School-Located Influenza Vaccination: Do Vaccine Clinics at School Raise Vaccination Rates?

BACKGROUND: Only half of US schoolchildren receive influenza vaccine. School-located influenza vaccination (SLIV) might raise vaccination rates but conducting flu vaccine clinics at schools is challenging to implement. We compared 2 school-based programs designed to raise influenza vaccination rates: parent reminder/educational messages sent to parents from schools which is a low-intensity intervention vs the combination of reminder/educational messages plus SLIV clinics which is a high-intensity intervention. METHODS: We assigned 36 schools (6 school districts, 2 per group) to 3 groups: (1) control, ie, no SLIV and no parent reminder/education, (2) parent reminder/education emailed by schools, and (3) parent reminder/education plus SLIV clinics. Some schools had SLIV clinics in prior years. Health department nurses conducted SLIV clinics. RESULTS: Among 24,832 children at 36 schools, vaccination rates were control (51.3%), parent reminder/education-only (41.2%), and reminder/education + SLIV (58.7%). On multivariate analyses which controlled for vaccination in prior seasons, children in reminder/education + SLIV schools had higher vaccination rates (OR 1.27, 95% CI 1.10-1.47), but children in reminder/education-only schools had lower rates (OR 0.87, 95% CI 0.75-1.00) than children in control schools. CONCLUSIONS: Parent reminder/education combined with SLIV clinics raise vaccination rates, but parent reminder/education alone does not.

Text Message Reminders for Child Influenza Vaccination in the Setting of School-Located Influenza Vaccination: A Randomized Clinical Trial.

Half of US school children receive influenza vaccine. In our previous trials, school-located influenza vaccination (SLIV) raised vaccination rates by 5 to 8 percentage points. We assessed whether text message reminders to parents could raise vaccination rates above those observed with SLIV. Within urban elementary schools we randomized families into text message + SLIV (intervention) versus SLIV alone (comparison). All parents were sent 2 backpack notifications plus 2 autodialer phone reminders about SLIV at a single SLIV clinic. Intervention group parents also were sent 3 text messages from the school nurse encouraging flu vaccination via either primary care or SLIV. Among 15 768 children at 32 schools, vaccination rates were text + SLIV (40%) and SLIV control (40%); 4% of students per group received influenza vaccination at SLIV. Text message reminders did not raise influenza vaccination rates above those observed with SLIV alone. More intensive interventions are needed to raise influenza vaccination rates.

Impact of elementary school-located influenza vaccinations: A stepped wedge trial across a community.

BACKGROUND: Influenza vaccination rates among children are low and novel strategies are needed to raise coverage. We measured the impact of school-located influenza vaccination (SLIV) on coverage, examined whether SLIV substitutes for practice-based influenza vaccination ("substitution"), and estimated whether a second year of experience with SLIV increases its impact. METHODS: We implemented a stepped wedge study design with schools as clusters. In Year 1, we randomly allocated schools to SLIV or control. In Year 2, all schools performed SLIV. We used emails (suburban schools) or backpack fliers (both urban and suburban schools) to notify parents, and offered web-based (suburban) or paper-based vaccination (urban) consent forms. Local health department nurses administered SLIV vaccinations and billed insurers. We analyzed state immunization registry data to measure influenza vaccination rates. RESULTS: 42 schools (38,078 children) participated over 2 years. Overall vaccination rates were 5 and 7 percentage points higher among SLIV- school children versus control-school children in suburban (aOR 1.36, 95% CI 1.25-1.49 in Years 1-2 SLIV vs. Year 1 control schools) and urban schools (aOR 1.22, 95% CI 1.10-1.36), respectively, adjusting for prior year's vaccination and other covariates. While no substitution occurred among children attending suburban schools, some substitution occurred among children attending urban schools, although overall vaccination rates were still higher in urban schools due to SLIV. Compared to an initial year of SLIV, more children were vaccinated in a second year of SLIV at urban (8.3% vs. 6.8%, aOR 1.24, 95% CI 1.04-1.47) but not suburban schools (3.5% vs. 2.7%, aOR 1.24, 95% CI 0.98-1.57). CONCLUSIONS: In this stepped wedge trial, SLIV increased overall influenza vaccination rates in suburban and urban schools. Some substitution for primary care vaccination occurred in urban settings. A second year of SLIV expanded its reach slightly in urban schools.

School-located Influenza Vaccinations for Adolescents: A Randomized Controlled Trial.

PURPOSE: We aimed to evaluate the effect of school-located influenza vaccination (SLIV) on adolescents' influenza vaccination rates. METHODS: In 2015-2016, we performed a cluster-randomized trial of adolescent SLIV in middle/high schools. We selected 10 pairs of schools (identical grades within pairs) and randomly allocated schools within pairs to SLIV or usual care control. At eight suburban SLIV schools, we sent parents e-mail notifications about upcoming SLIV clinics and promoted online immunization consent. At two urban SLIV schools, we sent parents (via student backpack fliers) paper immunization consent forms and information about SLIV. E-mails were unavailable at these schools. Local health department nurses administered nasal or injectable influenza vaccine at dedicated SLIV clinics and billed insurers. We compared influenza vaccination rates at SLIV versus control schools using school directories to identify the student sample in each school. We used the state immunization registry to determine receipt of influenza vaccination. RESULTS: The final sample comprised 17,650 students enrolled in the 20 schools. Adolescents at suburban SLIV schools had higher overall influenza vaccination rates than did adolescents at control schools (51% vs. 46%, p < .001; adjusted odds ratio = 1.27, 95% confidence interval 1.18-1.38, controlling for vaccination during the prior two seasons). No effect of SLIV was noted among urbanschools on multivariate analysis. SLIV did not substitute for vaccinations in primary care or other settings; in suburban settings, SLIV was associated with increased vaccinations in primary care or other settings (adjusted odds ratio = 1.10, 95% confidence interval 1.02-1.19). CONCLUSIONS: SLIV in this community increased influenza vaccination rates among adolescents attending suburban schools.

School-Located Influenza Vaccinations: A Randomized Trial.

OBJECTIVE: Assess impact of offering school-located influenza vaccination (SLIV) clinics using both Web-based and paper consent upon overall influenza vaccination rates among elementary school children. METHODS: We conducted a cluster-randomized trial (stratified by suburban/urban districts) in upstate New York in 2014-2015. We randomized 44 elementary schools, selected similar pairs of schools within districts, and allocated schools to SLIV versus usual care (control). Parents of children at SLIV schools were sent information and vaccination consent forms via e-mail, backpack fliers, or both (depending on school preferences) regarding school vaccine clinics. Health department nurses conducted vaccine clinics and billed insurers. For all children registered at SLIV/control schools, we compared receipt of influenza vaccination anywhere (primary outcome). RESULTS: The 44 schools served 19 776 eligible children in 2014-2015. Children in SLIV schools had higher influenza vaccination rates than children in control schools county-wide (54.1% vs 47.4%, P < .001) and in suburban (61.9% vs 53.6%, P < .001) and urban schools (43.9% vs 39.2%; P < .001). Multivariate analyses (controlling for age, grade, vaccination in previous season) confirmed bivariate findings. Among parents who consented for SLIV, nearly half of those notified by backpack fliers and four-fifths of those notified by e-mail consented online. In suburban districts, SLIV did not substitute for primary care influenza vaccination. In urban schools, some substitution occurred. CONCLUSIONS: SLIV raised seasonal influenza vaccination rates county-wide and in both suburban and urban settings. SLIV did not substitute for primary care vaccinations in suburban settings where pediatricians often preorder influenza vaccine but did substitute somewhat in urban settings.

Acute gastrointestinal illness following a prolonged community-wide water emergency.

The drinking water infrastructure in the United States is ageing; extreme weather events place additional stress on water systems that can lead to interruptions in the delivery of safe drinking water. We investigated the association between household exposures to water service problems and acute gastrointestinal illness (AGI) and acute respiratory illness (ARI) in Alabama communities that experienced a freeze-related community-wide water emergency. Following the water emergency, investigators conducted a household survey. Logistic regression models were used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for self-reported AGI and ARI by water exposures. AGI was higher in households that lost water service for ⩾7 days (aPR 2·4, 95% CI 1·1-5·2) and experienced low water pressure for ⩾7 days (aPR 3·6, 95% CI 1·4-9·0) compared to households that experienced normal service and pressure; prevalence of AGI increased with increasing duration of water service interruptions. Investments in the ageing drinking water infrastructure are needed to prevent future low-pressure events and to maintain uninterrupted access to the fundamental public health protection provided by safe water supplies. Households and communities need to increase their awareness of and preparedness for water emergencies to mitigate adverse health impacts.

Rift Valley fever in Kenya: history of epizootics and identification of vulnerable districts.

Since Kenya first reported Rift Valley fever (RVF)-like disease in livestock in 1912, the country has reported the most frequent epizootics of RVF disease. To determine the pattern of disease spread across the country after its introduction in 1912, and to identify regions vulnerable to the periodic epizootics, annual livestock disease records at the Department of Veterinary Services from 1910 to 2007 were analysed in order to document the number and location of RVF-infected livestock herds. A total of 38/69 (55%) administrative districts in the country had reported RVF epizootics by the end of 2007. During the 1912-1950 period, the disease was confined to a district in Rift Valley province that is prone to flooding and where livestock were raised in proximity with wildlife. Between 1951 and 2007, 11 national RVF epizootics were recorded with an average inter-epizootic period of 3·6 years (range 1-7 years); in addition, all epizootics occurred in years when the average annual rainfall increased by more than 50% in the affected districts. Whereas the first two national epizootics in 1951 and 1955 were confined to eight districts in the Rift Valley province, there was a sustained epizootic between 1961 and 1964 that spread the virus to over 30% of the districts across six out of eight provinces. The Western and Nyanza provinces, located on the southwestern region of the country, had never reported RVF infections by 2007. The probability of a district being involved in a national epizootic was fivefold higher (62%) in districts that had previously reported disease compared to districts that had no prior disease activity (11%). These findings suggests that once introduced into certain permissive ecologies, the RVF virus becomes enzootic, making the region vulnerable to periodic epizootics that were probably precipitated by amplification of resident virus associated with heavy rainfall and flooding.

Piloting the use of personal digital assistants for tuberculosis and human immunodeficiency virus surveillance, Kenya, 2007.

SETTING: Improved documentation of human immunodeficiency virus (HIV) testing and care among tuberculosis (TB) patients is needed to strengthen TB-HIV programs. In 2007, Kenya piloted the use of personal digital assistants (PDAs) instead of paper registers to collect TB-HIV surveillance data from TB clinics. OBJECTIVE: To evaluate the acceptability, data quality and usefulness of PDAs. DESIGN: We interviewed four of 31 district coordinators who collected data in PDAs for patients initiating TB treatment from April to June 2007. In 10 of 93 clinics, we randomly selected patient records for comparison with corresponding records in paper registers or PDAs. Using Cochran-Mantel-Haenszel tests, we compared missing data proportions in paper registers with PDAs. We evaluated PDA usefulness by analyzing PDA data from all 93 clinics. RESULTS: PDAs were well accepted. Patient records were more frequently missing (28/97 vs. 1/112, P < 0.001) and data fields more frequently incomplete (148/1449 vs. 167/2331, P = 0.03) in PDAs compared with paper registers. PDAs, however, facilitated clinic-level analyses: 48/93 (52%) clinics were not reaching the targets of testing >or=80% of TB patients for HIV, and 8 (9%) clinics were providing <80% of TB-HIV co-infected patients with cotrimoxazole (CTX). CONCLUSION: PDAs had high rates of missing data but helped identify clinics that were undertesting for HIV or underprescribing CTX.

A supervised land cover classification of a western Kenya lowland endemic for human malaria: associations of land cover with larval Anopheles habitats.

BACKGROUND: A supervised land cover classification was developed from very high resolution IKONOS satellite data and extensive ground truth sampling of a ca. 10 sq km malaria-endemic lowland in western Kenya. The classification was then applied to an investigation of distribution of larval Anopheles habitats. The hypothesis was that the distribution and abundance of aquatic habitats of larvae of various species of mosquitoes in the genus Anopheles is associated with identifiable landscape features. RESULTS AND DISCUSSION: The classification resulted in 7 distinguishable land cover types, each with a distinguishable vegetation pattern, was highly accurate (89%, Kappa statistic = 0.86), and had a low rate of omission and commission errors. A total of 1,198 habitats and 19,776 Anopheles larvae of 9 species were quantified in samples from a rainy season, and 184 habitats and 582 larvae from a dry season. Anopheles gambiae s.l. was the dominant species complex (51% of total) and A. arabiensis the dominant species. Agricultural land covers (mature maize fields, newly cultivated fields, and pastured grasslands) were positively associated with presence of larval habitats, and were located relatively close to stream channels; whilst nonagricultural land covers (short shrubs, medium shrubs, tall shrubs, and bare soil around residences) were negatively associated with presence of larval habitats and were more distant from stream channels. Number of larval habitats declined exponentially with distance from streams. IKONOS imagery was not useful in direct detection of larval habitats because they were small and turbid (resembling bare soil), but was useful in localization of them through statistical associations with specific land covers. CONCLUSION: A supervised classification of land cover types in rural, lowland, western Kenya revealed a largely human-modified and fragmented landscape consisting of agricultural and domestic land uses. Within it, larval habitats of Anopheles vectors of human malaria were associated with certain land cover types, of largely agricultural origin, and close to streams. Knowledge of these associations can inform malaria control to gather information on potential larval habitats more efficiently than by field survey and can do so over large areas.

A peer-led HIV counselling and testing programme for the deaf in Kenya.

PURPOSE: To describe and evaluate the establishment of the first VCT services for the Deaf in Africa. METHOD: Operational research methods were used to document programme establishment. The demographics of deaf VCT clients were compared with hearing clients at the same sites as well as where clients had learned of the service, HIV risks, and HIV test results. Univariate and multivariate analyses were used. RESULTS: During the two year period (January 2004 to December 2005) 1709 Deaf and 1649 hearing clients were seen at three Deaf VCT sites. The majority of Deaf clients in this sample learned of the services through the peer education programme. Data indicate that Deaf VCT clients are as much at risk of HIV from sexual transmission as their hearing counterparts and that Deaf persons seeking VCT services have an HIV prevalence of 7%, similar to the national rate of 6.7%. CONCLUSIONS: The Deaf in Kenya are at risk of HIV and there is an urgent need for Deaf-friendly HIV services, supplemented by peer education programmes. This is the first published report describing HIV services run by the Deaf for the Deaf in the developing world.

Relations among family discord, caregiver communication, and children's family representations.

This study examined associations among family discord, caregiver communication quality about emotionally stressful family events, and child internal representations of family security in 50 preschool children and their primary caregivers. Consistent with risk and protective models, findings indicate that children's representations were predicted by the interaction between family discord and caregiver communication quality. Children exhibiting the highest level of secure representations of the family experienced a consistency between low levels of family discord and communications emphasizing family security. Conversely, incongruency between family experiences and communication, reflected in high levels of family discord and communications underscoring family security, was associated with the lowest level of child secure representations. Results suggest that child representations hinge on the fit between caregiver communication quality and family experience.

Behavior problems among inner-city children with asthma: findings from a community-based sample.

OBJECTIVE: Previous studies have suggested a relationship between childhood asthma and behavior problems. However, few studies have used community-based samples to assess the prevalence of behavior problems among urban children with asthma symptoms. The objective of this study was to evaluate the relationship between asthma symptoms and behavior among a population-based sample of inner-city children and to determine the prevalence of behavioral comorbidity among children with asthma symptoms. METHODS: In 2003, parents of children who were entering kindergarten in the city of Rochester completed a detailed survey regarding the child's background, medical history (with specific questions about asthma symptoms), and behavior. We compared children with no asthma symptoms, intermittent symptoms, and persistent symptoms with regard to positive peer social skills (eg, makes friends easily), negative peer social skills (eg, fights with other children), task orientation (eg, concentrates well), and shy/anxious behavior (eg, is withdrawn) (validated scales; range: 1-4). We used multivariate regression to determine the independent association between symptom severity and behavioral outcomes. RESULTS: A total of 1619 children were included (response rate: 80%; mean age: 5.1 year), and 15% had asthma symptoms (8% persistent, 7% intermittent). Average negative peer scores were worse for children with persistent asthma symptoms compared with children with intermittent and no symptoms (mean scores: 1.88, 1.70, and 1.65). Children with persistent symptoms also scored worse than children with no symptoms on the assessment of task orientation (2.85 vs 3.03) and shy/anxious behavior (2.11 vs 1.89). Among children with persistent asthma symptoms, >20% scored >1 SD below average on 2 or more scales, compared with 16% of children with intermittent symptoms and 10% with no symptoms. CONCLUSIONS: Urban children with persistent asthma symptoms demonstrate more behavior problems across several domains compared with children with no symptoms. These findings suggest a clear need for an early biopsychosocial approach to care for vulnerable children with asthma.

Maternal depressive symptoms are adversely associated with prevention practices and parenting behaviors for preschool children.

OBJECTIVE: To determine the relationship between maternal depressive symptoms and select prevention practices and parenting behaviors for older preschool children. METHODS: A telephone survey of mothers and female guardians of children entering kindergarten in Monroe County, New York, was administered to 400 eligible parents in 2001. The Mental Health Inventory-5 was used to determine maternal depressive symptoms. We examined the impact of maternal depression on well-child care, immunizations, routine dental care, tooth brushing, frequent reading, safe motor vehicle seating location, car seat or booster seat use, discipline consistency, and parenting confidence. RESULTS: A total of 17.7% of mothers had depressive symptoms, with increased rates among women who were poor, less educated, and single parents. Children of mothers with depressive symptoms were more likely to have not received routine dental care in the past year (21.1% vs 8.2%, P = .001), brush their teeth less than twice a day (37.1% vs 25.2%, P = .041), or be read to less than 3 times per week (31.0% vs 13.7%, P < .001) compared with children of mothers without depressive symptoms. In addition, mothers with depressive symptoms were more likely to describe inconsistent discipline practices (36.6% vs 20.1%, P = .005) and less confidence in their parenting (39.4% vs 18.5%, P < .001). All associations remained significant in multivariate analyses controlling for maternal race, ethnicity, education, income, age, and household structure. CONCLUSIONS: Maternal depressive symptoms are associated with diminished positive parenting behaviors including dental care, reading, and discipline consistency for older preschoolers. These findings have implications for clinical pediatrics as well as preventive public health efforts.

Efficient energy based modeling and experimental validation of liquid filling in planar micro-fluidic components and networks.

This paper presents a model that describes how liquid flow fills micro-fluidic components and networks. As an alternative to computational fluid dynamic (CFD) simulations, we use a constrained energy minimization approach. This approach is based on two assumptions that hold in many micro-fluidic devices: (i) The length scales are small, and we consider slow filling rates, hence fluid momentum and viscous terms are small compared to surface tension forces, consequently the liquid/gas interfaces can be viewed as a succession of quasi-steady equilibrium configurations. (ii) Any equilibrium configuration corresponds to a surface tension energy minima which is constrained by the device shape and the volume of liquid in the device. The model is developed for planar micro-fluidic devices, is based on a fundamental physical principle, and shows accurate agreement with experimental data. It takes us only a few minutes to evaluate the model for a planar component of any shape using the Surface Evolver software, and this is significantly less then the computer run time required for CFD simulations. Moreover, once a library of component models has been created (which takes less than an hour of computer time) it then takes only seconds to simulate different network architectures with thousands of components. This fast "reconfigure the network and simulate in seconds" capability is essential for the design of truly complex networks that will enable the next generation of passive, micro-fluidic, lab-on-a-chip systems.

Prevalence of viable Toxoplasma gondii in beef, chicken, and pork from retail meat stores in the United States: risk assessment to consumers.

The prevalence of viable Toxoplasma gondii was determined in 6,282 samples (2,094 each of beef, chicken, and pork) obtained from 698 retail meat stores from 28 major geographic areas of the United States. Each sample consisted of a minimum of 1 kg of meat purchased from the retail meat case. To detect viable T. gondii, meat samples were fed to T. gondii-free cats and feces of cats were examined for oocyst shedding. Initially, 100 g of meat from 6 individual samples of a given species were pooled (total, 600 g), fed to a cat over a period of 3 days, and feces were examined for oocysts for 14 days; the remaining meat samples were stored at 4 C for 14 days (until results of the initial cat fecal examination were known). When a cat fed pooled samples had shed oocysts, 6 individual meat samples from each pool were bioassayed for T. gondii in cats and mice. Toxoplasma gondii isolates were then genetically characterized using the SAG2 locus and 5 hypervariable microsatellite loci. In all, 7 cats fed pooled pork samples shed oocysts. Toxoplasma gondii oocysts were detected microscopically in the feces of 2 of the cats; 1 isolate was Type II and the second was Type III. Analyzed individually, T. gondii was detected by bioassay in 3 of the 12 associated samples with genetic data indicating T. gondii isolates present in 2. The remaining 5 pooled pork samples had so few oocysts that they were not initially detected by microscopic examination, but rather by mouse bioassay of cat feces. Two were Type I, 1 was Type II, and 2 were Type III. None of the cats fed chicken or beef samples shed oocysts. Overall, the prevalence of viable T. gondii in retail meat was very low. Nevertheless, consumers, especially pregnant women, should be aware that they can acquire T. gondii infection from ingestion of undercooked meat, and in particular, pork. Cooking meat to an internal temperature of 66 C kills T. gondii.

Effect of mutations in Pneumocystis carinii dihydropteroate synthase gene on outcome of P carinii pneumonia in patients with HIV-1: a prospective study.

BACKGROUND: Investigators have reported that patients infected with Pneumocystis carinii containing mutations in the DHPS (dihydropteroate synthase) gene have a worse outcome than those infected with P carinii containing wild-type DHPS. We investigated patients with HIV-1 infection and P carinii pneumonia to determine if DHPS mutations were associated with poor outcomes in these patients. METHODS: We compared presence of mutations at the DHPS locus with survival and response of patients to co-trimoxazole or other drugs. FINDINGS: For patients initially given co-trimoxazole, nine (14%) of 66 with DHPS mutant died, compared with nine (25%) of 36 with wild type (risk ratio50.55 [95% CI=0.24-1.25]; p=0.15). Ten (15%) of 66 patients with a DHPS mutant did not respond to treatment, compared with 13 (36%) of 36 patients with the wild type (0.42 [0.20-0.86]; p=0.02). For patients aged 40 years or older, four (14%) of 29 with the mutant and nine (56%) of 16 with the wild type died (0.25 [0.09-0.67]; p=0.005). INTERPRETATION: These results, by contrast with those of previous studies, suggest that patients with wild-type P carinii do not have a better outcome than patients with the mutant when given co-trimoxazole. Our results suggest that presence of a DHPS mutation should be only one of several criteria guiding the choice of initial drug treatment of P carinii pneumonia in patients with HIV-1 infection.

All-cause mortality among young children in western Kenya. VI: the Asembo Bay Cohort Project.

Although all-cause mortality has been used as an indicator of the health status of childhood populations, such data are sparse for most rural areas of sub-Saharan Africa, particularly community-based estimates of infant mortality rates. The longitudinal follow-up of more than 1,500 children enrolled at birth into the Asembo Bay Cohort Project (ABCP) in western Kenya between 1992 and 1996 has provided a fixed birth cohort for estimating all-cause mortality over the first 5 yr of life. We surveyed mothers and guardians of cohort children in early 1999 to determine survival status. A total of 1,260 households were surveyed to determine the survival status of 1,556 live births (99.2% of original cohort, n = 1,570). Most mothers (66%) still resided but 27.5% had migrated, and 5.5% had died. In early 1999, the overall cumulative incidence of all-cause mortality for the entire 1992-1996 birth cohort was 26.5% (95% confidence interval, 24.1-28.9%). Neonatal and infant mortality were 32 and 176 per 1,000 live births, respectively. These community-based estimates of mortality in the ABCP area are substantially higher than for Kenya overall (nationally, infant mortality is 75 per 1,000 live births). The results provide a baseline description of all-cause mortality among children in an area with intense Plasmodium falciparum transmission and will be useful in future efforts to monitor changes in death rates attributable to control programs for specific diseases (e.g., malaria and HIV/AIDS) in Africa.

Lice, nits, and school policy.

BACKGROUND: The epidemiology of head lice infestation is poorly understood. Many schools treat all children with nits as though they are contagious. Children with nits but no lice are often removed from school until they are treated and all visible nits are removed. OBJECTIVE: To investigate the probability that children with nits alone will become infested with lice. DESIGNS: Prospective cohort study. SETTING: Two metropolitan Atlanta elementary schools. PARTICIPANTS: A total of 1729 children were screened for head lice. Twenty-eight children (1.6%) had lice, whereas 63 (3.6%) had nits without lice. Fifty of the 63 children (79%) with nits alone completed follow-up. OUTCOME MEASURE: Conversion (ie, becoming infested with lice) within 14 days after initial screening. RESULTS: Nine of 50 children (18.0%) followed for nits alone converted. Although children who converted did not have significantly more nits than did nonconverters, having nits near the scalp was a risk factor for conversion. Seven of 22 children (31.8%) with >/=5 nits within one fourth inch of the scalp converted, compared with 2 of 28 children (7.1%) with fewer (relative risk: 4.45; 95% confidence interval: 1.03-19.35). This risk remained statistically significant after separately stratifying for sex, recent treatment, and total number of nits. CONCLUSIONS: Although having >/=5 nits within one fourth inch of the scalp was a risk factor for conversion, most children with nits alone did not become infested. Policies requiring exclusion from school and treatment for all children with nits alone are likely excessive. Instead, these children may benefit from repeated examination to exclude the presence of crawling lice.lice, pediculus, lice infestations, pediatrics, school.