Seasonal Influenza

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What is influenza?

Influenza is an acute respiratory illness caused by influenza A or B viruses. It usually gets worse in the winter because people are inside and closer to each other, thus allowing more efficient transmission.
What are the symptoms? Most of the time the flu will appear as runny nose, cough, headache, body aches and fever, but vomiting and diarrhea can be present. Younger kids tend to have higher fevers, febrile seizures, less cough/runny nose, and more intestinal symptoms (nausea, vomiting, diarrhea, poor appetite).

The severity of symptoms depends on your child’s age and prior exposure to the virus, which is why the flu vaccine is so important. The vaccine allows the body to have a warm-up fight with the virus, so when the real virus appears, the body is ready to knock it down fast. Kids older than 6 months can receive the vaccine, and even if flu season is well underway, you should still vaccinate your child.

How long does the flu last?

Uncomplicated influenza usually improves gradually over 7-10 days, but some symptoms, especially cough, last longer, particularly in young children. Weakness and tiredness may last for several weeks in older children and are sometimes referred to as “post-influenza asthenia.” This year we’ve seen that the abdominal symptoms of stomach cramping and poor appetite are lasting about 10 days.

Can my child get the flu twice?

Children who recover from one episode of influenza may be infected with a different influenza strain later in the season. In one study of 647 patients with laboratory-confirmed influenza, 13 children had later influenza A and B infections during a single season. None of the children had received influenza vaccine or antiviral therapy; all of the children presented with typical influenza for both episodes. Again, this reinforces the need to administer influenza vaccine, even after the start of the season in order to protect against other circulating strains.

Who is at risk for severe flu?

Although a healthy immune system can usually handle the flu, it can sometimes become a severe illness. Also, certain groups of people are at increased risk:

  • Children<5 years, but especially <2 years (In young children, <6 months of age, the rates of hospitalization are highest)
  • Asthma
  • Chronic lung disease (cystic fibrosis)
  • Heart disease
  • Kidney disorders
  • Liver disorders
  • Blood disorders (including sickle cell disease)
  • Endocrine disorders (including diabetes mellitus)
  • Metabolic disorders (including inherited metabolic disorders and mitochondrial disorders)
  • Neurologic and neurodevelopmental conditions (including disorders of the brain, spinal cord, and peripheral nerve and muscle such as cerebral palsy, epilepsy, stroke, intellectual disability [mental retardation], moderate to severe developmental delay, muscular dystrophy, and spinal cord injury)
  • Immunosuppression due to disease or medications (including HIV, cancer, and chronic glucocorticoids)
  • Women who are pregnant or postpartum (within two weeks after delivery)
  • Children and adolescents &lt;19 years of age and receiving long-term aspirin therapy
  • Native Americans and Alaskan Natives
Why are there different kinds of flu?

Influenza infection is caused by influenza virus types A and B. Influenza viruses are classified into two groups because they have different proteins on the surface of the virus, so researchers name them based on these proteins. This year the worst strain is caused by influenza A, H3N2. Viruses can mutate, or change, very quickly, so although a vaccine is tailored for the worst viruses predicted for a season, it’s not always and exact hit. But your immune system still gears up the fight and is stronger, even if the opponent looks a little different than expected.

How is the flu spread?

Influenza viruses are spread from person to person, primarily from respiratory droplets: sneezing, coughing, talking, or touching contaminated objects. Children are spread of disease easily for obvious reasons! It takes one to four days for symptoms to appear after someone has been infected. The flu can be passed on even before symptoms appear and for several days after the last symptom as passed.

How many kids get the flu?

The attack rate of influenza in children (<18 years) varies from year to year, ranging between 10 and 40 percent during a typical influenza season. Influenza virus infections in children mean that the whole community has more outpatient visits, hospitalization, antibiotic utilization, missed school days and missed workdays for parents. This is why it’s so important that everyone be vaccinated: if the flu cannot spread between people, the whole community benefits.

Young children and those with certain underlying medical conditions (see the list above) are at increased risk for hospitalization for severe or complicated influenza infection, but severe disease can also occur in healthy children. The majority of kids who are hospitalized are previously healthy and have fevers that need to be evaluated for the potential of bacterial infection.
One more time, this is why vaccination is so important.

Thus far into the flu season (2017-18), 30 kids have died.  Historically, 37-171 children will die of influenza in the US each year, 40% of those deaths are in healthy kids. These factors are associated with increased risk:

  • Underlying medical problems associated with increased risk of severe or complicated influenza (the list above)
  • Age < 5
  • Associated bacterial infections
  • Higher circulation of influenza A H3N2 (this is the major strain in 2017-18)
Should I ask my doctor to test my child for the flu?

Laboratory testing for influenza virus should be performed only when the results will affect management (eg, initiation of antibiotic or antiviral therapy, performance of other diagnostic tests, infection control, need for immunization of contacts, etc.) If your child is tolerating the symptoms well, and has no other complicating factors, testing is not necessary. Also, the test for flu is not completely reliable. Some studies show it is about 50-70% accurate. So, if the test will not change how you take care of your family, there is no need to perform it.

How can I track influenza activity?

There are 2 groups who watch flu activity carefully: Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). Local hospital or clinic laboratories may also collect information to monitor influenza activity in a specific geographic area.

What are some complications of influenza?

Sometimes the flu can lead the way for a bacterial infection. If your child had the flu, got better, and then suddenly developed a fever again 7-14 days afterwards, a bacterial infection may be present.  Seek medical care immediately.

Otitis media: Otitis media complicates the course of influenza in 10 to 50 percent of children, and usually occurs three to four days after the onset of influenza symptoms.

Pneumonia: Pneumonia is a major complication of influenza, particularly in high-risk children (see the list above). In children without underlying high-risk conditions, influenza pneumonia occurs most frequently in children younger than 2. Influenza pneumonia is usually mild and of short duration; however, in hospitalized children, it increases the risk of a severe clinical course. If the pneumonia is caused by a bacterial (S. aureus or S. pneumonia) it may be particularly severe and rapidly fatal.

Other respiratory complications: Other respiratory tract complications of influenza infection include: worsening of underlying chronic pulmonary conditions, particularly asthma.  The infection may turn into croup or a bacterial infection of the upper airway.  Seek care immediately if your child struggles to breath.

S. pneumoniae (strep) or S. aureus (staph) bacterial infection:  Pneumonia or bacteria in the blood, most commonly due to S. pneumoniae or S. aureus, can occur in children with or without high-risk conditions, and can be particularly severe and rapidly fatal. This is a rare but dangerous complication of influenza.  You can decrease your child’s risk of S. pneumonia infection with immunization (Prevnar).

Central nervous system: Central nervous system (CNS) complications of influenza are rare in children. The risk is increased in young children (<4 years) children with pre-existing neurologic conditions. CNS complications of influenza include febrile seizures, meningitis, weakness, and confusion.

Musculoskeletal infection:  Myositis is a complication in which the flu affects the muscles. Again this is rare. The hallmark of acute myositis is extreme tenderness of the affected muscles, most commonly the calves, and your child will not want to walk or move the muscles. In severe cases, swelling and bogginess of the muscles may be noted. It is more frequently observed with influenza B than influenza A.

Cardiac: Influenza-related infection of the heart muscle (myocarditis) is extremely rare, but newborns are at a higher risk for myocarditis than other age groups. Symptoms tend to be more severe in infants, and can include: pale skin, fatigue, irritability, difficulty breathing and eating. In older children, symptoms can include: fever rapid or labored breathing, cough, pale skin, cool hands and feet.  Older children may also experience chest pain or heart palpitations and feel unusually tired. Some children have recognizable symptoms of the flu beforehand. In other cases, children are not noticeably sick before cardiac symptoms appear.

How can you treat the flu?

As mentioned before, most of the time your child’s immune system will be able to overcome the flu, especially with the added help of prior vaccination. And, there are good reasons not to treat it, such as risk of reaction to the medicine and increasing viral resistance to the medication.  Viruses and bacteria are both able to develop tools to evade drugs if they are exposed too often to the drugs in the community, so it’s best to take antibiotics and antivirals only if necessary.  If your doctor thinks treatment will help, research has shown that Oseltamivir (Tamiflu) decreases the symptoms by about 1 day, and it decreases risk of complications of the flu.

The Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) provide the following indications for antiviral treatment.

  • Any child hospitalized with presumed influenza
  • Children with confirmed or suspected influenza who have severe, complicated, or progressive illness
  • Influenza infection of any severity in children at high risk for complications, regardless of influenza-immunization status
  • Any otherwise healthy child with influenza infection for whom a decrease in duration of clinical symptoms is felt to be warranted by his or her provider (particularly if treatment can be initiated within 48 hours of illness onset)
How long is the antiviral treatment?

The usual duration of antiviral therapy for influenza is five days. As with antibiotics (for bacterial infections) you should give your child the full course of medicine unless your doctor finds another diagnosis for the symptoms. Hospitalized patients with severe illness may require a longer course of therapy.

What are some adverse reactions I should look out for while my child is taking oseltamivir?

Oseltamivir  (Tamiflu) is usually well tolerated, but some reactions that have been reported: nausea, vomiting, and rash. Rarely children can experience hallucinations, confusion, abnormal behavior, or convulsions.  Many children have difficulty taking Oseltamivir (Tamiflu) due to the taste.  Pacidose by AGGIE MD is the safest, easiest way to administer all medications to your child, even up to grade school kids.  Contact your doctor immediately if you are concerned that your child is having a reaction to Oseltamivir  (Tamiflu).

What else can I do help my child get better?

The best thing you can do is help your child manage the symptoms. Treat fever, headache, and body aches with acetaminophen (Tylenol). In children older than 6 months you may also use ibuprofen (Motrin). Never use aspirin (salicylates) in children younger than 18 years of age because of the association with Reye syndrome.  Humidifiers can help clear congestion. In babies, remember that they naturally nose breath until about 3 or 4 months. So you may need to use saline drops and a bulb syringe repeatedly to clear the nose of mucus.  We do not recommend using your own mouth to suction your child’s using a tube device, as this will expose you to viral droplets.

Over-the-counter cold medications have no proven benefit and have been associated with fatal overdoses in young children. They are not recommended.

Encourage fluids and rest.  This can be hard in active toddlers or big kids, but reading, quiet crafts in bed, or movies are good ways to keep them calm. There is no substitute for sleep in healing the body. Make the bed and room as cozy as possible and encourage the whole family to go to bed earlier so that your young child has less incentive to resist bedtime when sick.

If your child experiences vomiting or diarrhea as part of the illness, Pacidose is a great way to encourage small amounts of liquids.  Give 5 mL of fluid every 15 minutes.  The goal is to ensure your child does not become dehydrated. He or she should be making urine at least once every 8 hours.

With this flu season (2017-18) we’ve noticed that the intestinal irritation can last for about 10 days, after the other symptoms have abated.  Your little one may have a poor appetite, and complain of discomfort after eating.  Gripebelt by AGGIE MD is another tool to soothe the tummy. If pain persists more than 2 hours, or if your child is not able to keep solids or liquids down, seek medical attention.

How can I control the spread of influenza?

Children with an influenza-like illness should stay away from school, health care settings, high-risk individuals, camp, stores, community gatherings, etc. until at least 7 days after onset of symptoms, or 24 hours after the fever is gone, whichever is longer.  The virus is still reproducing in the body (“viral shedding”), even with treatment, for 10+ days.  If you do seek medical attention for your child’s illness, be sure to tell the staff that you are concerned about flu, so that you and your child can wear a mask to decrease transmission to other patients.

At home it’s very difficult to keep children from passing the virus to siblings or parents. The virus is spread from droplets, so limit coughing and sneezing or touching your face. Clean the bathroom regularly, especially handles and knobs.  Encourage hand washing as soon as you come home from public spaces. Wash clothing and linens more frequently.

In summary

The most effective way to prevent influenza is by getting the influenza vaccine (the flu shot), and using simple infection control measures such as hand washing. People who are vaccinated form antibodies (proteins), which destroy the influenza virus after the person is exposed. It generally takes about two weeks to make these antibodies. The vaccine usually protects 50 to 80 percent of those who are vaccinated from getting the flu.

Take your child to the doctor immediately if he or she:

  • Starts breathing fast or has trouble breathing
  • Starts to turn blue or purple
  • Is not drinking enough fluids
  • Will not wake up or will not interact with you
  • Is so unhappy that he or she does not want to be held
  • Gets better from the flu but then gets sick again with a fever or cough
  • Has a fever with a rash