Risk of infection with hepatitis A, B or C, cytomegalovirus, varicella or measles among child care providers

Vaccine-Preventable Infections in Childcare Workers

BACKGROUND

Adequate immunity to so-called childhood diseases can lower the occupational risk of vaccine-preventable infectious diseases in persons who work in day-care centers for children.

METHODS

A systematic literature survey was carried out in PubMed and Embase for the period January 2000 to February 2019. Studies on immune status and vaccination status were included. In addition, data from the first wave of the German Health Interview and Examination Survey for Adults (Studie zur Gesundheit Erwachsener in Deutschland, DEGS1) and surveillance data on notifiable infections in Germany were evaluated.

RESULTS

Six studies and the DEGS1 analysis of vaccination or immune status for varicella zoster, rubella, hepatitis A (HAV), pertussis, measles, and mumps in persons caring for children in day-care centers, most of whom are women, were included in this review. According to DEGS1, childcare workers are more commonly vaccinated against HAV and pertussis than the general female population (prevalence ratios [PR]: 1.46 [1.12; 1.90] and 1.57 [1.05; 2.36]), yet 57% had not been vaccinated against HAV and 77% had not been vaccinated against pertussis. Childcare workers were found to be less commonly vaccinated against rubella than the general female population, although the difference was not statistically significant (PR: 0.87 [0.71; 1.07]). In a Canadian study, positive HAV serology was found to be correlated with the duration of activity as a childcare worker. In the DEGS1 study, large proportions of the younger childcare workers in particular were seronegative against measles (16%), mumps (19%), and HAV (37%). Notifiable disease statistics show that those working in community facilities had a markedly higher risk of mumps, pertussis, and varicella (relative risk [RR]: 1.8-2.6) and a somewhat higher risk of rubella and HAV (RR: 1.47 and 1.21, respectively).

CONCLUSION

Childcare workers have a higher occupational risk of infection but do not always receive the appropriate vaccinations. In particular, women of child-bearing age working in day-care centers should be made more aware of the need for vaccination.

Identifying Health and Safety Risks for Childcare Workers

Childcare workers are exposed to several health and safety risks in their work environment, the most common being infectious diseases, musculoskeletal injuries, accidents, and occupational stress. Pregnant childcare workers have an additional risk of potential harm to the fetus. Occupational health nurses can work collaboratively with childcare workers to reduce these risks and provide workplace health promotion programs. This article explores the occupational health and safety issues for childcare workers and suggests health promotion strategies that could be implemented by occupational health nurses working in this arena.

Are female daycare workers at greater risk of cytomegalovirus infection? A secondary data analysis of CMV seroprevalence between 2010 and 2013 in Hamburg, Germany

Background: Close contact with asymptomatic children younger than three years is a risk factor for a primary cytomegalovirus (CMV) infection. In pregnant women, such primary infection increases the risk of CMV-induced feto- or embryopathy. Daycare providers have therefore implemented working restrictions for pregnant daycare workers (DCWs) in accordance with legislation and guidelines for maternity protection. However, little is known about the infection risk for DCWs. We therefore compared the prevalence of CMV antibodies of pregnant DCWs to that of female blood donors (BDs).

Method: In a secondary data analysis, the prevalence of anti-CMV IgG among pregnant DCWs (N=509) in daycare centers (DCCs) was compared to the prevalence of female first-time BDs (N=14,358) from the greater region of Hamburg, Germany. Data collection took place between 2010 and 2013. The influence of other risk factors such as age, pregnancies and place of residence was evaluated using logistic regression models.

Results: The prevalence of CMV antibodies in pregnant DCWs was higher than in female BDs (54.6 vs 41.5%; OR 1.6; 95%CI 1.3–1.9). The subgroup of BDs who had given birth to at least one child and who lived in the city of Hamburg (N=2,591) had a prevalence of CMV antibodies similar to the prevalence in pregnant DCWs (53.9 vs 54.6%; OR 0.9; 95%CI 0.8–1.2). Age, pregnancy history and living in the center of Hamburg were risk factors for CMV infections.

Conclusion: The comparison of pregnant DCWs to the best-matching subgroup of female first-time BDs with past pregnancies and living in the city of Hamburg does not indicate an elevated risk of CMV infection among DCWs. However, as two secondary data sets from convenience samples were used, a more detailed investigation of the risk factors other than place of residence, age and maternity was not possible. Therefore, the CMV infection risk in DCWs should be further studied by taking into consideration the potential preventive effect of hygiene measures.

Varicella-zoster virus immunity among health care workers in Catalonia

OBJECTIVE

To determine varicella-zoster virus (VZV) immunity among healthcare workers (HCWs). Cross-sectional study.

PARTICIPANTS

HCWs attending voluntary periodic health examinations between June 2008 and December 2010.

SETTING

Six public hospitals and five primary care areas in Catalonia, Spain.

METHODS

A self-administered questionnaire was given to eligible HCWs. Variables including age, sex, professional category, type of centre, history of varicella infection, and VZV vaccination were collected. The study was carried out using a convenience sample. The prevalence of antibodies and positive and negative predictive values (PPV and NPV) of the history of clinical VZV infection or vaccination were calculated. Crude and adjusted odds ratios (OR and ORa) and their 95% confidence intervals (CI) were calculated to determine the variables associated with antibody prevalence.

RESULTS

Of 705 HCWs who agreed to participate, 644 were finally included. The overall prevalence of antibodies to varicella was 94.9% (95% CI: 92.9-96.4). Of the variables studied, only age was associated with serological susceptibility to VZV. HCWs aged 25-35 years had the highest serological susceptibility (8.1%, 95% CI: 4.6-13.0). The prevalence of antibodies was 96% in subjects reporting previous VZV infection or vaccination, compared with 93% in subjects who did not report these states or did not know.

CONCLUSIONS

The high proportion of serologically-susceptible HCWs found in this study indicates the need to develop for screening and vaccination strategies in Catalonia. Due to the high capacity of propagation of the VZV in health settings and its consequences, VZV vaccination programmes in HCWs should be reinforced.

A novel and potentially valuable exposure measure: Escherichia coli in oral cavity and its association with child daycare center attendance

This study investigated the occurrence of Escherichia coli, an indicator of fecal contamination, in saliva samples from 141 children up to 36 months old, 53 not attending and 88 attending a child daycare center after exposure to a public daycare center and home environments. Two samples from each child were collected on the same day at 07:00 and 15:00 h and plated on MacConkey agar for identification. Samples E. coli negative in the morning and positive in the afternoon were statistically associated with the condition of the child attending daycare center (Odds ratio = 2.72; 95% confidence interval = 1.15/6.46). Exposure to the daycare center environment favored the potential risk of transmission of enteropathogens, as demonstrated by the presence of E. coli in saliva. The method proved to be easy to sample, non-invasive and feasible in young children. The findings suggest a novel and potentially valuable exposure measure.

Risk ofStaphylococcus aureuscarriage in childcare employees

Asymptomatic carriage ofStaphylococcus aureusis an important risk factor for developing infection, as well as a key contributor to transmission. Despite the fact that childcare workers are at known risk for infections, little research has focused on bacterial carriage in this occupational group. We conducted a cross-sectional study comparing the prevalence ofS. aureusin 110 childcare employees with the prevalence in 111 unexposed participants. Questionnaire data was collected for employees, unexposed adults, and children. Multivariate analysis allowed for adjustment for confounders. Data on work-related exposures are presented as well. The prevalence ofS. aureusin employees, unexposed adults, children, and on surfaces was 35·2%, 33·6%, 19·8%, and 9·8%, respectively. Washing children's hands upon their arrival at childcare facilities may decrease the risk ofS. aureuscarriage in employees (odds ratio 0·17, 95% confidence interval 0·095–0·32,P < 0·0001).

Occupational risk for cytomegalovirus, but not for parvovirus B19 in child-care personnel in France

BACKGROUND

Studies assessing the risk of cytomegalovirus (CMV), parvovirus B19 (B19V), rubella and varicella infections in female child-care personnel may help define appropriate preventive strategies during pregnancy.

METHODS

Serologic testing for all four viruses and a self-administered questionnaire to identify risk factors were conducted on child-care staff aged 20-50 years old and on a reference group of women.

RESULTS

In 395 exposed and 382 reference women, CMV, B19V, rubella and varicella seroprevalence were 69.4, 79.4, 98.7, 100% for exposed women, and 41.1, 68.0, 98.2, 99.7% for reference women, respectively. For CMV, the adjusted seroprevalence ratio (PR) of exposed versus reference workers, (PR, 1.43 [95% IC, 1.22-1.69]) was observed as of the first year of exposure. The risk attributed to occupation was 30.1%. Identified risk factors included exposure duration, past employment in maternity hospital, and participation in cleaning tasks. The risk attributable to personal factors ranged from 14.5% to 32.4%. The adjusted B19V PR was not significant (PR, 1.05 [95% IC, 0.94-1.16]).

CONCLUSIONS

French female child-care staff runs an occupational risk for CMV infection, but not for B19V infection. The fraction attributable to this CMV occupational risk was not higher than the risk associated with personal factors.

Socioeconomic and psychosocial gradients in cardiovascular pathogen burden and immune response: the multi-ethnic study of atherosclerosis

BACKGROUND

The biologic mechanisms linking socioeconomic position and psychosocial factors to cardiovascular disease (CVD) are not well understood. Immune response to persistent pathogens may be one of these mechanisms.

METHODS

We analyzed cross-sectional data from the multi-ethnic study of atherosclerosis (N=999) composed of adults age 45-84. Log-binomial regression and ordinal logistic regression models were used to examine associations of socioeconomic factors and psychosocial factors with pathogen burden and immune response among those infected. Pathogen burden was assessed based on seroprevalence of Helicobacter pylori, cytomegalovirus, herpes simplex virus-1, and Chlamydia pneumoniae and antibody levels were used to characterize high immune response to all four pathogens.

RESULTS

Low education was a strong and significant independent predictor of higher pathogen burden after adjustment for covariates (adjusted odds ratio (OR) 95% confidence interval (CI) 1.37, 1.19-1.57). Among subjects seropositive for all four pathogens, low education and a higher level of chronic psychosocial stress showed a positive association with higher antibody response, although associations were no longer significant in models with all covariates included (OR=1.64, 95% CI 0.82-3.31 for lowest vs. highest educational category and OR=1.29, 95% CI 0.96-1.73 for a one level increase in chronic stress).

CONCLUSION

Pathogen burden and heightened immune response may represent a biological pathway by which low socioeconomic position and chronic stress are related to increased rates of cardiovascular disease.

Hepatitis A vaccine recommendations

Since licensure in 1995 of a hepatitis A vaccine, the Centers for Disease Control and Prevention and the American Academy of Pediatrics have been implementing an incremental hepatitis A immunization strategy for children. In 1996, children living in populations with the highest rates of disease were targeted for immunization, and in 1999 the program was expanded to immunization of children 2 years and older living in states and counties with rates of hepatitis A that historically have been higher than the national average. The 1999 program has been successful; the current rate of hepatitis A is the lowest ever reported in the United States. Regional, ethnic, and racial differences in the incidence of hepatitis A have been eliminated. The incidence of hepatitis A in adults in immunizing states has decreased significantly, suggesting a strong herd-immunity effect associated with immunization. In 2005, the US Food and Drug Administration changed the youngest approved age of administration of hepatitis A vaccine from 24 to 12 months of age, which facilitated incorporation of the vaccine into the recommended childhood immunization schedule. As the next step in the implementation of the incremental vaccine immunization strategy, the American Academy of Pediatrics now recommends routine administration of a Food and Drug Administration-licensed hepatitis A vaccine to all children 12 to 23 months of age in all states according to a Centers for Disease Control and Prevention-approved immunization schedule. Available data suggest that hepatitis A vaccine can be coadministered with other childhood vaccines without decreasing immunogenicity. Hepatitis A vaccines have proven to be extremely safe. In prelicensure clinical trials of both Havrix (GlaxoSmithKline, Rixensart, Belgium) and Vaqta (Merck & Co Inc, Whitehouse Station, NJ), adverse events were uncommon and mild when they occurred, with resolution typically in less than 1 day. Hepatitis A vaccine is contraindicated in people with a history of severe allergic reaction to a previous dose of hepatitis A vaccine or to a vaccine component. Because the hepatitis A vaccine is an inactivated product, no special precautions are needed for administration to people who are immunocompromised. No data exist about administration of the hepatitis A vaccine to pregnant women, but because it is not a live vaccine, the risk to mother and fetus should be extremely low to nonexistent.

Cytomegalovirus as an occupational risk in daycare educators

BACKGROUND

Cytomegalovirus (CMV) infection continues to be an important occupational risk in the daycare setting. A comprehensive update of scientific evidence is timely to inform and promote appropriate preventive measures.

METHODS

A review of the literature was conducted to examine the evidence for an occupational risk of CMV infection in daycare educators. Sources included Medline, government documents and additional references from published bibliographies. The key words used for searches were 'child day care centres' or 'nurseries' and 'cytomegalovirus' or 'cytomegalovirus infection'.

RESULTS

EIGHT CMV SEROPREVALENCE STUDIES ON DAYCARE EDUCATORS IN INDUSTRIALIZED COUNTRIES WERE FOUND: four in the United States, three in Canada and one in Italy. Risk factors for seropositivity were older age, nonwhite race, foreign birth, birth in a low- or middle-income country, diaper changing, having children at home, and a child to educator ratio greater than 6:1 in children 18 to 35 months of age. Risk factors for seroconversion were younger age and working with young children. These studies suggest that daycare centres may be a high-risk setting for CMV infection.

DISCUSSION

Recommendations to prevent CMV infection in this setting include handwashing, selective serological screening, avoiding work with younger children if pregnant and, in some cases, preventive leave from work. Evaluation and expert opinion of the effectiveness of various preventive options for CMV acquisition are needed to ensure that recommendations are evidence-based.

Risk factors for cytomegalovirus seropositivity in a population of day care educators in Montréal, Canada

BACKGROUND

Horizontal transmission of cytomegalovirus (CMV) is common in the day care setting. Day care educators appear to be at a high risk of infection; however, studies are limited.

AIMS

To determine the proportion of CMV-seropositive female educators in the day care setting and to identify associated risk factors.

METHODS

Educator- and day care-level risk factors for CMV seropositivity were obtained by questionnaires from day care educators and directors, respectively. Sera were collected from educators and analyzed by enzyme-linked immunosorbent assay. Significant independent risk factors for CMV seropositivity were determined using a multivariable logistic regression model which was fitted using the generalized estimating equation method.

RESULTS

CMV seroprevalence in 473 female educators from 81 day care centers in Montréal, Canada, was 57%. Significant risk factors for CMV seropositivity were (i) increasing age (OR5-yr = 1.19; 95% CI = 1.05-1.35), (ii) low-income country of birth (OR = 10.23; 95% CI = 2.64-39.50) or middle-income country of birth (OR = 4.99; 95% CI = 2.39-10.40), (iii) having > or =2 children of their own (OR = 1.98; 95% CI = 1.19-3.31) and (iv) child-to-educator ratio >6 (18-35 months old) in a day care center (OR = 1.87; 95% CI = 1.25-2.81).

CONCLUSIONS

Day care educators have risks for CMV infection related to their work in the day care setting, as well as personal risk factors. A review of current guidelines for the prevention of CMV infection in day care is needed to ensure that recommendations are evidence based.

Occupational risk for hepatitis A: a literature-based analysis

Hepatitis A virus is the most frequently occurring vaccine-preventable disease. Although generally self-limiting, acute hepatitis A is associated with substantial morbidity and related economic burden. Hepatitis A virus is transmitted by the fecal-oral route, and children are a main source of infection. Some occupational workers are at risk for hepatitis A virus infection based on the potential for contact with infected fecal matter and, in many regions in the United States and other developed countries, low overall rates of natural immunity. These at-risk occupations include daycare providers, hospital workers who have direct patient contact (nurses, nurses' aides, laundry workers), and sewage workers. Additionally, food handlers, particularly in the hospital setting, should be vaccinated if seronegative for hepatitis A virus because of their ability to rapidly spread disease among vulnerable populations if infected.

Varicella in Americans from NHANES III: implications for control through routine immunization

At the time of varicella vaccine introduction in the United States, an estimated 4 million episodes of varicella occurred annually. This survey of varicella seroprevalence is the first to describe immunity to a vaccine-preventable disease prior to vaccine introduction in the United States population. The objective of this analysis is to describe patterns of naturally-acquired varicella and understand characteristics associated with infection in the varicella vaccine-naive United States population. A nationally representative cross-sectional health examination survey that included venipuncture was conducted among 21,288 U.S. participants aged 6 years and older from 1988 through 1994. Serologic evidence of varicella-zoster virus infection was measured by enzyme immunoassay of varicella-zoster virus-specific IgG antibody. The seroprevalence of IgG antibody to varicella-zoster virus increased from 86.0% in children aged 6 through 11 years to 99.6% in adults aged 40 through 49 years. Immunity to varicella remained at 99% or higher in Americans aged 50 years and older. Among persons aged 6 through 19 years, non-Hispanic black children were 40% less likely to be seropositive compared with white children (odds ratio [OR], 0.6; 95% confidence interval [CI], 0.4-0.8). Among young adults aged 20 through 39 years, women with a history of live birth (OR, 4.3; 95% CI, 2.1-8.7) and married men (OR, 2.7; 95% CI, 1.2-5.7) were more likely to have naturally-acquired immunity to varicella. This study found that, prior to use of varicella vaccine in the United States, age, race, and marital characteristics were independently associated with naturally acquired varicella. Future varicella serosurveys in Americans will provide essential information to interpret the population impact of varicella vaccine.

Risk groups for hepatitis A virus infection

We report the conduct and results of a systematic search for evidence of risk of infection with hepatitis A virus (HAV) among blood transfusion recipients, travellers, the military, healthcare workers, sewage workers, foodhandlers, day care assistants, institutionalised subjects, blood transfusion recipients, drug addicts, homosexuals, prisoners and other risk groups such a liver transplantees. We report our recommendations for the use of the HAV vaccine in these groups.

Prevalence of hepatitis A virus infection among sewage workers in Georgia

BACKGROUND

Wastewater (WW) workers could have opportunity for direct contact with raw sewage, which might contain hepatitis A virus (HAV).

METHODS

A serologic survey of WW workers and a comparison population of roads and drainage workers (RD). Factors potentially associated with anti-HAV positivity were evaluated in univariate and multivariate analyses.

RESULTS

Among the 365 WW workers, overall anti-HAV prevalence was 38%, similar to that (35%) of the 166 RD workers (P = 0.5). Prevalence varied by wastewater job type from 45% among the 164 field crew workers to 32% among the 201 treatment plant workers. In multivariate modeling, factors associated with anti-HAV positivity included age > or = 40 years (odds ratio [OR] = 2.4; 95% CI = 1.6-3.7), black compared to other races (OR = 2.4; 95% CI = 1.5-3.8), birth outside the United States (OR = 7.5; 95% CI = 3.0-18.6), a high school education or less (OR 2.1; 95% CI = 1.4-3.2) and work on the field crew compared to RD work (OR 1.6; 95% CI = 1.1-2.4).

CONCLUSIONS

These results are consistent with no or a small increased risk of hepatitis A among WW workers, and do not provide a clear mandate for hepatitis A vaccination of these workers. Am. J. Ind. Med. 43: 172-178, 2003.

Macrolide-resistant pneumococcal endocarditis and epidural abscess that develop during erythromycin therapy

Suppurative complications of Streptococcus pneumoniae infections have become uncommon in the antibiotic era. We report a case of pneumococcal bacteremia and pneumonia complicated with epidural abscess and endocarditis in which macrolide resistance (the MLS(B) phenotype) emerged during erythromycin therapy. Genetic determinants known to mediate the most common mechanisms of macrolide resistance (methylation of the 23S rRNA and antibiotic efflux) were not detected by polymerase chain reaction or DNA hybridization. Sequence analysis of the DNA encoding the 23S rRNA of the macrolide-resistant isolate from the patient demonstrated the replacement of adenine by thymine at position 2058 (A2058T) in 2 of 4 alleles. Clinicians should be alert to the possibility of the emergence of resistance during macrolide therapy for community-acquired pneumonia, particularly if suppurative complications of pneumococcal infection are suspected.

Characteristics of Streptococcus pneumoniae and atypical bacterial infections in children 2-5 years of age with community-acquired pneumonia

The characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae infection were compared with those associated with atypical bacterial infection and with mixed S. pneumoniae-atypical bacterial infection in 196 children aged 2-5 years. S. pneumoniae infections were diagnosed in 48 patients (24.5%); atypical bacterial infections, in 46 (23.5%); and mixed infections, in 16 (8.2%). Although white blood cell counts and C-reactive protein levels were higher in patients with pneumococcal infections, no other clinical, laboratory, or radiographic characteristic was significantly correlated with the different etiologic diagnoses. There was no significant difference in the efficacy of the different treatment regimens followed by children with S. pneumoniae infection, whereas clinical failure occurred significantly more frequently among children with atypical bacterial or mixed infection who were not treated with a macrolide. This study shows the major role of both S. pneumoniae and atypical bacteria in the development of community-acquired pneumonia in young children, the limited role of clinical, laboratory, and radiological features in predicting etiology, and the importance of the use of adequate antimicrobial agents for treatment.

Failure of macrolide antibiotic treatment in patients with bacteremia due to erythromycin-resistant Streptococcus pneumoniae

The rate of macrolide resistance among Streptococcus pneumoniae is increasing, but some investigators have questioned its clinical relevance. We conducted a matched case-control study of patients with bacteremic pneumococcal infection at 4 hospitals to determine whether development of breakthrough bacteremia during macrolide treatment was related to macrolide susceptibility of the pneumococcal isolate. Case patients (n=86) were patients who had pneumococcal bacteremia and an isolate that was either resistant or intermediately resistant to erythromycin. Controls (n=141) were patients matched for age, sex, location, and year that bacteremia developed who had an erythromycin-susceptible pneumococcus isolated. Excluding patients with meningitis, 18 (24%) of 76 case patients and none of 136 matched controls were taking a macrolide when blood was obtained for culture (P=.00000012). Moreover, 5 (24%) of 21 case patients with the low-level-resistant M phenotype and none of 40 controls were taking a macrolide (P=.00157). These data show that development of breakthrough bacteremia during macrolide or azalide therapy is more likely to occur among patients infected with an erythromycin-resistant pneumococcus, and they also indicate that in vitro macrolide resistance resulting from both the efflux and methylase mechanisms is clinically relevant.

Risk of exposure to hepatitis A virus among day-care workers in Israel: implications for preventive measures

Hepatitis A is an important infectious disease in Israel. The high incidence of hepatitis A, the declining prevalence of antibodies against hepatitis A virus throughout the past decade, and the availability of an active immunization for hepatitis A have engendered the identification of occupations in which workers are at increased risk of acquiring the disease. A prevalence study for hepatitis A antibodies was conducted during the first half of 1998 in a random sample of 37 day-care centers in different parts of Israel. A short interview was conducted, and serum samples were then collected from each worker. The control group comprised a sample of factory workers, blood donors, and women in maternity wards. Ninety percent (402 of 446) of the day-care workers had antibodies to hepatitis A. In a logistic-regression analysis, seropositivity was associated with increased age, minimal education, and lack of military service. When the authors compared a subsample of workers aged 18-40 yr with the control group, seropositivity was associated with the following: birth in Israel, duration of residence in Israel, very minimal education, military service, and employment in a day-care center. These results, together with earlier reports, indicate that day-care workers are at high risk of occupational exposure to hepatitis A. These results may imply that seronegative workers have a 2-fold chance of acquiring hepatitis A. Appropriate preventive measures should be considered, and active immunization of susceptible workers should be undertaken.

The role of child care in a community-wide outbreak of hepatitis A

OBJECTIVE

To evaluate the role of child care centers in a community-wide hepatitis A epidemic.

METHODS

We analyzed surveillance data during an epidemic in Maricopa County, Arizona, from January to October 1997 and conducted a case-control study using a sample of cases reported from June to November. Cases were physician-diagnosed and laboratory confirmed; control subjects were frequency matched by age and neighborhood. Information regarding hepatitis A risk factors, including child care-related exposures, was collected. Characteristics of all licensed child care centers in the county were obtained through review of computerized lists from the Arizona Office of Child Day Care Licensing. Surveillance data were linked to the child care list to determine which centers had reported hepatitis A cases. We conducted univariate and multivariate conditional logistic analyses and calculated population attributable risks (PAR).

RESULTS

In total, 1242 cases (50/100 000 population) were reported. The highest rates occurred among people aged 0 to 4 (76/100 000), 5 to 14 (95/100 000), and 15 to 29 (79/100 000) years. The most frequently reported risk factor was contact with a hepatitis A patient (45%). However, nearly 80% of these contacts were with individuals who attended or worked in a child care center. Overall, child care center-related contact could have been the source of infection for 34% of case-patients. In the case-control study, case-patients (n = 116) and control subjects (n = 116) did not differ with respect to demographic characteristics. A total of 51% of case-patients compared with 18% of control subjects reported attending or working in a child care setting (direct contact; adjusted odds ratio [OR]: 6.0; 95% confidence interval [CI]: 2.1-23.0) or being a household contact of such a person (indirect contact; OR: 3.0; 95% CI: 1.3-8.0). In age-stratified analyses, the association between hepatitis A and direct or indirect contact with child care settings was strongest for children <6 years old and adults aged 18 to 34 years. Household contact with a person with hepatitis A also was associated with hepatitis A (OR: 9.2; 95% CI: 2.6-58.2). The presence of a child <5 years old in the household was not associated with hepatitis A. The estimated PAR for direct child care contact was 23% (95% CI: 16-34), for indirect child care contact was 21% (95% CI: 13-35), and for any child care contact was 40% (95% CI: 30-53). Information on 1243 licensed child care centers was obtained, with capacity ranging from 5 to 479 slots (mean: 87). Thirty-four (2.7%) centers reported hepatitis A cases. Centers that had a mean capacity of >50 children were more than twice as likely to have had a reported case of hepatitis A (OR: 2.6; 95% CI: 1.1-6.7). Among the 747 centers that accepted >50 children, having infant (OR: 3.7; 95% CI: 1.6-8.3), toddler (OR: 6.3; 95% CI: 2.2-20.0), or full-day service (OR; undefined; 95% CI: 1.7- ~) was associated with having a reported case of hepatitis A.

CONCLUSIONS

In Maricopa County, people associated with child care settings are at increased risk of hepatitis A, and child care attendees may be an appropriate target group for hepatitis A vaccination. Considering the estimated proportion of children who attended child care and were old enough to receive hepatitis A vaccine (>/=2 years of age) and the calculated PAR, approximately 40% of cases might have been prevented if child care center attendees and staff had been vaccinated. However, epidemiologic studies indicate that the proportion of cases that are attributable to child care center exposure varies considerably among counties, suggesting that this exposure may be associated with an increased risk of hepatitis A in some communities but not in others. To prevent and control hepatitis A epidemics in communities, the Advisory Committee on Immunization Practices and the American Academy of Pediatrics have adopted a long-term strategy of routine vaccination of children who live in areas with consistently elevated hepatitis A rates. After demonstrating cost-effectiveness, a rule was implemented in January 1999 to require hepatitis A vaccination of all children who are aged 2 to 5 years and enrolled in a licensed child care facility in Maricopa County. Other communities with similar epidemiologic features might consider routine vaccination of child care center attendees as a long-term hepatitis A prevention strategy. Consistent with current recommendations, in communities with persistently elevated hepatitis A rates where child care center attendance does not play an important role in hepatitis A virus transmission in the community, child care centers may nonetheless provide a convenient access point for delivering hepatitis A as well as other routine childhood vaccinations.

Active immunization in the United States: developments over the past decade

The Centers for Disease Control and Prevention has identified immunization as the most important public health advance of the 20th century. The purpose of this article is to review the changes that have taken place in active immunization in the United States over the past decade. Since 1990, new vaccines have become available to prevent five infectious diseases: varicella, rotavirus, hepatitis A, Lyme disease, and Japanese encephalitis virus infection. Improved vaccines have been developed to prevent Haemophilus influenzae type b, pneumococcus, pertussis, rabies, and typhoid infections. Immunization strategies for the prevention of hepatitis B, measles, meningococcal infections, and poliomyelitis have changed as a result of the changing epidemiology of these diseases. Combination vaccines are being developed to facilitate the delivery of multiple antigens, and improved vaccines are under development for cholera, influenza, and meningococcal disease. Major advances in molecular biology have enabled scientists to devise new approaches to the development of vaccines against diseases ranging from respiratory viral to enteric bacterial infections that continue to plague the world's population.

Breakthrough pneumococcal bacteremia in patients being treated with azithromycin and clarithromycin

Streptococcus pneumoniae strains have exhibited decreasing susceptibility to penicillins and macrolides during the past several years. We reviewed the medical charts of all patients with pneumococcal bacteremia who were admitted to a university hospital over a period of 1 year, to identify failures of outpatient therapy. Of 41 patients admitted with pneumococcal bacteremia, 4 had previously taken either azithromycin or clarithromycin for 3-5 days. All 4 had pneumococcal strains that exhibited low-level resistance to macrolide antibiotics. Among pneumococci, low-level resistance to macrolides can lead to clinical failure, and resistance to macrolides should be considered during the selection of empiric therapy for patients with presumed pneumococcal infections.

Occupational risk of infection by varicella zoster virus in Belgian healthcare workers: a seroprevalence study

OBJECTIVES

To assess the prevalence of varicella zoster virus (VZV) antibodies in Flemish (Belgian) healthcare workers, to investigate the association between seronegativity and selected variables, and to assess the reliability of recall about disease as a predictor of immunity.

METHODS

A seroprevalence study of VZV antibodies (IgG) was conducted among a systematic sample of 4923 employees in various professional groups, employed in 22 hospitals in Flanders and Brussels (Belgium). Information about sex, age, department, job, and years of employment, the country of origin, and history of varicella was obtained. The presence of VZV antibodies was investigated with the enzyme linked immunosorbent assay (ELISA), Enzygnost anti VZV / IgG (Dade Behring, Marburg, Germany). Statistical analysis was performed by calculating prevalences and prevalence ratios (PRs) and their 95% confidence intervals (95% CIs). Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of the recalled history were determined.

RESULTS

The prevalence of VZV seropositivity in Flemish healthcare workers was 98.5% (95% CI 98.1 to 98.8). Seronegativity was significantly associated with age and job, increasing with both older and younger age. The prevalence of seronegative workers was significantly less in nursing staff than non-nursing staff. There was no significant difference for sex and years of employment. The PPV and NPV of recalled history were 98.9% and 3.4%. Sensitivity and specificity were 83% and 38.9%.

CONCLUSION

The prevalence of VZV seropositivity was very high in this sample of Flemish healthcare workers. Because of this low overall susceptibility, VZV infection seems not to be an important occupational risk among healthcare workers in Flanders. The increasing seronegativity above the age of 45 is possibly due to a loss of detectable antibodies. A positive history of varicella was a good predictor of immunity, but a negative history had no value as a predictor of susceptibility in adults.

Ribosomal Resistance: Emerging Problems and Potential Solutions

Many systemic antibiotics use ribosomal inhibition to suppress the replication of bacteria. Current research suggests that resistance to macrolide, lincosamide, and streptogramin B (MLS(B)) antibiotics is emerging among clinical isolates of Streptococcus pyogenes and Streptococcus pneumoniae. Erythromycin methylases, encoded by erm genes, modify an essential adenine residue in 23S rRNA and confer cross-resistance to MLS(B) antibiotics. More recently, macrolide efflux (mef) genes were identified in isolates of S. pyogenes and S. pneumoniae that show resistance to 14- and 15-membered macrolides (M phenotype). Resistance to MLSB has been associated with the increased use of erythromycin, and the recent emergence of the M phenotype has coincided with the marketing of newer macrolides. However, despite increasing macrolide resistance among clinical isolates of S. pneumoniae, convincing data on treatment failures directly attributable to MLS(B) or M phenotypes are limited. Possible solutions to emerging MLS(B) and M phenotype resistance include the introduction of alternative antibiotics, the more prudent use of antibiotics, combination therapy, molecular diagnostics, enhanced understanding of pharmacodynamic variables, and redefined resistance breakpoints.

Immune globulin and vaccine therapy to prevent hepatitis A infection

The hepatitis A virus is usually transmitted person-to-person due to fecal-oral exchange of virus. Approximately 30,000 infections are reported each year in the United States, with the actual incidence being much greater. Prophylaxis with immune globulin has had a minimal impact on the overall incidence of hepatitis A. The recent availability and proven efficacy of a hepatitis A vaccine offers the hope that the incidence of infection may be substantially reduced. Pre- and postexposure prophylaxis should be targeted to individuals at increased risk of either acquiring infection, transmitting infection, or developing fulminant hepatitis, or to help control epidemics. This article reviews the current literature and discusses recommendations for pre- and postexposure prophylaxis against hepatitis A virus.

Infection control challenges in child-care centers

The child-care environment predisposes young children to infection with a variety of pathogens. Factors contributing to increased incidence of certain infections include age-specific hygiene behaviors, immunologic immaturity of young children, and exposure to pathogens with high infectivity. Respiratory tract and enteric pathogens are responsible for most illnesses, but a number of other agents are also important. Hygienic interventions, especially handwashing, remain important in infection control, but maintenance of appropriate immunization levels plays a crucial role in disease prevention in the child-care setting. Future interventions will center on development of new vaccines to eliminate susceptibility of young children to as many infectious agents as possible and continued evaluation of other preventive measures.