Viral infections are widespread in the autumn and winter period, which now begins. They usually manifest themselves as an ordinary cold, which does not have negative health consequences and, despite bothersome symptoms (such as runny nose, cough, headache, sore throat), passes by itself within a week or two. Staying in closed rooms, less sun exposure, hypothermia and seasonal activity of some pathogens will also cause the common cold. However, this year we will once again face the additional threat of COVID-19. How can we tell if we suffer from the flu or the coronavirus causing COVID-19? How to distinguish a cold from the SARS-CoV-2 coronavirus? Unfortunately, it is difficult to provide clear answers to these questions because the symptoms of these diseases can be very similar.

One of these diseases can have clinical symptoms that are difficult to distinguish from COVID-19. We are talking here about influenza (flu). This is why it is so important to properly educate people about the characteristics of both these diseases, so that patients themselves can distinguish the two to some extent, which will greatly facilitate further diagnostic and treatment procedures. The flu poses a lower epidemiological risk as there are effective vaccines against this disease and the risk of serious complications (including death) is lower than in the case of COVID-19.
What is a cold
A cold, or more specifically the common cold or viral nasopharyngitis, is associated with a viral infection which can be caused by a large number of different viruses. It is estimated that in almost half of the cases, the disease is caused by a rhinovirus infection, in the remaining cases – by coronaviruses, adenoviruses, enteroviruses and others. A cold is an airborne disease but depending on the pathogen type, it can also be transmitted through direct contact or be foodborne. Unlike the flu, a cold usually begins with mild symptoms.
Cold symptoms are the following:
• sore throat
• runny nose
• cough
• sneezing
• headaches (rarely)
• muscle aches
• fever (rarely and not high)
Symptoms build up gradually and in most cases, recovery occurs within 7-10 days. A cold is a mild disease, usually without complications (people with bronchial asthma or other chronic respiratory diseases and immunodeficiency might develop bronchitis and/or pneumonia).
What is seasonal flu?
The flu season in Poland is from October to April. The etiological factor of this disease is influenza
A virus or, to a small extent, influenza B virus. The flu is an airborne disease, however, it can be also transmitted (less often) through contaminated hands or objects. The main risk factors include direct contact with the patient and being closer to the patient than 1.5 m for a longer time. Spending time in large groups of people and not taking care of proper hand hygiene are conducive to getting sick.
Symptoms come on suddenly:
• fever or subjective feeling of fever, chills
• cough, usually dry
• sore throat
• runny or blocked nose
• muscle and joint aches
• headaches
• tiredness
• vomiting and diarrhoea in some patients (more often in children than in adults)
What is Covid-19?
It is a disease caused by the novel SARS-CoV-2 coronavirus, associated with severe respiratory distress syndrome. Symptoms of COVID-19, except for the loss of smell and/or taste, can also occur in the course of the flu. The loss of smell and/or taste is characteristic of COVID-19, rarely seen in other viral infections. In the absence of this symptom, the flu can be distinguished from COVID-19 only on the basis of nasopharyngeal swab testing (RT-PCR method) for SARS-CoV-2 or antigen testing.