Influenza: What parents should know

“The Flu” or Influenza season is almost upon us. Every year, I see so many misconceptions about the illness.

So let’s break down what influenza can look like, how to tell if your child has it, and why we care. I have an instagram post that I published today going over FAQs relating to the flu vaccine specifically.

How bad will it be?

We often use information from the Southern Hemisphere flu season to give us a sense of what our upcoming flu season may look like. Unfortunately, many countries experienced a more significant and severe flu season this year; H3N2 was the dominant strain in South America and Australia, while H1N1 was dominant in Africa.

This is not always a perfect predictor but the other factor at play is that a recent CDC report found the current vaccination was not as well-matched to circulating strains in multiple South American countries.

I share this information because I think it’s important for parents to make well-informed choices. In prior years, studies have found that even when the vaccine is not perfectly matched to circulating strains, it still can do a good job of protecting kids, especially, from severe illness (PMID 35024795 showed a decreased risk of critical illness of up to 75% in kids, while PMID 33020249 showed decreased risk of hospitalization and ER visits in kids of up to 40-60%). Overall, even when the strain is not a perfect match to the vaccine, vaccinated people still tend to have a shorter, milder course of illness..

What is “the flu”?

Influenza is a viral infection that can be caused by different strains of Influenza virus. In the US, it typically circulates between October and May.

Although most people recover without incident, similar to COVID-19, certain groups are higher risk for severe illness (and even death): the elderly, those with underlying health conditions, and young children (under age 5y - and especially those under 2y).

During the 2023-2024 season, there was a record high of 200 pediatric deaths reported to the CDC (about 80% of these were in unvaccinated children). Historically, about 50% of deaths occur in previously healthy children.

Symptoms

• Abrupt onset of fever (95% of kids will have temps >102.2)

• Respiratory symptoms (cough, congestion, sore throat, etc)

• Headaches

• Body aches

• Fatigue/malaise

• Gastrointestinal symptoms (vomiting, diarrhea, nausea)

Incubation and transmission

Symptoms typically develop within about 1-4 days after exposure.

Influenza is contagious via:

• Respiratory secretions (sneezing, coughing, talking)

• Contact with contaminated objects/surfaces

• Aerosolized particles that are released into the air during breathing

The pattern of viral shedding/infectivity depends a bit on the strain, but in general you are most contagious in the first few days of illness. Influenza B can actually be transmitted before symptom onset. Most of the time, you are no longer contagious by about day 5-10

The Pediatrician Mom Note: Children (and immune-compromised people) are known to shed virus for longer than healthy adults

How is influenza diagnosed?

In many cases we can diagnose flu clinically based on history and knowing what is going on in the community. In most cases, we diagnose it in the office using nasopharyngeal swabs (antigen tests and PCR).

Expected clinical course

The majority of children recover on their own within about a week. Antiviral therapy (see below) can shorten the duration of illness but it has its drawbacks. It is worth knowing that some symptoms (such as cough and fatigue) can linger for several weeks after illness.

Complications

Influenza can lead to hospitalization due to severe dehydration, respirator failure, or serious secondary bacterial infections. But even on an outpatient basis, secondary bacterial infections are a common complication: eg pneumonia, ear infections, abscesses in the throat. Febrile seizures can occur in 5% of kids. Rare complications can include sepsis, meningitis, myositis and myocarditis.

Treatment

Antiviral medications do exist, although only some of them are licensed for young children. As with many viruses, the most important component of treatment is primarily supportive: focusing on hydration, fever management and comfort.

What is the deal with Tamiflu?

Tamiflu (or Oseltamivir) is a “neuraminidase inhibitor” - it works by preventing the replication of the virus and can decrease severity, shorter duration of illness (by 1-2 days) and decrease complications. It can also be used for prevention if someone has been exposed and is higher risk for complications.

Dosing: Tamiflu is usually dosed twice per day for 5 days (for treatment) or once daily for 10 days (for prevention). The actual dose depends on weight in children, and it comes in both a liquid and a pill form.

Drawbacks: Tamiflu must be given within 48 hours of symptom onset in the outpatient setting, and it can be hard for some children to tolerate due to its side effects (it can cause nausea/vomiting, headaches, and neuropsychiatric symptoms eg seizures, nightmares, etc). It also doesn’t taste great.

So should you give it to your child? There is no single right answer here. For every intervention, the decision must be individualized based on risks and benefits - and the best guide for your child will be their pediatrician. Some healthcare providers seem to have a blanket “I don’t prescribe Tamiflu” mentality but I am not in this camp. Because young children are at high risk, there is a strong argument to be made for using it in many circumstances.

The Pediatrician Mom Tip: There are also other newer antiviral medications that are available. Learn more here.

When can children return to school?

https://unsplash.com/@kellysikkema

Per the CDC, children can return to school when they have been fever free for 24h (without antifever medication) and they are overall feeling better, hydrated, etc.

Flu prevention

The best way to prevent the flu is by vaccination. Stay tuned for a post later this week that goes into details about the flu vaccine.

Other important prevention methods are the same as with most other viral illnesses: wash hands, wipe frequently sued surfaces such as door handles and countertops, and avoid sick people. If you are interested in learning more about evidence based ways to support immune function, check out my free download here.

When to call the pediatrician

This is not a comprehensive list. In general, always err on the side of calling your pediatrician if you have any concerns about your child.

There is a lot to be said for a parent’s gut instinct, and I promise: your pediatrician would rather you called!

If your child is under 3 months and seems sick, call your pediatrician. If they are older and are not improving within a few days, or if they seem to be getting worse, call your pediatrician.

Other concerning symptoms include:

• Any illness in infants under 3 months

• Severe pain, irritability or difficulty being consoled

• Lethargy

• Poor feeding

• Dehydration — see this post for signs to look for

• Difficulty breathing

• Ongoing fever beyond 3-5 days

• Anything else tickling your spidey sense!!

Hope this post helps you understand why pediatricians are so concerned, every year, about influenza.

My kids got their flu vaccines this past weekend. If you haven’t done it yet, I highly recommend scheduling it ASAP!

Note: some kids need 2 doses of the flu vaccine. Check out my instagram post to determine if your child needs 1 or 2 doses this year.