Influenza Basics

By Ashli N. Collins, M.D.

Just as May is synonymous with the Derby around Louisville two things come to mind when I think about October…Midnight Madness for basketball and the start of flu shot season in my pediatric office. Many don't realize there is a specific season for the flu (October thru May) as they associate any illness with vomiting and diarrhea as “stomach flu” or any other febrile, achy illness with just plain flu. However, every fall we get different strains of influenza appearing across the country. I would like to take this opportunity to discuss Influenza…the illness, its main consequences, who it affects, and how we can prevent it from happening.

Influenza, often known as the flu, is a virus that can affect anyone. Many think of flu as an illness that hits only adults but unfortunately, children under two are highly susceptible to the life threatening consequences of the disease. It is highly contagious and can cause symptoms ranging from just a cold to death. The CDC (Centers for Disease Control) reports that 5-20% of the United States population gets the flu each year with more than 200,000 people hospitalized from complications of the flu and unfortunately about 36,000 people die from flu. At Kosair Childrens Hospital last year, many children were hospitalized and at least one child died from complications of the flu according to Robin Livingston, a Pediatric Infectious Disease Fellow at U of L. Children and elderly are most at risk of having serious complications from the virus.

Spread of the flu is rapid. It travels in respiratory droplets usually from coughing, sneezing or as in daycares, lots of runny noses with mucus being passed from child to toy to child. In a person carrying the flu virus, they are generally considered contagious one day before symptoms begin and up to five days after becoming sick. The take home message is that unfortunately people can unknowingly be passing the flu before they even realize they are sick. This is why it is imperative to vaccinate those that are at highest risk of complications from the disease so that when they are exposed to people carrying the disease unknowingly, they are already protected.

Symptoms of the flu include high fevers, headache, tiredness, sore throat, runny or stuffy nose, muscle aches and occasionally stomach complaints like nausea, vomiting and diarrhea. Secondary complications can include pneumonia, asthma attacks, dehydration and in kids especially we see a lot of ear infections and sinus infections.

There are currently two types of vaccines available to protect from the flu, the flu shot and the nasal spray flu vaccine. The flu shot is an inactivated vaccine-that means it contains killed virus-and therefore cannot cause the flu as many people fear. It can be given to children from 6 months of age and older. The shot may be given to both healthy people and those with chronic medical problems. The nasal spray flu vaccine is actually a LAIV or Live Attenuated Influenza Vaccine. It is made from a live, weakened flu virus that does not cause the flu. It is currently approved for use in healthy people ages 5 to 49 that are not pregnant. Side effects of the vaccine include fever, aches and redness at the site of injection. The LAIV can also cause cold like symptoms. Previously the flu vaccine was manufactured with mercury as a preservative. It is now available in a thimerosol free solution.

After vaccination, protection from the influenza virus is usually complete in about two weeks. Each year the flu vaccine is made with several strains of influenza virus that were most common the preceding year. How closely those viruses match the ones in the new years outbreak will help determine the effectiveness of the vaccine. It is also important to remember the vaccine only protects against those strains of the flu and not other flu-like illnesses.

The distribution of flu vaccine has been difficult in recent years due to shortages causing the vaccine be rationed to those at greatest risk. Our hope is that this year there will be plenty of vaccine to be administered to all who ask for it. So then, who really needs to be vaccinated? Anyone who wants to reduce the risk of getting the flu should be immunized. The people who should get vaccinated each year are children aged 6-59 months, pregnant women, people aged 50 and older, people of any age with chronic medical conditions (asthma, immune disorders, and others) and people who live in long term care facilities. Others who should receive the flu shot are health care providers, close contacts to children under 6 months of age or greater than 65 years, or a close contact to anyone with a chronic medical condition. Remember, we are not just vaccinating to protect ourselves but also to protect those around us that cannot receive the vaccine.

There are only a few people who cannot receive the flu vaccine: those with a severe egg allergy, severe reaction to the vaccine in the past, children less than 6 months of age, people with a fever, and people who developed Guillain-Barre from an influenza vaccine in the past.

As an advocate for the health of our kids, I would like to remind you to check with your primary care provider about the flu vaccine and immunize wisely!

Ashli N. Collins, M.D. is a pediatrician with offices in LaGrange and Louisville . She is married to Paul Loheide, M.D. and they have twins, Sarah and P.J. She enjoys running, swimming, cycling and sewing.