Schools and infectious disease

Definition

Infectious diseases were rarely the top concern of school and public health officials in the United States. Other issues, such as obesity, diabetes, asthma, smoking, substance abuse, eating disorders, and bullying behaviors, garner more attention, perhaps because immunization requirements have reduced infectious diseases in developed countries. Nonetheless, these diseases have not been completely eradicated. Seasonal infections such as influenza still require preparedness from schools. Following the COVID-19 pandemic in the 2020s, accompanied by an increased prevalence of respiratory syncytial virus (RSV), influenza, and the reemergence of measles due to vaccine hesitancy, infectious diseases in schools became a primary concern for educators and policymakers. Schools increased infection control measures, improved ventilation, and began back-to-school campaigns that encouraged vaccinations.

Contagious Diseases of the Skin, Hair, and Eyes

Infections that visibly affect the skin, hair, and eyes are fairly common in both preschool and elementary schools. These diseases may be caused by viruses, bacteria, fungi, or lice. They can either be mild with no other symptoms outside the skin, or they may cause significant illness.

Chickenpox. Although less common since the varicella vaccine was licensed in 1995, chickenpox still occurs among children who are not immunized, and some cases of breakthrough chickenpox occur in vaccinated children. Chickenpox is caused by the varicella virus, which spreads easily by inhaling infected droplets released through sneezes or coughs. The virus can also be spread through direct contact with chickenpox skin blisters. The varicella vaccine is 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. The CDC recommends a second dose of the vaccine to prevent these cases.

For non-immunized children, chickenpox is more severe and may result in pneumonia, infection of the brain (encephalitis), and other complications. A discredited practice is to deliberately expose a child to chickenpox to “get the infection over with.” An infected child may be contagious for one or two days before skin blisters appear. 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 non-immune 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) infestation 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 uninfected children being excluded from school for an average of twenty days.

Many school policies have changed. 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 sharing beds at sleepovers and summer camps rather than at school. The American Academy of Pediatrics (AAP) recommends that school nurses be well-trained in properly diagnosing head lice, particularly in recognizing nits, 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. However, some schools continue to enforce no-nit policies.

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, pus-like, yellow or green eye secretions and 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 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 Staphylococcus (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 with a break in the skin should clean and cover the area to prevent infection. Those with an MRSA-infected wound should always keep the area covered to avoid spreading the disease 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. Closing or completely disinfecting a school is unnecessary if a student has been diagnosed with MRSA.

The World Health Organization (WHO) and CDC warned about declining childhood immunization rates in the US and Europe in the early twenty-first century, which increases the risk of measles, mumps, and pertussis (whooping cough) outbreaks in schools. With a rise in vaccine hesitancy, measles outbreaks in schools became an increasing concern in the 2010s and 2020s. Ringworm (tinea) outbreaks in schools also increased due to the rise of antifungal-resistant strains.

Respiratory Infections

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 in the Northern Hemisphere, which peaks in January. In the Southern Hemisphere, influenza cases are greatest in July and August. Several slightly different influenza viruses circulate each year, changing from year to year. Each year’s flu vaccine is tailored to prevent that year's viruses as predicted by virologists. These predictions are not always correct, meaning that in some years, even those who get that season’s vaccine will not be well protected.

Schools have three main strategies for preventing large outbreaks of influenza among students and staff. The primary tool is immunization. The CDC recommends that all children older than six months receive an annual seasonal influenza vaccine. Schools often encourage this through 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. Nasal spray vaccines are an encouraged option for children who fear needles.

The second strategy available to schools to prevent 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, schools are teaching children to sneeze into their arms near their elbows, instead of into their bare hands, if no tissue is available. Handwashing is emphasized to prevent transmission after coughing, sneezing, blowing one’s nose, or touching an object a sick person has used. In preschools and elementary schools, children should receive frequent opportunities for handwashing or access to a gel-based hand sanitizer. These concepts can be reinforced during morning announcements, handouts, and frequent review.

The third tool available to schools to manage influenza is the attendance policy. Children and staff who display flu-like symptoms should not attend school. However, this attendance policy cannot completely protect students and staff because persons with the flu are contagious for about twenty-four hours before showing any symptoms and will remain contagious for several days. During the 2009 pandemic flu season, some schools closed when many students became ill. In general, however, this practice is not recommended for various 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 containing it. 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. Most 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 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 preventing 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, with a booster dose recommended at age sixteen for continued protection. Meningitis is also caused by a wide variety of viruses and is generally less severe. It is not prevented by or treated with antibiotics.

COVID-19. A particularly infectious novel coronavirus causing a largely respiratory disease, COVID-19 was initially identified in China in late 2019, and the WHO declared a pandemic in early March 2020. The virus spread rapidly worldwide, and schools and other public venues began closing in an effort to slow the spread of the virus. As the number of COVID-19 cases and the death toll rose, experts determined that the virus could be easily transmitted due to close human contact. This led the US and many other nations to implement social distancing policies and quarantines to limit such interactions. Many states ordered the closure of schools beginning in March 2020, and teachers and students were compelled to adapt to virtual schooling from home. This adaptation was often difficult, as districts struggled with ensuring technology access and equity in learning through this method. By the mid-2020s, the pandemic transitioned into an endemic stage in many countries, and schools incorporated COVID-19 into standard respiratory illness policies, emphasizing vaccines, improved ventilation, and flexible attendance policies. Some schools offered on-site rapid tests for COVID-19 and the flu to avoid unintended student contact with individuals who are not yet symptomatic.

Gastrointestinal Infections

Gastroenteritis. Diarrhea and vomiting (gastroenteritis) are 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 waterborne, food-borne, or acquired from another person or animal through contact with 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 then investigate the outbreak to determine the cause, which includes 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.

Impact

Millions of children eighteen and younger attend schools daily in the United States; therefore, an infectious disease in one child could potentially infect many more. Because of stringent, compulsory school immunization laws, many of the worst contagious diseases are rare in modern schools. However, other challenges, including the emergence of new viruses and the evolution of antibiotic resistance, lead to the closure and intensive disinfecting of schools to slow the spread as scientists learn about the viruses and create vaccines and treatments.

Several years after the peak of the COVID-19 pandemic, its impacts on schoolchildren continue to be assessed. The learning deficits incurred by schoolchildren amounted to about the loss of a third of a total school year. Even multiple years after the first learning disruptions, school systems continued to grapple with efforts to recover. These impacts were more acutely felt by children in families with lower economic resources.

Some students remain unimmunized for religious or other reasons, providing an opportunity for disease outbreaks. Antibiotic resistance, such as that seen with MRSA infections, continues to be a widespread problem. As teens engage in oral and genital sex at earlier ages, herpes infections, gonorrhea, human immunodeficiency virus (HIV) infection, and other sexually transmitted infections become more prevalent among teen social networks, which tend to revolve around school activities. School nurses, administrators, and public health officials should continue to devote time and attention to infectious diseases in schools.

Bibliography

Aronson, Susan S., and Timothy R. Shope. Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide. 6th ed., American Academy of Pediatrics, 2023.

“Between a Rock and a Hard Place, March 2022.” Association for Professionals in Infection Control and Epidemiology, apic.org/between-a-rock-and-hard-place-march-2022. Accessed 20 Mar. 2026.

“Early Care and Education Portal.” Centers for Disease Control and Prevention, www.cdc.gov/early-care/index.html. Accessed 20 Mar. 2026.

Fisher, Margaret C. Immunizations and Infectious Diseases: An Informed Parent’s Guide. American Academy of Pediatrics, 2006.

Lee, Marilyn B., and Judy D. Greig. “A Review of Gastrointestinal Outbreaks in Schools: Effective Infection Control Interventions.” Journal of School Health, vol. 80, no. 12, 2010, pp. 588–98, doi:10.1111/j.1746-1561.2010.00546.x. Accessed 20 Mar. 2026.

M’ikanatha, Nkuchia M., and John K. Iskander, editors. Concepts and Methods in Infectious Disease Surveillance. Wiley Blackwell, 2015.

“Reducing the Spread of Illness in Child Care.” HealthyChildren.org, 21 Nov. 2018, www.healthychildren.org/English/health-issues/conditions/prevention/Pages/Prevention-In-Child-Care-or-School.aspx. Accessed 20 Mar. 2026.

“Schools and Daycares: MRSA Prevention and Response.” Centers for Disease Control and Prevention, 27 June 2025, www.cdc.gov/mrsa/prevention/schools-and-daycares.html. Accessed 20 Mar. 2026.

St. George, Donna, et al. “Schools Are Shut, So How Will Kids Learn amid the Covid-19 Pandemic?” The Washington Post, 22 Mar. 2020, www.washingtonpost.com/local/education/schools-are-shut-so-how-will-kids-learn-amid-the-covid-19-pandemic/2020/03/22/dac4742e-6ab7-11ea-9923-57073adce27c_story.html. Accessed 20 Mar. 2026.

Wiley, David C., and Amy C. Cory, editors. Encyclopedia of School Health. Sage Publications, 2013.