Cold & flu – The most common viral infections

Cold & flu – The most common viral infections

The common cold gets its name from being the most common infectious disease out there. Yet still it is often confused with the seasonal flu. While common colds are the main reason children miss school and adults miss work, the flu is responsible for seasonal flu epidemics each year.

What is the difference between cold and flu?

The cold and the flu, also called influenza, have a lot in common. They both are contagious respiratory illnesses; both are caused by viruses – but different ones – and they both cause similar symptoms. These similarities make it extremely difficult to differentiate between the two, especially during the early stages of the illness. Usually, the flu symptoms are worse compared to those of the common cold, and they are typically more intense and begin abruptly. On the other hand, colds are usually milder and, in most cases, do not result in serious health problems. The flu, if not treated properly, can lead to serious associated complications such as pneumonia, bacterial infections, or even hospitalizations.

Common cold

The common cold is a self-limited, contagious condition caused by several different types of viruses, including rhinoviruses, parainfluenza, and seasonal coronaviruses. However, these seasonal coronaviruses should not be confused with SARS-COV-2, the virus that causes COVID-19. The common cold is the leading cause of acute morbidity and missed days from school or work. Adults have an average of 2-3 colds per year, and children have even more. People often get colds in the winter and spring, but it is possible to get a cold any time of the year. Especially during the winter, the common cold spreads quickly to other people. This happens through airborne droplets coughed or sneezed into the air by a sick person, and another person then inhales these droplets. But the virus can also spread through contamination when a sick person touches surfaces or touches other people.

Flu (influenza)

The flu is caused by influenza viruses only. The two main types of influenza viruses are Types A and B. Both types are responsible for seasonal flu epidemics each year. Sometimes the flu causes mild illness. But it can also have a serious progression and even lead to death. The flu is especially dangerous for vulnerable people over 65, newborn babies, and people with certain chronic illnesses and immune deficiency. Similar to cold viruses, flu viruses also enter the body through the mucous membranes of the nose, eyes, or mouth. They spread quickly from person to person through tiny droplets from coughing, sneezing, or even just talking. The chance of contracting these viruses by touching a contaminated surface or object is less likely; however, still possible.

Common symptoms

Even though it’s not always easy to tell if it’s the common cold or the flu, it is good to know the difference between the symptoms. In general, a cold is a milder respiratory illness compared to the flu.

Cold symptoms

The first cold symptoms usually start 2 to 3 days after the virus enters the body, and symptoms last up to 10 days. The course of the illness is usually less intense without fever, and milder symptoms such as runny nose can last several weeks. Additionally, the onset and types of symptoms and signs observed may vary depending on the virus responsible for the infection.

Here are the most common cold symptoms:

  • Runny or stuffy nose
  • Scratchy throat
  • Sneezing
  • Watering eyes
  • Low-grade fever
  • Sore throat
  • Mild cough
  • Muscle or body aches
  • Headaches
  • Mild fatigue
  • Chills

Flu symptoms

Most flu symptoms improve over two to five days. Many symptoms such as sore throat, fever, and cough tend to develop rapidly. General fatigue can even last for weeks. The flu's progression is more severe than a cold, and as a complication, the flu can even lead to pneumonia, particularly in the young, elderly, or people with lung or heart problems.

Here are the most common flu symptoms:

  • Fever
  • Chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Vomiting and diarrhea (more common among children)

The difference between a cold and the flu

It’s not easy to differentiate between the two. Here’s an overview of symptoms that can indicate the cause of the illness.


Symptom onset

gradual (1-3 days)

Symptom severity
mild to moderate
moderate to severe
Sore throat
Aches and pain
mildmoderate to severe

Cough, chest discomfort

mild to moderate
common, can be severe

Vomiting, upset stomach




How to prevent common colds and the flu?

There are certain everyday preventive actions that can minimize the chance of contracting viruses as well as reduce the spread of viral infections.

Get vaccinated – The first and most crucial step in protecting against flu viruses is getting vaccinated. A yearly flu vaccine is available that can help reduce the burden of flu illnesses, hospitalizations, and deaths in the health care system.

Wash hands

The most straightforward and fastest task is to wash hands thoroughly and often with soap and water for at least 20 seconds. An alcohol-based hand rub is a good alternative if soap and water are unavailable.

Disinfect stuff

Doorknobs, light switches, electronics, as well as kitchen and bathroom countertops are considered high-touch surfaces and should be cleaned and disinfected daily. 

Avoid people with viral infections

Close contact with people who have viral infections increases the chances of getting it. Avoid such situations but also stay out of large crowds, especially during flu season.

Maintain a healthy lifestyle

A healthy diet, exercise, and sufficient sleep, in general, promote overall health.

Strengthen the immune system

Another very effective way to prevent viral diseases is maintaining an overall strong immune system. There are healthy strategies that have proven health benefits. These include diet, exercise, meditation, and stress management. And overall, good health has positive effects on the immune system itself. Vitamins and supplements are also very popular when it comes to boosting the immune system. Vitamin C, B6, and E are the most common. However, these vitamins are already available in a healthy diet, and supplements sometimes come with side effects. Natural medication has proven itself as a safe and effective alternative, especially remedies with Swallowwort and Sulfur. These natural ingredients can stimulate the immune system as a treatment for viral infections and as a form of prevention.

How to treat common colds and the flu?

There is no cure for most viral respiratory illnesses. Therefore, the focus is primarily on symptomatic relief, and however, there are some proven ways to help treat the symptoms.

Drink plenty

Water, tea, broth, and warm liquids, in general, can be soothing for a sore throat, prevent dehydration and ease congestion. At the same time, it is good to restrain from salty foods, alcohol, coffee, and sugary drinks.

Gargle salt water

Gargling a glass of warm water with about one teaspoon of salt can help reduce the pain of a sore throat.

Humidify the air

Viruses spread better in dry air, and at the same time, dry air can worsen a sore throat. A humidifier will evaporate the water, especially in the bedroom, making it more soothing. Another option is to place a shallow water bowl out near a heat source.


During an illness, the body works non-stop, and the immune system needs time to recharge. Rest and sleep are essential in overcoming a cold or the flu, which also means restraining from exercise.

Avoid smoking

Smoking and exposure to smoke can irritate the nose, throat, and lungs and therefore prolong the illness.

Pharmacological approach

Most mild viral respiratory illnesses are managed symptomatically with synthetic medications. These include nasal decongestants, antipyretics/analgesics, and non-steroidal anti-inflammatory drugs (NSAIDs) such as paracetamol, aspirin, or ibuprofen. Even though the majority of these conventional treatment options are readily available as over-the-counter (OTC) medications for relief without a prescription, patients should be aware of the risks or potentially harmful effects associated with them, particularly in young children. Especially NSAIDs can lead to harmful cardiovascular events, including heart attack, stroke, heart failure, and atrial fibrillation. In addition, a Cochrane review concluded that there is no clear evidence of the effectiveness of NSAIDs in treating respiratory symptoms of the common cold other than relieving associated discomfort and that the balance of benefits and harms needs to be considered when using NSAIDs for colds.9
Decongestants can harm the nasal mucosa, and long-term use may lead to tolerance, addiction, and re-bound effects.

Natural medicine approach

Since pharmaceutical antiviral substances are often associated with side effects, a growing number of people rely on natural alternatives that have a good safety profile and are well tolerated in a broad range of patient types. These non-prescription plant-based medications are used in treating viral infections and the common cold. Swallowwort is a plant known for stimulating the body's own defenses with vascular and sympathetic action, e.g., in feverish viral diseases, such as influenza. Sulfur has proven itself as a reactant in all chronic diseases, e.g., acute and chronic inflammation of the respiratory organs, catarrh of the upper respiratory tract, dyspnea, bronchial asthma, and throbbing headache. And in combination, these ingredients strengthen the innate immune response in cases of viral invasion, resulting in milder symptoms and a shorter duration of infection.10-12

Heel natural medicines









9. Kim S, Chang Y, Cho H, Hwang Y, Moon Y. Non-steroidal anti-inflammatory drugs for the common cold (Review). Cochrane Database Syst Rev. 2015;(9):1-66. doi:DOI: 10.1002/14651858 CD006362.pub4 

10. Enbergs H. Effects of the homeopathic preparation Engystol on interferon-gamma production by human T-lymphocytes. Immunol Invest. 2006;35(1):19-27. doi:10.1080/0882013050049675

11. Roeska K, Seilheimer B. Antiviral activity of Engystol(R) and Gripp-Heel(R): an in-vitro assessment. J Immune Based Ther Vaccines. 2010;8(1):6. doi:10.1186/1476-8518-8-6

12. Wronski S, Dannenmaier J, Schild S, et al. Engystol reduces onset of experimental respiratory syncytial virus-induced respiratory inflammation in mice by modulating macrophage phagocytic capacity. PLoS One 2018;13(4):e0195822. doi:10.1371.journal.pone.0195822