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Influenza

What is Influenza? 

Influenza (flu) is a very contagious viral respiratory illness caused by the Influenza virus and should not be confused with what is sometimes referred to as the “stomach flu” (viral gastroenteritis). Influenza causes community-wide outbreaks every winter, usually from October through May. In general, healthy children tolerate influenza well and suffer only a few days of illness. People most at risk for complications from influenza are children younger than 5 years, the elderly age 65 years and older, pregnant people, and those with certain chronic underlying medical conditions (including, but not limited to, asthma, neurological and neurodevelopmental conditions, chronic lung disease, heart disease, blood disorders, endocrine disorders, kidney disorders, liver disorders, metabolic disorders, weakened immune system, and individuals with a BMI over 40). 

Signs and symptoms

  • Fever (typically sudden onset)
  • Headache
  • Muscle aches
  • Cough
  • Sore throat


 

  • Runny or stuffy nose
  • Chills
  • Fatigue
  • Vomiting
  • Diarrhea

Incubation period

1-4 days (usually 2 days)

Contagious period and spread

The influenza virus is spread from person-to-person primarily by respiratory droplets created by talking, coughing, or sneezing. These droplets can land on or be rubbed into the eyes, nose, or mouth. Droplets do not stay in the air, but can travel less than six feet and fall onto the ground. Transmission may also occur through contact with contaminated surfaces, hands, used tissues, or other articles soiled by nose and throat secretions. 

People with infection are usually contagious in the first 3-4 days after the onset of symptoms. Children may be contagious for longer than 10 days.

Public health reporting requirements

  • Influenza-associated hospitalizations and pediatric deaths are reportable to public health.
  • Report the infection to the facility director, school nurse, or child care health consultant. Child health concerns should be discussed with the school nurse or child care health consultant. Consultation with the state or local public health agency is also available.
  • If the child develops more severe symptoms or experiences ongoing symptoms, they should be referred to a health care provider.
  • If two or more children are experiencing symptoms of influenza or have received this diagnosis from a health care provider, this may be considered a suspect or confirmed outbreak and should be reported to state or local public health.
  • Outbreaks of influenza can cause significant increases in absenteeism among staff and students. Determining whether an influenza outbreak is occurring may be difficult in school or child care settings. However, significant increases in school absenteeism resulting from influenza-like illness should be reported to local and state public health agencies.
  • More information on reportability of respiratory illnesses in schools and child care are on CDPHE’s website under the link titled “Guidance for Prevention and Control of Viral Respiratory Illnesses in School and Childcare Settings.”

Control of spread

Teach children to:

  • Cover their nose and mouth with a tissue when they cough or sneeze, and throw away the tissue after they use it.
  • Avoid touching their eyes, nose, or mouth.
  • Wash their hands frequently with soap and water, especially after they cough or sneeze; an alcohol-based hand sanitizer can be used if soap and water are not nearby.
  • Avoid sharing cups and eating utensils with others.
  • Stay home when sick.

Provide adequate ventilation to occupied spaces. Increase filtration or indoor air through HVAC and/or with HEPA portable air cleaners. 

School closure is not indicated to control spread. However, some schools may decide to close based on local considerations, such as high student/child and staff absenteeism.

Consult with local public health for assistance with implementation of control measures/school closures.

Vaccination

Routine child/adolescent recommendations:

  • Seasonal influenza vaccination is routinely recommended for everyone 6 months and older. Say boo to the flu and get vaccinated in the fall, ideally before October. 

Colorado school-required vaccines:

  • There is no school vaccine requirement for influenza vaccine. 

Routine adult/other recommendations:

  • Seasonal influenza vaccination is important for adults, especially for those at higher risk of complications from flu. 

Treatment

In certain circumstances, a health care provider may prescribe influenza antiviral medications. These medications may reduce symptoms and duration of illness by one or two days and may prevent serious complications. Acetaminophen-containing medicines (such as Tylenol®) can be used to lower temperature or reduce discomfort. Anyone aged 18 years or younger who has flu or is suspected of having flu should not be given aspirin or other salicylate-containing products (such as Pepto Bismol®) as it increases the risk of Reye syndrome, a rare but very serious complication. Antibiotics are not an effective treatment for viral infections and should not be used for influenza. Those at high risk of complications or those who are experiencing warning signs of more severe illness (i.e., chest pain, shortness of breath, yellowish or leathery skin, decreased urination, confusion) should seek medical care.

Exclusion

  • If a student or child presents with symptoms of respiratory illness, schools and child care centers should refer to CDC’s Preventing Spread of Respiratory Viruses When You’re Sick.
  • If flu has been confirmed, symptomatic children and staff should be excluded from school/child care until they are fever-free for at least 24 hours without the use of fever-reducing medications (fever defined as temperature 100.4o F or higher). Additionally, all other symptoms of respiratory illness, including cough, should be resolved or improved before returning to school or child care.
  • Ill children and students should be supervised separated from others until they can be picked up by a parent or guardian and taken home. 

Additional precautions are recommended for at least five days following the return of anyone recovering from respiratory symptoms, including increased hand and respiratory hygiene, improved ventilation, masking, physical distancing, and testing. 

Additional exclusion criteria are listed in a previous section: Exclusion Guidelines for Children and Staff.  

Role of teachers, caregivers, and family

  • Encourage annual seasonal flu vaccination for all people aged 6 months and older.
  • If you or your child is diagnosed with influenza, follow your health care provider’s instructions and take all prescriptions and medications as indicated.
  • Reduce crowding and touching in classrooms as much as possible during flu season.

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