second year of age, 100% of the excretors had been breast fed, but only 60% in the third year, indicating that maternal transmission is the most likely source of children's infection early in life. Serologic survey of 82 female workers in day care centers, 82 matched housewives, and 229 female students aged 14 to 18 years who were in training to care for children showed that at 14 years of age the CMV seropositivity rate is 85, which suggests that primary infection during childbearing age is an uncommon event in Rome.

Factors associated with cytomegalovirus excretion in hospitalized children

Hospital employees, especially pregnant women, have expressed concern over exposure to patients excreting cytomegalovirus (CMV). However, the vast majority of CMV excreters are asymptomatic and are not identified while hospitalized. As part of a 2-year, longitudinal study of nosocomial transmission of CMV in a children's hospital, the prevalence rates of CMV excretion by patients in different areas of the hospital were determined. The average prevalence rates were neonatal intensive care unit, 5.7%; intermediate care nurseries, 4%; premature nursery, 6.3%; normal newborn nursery, 3%; hematology-oncology, 3.7%; pediatric intensive care unit, 3.6%; general pediatric ward, 6%; and a chronic care unit, 16%. During this 2-year study, 315 patients admitted to the chronic care unit were investigated to determine which clinical factors might help predict children likely to excrete CMV. With the use of multiple logistic regression analysis of variables, prior excretion of CMV, multiple hospital admissions, female sex, and Hispanic ethnic background were correlated with excretion. Although not identified as significant factors, a history of premature, bronchopulmonary dysplasia and positive results of CMV serologic studies were more commonly associated with excretion. CMV excretion occurred in all areas within a children's hospital, and certain factors were associated with excretion, but it is unlikely that this information could adequately identify "safe" patients or safe areas within a hospital. This study reinforces the need to follow proper precautions with all patients.

Cytomegalovirus infection in pediatric house officers: susceptibility to and rate of primary infection

Hospital personnel, especially women in their child-bearing years, continue to express concern about the risk of acquiring cytomegalovirus (CMV) infection as a result of their occupation. Previous investigations of occupational risk of CMV infection have focused primarily on pediatric nursing personnel. However, assessment of the rate of CMV infection by other hospital personnel who have different clinical responsibilities and levels of patient contact cannot rely solely on the rates obtained for nursing personnel.

Cytomegalovirus: epidemiology and infection control

Cytomegalovirus (CMV) causes asymptomatic infection in most individuals but can produce devastating illness in immunocompromised hosts and in a small proportion of congenitally infected babies. New techniques in molecular biology have provided insights into the epidemiology and transmission of CMV. Children in day care, their parents, and sexually active individuals, especially homosexual men, are now known to be at particular risk for acquiring CMV. Recent studies show that the risk of CMV acquisition by health care workers is similar to the risk to the general public. Health care workers should be aware of the wide range of clinical manifestations, methods of laboratory diagnosis, and current limitations of treatment of CMV. Careful handwashing and avoidance of excretions and secretions are recommended to decrease the transmission of CMV in the hospital.

Comparative efficacy of handwashing agents against cytomegalovirus

Conscientious handwashing is often recommended as an important method for limiting transmission of cytomegalovirus (CMV) from infected individuals to health, education, and child care professionals. To assess the efficacy of handwashing, fingertips of radiation-sterilized latex gloves were inoculated with 0.2 mL of ten different CMV strains. Virus in each inoculum was quantitated by plaque assay. After five minutes, viral inocula were allowed to remain (control), or were washed away by dropwise application of 10 mL of distilled water (DI), 5 mL of 0.08% soap followed by 5 mL of DI, 5 mL of 0.01% chlorhexidine gluconate followed by 5 mL of DI, or 5 mL of 0.025% povidone-iodine solution followed by 5 mL of DI. Separate glove fingertips were sampled 5, 15, 30, 60, 120 and 240 minutes after washing and cultured in duplicate for CMV. Similar studies were performed using human cadaver skin. Ordinary soap was as effective at preventing CMV recovery as other more expensive agents. For inocula with less than 5 log10 pfu CMV/mL, washing with water alone was as effective as other agents. This was confirmed in similar studies with human hands using five CMV stains. Handwashing is probably an effective method for removing CMV from contaminated hands.

Cytomegalovirus infections: occupational risk for health professionals

Health care personnel are becoming increasingly aware of potential hazards associated with caring for patients with contagious diseases. The cytomegalovirus is of special concern, because infection with this virus in a pregnant female employee could be associated with significant neurologic injury in her fetus. Nosocomial transmission from patient to health care worker has not been documented. A review of cytomegalovirus excretion in hospitalized patients and prospective evaluations of primary infection in hospital personnel do not support frequent occurrence of cytomegalovirus infection despite ample opportunity for exposure. Adherence to proper isolation techniques should be adequate to prevent nosocomial transmission of the cytomegalovirus.

Is primary cytomegalovirus infection an occupational hazard for obstetric nurses? A serological study

The results are reported of a 4-year prospective study of the incidence of primary cytomegalovirus (CMV) infection in the nursing staff of a specialist obstetric hospital. The absence of seroconversion found in personnel attending patients with confirmed CMV-infection justifies reassuring staff members in "high-risk" areas of the adequacy of the methods used to combat cross-infection. On the other hand, a low rate of seroconversion (1.2% per annum) in the staff who nurse normal mothers and "rooming-in" babies emphasizes the need for the rigorous observance of hygienic precautions by all personnel in all areas. The results of this Australian investigation are discussed in relation to the northern hemisphere experience of CMV-seroconversion in pediatric nurses.

Prevalence of cytomegalovirus antibody in nursing personnel

To evaluate the risk to nurses of childbearing age of acquiring cytomegalovirus (CMV) infection during the care of patients at high risk of the infection, 374 female hospital employees (288 nursing personnel) were interviewed and screened for antibody to CMV. Fifty-six percent of the population surveyed had antibody to CMV as measured by an immunofluorescent assay. Among nursing personnel, analysis of antibody prevalence by job title, work area, and duration of work showed no association between seropositivity and either current or past exposure to "high-risk" patients, such as infants and immunosuppressed individuals. Age, race (non-white), and the number of pregnancies reported by participants were significantly associated with the presence of antibody. Among 73 employees of a children's hospital, the prevalence of CMV antibody was 41%. This survey suggests that hospital nursing is not a major risk factor for acquiring CMV infection. However, this finding needs further evaluation in a prospective study of seroconversion rates among seronegative nurses.

Caring for the infectious patient: risk factors during pregnancy

Health care personnel are exposed to infectious diseases in the community as well as in the health care setting when they care for patients with transmissible conditions. Pregnant nurses, physicians and others face an additional risk--that of exposing their unborn children to some of these infections. Risk factors vary greatly between diseases and it is, therefore, important that each be evaluated and acted upon realistically. We will discuss and compare the risk of infections such as hepatitis, cytomegalovirus, tuberculosis, chickenpox, and others. With this knowledge, administrators and personnel involved will be able to make decisions about which patients should not be cared for by pregnant personnel, and which areas pose too high a risk for the mother and child so that a temporary transfer may be advisable. We address the multiplicity of preventive measures available for the prevention of maternal infections.

The acquired immune deficiency syndrome: an international health problem of increasing importance

The Acquired Immune Deficiency Syndrome (AIDS) is a new disease which first appeared in human populations about 1979. The disease is defined by the development of unusual types of cancer (e.g. Kaposi's sarcoma), or severe cellular immunodeficiency manifested by opportunistic infections (e.g. Pneumocystis carinii infection), or both. Although the etiology of AIDS is unknown, the epidemiologic evidence is consistent with an infectious agent transmitted by blood (e.g. transfusion, needle sharing) or sexual intercourse. Over three-quarters of the cases have been in homosexual or bisexual males and in intravenous drug abusers; about 5% of cases do not have recognized risk factors. A small number of cases have resulted from transfusion of blood or blood products. The early clinical manifestations are non-specific, and may include asymptomatic skin lesions, dyspnea and dry cough, weight loss, chronic diarrhea, and focal and non-focal central nervous system findings. Treatment for the associated cancers and opportunistic infections may be successful in individual instances, but the underlying immunosuppression of AIDS appears to progress inexorably and the fatality rate approaches 100% within a few years from diagnosis. Although nosocomial transmission has not been documented, infection control guidelines have been developed by analogy with hepatitis B infection.

Occupational risk for primary cytomegalovirus infection among pediatric health-care workers

The risk of acquiring cytomegalovirus (CMV) from infected infants concerns pediatric health-care workers, particularly those who may be pregnant. We determined the prevalence of CMV antibody, and thus of past infection, in groups of medical students and house staff, nurses, and physicians, and in groups of pregnant and nonpregnant young women in the community. Although age, sex, and race influenced the results, occupation did not. We then estimated the exposure of the health-care workers by determining the prevalence of CMV infection in three groups of asymptomatic infants for whom they provided care; CMV was shed in urine or saliva of 1.6 per cent of newborns, 13 per cent of premature infants hospitalized for over a month, and 5 per cent of older infants seen in outpatient settings. When we determined the incidence of primary infection in the adult groups by retesting the seronegative members about two years later, we found that the annual attack rates in the medical students (0.6 per cent), house staff (2.7 per cent), and nurses (3.3 per cent) were not higher than in young women in the community (2.5 per cent during pregnancy and 5.5 per cent between pregnancies). We conclude that although pediatric health-care workers frequently and unknowingly care for infants shedding CMV, this occupational contact confers no greater risk than that faced by young women in the community at large.