What is the relationship between schools and infectious disease?
Infectious diseases are rarely the top concern of school and public health officials in the United States. Instead, of central concern are obesity, diabetes, asthma, smoking, substance abuse, eating disorders, and bullying behaviors. Now-routine immunization requirements for school entrance have reduced the occurrence of infectious diseases in schools in industrialized nations. However, these diseases have not been completely eradicated, and seasonal infections such as influenza require ongoing school readiness.
Particularly in the preschool and elementary school years, infections that visibly affect the skin, hair, and eyes are fairly common. These diseases may be caused by viruses, bacteria, fungi, or lice; they may be mild and self-limited with no other symptoms outside the skin, or they may cause significant illness.
Chickenpox. Although it is seen less commonly since the varicella vaccine was licensed in 1995, chickenpox still occurs in localized outbreaks in children who are not immunized. Chickenpox is caused by the varicella virus, which spreads easily by inhaling infected droplets released when a child sneezes or coughs. The virus can also be spread though direct contact with chickenpox skin blisters. Varicella vaccine is now required for school entrance in nearly every state, and it is about 90 percent effective in preventing the illness. For the small percentage of children who still develop chickenpox, even after being vaccinated, the illness is usually mild and, generally, comes with fewer than fifty skin lesions.
For nonimmunized children, chickenpox is more severe and may result in pneumonia, infection of the brain (encephalitis), and other complications. For this reason, one should never deliberately expose a child to chickenpox to “get the infection over with.” An infected child may be contagious for one or two days before any skin blisters appear, and the child will remain contagious (and should be kept home from school) until all of the blisters have dried up and crusted over.
Impetigo. Impetigo is an infection of the skin caused by Staphylococcus or Streptococcus bacteria. Both types of this disease are highly contagious by direct contact, and both spread easily among young children in preschool settings. Impetigo develops as an area of redness and blistering of the skin that quickly weeps (oozes) yellowish fluid and becomes covered with honey-colored crusts. This often occurs on the face or arms and begins in an area of irritated skin, such as a patch of eczema or a scratch. Treatment is with either oral antibiotics or an antibiotic cream, and the child should be kept from school until twenty-four hours after treatment is begun.
Erythema infectiosum. Also called fifth disease, erythema infectiosum is a mild illness often seen in school outbreaks in the late winter and spring months. Generally, the only symptoms are reddened cheeks followed by a fine, lacy, red rash over the trunk that may be slightly itchy. This infection is caused by parvovirus B19; about one-half of adults are immune. However, adults and older children not previously exposed may also have painful and swollen joints, and there can be some risk of miscarriage for nonimmune pregnant women exposed to the virus. Children with fifth disease are contagious only before they break out in the rash, and they are no longer contagious by the time the rash appears. For this reason, most school systems do not advise keeping an otherwise asymptomatic child with fifth disease at home.
Head lice. Head lice (pediculosis capitis) has long been associated with school-related infectious diseases, and it is most common in preschool and elementary school children. Infestation of the hair with these 2 millimeter parasitic insects generally causes more anxiety than actual physical discomfort, as the lice do not carry disease and tend to cause only minor itching. In many countries, cases of head lice appear in nearly all children.
Lice treatments involve the application of one of several approved treatments (available over the counter and by prescription), with repeat treatments either on day nine or in a three-dose regimen with repeat treatments on days seven and fourteen. In the past, undergoing treatment meant that children would be refused readmission to school until treatment was completed and there were no remaining visible “nits” (eggs and dead egg-casings) clinging to the hair shaft. However, the difficulty in removing all nits even after successful treatment, and the frequent misidentification of dandruff, skin particles, and scabs as nits, led to many uninfested children being excluded from school for an average of twenty days.
Many school policies are changing. Head lice are most commonly spread by direct head-to-head contact, which is not commonplace in the classroom beyond the preschool years. Lice are much less likely to be spread by the shared use of brushes, combs, and headgear. In the United States, most head lice are probably transmitted during close sleeping arrangements, such as the sharing of beds at sleepovers and summer camps, rather than at school. The American Academy of Pediatrics (AAP) recommends that school nurses be well trained in proper diagnosis of head lice, particularly in recognizing nits, mainly to avoid diagnostic confusion. At the same time, the AAP recommends that school districts abandon their “no-nit” policies for a child’s return to school, and that children should return to school the day after their first treatment, even if nits remain visible in the hair.
Conjunctivitis. The most common cause of conjunctivitis, or pinkeye, is a viral infection of the clear membrane covering the white of the eye and lining the eyelids. Viral conjunctivitis causes reddened, itchy eyes with a clear watery discharge, and it is spread by contact with secretions (tears and nasal discharge) that often are spread from the fingers. Children may remain contagious for ten to twelve days. Bacterial conjunctivitis also causes reddened eyes, but it is more likely to result in thick, puslike, yellow or green eye secretions, and it responds quickly to antibiotic drops. Students with bacterial conjunctivitis can usually return to school twenty-four hours after beginning treatment, but students with viral conjunctivitis should remain home until they are symptom free or until cleared by a physician.
Methicillin-resistant Staphylococcus aureus (MRSA). MRSA has become a problem in schools, particularly in physical education classes and high school athletic programs. This type of bacteria mainly causes skin infections, usually of open wounds, and is resistant to many common antibiotics that were previously able to treat Staphyloccocus (staph) infections. MRSA causes redness, swelling, pain, and pus, and it must be diagnosed by a bacterial culture. It spreads by direct skin-to-skin contact or by contact with a used bandage, towel, or surface in a locker room or other athletic facility. Athletes who have a break in the skin should clean the area and cover it to prevent infection. Those who already have an MRSA-infected wound should always keep the area completely covered to prevent spreading the infection to another person. As long as the infected area is not draining and can be completely covered, infected athletes, according to the CDC, do not need to be excluded from athletic participation. It also is not necessary to close or completely disinfect a school if a student has been diagnosed with MRSA.
Common cold. The most common respiratory illness in schools is the viral infection known as the common cold. Caused by a variety of viruses and spread by coughs, sneezes, and contaminated surfaces such as doorknobs, colds affect otherwise healthy young children up to six times per year. Chances are that each classroom will have a minimum of one child with a cold. Although some preschools and day-care centers may exclude children from attending if they exhibit cold symptoms, no medical reason exists for doing so, because these illnesses are mild, self-limited, and ubiquitous.
Influenza. Another respiratory illness, influenza, is of much greater concern in schools. Influenza, commonly referred to as the flu, is characterized by respiratory symptoms more severe than those of the common cold. Flu symptoms also include high fever, headache, and muscle aches, and the flu has the potential for complications, including pneumonia and, rarely, death. The illness is contagious and is transmitted through inhaling or contacting the droplets of an infected person’s cough or sneeze.
Influenza occurs in predictable seasonal outbreaks during the winter months in both the Northern (peaking in January and February) and Southern (peaking in July and August) hemispheres. Several slightly different influenza viruses circulate each year, and these viruses tend to change year to year. Each year’s flu vaccine is tailored to prevent the viruses that are predicted for that year by virologists. These predictions are not always completely correct, meaning that in some years, even those persons who get that season’s vaccine will not be well protected.
Schools have three main strategies at their disposal for preventing large outbreaks of influenza among students and staff. The primary tool is immunization. The CDC recommends that all children older than age six months receive an annual seasonal influenza vaccine, and schools often encourage this by means of letters and other reminders to parents. Particularly in years in which a new strain of flu is causing a pandemic, such as the 2009 H1N1 virus pandemic, schools may provide in-school vaccinations with parental approval.
The second strategy available to schools for the prevention of influenza outbreaks is attention to basic hygiene measures. Schools are teaching children to cover their mouths and noses with a tissue when coughing or sneezing and to discard the tissue in the trash immediately afterward. Alternatively, children are being taught to sneeze into their arms near their elbows, instead of into their bare hands, if no tissue is available. Handwashing is emphasized as a means to prevent transmission after coughing, sneezing, blowing one’s nose, or touching an object that has been used by a sick person. In preschools and elementary schools, children should be given frequent opportunities for handwashing, and when no water is available, children should have access to a gel-based hand sanitizer. These concepts can be reinforced as part of morning announcements, in handouts, and through frequent review.
The third tool available to schools to manage influenza is attendance policy. Children and staff who display flulike symptoms should not attend school. However, because persons with influenza are contagious for about twenty-four hours before showing any symptoms, and will remain contagious until about the fifth day of illness, this type of attendance policy cannot completely protect students and staff. During the 2009 pandemic flu season, some schools closed when a significant number of students became ill. In general, however, this practice is not recommended for a variety of reasons, including that when schools are closed, parents often bring younger children to a babysitter, a neighbor, or even to the workplace. Older children, especially teenagers, often use this time away from school to congregate with their friends, often in public places. Overall, it appears that a school closure because of a flu scare aids in spreading the virus into the community, rather than keeping it contained. However, if absenteeism among teachers and staff is so high that the school cannot function appropriately, school closures may be inevitable.
Strep throat. Streptococcal pharyngitis, or strep throat, is another common respiratory illness in school-age children. The majority of sore throats are caused by some of the many viruses that cause the common cold, but up to 30 percent may be caused by the bacterium Streptococcus pyogenes. Children with a sore throat, fever, swollen lymph nodes (glands) in the neck, headache, and, sometimes, abdominal pain and vomiting are most likely to have strep throat, which is spread by infected droplets from coughing and sneezing and from contaminated hands. Strep throat should be diagnosed either by a rapid screening test or a throat culture, so that antibiotics are not used unnecessarily for a viral infection. Antibiotics should be given for a minimum of twenty-four hours before an infected child returns to school, and they are critical for the prevention of later complications from S. pyogenes. These complications include scarlet fever, heart valve damage, and kidney damage.
Bacterial meningitis. Bacterial meningitis is a serious illness that is life-threatening, may begin during the school day, and may progress in severity in a matter of hours. Any child who develops a headache, along with a stiff neck, fever, confusion, or rash or discoloration of the skin, should be taken to a hospital for emergency treatment. If a certain type of bacterial meningitis (meningococcal meningitis) is diagnosed, health officials will contact the school and identify students and staff who were in direct contact with the infected child so that prophylactic (preventive) antibiotics can be administered to all who had contact.
Bacterial meningitis spreads by infected droplets from a cough or sneeze. A vaccine called meningococcal conjugate vaccine (MCV4) is routinely recommended at ages eleven and twelve years. Meningitis is also caused by a wide variety of viruses and is generally less severe. It is not prevented by or treated with antibiotics.
Gastroenteritis. Diarrhea and vomiting (gastroenteritis) is usually a more serious problem among preschool and early elementary age students, who are more likely to have poor restroom hygiene and more likely to put their hands, toys, and other items in or near their mouths. Infections causing these symptoms can be classified as being waterborne, food-borne, or acquired from another person or animal through contact with their feces or body secretions.
A sudden, large outbreak of gastroenteritis in a school is often caused by a food-borne illness from cafeteria food. In this case, school officials should alert local or state health officials. Health officials will conduct an investigation of the outbreak to determine the cause. The investigation will include extensive questioning of students and staff, microbiological testing of food remnants and kitchen surfaces, and medical testing of cafeteria staff.
Other sudden, large outbreaks in a school may prove to be caused by noroviruses, which can be food-borne but are more often spread quickly and easily from person to person through either direct contact with contaminated feces or vomit or from touching contaminated surfaces such as restroom doors or another person’s towel. A norovirus infection tends to cause a day or two of severe diarrhea in children, and then clears on its own.
Given that fifty-five million children age eighteen years and younger attend schools each day in the United States, an infectious disease affecting one child could potentially affect (and infect) many more. Many of the worst infectious diseases are rarely, if ever, seen in today’s schools because of stringent, compulsory school immunization laws. Today’s schools, however, face other potential infectious disease challenges.
Some students remain unimmunized because of their parent’s religion, or because of other reasons, providing an opening for disease outbreaks. Antibiotic resistance, such as that seen with MRSA infections, is likely to become a more widespread problem. Immigrant populations in some areas increase a student’s potential exposure to tuberculosis. As teens engage in oral and genital sex at earlier ages, herpes infections, gonorrhea, human immunodeficiency virus infection, and other sexually transmitted infections will likely become more prevalent among teen social networks, which tend to revolve around school activities. School nurses and administrators, and public health officials, should continue to devote time and attention to infectious disease in the schools.
Aronson, Susan S., and Timothy R. Shope. Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide. 2d ed. Elk Grove Village, Ill.: American Academy of Pediatrics, 2009. A reference on infectious disease management and prevention in school and child-care settings.
Centers for Disease Control and Prevention. “Questions and Answers About Methicillin-Resistant Staphylococcus aureus (MRSA) in Schools.” Available at http://www.cdc.gov/features/mrsainschools.
Fisher, Margaret C. Immunizations and Infectious Diseases: An Informed Parent’s Guide. American Academy of Pediatrics, 2006. A pediatrician explains childhood infection and its prevention.
Frankowski, Barbara L., and Joseph A. Bocchini, Jr. “Clinical Report: Head Lice.” Pediatrics 126 (August, 2010): 392-403. A report from the American Academy of Pediatrics’ Council on School Health and the Committee on Infectious Diseases includes a clinical overview of head lice diagnosis and treatment and expert opinion on school policies related to head lice.
Lee, Marilyn B., and Judy D. Greig. “A Review of Gastrointestinal Outbreaks in Schools: Effective Infection Control Interventions.” Journal of School Health 80 (2010): 588-598. A review of documented gastrointestinal illness outbreaks in schools since 2000.