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COVID-19 Guide

Written by Ada’s Medical Knowledge Team

Updated on


  • COVID-19 is an infectious disease with many variants. 
  • Currently, Omicron is the COVID-19 variant that is most present worldwide.
  • The symptoms of the coronavirus may vary, ranging from no symptoms or mild symptoms that resemble a common cold to severe symptoms that may lead to hospitalization and death.
  • Most cases of the coronavirus can be treated at home. Some people may be eligible for antiviral therapy.

As the coronavirus news may be overwhelming, we’ve created a full COVID-19 guide at Ada so you can access all the necessary information quickly. This guide will provide you with a complete overview of the coronavirus, its symptoms, diagnosis, treatment, and action points you can use to prevent getting ill.  

What is COVID-19?

Coronavirus is an infectious disease that originated in 2019 in Wuhan, China. Since then, the coronavirus has spread worldwide and mutated many times, resulting in different variants such as Alpha, Beta, Delta, Lambda, and Omicron, the latter of which is currently the dominant strain worldwide. 

The coronavirus spreads through tiny droplets and aerosol particles from an infected person’s mouth or nose when they cough, sneeze, speak, sing, or breathe. Most infected people experience mild to moderate symptoms. For some people, however, the coronavirus can cause severe illness, which may result in hospitalization or even death.  1

What are the symptoms of COVID-19?

COVID-19 can cause various symptoms, with slight differences depending on which variant you’ve been infected with. Overall, the coronavirus may cause: 2 3

  • Fever or chills: the range of this high temperature may vary but is usually mild to moderate. Although a fever is a normal body reaction when fighting off an infection, the effects can be uncomfortable.
  • Cough: a dry, non-productive cough is common in individuals with COVID. It may cause irritation and difficulty in breathing.
  • Shortness of breath or difficulty breathing: shortness of breath can range from mild to severe, depending on the severity of your infection. Difficulty breathing is a sign that you’re likely having a more serious reaction to the virus.
  • Fatigue: fatigue can be mild or severe, lasting for multiple days. It could feel like exhaustion that doesn’t seem to go away, even after you’ve had enough rest.
  • An aching body: muscle and body aches can range from mild to severe and may worsen as the virus progresses.
  • Headache: headaches can range from moderate to severe. They may be accompanied by other symptoms such as fatigue, fever, or general malaise.
  • Loss of taste or smell: this is one of the more common symptoms of COVID and can last for several weeks after your initial infection.
  • Sore throat: a sore throat could indicate that you’re infected with COVID. It can range from mild to severe and may cause discomfort when swallowing.
  • Congested or runny nose: congestion is another symptom of COVID and is often accompanied by a runny nose.
  • Loss of appetite: loss of appetite. This can range from mild to severe
  • Nausea or vomiting: nausea and vomiting may occur if the virus has affected your digestive system.
  • Diarrhea: diarrhea can be a sign that the virus has reached your digestive system, causing disruptions in its normal functioning.
  • Skin rashes: they appear as discolored skin patches and may be accompanied by itching or burning sensations.
  • Brain fog, confusion, disorientation, or difficulty concentrating: they can happen due to fever or other symptoms or potentially from the virus itself.
  • Menstrual irregularities: women may experience missed periods or changes in the flow and duration of their period. This can be due to an underlying inflammatory response caused by the virus.
  • Eye irritation or redness: this may worsen over time, so it's essential to seek medical attention if this symptom persists for more than a few days.
  • Tongue discoloration: It could be accompanied by white patches on the tongue, which may indicate an underlying inflammatory response.
  • Night sweats: they can occur as a sign that your body is fighting off infection, and you may also experience other symptoms such as chills, fever, and body aches.

The early signs of coronavirus detection may consist of any of these symptoms. As these signs of infection are similar to those you may experience with other common conditions, such as the flu and the common cold, getting tested as soon as possible is essential. Suppose you suspect that you may have been infected. In that case, keeping your distance from vulnerable people, such as older people and people with underlying health conditions or a weak immune system, is crucial.

Some people may experience severe symptoms due to COVID-19. You should seek immediate medical help if you’re experiencing: ref4

  • Trouble breathing
  • Persistent pain or pressure on the chest
  • Confusion
  • Inability to stay awake
  • Pale, gray, or blue-colored skin

How can COVID-19 be diagnosed? 

You can check for an active infection with the coronavirus through a PCR test or an antigen test. Both require a swab from the back of the throat or the nose, which can then be analyzed. The biggest differences between both are: 4

  • Their sensitivity: PCR tests are more likely to detect the coronavirus
  • The price: Antigen tests are less expensive and are available for at-home testing
  • Negative antigen tests do not entirely rule out coronavirus infection. They’re only to be used as preliminary results and should be confirmed by a PCR test
  • PCR tests may indicate a false positive result for people infected with COVID-19 in the past 90 days, as the viral RNA may linger in your body.

How long does COVID-19 last?

The symptoms of COVID-19 usually appear 2 to 14 days after exposure to the virus. This period is also known as the incubation period for COVID-19. Once you start to experience symptoms, they’ll generally last for a few days up to a few weeks. However, some people continue to experience symptoms of COVID-19 long after they’ve been infected. This situation is defined as long COVID and may be characterized by any of the following symptoms: 5 6

If you believe that you might be experiencing long COVID, it’s advised to contact your doctor to find out more about possible treatment options.

How to treat COVID-19?

The treatment for COVID-19 depends on your symptoms. While most infections with the coronavirus can be treated at home, some people qualify for antiviral therapy or monoclonal antibodies. Whether or not someone qualifies for this type of treatment depends on their risk of falling severely ill. The following risk factors affect how sick you might get from the coronavirus: 7 8 9 10 11

  • Being unvaccinated
  • Your age, especially if you’re over 50 years old
  • Certain medical treatments, such as chemotherapy and immune suppressive therapy
  • Particular illnesses and conditions such as cardiovascular disease and immune deficiencies
  • Smoking
  • High blood pressure
  • Obesity
  • Pregnancy
  • Chronic conditions of the lungs, such as COPD and asthma

If you have COVID-19, you should monitor your symptoms closely so you're ready to take action if they worsen. You should contact your doctor if: 12

  • You’re gradually feeling worse
  • You have difficulty breathing without exercising
  • You feel very weak, and basic tasks are becoming too difficult
  • You’re shaking or shivering
  • You still feel unwell after a month

To reduce your possibility of falling seriously ill due to the coronavirus, it’s advised to get vaccinated and to keep your vaccine status updated. This way, your body’s immune system can react quickly against the coronavirus, resulting in a less severe course of the disease. However, after being vaccinated, you may experience some common side effects of the COVID-19 vaccine, such as fever, headache, fatigue, and pain at the injection site.

How to protect yourself against the coronavirus variants

The coronavirus has a high transmissibility rate, so it’s easy to get infected and pass the virus to others. To avoid getting infected yourself and to protect others from the consequences of COVID-19, you can: 13

  • Get vaccinated and keep your vaccination up-to-date with the recommended booster shots
  • Wash your hands regularly and thoroughly with water and soap
  • Improve ventilation in indoor spaces
  • Avoid contact with people who are experiencing COVID-19 symptoms or who have tested positive
  • Wear a mask that fits well, covering both nose and mouth. Masks can set a barrier for the particles you breathe, cough, or sneeze out. The N95 masks provide higher protection as they fit closely on the face and filter out particles, including the coronavirus.
  • Keep a safe distance from others

When should you quarantine?

Keeping yourself away from others is vital to fighting the coronavirus's spread. If you're experiencing COVID-19 symptoms, you should get tested as soon as possible and isolate yourself even if you have yet to receive your results.

If your test returns positive, you should quarantine for at least 5 days. After this, you should keep your distance from people at a high risk of developing severe symptoms for at least 5 more days, even if they're vaccinated.

The quarantine period counts from the day after the first day of experiencing symptoms. After these 5 days, you should follow government guidelines on what to do next. Keep up to date with the latest guidelines, as they may change according to the current infection rate. 14

Wrapping up

The coronavirus and its different variants caused great concern during the past several years because of their easy transmissibility and the fact that COVID-19 could lead to sudden, severe illness within vulnerable groups. The overall outcome of an infection with the coronavirus has improved drastically through vaccination programs, a better understanding of the virus, and available treatment methods. However, it's still advised to be mindful and to keep a safe distance from others.


Q: Why is it called COVID-19? 
A: COVID-19 stands for coronavirus disease, a respiratory condition caused by the “novel coronavirus.” 19 indicates the year of the outbreak, which was 2019. 

Q: Is it possible to get COVID-19 twice? 
A: Yes, you can get infected with the coronavirus more than once, especially because different variants are circulating, which makes it more difficult for your immune system to defend itself. 

Q: How long are you contagious with COVID-19? 
A: You are most contagious for the 5 days after your symptoms have started and the 48 hours before you begin experiencing symptoms. Studies suggest that you remain contagious for 7 to 10 days starting from the first day you feel unwell. 

Q: When did COVID-19 start? 
A: COVID-19 started in China at the end of 2019 and spread throughout the world by the beginning of 2020. 

Q: How many variants of COVID-19 are there? 
A: There are numerous variants of the coronavirus which have circulated since the onset of the pandemic. Currently, the most dominant variant of the coronavirus is Omicron.