Infectious Diseases in Schools and Child Care Facilities

Objectives After completing this article, readers should be able to: Management of infectious diseases in schools and child care centers is becoming increasingly complex. The emergence of penicillin-resistant pneumococci (PRP) means that oral antibiotic treatment of common bacterial infections acquired in schools or child care facilities may be less successful in the future. The etiology of many rashes, fevers, and respiratory tract diseases now can be determined with relatively noninvasive procedures. If other children attending the same school or child care center have the same diagnosis, it is evident that a child probably acquired an infection such as parvovirus, influenza, or respiratory syncytial virus (RSV) in these facilities. Accordingly, issues related to infection control in these settings are of greater interest to parents and staff than in the past. Furthermore, because of immunization programs, serious infections are now less common in children, which has made parents less tolerant of their children acquiring these infections outside the home.Until the 1960s, the vast majority of preschool children were cared for in their own homes,initially entering a group setting at age 5 or 6 years, when they started school. Now, most preschoolers are exposed to large numbers of other children in a closed setting several days per week when they enter a child care facility. Child care facilities for preschoolers can be: The term “staff” refers to people who work in a school or child care facility.Respiratory and diarrheal illnesses have been shown consistently to be at least twice as common among preschool children cared for in child care centers than among preschool children cared for in their own homes. The incidence of these illnesses in children cared for in family day homes generally falls between these two rates.After the loss of passively transferred maternal antibody at 6 to 12 months of age, young children are susceptible to most infectious diseases. Children in a child care center typically spend their days in a room with 4 to 15 other children, some of whom may be asymptomatic, yet have infectious agents in their saliva or feces. On average,toddlers will put their hands or a toy in their mouths every 3 minutes. Staff usually have received minimal education about the importance of handwashing after diaper changes or prior to food preparation. Toilet-trained children often are not supervised to determine that they wash their hands after defecation. Therefore, infectious agents are transmitted readily from child to child in a child care center. Children cared for in their own homes or in a family day home probably have fewer infections, primarily because they are exposed to a smaller number of potentially infectious children.By school age, the incidence and severity of diarrheal and respiratory viral infections decreases. However,some viral illnesses, such as varicella or Epstein-Barr virus (EBV), result in more severe disease in adolescents than in younger children. The incidence of bacterial diseases such as acute otitis media or meningitis is lower in school-age children than in preschoolers; the incidence of group A Streptococcus (GAS) pharyngitis peaks between ages 5 and 15 years.The majority of viral respiratory tract infections(RSV, adenovirus, parainfluenza, and rhinovirus) are spread by large respiratory droplets. Organisms are believed to be transmitted only by direct contact with nasal secretions, eye secretions, or saliva. Therefore,infections that are spread by large droplets are far more likely to spread in a center in which there are very young children who share toys that are coated with saliva than in a school. Moreover, the attack rate in young children who acquire respiratory viral infections is almost 100% compared with possible asymptomatic infections in school-age children and adults. Caregivers who have asymptomatic infections caused by RSV or other respiratory viruses may spread these viruses by touching children after rubbing their own noses or eyes.Streptococcus pneumoniae, Haemophilus influenzae type B (HIB), nontypeable H influenzae, or Moraxella catarrhalis can be carried in the nasopharynx of asymptomatic children for weeks to months and are spread by large respiratory droplets. About 50% of 2-year-old children are carriers of S pneumoniae, with the carriage rate being highest in children who attend child care centers. This is probably because these children are more likely than children cared for at home to be exposed to the secretions of other children who are carriers. The carriage rate of all these organisms is highest in children who have viral upper respiratory tract infections and decreases with age. Usually, children who carry one of these organisms either remain well or develop acute otitis media with that organism when they have an intercurrent viral upper respiratory tract infection. However, occult bacteremia or invasive diseases such as pneumonia, meningitis, or a muskuloskeletal infection can follow carriage of S pneumoniae or HIB.Carriage of Neisseria meningitidis also usually is benign, but it can be followed by occult bacteremia, septic shock, meningitis, or septic arthritis. The risk of invasive disease with S pneumoniae, HIB, or N meningitidis is highest in children younger than 2 years of age because they lack antibodies to these organisms. The incidence of invasive disease with N meningitidis is highest in the first few days after the child has become colonized and is increased if the child is colonized by a virulent clone or has an intercurrent viral infection causing nasopharyngeal inflammation. The severity of illness is determined by the child’s immune response to the organism.GAS can be cultured from the throat of up to 30% of asymptomatic school-age children. Again,spread is usually by large respiratory droplets(although food- and waterborne outbreaks have been documented), and carriage of organisms frequently is not accompanied by clinical symptoms. However, some children develop pharyngitis or impetigo. More serious infections, such as pneumonia or necrotizing soft-tissue infections, occur rarely.Infections that are spread by small respiratory droplets include influenza, measles, mumps, rubella, and varicella. Pulmonary tuberculosis (TB) also is spread by small respiratory droplets, but children who have pulmonary TB usually are not contagious because they rarely develop cavitary disease. Because small droplets can be airborne over long distances, these infections are more contagious than are those spread only by large droplets.Bordetella pertussis is spread by respiratory droplets. Transmission is most common to people who have been within 5 ft of the infected person, but the high infectivity of the bacteria suggests that aerosolization also may occur.Diarrheal illnesses are spread primarily by oral contact with infectious agents in stool. Asymptomatic carriage of enteric pathogens such as Giardiacan persist for months. Fecal flora often can be grown from the hands of children and staff in child care centers. Therefore, spread can occur between children if a child who is a carrier of an enteric pathogen or who has infectious diarrhea touches a child who is not yet colonized or infected with that organism and the second child then puts his or her hands in the mouth. Child care workers who do not wash their hands after changing diapers can spread enteric infections among children. Children are most likely to acquire enteric infections during their initial 4 weeks in a child care facility,possibly because they acquire enteric pathogens from asymptomatic children and subsequently become immune to these pathogens. Spread of enteric organisms such as hepatitis A from asymptomatic children to child care staff and to parents has been well documented.The role of fecal contamination of the environment in spreading enteric pathogens is not known, but it seems likely that at least some cases of diarrhea are due to contact with a contaminated surface. Fecal contamination of diaper change areas, faucets, floors, and toys in child care centers is common, and organisms can remain viable on these surfaces for hours to days.Human immunodeficiency virus (HIV), hepatitis B, and hepatitis C are spread by direct contact with infected blood. HIV and hepatitis B (and possibly hepatitis C)also are spread by sexual contact. Therefore,transmission of these viruses in schools is only likely in the context of sexual contact or illicit drug use. Spread of hepatitis C or HIV has not been documented in a child care facility. Hepatitis B has been spread when a carrier child bit another child. The amount of hepatitis B in the saliva must have been sufficient to cause infection when delivered directly into the bloodstream. Transmission of hepatitis B never has been documented when an uninfected child has bitten a carrier child or in the absence of a biting incident. Cytomegalovirus (CMV) is spread by direct contact with infected urine or saliva. Child-to-child transmission in a child care facility occurs primarily among children younger than 3 years of age. Scabies is spread by direct contact with infected skin. Head lice are spread by direct contact with infected hair and possibly by fomites such as combs or hats. Impetigo, bacterial conjunctivitis, and tinea infections are spread by direct contact with infected lesions. Herpes simplex virus (HSV) infections of the skin or mucous membranes are spread by direct contact with lesions or infected secretions.Measures to prevent transmission of specific organisms are outlined in Table 1. Careful handwashing clearly decreases the spread of viral respiratory tract infections in a hospital, but this practice is far more difficult to enforce in a school or child care setting. Providing child care center staff with a single educational session about handwashing and proper disposal or decontamination of objects does not seem to decrease the incidence of viral infections. This may be because it is difficult to ensure that all staff attend the session, and there often is a high staff turnover rate. Ongoing education about the importance of handwashing has been shown in some child care settings to decrease the number of infections in children, their families, and child care center staff. However, ongoing surveillance for infections may be of more value, probably because compliance with handwashing improves if staff feel that they are being monitored. More data are required on the long-term efficacy and cost-effectiveness of educational and monitoring programs. In the mean time, the best way to encourage handwashing may be to educate staff in child care facilities about the potential benefits to their own health and to make handwashing convenient by having adequate sinks, soap, and towels. Staff who cook should not be responsible for child care.It is not known if exclusion of symptomatic children can decrease the spread of respiratory illnesses;organisms often are shed before symptoms are noticeable. Therefore, children who have respiratory tract infections and feel well enough to attend a child care center or school should be allowed to do so.Immunization of infants with conjugated vaccines for S pneumoniae and HIB decreases carriage and markedly decreases the risk of invasive disease. Prevention of spread of S pneumoniae, H influenzae, M catarrhalis, N meningitidis, and GAS infections probably is facilitated by handwashing by staff. Antibiotic prophylaxis for close contacts of children who have invasive N meningitidisinfections is indicated. Prophylaxis remains controversial for close contacts of patients who have invasive GAS infections. Now that most children are immunized against HIB, prophylaxis of contacts of children who have invasive HIB infection is indicated only if there are two cases within 60 days in a facility in which children are incompletely vaccinated. Antibiotic prophylaxis of contacts of children who have invasive S pneumoniae infections is not recommended; it has not been proven that contacts are at significantly increased risk of invasive disease, and the efficacy of prophylaxis has not been studied. However, interest in this issue has been renewed with the increasing prevalence of PRP that makes invasive pneumococcal infections more difficult to treat.Measures to prevent transmission of specific organisms are outlined in Table 2. Staff in schools and child care facilities play a limited role in preventing the spread of these infections. Immunization programs prevent the spread of measles, mumps, and rubella in group settings. They also decrease the spread of pertussis, but have not been as effective because pertussis vaccine efficacy in children is below 90%, and there is mounting evidence that most adults have waning immunity to pertussis. Therefore, adults develop mild pertussis that usually is not diagnosed and transmit the bacteria to susceptible children. Eradication eventually may be possible with routine booster immunization of adults with acellular pertussis vaccine.Ensuring that staff in schools and child care facilities have received all routine immunizations,including varicella immunization if they are not immune,may decrease the spread of vaccine-preventable infections.Exclusion of children who have varicella from child care facilities or school is controversial. The American Academy of Pediatrics (AAP) policy specifies that children can return to a child care facility or school once their lesions are crusted over, but the Canadian Pediatric Society policy allows children to return to a child care facility or school once they feel well enough to do so. Because children are contagious for at least 24 hours before they develop skin lesions, transmission commonly occurs before a child is recognized to have varicella. Therefore, exclusion of children who have skin lesions may not alter the course of an epidemic in a child care facility or school. If the goal is to eradicate varicella within schools and child care centers, a routine immunization program that includes postexposure immunization of nonimmune children or staff is likely to be the most effective measure. Postexposure immunization within 3 days of exposure is more than 90% effective in preventing clinical varicella.Measures to prevent transmission of specific organisms are outlined in Table 3. Developmentally normal children who have enteric infections can attend school. Exclusion of infected children from child care facilities is not necessary if toilet-trained children and staff practice adequate handwashing. However, because this is not always the case, children who are suspected of having infectious diarrhea should be excluded from child care facilities. Because the concentration of organisms in stool is lower in asymptomatic carriers, exclusion usually is not warranted. However, asymptomatic carriers of Escherichia coli 0157:H7 or Shigellashould be excluded from child care facilities because spread of Shigella requires only a small number of organisms, and infection with E coli 0157:H7 can result in severe sequelae. Establishing a separate room for children who have enteric or other infections may obviate the need for exclusion, but this often is not possible because of the extra staff and space required.Children and staff who have hepatitis A infection should be excluded from a child care facility or school for 7 days. Immune globulin (IG) prophylaxis is not indicated for school contacts unless there are multiple cases. Staff and children in the same room as an index case in a child care facility should receive IG. If the affected child wears diapers and hepatitis A appears to have been transmitted to a staff member or to two different families that have children in the center, all children and staff in the center should be give IG. Use of hepatitis A vaccine as prophylaxis is effective, but it is very expensive. Routine immunization of staff or children is recommended only in areas that have frequent outbreaks of hepatitis A infection.Measures to prevent transmission of specific organisms are outlined in Table 4. If universal precautions are enforced, the only situation in which infected children could pose a risk to others is by biting. Even then, the risk of transmission of HIV, hepatitis B, or hepatitis C is so low that routine screening for these viruses prior to a child entering a child care facility or school is not indicated.Children who have CMV infection usually are asymptomatic but will excrete the virus in their saliva and urine intermittently for years. Because CMV infection is usually benign in healthy children, spread among children in child care facilities is of little concern. However, a child who acquires CMV in a child care facility may spread it to a CMV-susceptible pregnant mother, resulting in teratogenicity. It has been shown that the annual seroconversion rate for seronegative adults who have children in child care centers is 15%. Pregnant child care center workers have a higher risk of having an infant who has congenital CMV infection than do women in other professions. Because CMV is shed in all body secretions for months or even years by asymptomatic children, it is not clear that good hygiene can prevent child-to-child transmission in a child care facility, but it may prevent child-to-staff transmission.Measures to prevent transmission of specific organisms are outlined in Table 5. Children who have HSV lesions of the skin, eyes, or mucous membranes usually can attend school or a child care facility because symptomatic disease rarely is transmitted to other children. However, preschool children who have primary gingivostomatitis from HSV should not attend a child care center because they have a much higher concentration of virus in their saliva,thereby increasing the risk of transmission.Transmission of infectious agents is a major problem in child care facilities and much less common in schools. Cost-effective interventions are available to prevent most serious infections. However, significant morbidity and inconvenience results from less serious infections such as viral diarrhea and upper respiratory tract infections. Until vaccines become available for these infections, future research should target the efficacy of different methods of improving general hygiene in schools and child care facilities.

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