Coronavirus SARS-CoV-2

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What is coronavirus SARS-CoV-2? 

Coronaviruses are a large set of viruses that have been detected in both humans and animals.  Coronavirus SARS-CoV-2 is one of these viruses. It causes COVID-19 disease. COVID-19 comes from the words corona, virus, disease, 2019.
Learn more about coronaviruses (in Finnish)

How does coronavirus spread and what is the incubation time? 

Coronavirus spreads through droplets when an infected person coughs or sneezes. It also spreads by air in the form of fine aerosols. For example, when a person coughs, sneezes, speaks, sings, or shouts, very small particles called aerosols are expelled, in addition to larger droplets. These remain airborne and move about, carried by the moving air, sometimes quite long distances. 

Coronavirus also spreads through touch, if the infected person has coughed in his hands, for example, and later touches another person. Coronavirus can also be transmitted from surfaces, such as door handles. However, the virus will not remain on the surfaces for long.

The incubation period of the disease has been estimated to be 1 to 14 days. The symptoms of the omicron variant usually occur for about three days after the infection. 

According to current information, a person who has contracted the virus is most infectious in the early stages of a symptomatic disease and 1–2 days before the symptoms begin. Infectiveness drops sharply after the first days of symptoms. Asymptomatic can also spread the disease further.

How to prevent coronavirus?      

The vaccine gives the best protection against coronavirus. Although protection against infection is moderate and short-term, the vaccine effectively prevents serious coronavirus disease.
Vaccines and coronavirus

Coronavirus infections can be prevented by the same means as other respiratory tract infections.

  • If you fall ill, stay at home until the symptoms have clearly decreased. If you are sick and have to go outside your home, you can wear a mask if you wish.
  • Wash your hands with soap and water or use handrub  
  • Cough and sneeze into a disposable tissue and put the tissue in the bin after use. If you do not have a tissue, cough or sneeze into your sleeve, not into your hands.
  • Assess your own risk, use a mask if necessary and keep a distance. A mask also protects the person wearing it to some degree. 
    Information on face masks, surgical masks and respirators (Finnish Institute of Occupational Health)
  • Take care of good ventilation

Read more about preventing respiratory tract infections 

What are the symptoms of coronavirus?

Coronavirus usually causes a sudden respiratory tract infection. Symptoms may vary from none to severe disease. The symptoms may also fluctuate as the disease progresses.

COVID-19 symptoms may include 

  • headache
  • loss of smell or taste
  • head cold, blocked nose
  • cough
  • shortness of breath
  • loss of energy, fatigue
  • aches and pains in muscles
  • sore throat, irritated throat 
  • fever
  • nausea, vomiting
  • diarrhoea

What is severe coronavirus disease like?

 A person with a severe coronavirus disease may receive, for example,

  • pneumonia
  • acute respiratory distress syndrome (ARDS).

The infected person’s state of health may deteriorate quickly. The deterioration usually happens when it has been a week since the symptoms started. Severe coronavirus disease can lead to death.

Many people with severe symptoms also had a risk factor, such as high age or several underlying diseases at the same time. 
Risk groups of severe coronavirus disease  

What are the consequences and complications of the coronavirus infection?

The majority of people with coronavirus have mild symptoms and do not need hospital care. 

The need for hospital treatment is more common among the elderly, especially those over 70, and in patients with underlying conditions. The risk of death among COVID-19 patients increases with age. The risk also increases in patients with multiple underlying diseases. 

Some patients with severe diseases need hospital and intensive care. Patients with respiratory difficulties may then require respiratory support, such as supplemental oxygen or even ventilator treatment. 

Coronavirus infection increases haemorrhagic tendencies. A person with coronavirus may have an increased risk of thrombosis, such as deep vein thrombosis in the lower limb or pulmonary thrombosis. 

Some patients may develop neurological symptoms, such as changes in the level of alertness. 

Prolonged symptoms may occur after acute coronavirus disease, as with other viral infections (so-called long covid). 
Prolonged coronavirus disease, or long COVID (in Finnish)

What is known about coronavirus disease in children?

Most children suffer from the disease as asymptomatic or mild. 

The risk of severe coronavirus disease is low for children and young people 

  • who are healthy
  • whose underlying condition, such as asthma or heart disease, is in good therapeutic control, or
  • who have diabetes but no other significant illnesses.

Moreover, the risk of falling ill is not generally greater in children who have a weakened immune system due to taking immunosuppressive medication.  Stopping such medication on your own may be dangerous. 

Coronavirus infection in children may be associated with secondary diseases, but these are rare. A severe general inflammatory condition, MIS-C, which is similar to the Kawasaki disease, has been associated with coronavirus infections as a rare secondary disease.

As with other virus infections, coronavirus infection may be associated with myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the pericardium, the fibrous sac surrounding the heart). However, according to current knowledge, they are very rare in children and young people. 
There has been less research on long-term symptoms (so-called long covid) in children than in adults. It has been estimated that prolongation of symptoms after COVID-19 infection is rare in children, but may be more common in adolescence. After severe coronavirus disease, prolonged symptoms are more common even in children.

How are coronavirus infections treated?

In most cases, coronavirus infection can be treated symptomatically, as can other acute respiratory tract infections.
Self-treatment of respiratory tract infections (Terveyskylä, in Finnish)

If you develop serious symptoms, including shortness of breath, or if your general condition gets worse, you should contact the healthcare services without delay. Deterioration in your overall condition means that you for example cannot take in enough fluids or that you have difficulty getting out of bed due to dizziness.    

If you are in a risk group, you should not hesitate to contact a health centre or a doctor. 
Risk groups of severe coronavirus disease 

Pharmacotherapies for COVID-19 coronavirus infection also exist and are under development. Their use may be considered if the person is at risk of developing a severe coronavirus infection due to age, disease or medication that weakens their body's defence capacity.  The decision to start medication is always made by a physician. See the instructions in your area on whether you belong to the target groups and how you can get the medication.

When can you return to work, school or day-care centre after a coronavirus infection?

You can return to work when the symptoms have clearly subsided and the temperature is gone. This usually takes 3-5 days. Workplaces can provide their own instructions.  

A child may go to school or day-care centre when the symptoms have clearly decreased, the temperature is gone and the child's general condition is such that he or she is able to participate in teaching or early childhood education and care. 

In viral infections, infectivity decreases rapidly after the onset of symptoms, even if the rhinitis or cough continues longer.  

What do I do if I have been exposed to coronavirus?

You can continue your normal daily life and act as you would if you had been exposed to another respiratory tract infection, such as influenza.  

For example, you can go to work, school, day-care centre and hobbies, even if someone in your family has a coronavirus infection.  

If you have symptoms, stay at home until the symptoms have clearly decreased.

How is the coronavirus diagnosed?

The infection caused by coronavirus is diagnosed in health care by means of a PCR test or an antigen test. Specialised virus laboratories are also able to culture coronaviruses.
COVID-19 laboratory tests – instructions for laboratories (in Finnish).

Coronavirus tests are carried out in health care if the person has symptoms related to coronavirus and if

  • a health care professional has recommended a test, or if
  • you work in customer, or patient services in social and health care, or if
  • you work at any job in a 24-hour facility for elderly care or services for the disabled, or if 
  • you are in a risk group for a severe coronavirus disease or
    Risk groups for severe coronavirus disease
  • you are pregnant.

You can take a symptom checker in Omaolo service.

Coronavirus home tests

If you wish, you may take a home test.  There are two types of home tests: an antigen test and an antibody test. 
Read more about home tests

How widespread is the coronavirus?

The Finnish institute for Health and Welfare follows the number of cases and keeps the website updated.
Situation update on coronavirus COVID-19

What is known about coronavirus variants?

Coronavirus variants are transformed coronaviruses. It is typical for viruses to constantly transform. Virus variants may differ in their properties from previously encountered virus strains. 
Read more about coronavirus variants

See also

Travel and the coronavirus pandemic