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PEDIATRICS Vol. 105 No. 4 April 2000, pp. 738-742
,
From the * National Centre for Epidemiology and Population
Health, Australian National University; and Epidemiology and
Surveillance Branch, New South Wales Health Department,
Australia.
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ABSTRACT |
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Top
Abstract
Methods
Results
Discussion
References
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Background. Acute upper respiratory infections are common in children who attend child care, and preventing transmission of disease in this setting depends on actions by child care staff. We set out to discover whether transmission of respiratory infections in child care could be reduced by improved infection control procedures.
Methods. We performed a cluster, randomized, controlled trial of an infection control intervention conducted in child care centers in 1 city in Australia. The intervention was training of child care staff about transmission of infection, handwashing, and aseptic nosewiping technique. Implementation of the intervention was recorded by an observer. Illness was measured by parent report in telephone interviews every 2 weeks.
Results. There were 311 child-years of surveillance for respiratory symptoms. By multivariable analysis, there was no significant reduction in colds in intervention center children across the full age range. However, a significant reduction in respiratory illness was present in children 24 months of age and younger. When compliance with infection control practices was high, colds in these children were reduced by 17%.
Conclusions. This trial supports the role of direct transmission of colds in young children in child care. The ability of infection control techniques to reduce episodes of colds in children in child care was limited to children 24 months of age and under. Key words: common cold transmission, child care, child day care centers.
Acute upper respiratory infections are common in children
who attend child care.1,2 The increased risk of illness
with child care attendance is greatest in the first 2 years of a
child's life but decreases in their third year.1 These
illnesses carry economic and opportunity costs from parent loss of work
and leisure time and can predispose to secondary infection, such as
otitis media. They may also result in secondary transmission to other
members of the child's household. Child care is a unique environment
for transmission of respiratory viruses; young children have developing
immune systems and little personal hygiene, they are unable to wipe or
blow their own nose, and they are exposed to their peers for long
periods. Preventing transmission of disease in this setting depends on
actions by child care staff who may have little training in or
understanding of disease transmission.
We set out to discover whether transmission of respiratory infections
in child care could be reduced by improved infection control
procedures. There is ongoing debate about how colds are transmitted and
the primary route may be different for adults and children. Colds may
be spread by aerosols produced by coughing and sneezing or they may be
transmitted by hand contamination. Hands contaminated by directly
touching respiratory secretions or indirectly from contaminated fomites
may then inoculate a new host with the virus. Spread of colds may also
result from a combination of both these methods.3-6 It is
clear that after blowing a nose, respiratory viruses are found on
hands.7,8 We hypothesized that in child care, where the
care giver wipes many children's noses, the care giver's hand may be
contaminated and transmit respiratory viruses. Similarly, the
children's hands may become contaminated with viruses as they touch or
wipe their hand around their nose or touch fomites contaminated by
another child. Prevention of spread of respiratory syncytial virus
infections in hospitals has been possible with use of infection control
methods and this is the most common virus isolated from children in
child care.9,10
Only 1 randomized, controlled trial in child care has reported the
impact of an infection control intervention on respiratory infections
and found no reduction in incidence.2 However, the
intervention may not have specifically targeted transmission of colds.
Here we describe a successful trial designed to alter incidence of
acute upper respiratory illness in children under 4 years of age in the
Australian Capital Territory (ACT) in 1996.
We performed a cluster, randomized, controlled trial to
investigate an infection control intervention conducted in child care centers in the ACT between March and November 1996. Centers eligible to
participate in the trial were those licensed in the ACT at February 1, 1996 to care for 50 or more children for 10 hours a day, 5 days a week.
We invited directors of all eligible day care centers to participate.
One center was used as a pilot center to develop and test methods for
the trial and did not participate in the trial. We delivered
information booklets about the trial for staff and parents at each
center and recruited parents of children by letter delivered through
the centers. Centers were randomized to the intervention group after
the center directors agreed to participate in the trial, using a random
number table generated using EpiInfo (Centers for Disease Control and
Prevention, Atlanta, GA).11
Eligible children were 3 years of age or younger at January 1, 1996, attended the child care center for at least 3 days per week, and had no
underlying chronic illness that predisposed to infection. Parents
enrolled their child by completing an enrolment and consent form
returned via the child care center.
A target sample size of 306 child-years of observation was determined
based on requiring 85% power to detect an 11% reduction in
respiratory illness from a background rate of 8 respiratory infections
per child-year, using a test of 5% significance level.12 We adjusted the sample size by a factor of 1.3 for clustering, this
being appropriate for an intracluster correlation coefficient of .01 with 20 clusters and 28 children in each cluster.13,14 The
required clustered sample was, therefore, 398 child-years of
observation or 530 children observed for 9 months.
Training for the intervention centers was performed by L.R. in March
1996. The training incorporated elements of good health training for
child care workers developed by Kendrick15 and a practical
exercise of handwashing using GloGerm (GloGerm, Moab,
UT).16 The training sessions were of 3 hours long and were
held in the evening in the child care centers for all staff of the
center. Staff, who were unable to attend training in their own center,
were invited to attend sessions in other centers. Staff who were not
able to attend any training, or who joined the center after March 1996 were trained in a 1-hour lesson during lunch periods. We reinforced
training and communicated techniques and routine practices in
fortnightly visits and newsletters for intervention centers. Staff in
control centers undertook training and received newsletters at the end
of the trial in November 1996. We did not ask parents to adopt any
intervention in the home.
The recommended handwashing technique is outlined in the Australian
National Health and Medical Research Council Guidelines for preventing
infectious diseases in child care.17 The duration of a
handwash of an approximate "count to 10" to wash and "count to
10" to rinse was emphasized. Child care staff were asked to teach the
handwashing method they had learned to the children in their care and
to perform handwashes for infants too young to be able to wash their
hands unassisted. We developed techniques to encouraged children to
wash their hands well, such as the use of songs about handwashing in
melodies of nursery rhymes. The recommended circumstances for
handwashing for staff and children were after toileting, before eating,
after changing a diaper (staff and child), and after wiping a nose
unless a barrier was used to protect the hand from contamination. Where
possible, nose wipes were conducted by staff using a small plastic bag
to cover their hand like a glove. The plastic bags used were bags for
sandwiches available at supermarkets.
The primary outcome measures were parent reports of symptoms of illness
in telephone interviews every 2 weeks. To improve the parents' recall
of illness, we issued calendars at the beginning and middle of the
trial. The calendars included definitions of illness and were
A4-sized pages that could be secured with refrigerator door
magnets incorporating the trial logo. The interviewers asked a standard
set of questions about symptoms of respiratory and diarrheal illness,
general practitioner diagnosis of otitis media, medication given,
health service use, and parent and child absenteeism from work and
child care. The symptoms of acute upper respiratory illness elicited
from parents were: a runny nose, a blocked nose, and cough. We used a
definition of colds based on a community intervention trial of
virucidal impregnated tissues.18 A cold was defined as
either two symptoms for 1 day or 1 of the respiratory symptoms for at
least 2 consecutive days but not including 2 consecutive days of cough
alone. We defined a new episode of a cold as the occurrence of
respiratory symptoms after a period of 3 symptom-free days.
Parents also completed a self-administered questionnaire about risk
factors that may modify respiratory infections as described in Table
1.
TABLE 1
METHODS
Top
Abstract
Methods
Results
Discussion
References
Risk Factors for Respiratory Illness Included in Multivariable Model
The secondary outcome measure was implementation of the intervention. One observer recorded compliance with recommended practices for a period of 3 hours in the morning in each center, both intervention and control, every 6 weeks. The observer was not informed of the content of the training sessions or the intervention status of the centers. The staff members in the centers were aware the observer was watching hygiene practices but not which specific practices were being recorded. From the observational data, we graded compliance, by quantiles of frequency of recommended handwashing by children and nose wiping by staff.
We analyzed the data using Stata Statistical Software Release 5.0 (Stata Corporation, College Station, TX).19 We calculated incidence of colds per child-year for all children and then for children in 2 age groups (over 24 months of age and 24 months of age or under). We constructed Poisson regression models with robust confidence interval (CI) estimates adjusting standard errors for the impact of clustering by center. Our modeling strategy followed recommendations by Kleinbaum.20 The goal of our model was to obtain a valid estimate of the exposure disease relationship. We applied the multivariable model for all children and children in the 2 age groups. We further analyzed the results by grading compliance in intervention centers, maintaining analysis by intent-to-treat by comparing intervention grades with control centers.
We explored the impact of the intervention on days children were absent from care with an upper respiratory infection. We defined a day absent from child care with respiratory infection as a day where the parent reported the child was away from child care because of illness, had symptoms of an upper respiratory infection that met our definition of a cold, and did not have diarrhea.
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RESULTS |
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Top
Abstract
Methods
Results
Discussion
References
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The recruitment rate for child care centers was 88% (23/26). After randomization, there were 11 intervention and 12 control centers. Sixteen of the centers were commercially operated (8 intervention and 8 control centers). The remainder were community-operated, nonprofit centers (3 intervention and 4 control centers). There was no difference between the proportion of staff with child care qualifications in intervention and control centers (59/125 and 58/110, respectively; P = .4). In all centers, children were separated by age into differing care rooms with a range of between 3 and 5 rooms per center. Staff to child ratios, regulated by the government, ranged from 1 to 5 for care of infants to 1 to 12 for care of preschool children.
Children were enrolled in the trial for 113 677 days representing 311 child-years (Fig 1). Approximately one third of the children were 1, 2, or 3 years old, respectively (Fig 2). The attrition rate during the trial was 22% (51/299, 17% intervention and 72/259, 28% control). This coincided with offers of young retirement with remuneration from the principal employer in the city, the Commonwealth Government of Australia.
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The incidence of episodes of colds per child-year was lower in intervention centers than in control centers. However, this was attributable to a decrease in infections in children 24 months of age and younger, not in children over 24 months of age (Table 2). There was no difference in incidence by intervention status in males compared with females, the stratified incidence rate ratio for males being .91 and for females .93. The intracluster correlation coefficient for colds in intervention centers was .008 and in control centers was .016.
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The final multivariable model adjusted for confounding by 17 variables and clustering by center. There were no significant interaction terms between confounding variables and the exposure. No subset of confounders improved precision and identified the same risk as the model with all confounders. The variables in the final model are listed in Table 1.
Using the fully adjusted model, there was no significant reduction in colds in intervention center children across the full age range. However, a significant reduction in illness was present in children 24 months of age and under (Table 3).
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We graded compliance for children washing their hands into 3 groups, corresponding to intervention centers with a score of low, moderate, and high compliance. Performance of nose wiping could only be divided into 2 groups because overall compliance was very good with a mean of 97%. Improved compliance with infection control procedures was associated with lower illness but the effect was still confined to younger children. With high compliance of nose wiping and child handwashing, colds were reduced by between 11% and 17% in young children (relative risk [RR]: .89 and .83, respectively; P < .001; Tables 4 and 5).
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The incidence of children absent from child care with a cold was lower in the intervention group (6 per child-year, 1014/62 159 child-days) compared with the control group (7 per child-year, 1033/51 518 child-days). After adjusting for confounding and clustering by center, the RR of absence from child care with a respiratory infection was reduced by 15% but was not statistically significant (RR: .85; 95% CI: .66,1.08; P = .19). No significant reduction was present in children 24 months of age and under (RR: .89; 95% CI: .65,1.21; P = .45) or children over 24 months of age (RR: .78; 95% CI: .55,1.11; P = .18).
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DISCUSSION |
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Top
Abstract
Methods
Results
Discussion
References
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This trial supports the role of direct transmission of colds in young children in child care and interruption of transmission by infection control techniques that reduce hand contamination with respiratory viruses. The ability of infection control techniques to reduce episodes of colds in children in child care was limited to young children 24 months of age and under. It is not surprising that this effect was only seen in very young children. In a longitudinal study, Wald et al1 showed that in the first 2 years of life, children who attend child care have an increased risk of frequent respiratory infection. It is plausible that the intervention had a demonstrable impact on the youngest children who are those least able to blow their own noses and wash their own hands. Mobility and the number of contacts a child plays with may also be plausible reasons for why the intervention reduced illness only in younger children.
When compliance was good, the effect in young children was substantial. A 17% reduction in respiratory infections in the youngest children attending formal child care in Australia translates to preventing over 100 000 colds per year. Apart from reducing child morbidity, there are other likely effects on secondary illness for families because young children frequently introduce respiratory infections to a household.21 We were unable to measure secondary infections in this trial. Although reduction in respiratory illness in this setting did not translate to a significant reduction in absence from child care, this is consistent with practice in Australia where children with upper respiratory infection are rarely kept away from care.
The inverse dose-response effect of 2 aspects of the infection control intervention, nose wiping and child handwashing, supports the argument that infection control procedures were responsible for reducing illness as implementation of the practices improved the RR of illness decreased. To have an impact in young children, infection control techniques needed to be used consistently. Implementing recommended handwashing <70% of the time had no impact on infection at all and recommended nose wipes needed to be performed at least 97% of the time to reduce infection. We did not separate nose wipes performed with a sandwich bag barrier from handwashing after a nose wipe; however, the observer commented that she rarely observed a handwash after a nose wipe. The sandwich bag barrier was a welcomed intervention. As the training in this intervention was a comprehensive approach to infection control, it may be that these 2 measured infection control procedures may not be responsible alone for reducing illness. They may be markers of general good performance of infection control including techniques not measured in the observations but implemented in the trial, such as daily washing of toys.
This is the first work that reports a significant reduction of respiratory illness in child care in a community based intervention and, therefore, needs to be replicated. The study population may not be generalizable to other settings, the families in this trial were predominantly affluent, Caucasian, with 2 well educated parents in the home. We did not directly inform parents of their center's intervention status, but they may have recognized this from other sources and parent reporting of illness may have been biased by this knowledge. The ability of the intervention to reduce illness is supported by the dose-response effect of compliance with the infection control methods. However, the recording of this compliance could have been prone to bias from the observer. The dropout rate in the control group was higher than in the intervention group and this may have introduced a selection bias if related to occurrence of respiratory infection. This is unlikely because the out migration occurred from children reducing their care attendance at a time of downturn in employment in the city.
This study supports the need and benefit of training of child care staff who care for young children about infection control methods. Because reduction in illness was only seen when infection control techniques were rigorously applied, measurement of compliance with training is crucial. Good handwashing of infants and toddlers hands and protection of caregivers' hands when wiping noses are simple interventions readily applicable to child care settings.
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ACKNOWLEDGMENTS |
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This work was supported by a grant from the Commonwealth Department of Family Services and Health, Research and Development Scheme.
We thank the staff and parents of all participating child care centers, Datacol Research, and Sharon Dale.
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FOOTNOTES |
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Received for publication Feb 18, 1999; accepted Sep 28, 1999.
Reprint requests to (L.R.) National Center for Epidemiology and Population Health, Australian National University, 0200, Canberra, Australia. E-mail: leslee.roberts{at}anu.edu.au
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ABBREVIATIONS |
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ACT, Australian Capital Territory; CI, confidence interval; RR, relative risk.
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REFERENCES |
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1110This article has been cited by other articles:
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  A. E. Aiello, R. M. Coulborn, V. Perez, and E. L. Larson Effect of Hand Hygiene on Infectious Disease Risk in the Community Setting: A Meta-Analysis Am J Public Health, August 1, 2008; 98(8): 1372 - 1381. [Abstract] [Full Text] [PDF]
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 V. Rhee, L. C. Mullany, S. K. Khatry, J. Katz, S. C. LeClerq, G. L. Darmstadt, and J. M. Tielsch Maternal and Birth Attendant Hand Washing and Neonatal Mortality in Southern Nepal Arch Pediatr Adolesc Med, July 1, 2008; 162(7): 603 - 608. [Abstract] [Full Text] [PDF]
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 T. J. Sandora, M.-C. Shih, and D. A. Goldmann Reducing Absenteeism From Gastrointestinal and Respiratory Illness in Elementary School Students: A Randomized, Controlled Trial of an Infection-Control Intervention Pediatrics, June 1, 2008; 121(6): e1555 - e1562. [Abstract] [Full Text] [PDF]
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 W. J. Durbin and C. Stille Pneumonia Pediatr. Rev., May 1, 2008; 29(5): 147 - 160. [Full Text] [PDF]
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S. B. Lambert, K. M. Allen, J. D. Druce, C. J. Birch, I. M. Mackay, J. B. Carlin, J. R. Carapetis, T. P. Sloots, M. D. Nissen, and T. M. Nolan Community Epidemiology of Human Metapneumovirus, Human Coronavirus NL63, and Other Respiratory Viruses in Healthy Preschool-Aged Children Using Parent-Collected Specimens Pediatrics, October 1, 2007; 120(4): e929 - e937. [Abstract] [Full Text] [PDF]
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 L. Rosen, O. Manor, D. Engelhard, and D. Zucker Design of the Jerusalem Handwashing Study: meeting the challenges of a preschool-based public health intervention trial Clinical Trials, August 1, 2006; 3(4): 376 - 384. [Abstract] [PDF]
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L. Rosen, O. Manor, D. Engelhard, and D. Zucker In Defense of the Randomized Controlled Trial for Health Promotion Research Am J Public Health, July 1, 2006; 96(7): 1181 - 1186. [Abstract] [Full Text] [PDF]
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T. J. Sandora, E. M. Taveras, M.-C. Shih, E. A. Resnick, G. M. Lee, D. Ross-Degnan, and D. A. Goldmann A Randomized, Controlled Trial of a Multifaceted Intervention Including Alcohol-Based Hand Sanitizer and Hand-Hygiene Education to Reduce Illness Transmission in the Home Pediatrics, September 1, 2005; 116(3): 587 - 594. [Abstract] [Full Text] [PDF]
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S. S. Aronson 2004 Job Lewis Smith Acceptance Address Pediatrics, May 1, 2005; 115(5): 1397 - 1401. [Full Text] [PDF]
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G. M. Lee, J. A. Salomon, J. F. Friedman, P. L. Hibberd, D. Ross-Degnan, E. Zasloff, S. Bediako, and D. A. Goldmann Illness Transmission in the Home: A Possible Role for Alcohol-Based Hand Gels Pediatrics, April 1, 2005; 115(4): 852 - 860. [Abstract] [Full Text] [PDF]
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T. R. Shope and S. Aronson Improving the Health and Safety of Children in Nonparental Early Education and Child Care Pediatr. Rev., March 1, 2005; 26(3): 86 - 95. [Full Text] [PDF]
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L. F. Kelly Pediatric Cough and Cold Preparations Pediatr. Rev., April 1, 2004; 25(4): 115 - 123. [Full Text] [PDF]
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 J. T. Weber and J. M. Hughes Beyond Semmelweis: Moving Infection Control into the Community Ann Intern Med, March 2, 2004; 140(5): 397 - 398. [Full Text] [PDF]
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 J. R. Rubino Economic Impact of a Healthy School Environment The Journal of School Nursing, October 1, 2002; 18(4_suppl): 27 - 30. [PDF]
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 Other articles noted Evid. Based Nurs., October 1, 2000; 3(4): 106 - 112. [Full Text]
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 Infection Control Measures Reduce URIs and Diarrhea in Day-Care Centers Journal Watch Infectious Diseases, July 1, 2000; 2000(701): 10 - 10. [Full Text]
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