Influenza Symptoms, Risks, Causes and Treatment

The flu is a term that gets thrown around quite a bit, but what exactly is influenza? What are the causes? What are the symptoms, and the treatments? When is the flu season? And what about the flu vaccine? Can you get the flu from the flu vaccine and why in the world is there a different flu vaccine every year? Well, today is your lucky day because I'm going to answer your questions about the flu. This is Influenza explained. Influenza symptoms, risks, causes, and treatment.

What Is The Flu?

Well, the flu is an acute respiratory illness caused by a virus, influenza. There are three types of influenza: type A, type B, and type C. Now types A and B are the ones that tend to cause the epidemics or the outbreaks, and type C is a milder form. You are actually probably already familiar with type A influenza. So for type A influenza, it's envelope or its surface is covered with proteins. You have the H and the N proteins, the hemagglutinin, H type, and neuraminidase, N-type, H, and N. Type A influenza is actually classified based on the subtypes of these H and N proteins. H1N1, H3N2, H5N1.

And actually, the Spanish flu back in 1918, was a pandemic caused by the type A influenza of the H1N1 subtype. Type B influenzas only infect humans but type A influenza can infect both animals and humans and it can actually have cross-species infection. So a bird can infect a pig, can affect a human, and then influenza goes from human to human. And the tricky thing about the influenza viruses, the flu, is that they multiply rapidly and they can change their genetic material. So even if you become immune to one type of influenza the very next season, the virus may have changed in such a way that you are no longer immune to the new form of influenza. This is why scientists have to update influenza vaccines each year. The influenza viruses tend to change their antigens, therefore, we must change our vaccines in order to be immune.

How Is The Flu Transmitted?

Well, there are three main modes of transmission. You can get influenza if you inhale someone's respiratory droplets. So what are respiratory droplets? Spit particles. When one person who is infected with the flu sneezes, they release many, many, many respiratory droplets, and within even small droplets you can have hundreds of influenza viruses. And if you happen to be walking near that person, certainly within six feet of the person who has been infected and who has sneezed all of these respiratory particles, you can inhale an infected respiratory particle into your respiratory system. It can combine with your respiratory mucosa and you can become infected with the flu.

In addition to influenza being spread through respiratory particles, which are a little larger you can also have an aerosolized transmission. This means that you can have really tiny particles that can float around in the air for longer periods of time and they can travel farther than the bigger respiratory droplets. They can definitely travel farther than six feet. And in these cases, even if you walk into a room where an infected person has been, you can potentially inhale an aerosolized particle which has influenza, and you can still become infected.

For example, if an infected person has been in an elevator, that person could be long gone from the elevator but could have left some aerosolized influenza particles. You go into the elevator, take a nice breath in, and you too can be infected with influenza. You can also pick up influenza from surfaces, surfaces that have been contaminated with infected respiratory particles. So you can be in an elevator again, you can touch a button that has respiratory particles from someone who's been infected, and then touch your face and get infected with influenza. Table surfaces can have influenza contamination, doorknobs, rails on stairs, you name it.

What Causes Influenza?

So what causes the transmission of influenza? Respiratory droplets, aerosolized particles, and contaminated surfaces. So now, if you've been exposed to influenza, it usually takes between one and four days before you develop symptoms, but you can be infectious or shedding the virus up to 48 hours before you develop symptoms. So asymptomatic people who have been infected with the flu can transmit it to other people. So here's what happens when you are exposed to influenza. You breathe in the infected particle and the influenza virus finds one of your healthy host cells, one of the healthy cells in your body.

That influenza virus has proteins on its surface, which act as keys, and they find a receptor protein on your healthy host cell. They unlock it and now the influenza virus enters into your healthy cell. The virus then takes over that cell and starts to replicate or to multiply, and it uses the genetic material of your healthy host cell. These newly replicated viruses exit, they go and infect neighboring cells. Some of them go back to the respiratory mucosa, your breathing system where they came in, and basically, they just take over and they can make you very, very sick.

They cause inflammation in your body once you've been infected. And this inflammation or this irritation can make you sneeze, they can make you cough, and then guess what? Now you've been infected with influenza, now you are contagious and when you sneeze, you spread respiratory droplets, and then the human to human transmission continues.

Please watch my YouTube video on the truth about vaccines. I explain how viruses infect the body and how your immune system works. Watch that video after you finished watching this video.

What Are Influenza Symptoms or Symptoms of The Flu?

Symptoms may include high fever, myalgias or muscle pains, and joint pains. You can have extreme fatigue or malaise. You can also get headaches if you have influenza. Sneezing, coughing, or running nose are also symptoms of the flu. There's a lot of crossover in the symptoms of the flu versus the symptoms of a common cold, but you tend to be more severely ill if you actually have the flu.

So in the flu, you're really going to get those high fevers like 102 degrees Fahrenheit, or 104 degrees Fahrenheit, and the myalgias the muscle pains, and the fatigue will be more severe than the common cold. Now for most people, flu symptoms are self-limiting, meaning you'll get over it on your own between one week or maybe two weeks, and most people do not have to go to the hospital. So if that's the case, what's the big deal about the flu? Why do we talk about it so much every year? Why do we talk about these vaccinations? Well, that's because some people can develop severe symptoms of the flu and complications which are life-threatening and can even cause death.

Flu Complications

So what are the potential complications from the flu from influenza? You can get pneumonia, it can be viral pneumonia or you can get a secondary infection with the bacteria and get bacterial pneumonia, like from strep pneumonia or from Staphylococcus aureus. So you can even get a CA-MRSA or a Community-Acquired Methicillin-Resistant Staphylococcus Aureus.

Pneumonia can cause you to have severe respiratory failure and even cause you to be intubated in the ICU. If you have severe complications from the flu, you can also get a multi-organ failure, which means, beyond your respiratory system being infected, and beyond your lungs and your throat being infected, you can get kidney failure, you can go into shock where your blood pressure is too low to be compatible with life. You can get central nervous system symptoms, including encephalopathy or encephalitis, where you get confusion because of central nervous system involvement.

In other words, we make a big deal about the flu because the flu can be a big deal. People, especially immunocompromised people, can have complications from the flu that lead to severe illness or even death. So who are these immunocompromised people?

Who Is At Risk For Getting The Flu?

Well, the very young, especially less than six months, and the very elderly are at risk. Also, if you're a patient who's taking medications to suppress or to push down your immune system like a patient who has had an organ transplant, or a kidney transplant, you're at high risk for complications. Pregnant ladies are also at high risk for complications from the flu, and patients with HIV and other chronic illnesses that compromise the immune system.

How To Prevent The Flu

So what can we do to protect people from getting complications, potentially fatal complications from the flu? We do our best to prevent the flu. Here are a few basic things we can do to prevent the spread of influenza. We can practice good hand hygiene, making sure we cover our noses and our mouths when we sneezed and when we cough. We can even wear face masks to prevent the spread of the flu. But a very effective prevention method we have, the flu vaccine. Getting the influenza vaccination is a very important measure in preventing influenza, epidemics, outbreaks, and even pandemics.

There are different types of flu vaccines. You have the flu vaccine that is injected, the shot. That vaccine is an inactivated virus. It's a dead virus that is just strong enough to allow your body to mount an immune response without you getting very sick. And then you also have the type of flu vaccination which is inhaled through the nose. Now that one is a weak virus, but it is a living virus. When we talk about the flu shot, we are typically talking about the injection that goes into your arm.

Can Flu Shots Cause The Flu?

So here's the famous question. Can you get the flu from the flu shot, the flu injection? The answer is no. You are being injected with an inactivated virus, a dead virus. So you cannot actually get the flu from the flu shot. But, what happens when you get the flu shot is that you are activating your immune system. And when this happens, you can get some headaches, some stiffness, and you can feel a little sick.

For some patients after getting the flu shot, they feel really sick but it is not actually the flu that they are getting, and whatever sick feeling they have, it is definitely not as bad as actually getting the flu. And the flu shot will certainly prevent you from getting major complications from the flu. So can you get the flu from the flu shot or the flu injection? No.

Who Should Get The Flu Shot?

Who should be getting the influenza vaccine? Well, anyone who is greater than or equal to six months of age who does not have a contrary indication. So this includes pregnant women. Yes, you should get the flu shot. Patients with HIV, yes, you should get the flu shot. Patients who have had organ transplantations. Yes, you should get the flu shot. And healthy people. Yes, you should get the flu shot.

I have a lot of patients who say, I never get the flu, I'm not gonna get the flu shot. But think about it, even if you're blessed enough to be a healthy person surely you come into contact with people who are immunocompromised or with loved ones who are elderly and at higher risk for complications of the flu. You get the flu shot, yes, to protect yourself from having complications, but also to protect your neighbor, to protect your community at large. My YouTube video on herd immunity explains this in more detail.

When Is Flu Season?

In certain parts of the world, influenza can be present year-round like in tropical areas. In the United States, flu season tends to have its peak between December and February, but flu season can start as early as October and can go on all the way through May. But again, the peak of flu season in the United States is between December and February. So the fall and the winter of each year.

Flu Diagnosis and Treatment

If you suspect that you have the flu, say you've been exposed to someone with the flu, or you have some of the symptoms I mentioned of the flu, how can you be diagnosed? Well, you can go in and see your doctor and they'll do a history and a physical and they will determine if they are suspicious that you have the flu, but then there are actually tests that can be done.

There's a rapid antigen test that can come back in less than 15 minutes. And it actually tests for the antigens of influenza. There are also immunoassays and viral cultures that can be done. And there are treatments for influenza. Now, again, for most people especially healthy people, influenza is self-limited. You will get over the flu on your own within a week to two weeks. But for certain patients who are at high risk for complications, or for patients who have severe symptoms, or for patients who have close contacts with high-risk patients.

If you, for example, get the flu and you are a young healthy person who happens to be symptomatic but you're not at high risk for complications you may still be a candidate for treatment, if you, for example, live with a person who is at high risk. If you live with your elderly grandmother or if you live with a transplant patient who is on medications that suppress his or her immune system. In general, the flu can be treated with supportive care. If you have a fever, you can take a fever reducer like acetaminophen, but not aspirin. You need to stay well hydrated, have good nutrition support. But there are medications for the flu such as Oseltamivir, also known as Tamiflu. There are other antiviral medications as well.