Comparative Anatomy of the Cold or Flu

By Dr. Leigh Vinocur, Emergency Physician and a Dr. Oz Expert.

Posted on | By Leigh Vinocur, MD, FACEP

This seasonal question is age-old: Is it a cold or is it the flu? While it often feels like you’re only choice to wait and see how sick you get, there are clues to help you differentiate one from the other. Typically, colds begin gradually with a sore throat that is rarely accompanied by a fever, headache and/or muscle aches. The main symptoms of a cold are sniffles, a runny nose and a wet sounding productive cough. Flu on the other hand, hits you like a freight train with a high fever that’s usually greater than 100-102 degrees Fahrenheit, a bad headache and muscle aches. Rarely do you have sniffles, and if there is a cough, it is usually a dry non-productive cough. The flu causes severe fatigue; you will be wiped out. Colds usually get better by 1 week at the most but the flu can linger longer.

 

And while colds and flu are simply a nuisance for most of us, they can be deadly for those with severe asthma or other respiratory problems, or those who are immune compromised. While our bodies are fighting off these viral infections they become more susceptible to secondary, more serious bacterial super infections.  In fact, the death rate attributed to the flu is primarily due to the secondary bacterial pneumonias that develop. Click here to read more about super infections.

It is also believed that colds in young people may play a role in the development of asthma by programming their immunes systems.


The Uncommon Cold

The common cold is somewhat of a misnomer. It isn’t caused by a single virus. There are over 200 different viruses that cause the “common” cold.  Over half of them are a type of virus called the rhinovirus and there are 99 different types of rhinoviruses!  That is why we can send a man to the moon but we can’t cure the common cold. All these heterogeneous distinct viruses make it difficult to develop a vaccine to prevent the cold or even an antiviral drug to combat it.

Fighting the Flu
An RNA virus in the Orthomyxovirus family causes the flu.  There are 3 main types, Influenza A, B, and C. (Influenza A is further divided into subtypes.) Humans can be infected with all 3 types of Influenza. Most of the virus subtypes of Influenza A also have natural animal hosts such as birds and pigs. And even though from year to year the viruses mutate and change through a process called antigenic shift and drift, we still develop new vaccines every year to prevent infection.  Occasionally, as seen in last year’s H1N1 outbreak, there is a completely new mutated subtype of the flu virus that causes a pandemic. But our global surveillance system caught it and, even though it took some time and effort, a vaccine was developed for this new subtype of influenza virus. 

Also, because the flu is more homogenous and uniform when compared to the cold, we have been able to develop antiviral medications. These medications can help prevent the flu if you take them after exposure but before you get sick, or they can help shorten the course of the illness (but only by a day or so).

However, most healthy people don’t need antiviral medicine; they are a good idea for individuals at high-risk for experiencing serious complications from the flu. Those are people with compromised immune systems, chronic illnesses such as diabetes, or respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD) and emphysema.


Prevention Tips

Good hand washing is key to preventing both colds and the flu. Also, be careful not to touch your face, eyes, nose and mouth during this cold and flu season without washing your hands since this is how viruses can be transmitted. Cover your sneezes and cough with the inside crook of your elbow (if you don’t have a tissue). Throw out used tissues immediately.

The best way to prevent the flu and any complications that can develop from it, such as pneumonia, is to get a yearly vaccination. The CDC recommends that everyone 6 months and older get a flu shot. And this year the H1N1 is included in the regular flu vaccine.

As with many diseases and medical conditions, your lifestyle can critically affect your health.  So eating healthy is an important prevention technique, as well as being good for your overall health. Bright, colorful fruits and vegetables contain phytochemicals, which have anti-oxidant properties to boost your immune system.

Yogurt has probiotics that can strengthen your GI tract’s immune system and mucus membranes. It increases the amount of antibodies in your mouth and nasal passage, points of entry for many viruses. Some studies showed a daily helping of yogurt may decrease cold and flu susceptibility by 25%. 

Green tea contains catchins, anti-oxidants that help stimulate the immune system’s T-cells. There is actually very little evidence that vitamin C prevents colds, but studies show that people with low levels of vitamin D are almost 40% more likely to get a respiratory infection. Sun exposure can be in short supply during the winter months, so try foods that are vitamin-D fortified, such as dairy, tuna and salmon or taking a supplement of about 1,000 IU/day can help.

Cutting your alcohol consumption is also a good idea as heavy alcohol use suppresses your immune system and makes you more susceptible to viruses and secondary complications.

Lifestyle strategies can also help prevent cold and flu.  Try reducing your stress level; natural virus-killing chemicals are released during relaxation techniques, such as biofeedback.

Massage and saunas also have been found to bolster your immune system and lower your level of cortisol, a stress hormone that decreases immune function.  A German study found that people who took a sauna twice a week had half as many colds as those who did not.  They theorized that as you inhale the hot air, it helps kill viruses.

If you smoke, quit. Statistics show smokers have more frequent and severe colds that more often produce secondary complications like pneumonia.

Regular, moderate exercise releases endorphins and reduces stress and cortisol levels Studies found that people who exercise experienced a 23% reduction in upper respiratory infections.

Lastly, keep in touch with friends and families. Research shows people with close ties to their loved ones were less susceptible to colds than socially isolated individuals.


Medical Advances

Looking to the future, there is exciting new research that shows promise for treating and preventing colds and the flu. New studies may lead to a single universal flu vaccine. Currently, vaccines target the head of the flu virus, an area that is able to mutate (thus requiring yearly new vaccines.) A newly discovered antibody targets the stem area of the virus, which is similar in many different types of flu strains and doesn’t mutate as often. Animal studies are being conducted now, but as early as 2011-2012 there may be human clinical trials in the works. 

Another recent study just cracked the genetic code for the common cold, identifying the DNA sequence of all 99 different strains of human rhinoviruses. This has allowed researchers to pinpoint areas of similarities, grouping the 99 diverse strains into 15 smaller similar groups. The hope is to eventually develop classes of antiviral medications and vaccines aimed at these 15 different groups. Researchers believe we may see development of these new types of therapies within the next several years!

But for now we will have to use common sense and listen to our grandmothers, an ounce of prevention is worth a pound of cure!

Article written by Leigh Vinocur, MD, FACEP
Board-certified Emergency Physician, Adjunct Assistant Professor LSU Health-Shreveport