Unit 1 : Covid-19

What is COVID-19?

COVID-19 is the disease caused by a new coronavirus called SARS-CoV-2. WHO first learned of this new virus on 31 December 2019, following a report of a cluster of cases of ‘viral pneumonia’ in Wuhan, People’s Republic of China.

What are the symptoms of COVID-19?

The most common symptoms of COVID-19 are

• Fever

• Dry cough

• Fatigue

Other symptoms that are less common and may affect some patients include:

• Loss of taste or smell,

• Nasal congestion,

• Conjunctivitis (also known as red eyes)

• Sore throat,

• Headache,

• Muscle or joint pain,

• Different types of skin rash,

• Nausea or vomiting,

• Diarrhea,

• Chills or dizziness.

Symptoms of severe COVID‐19 disease include:

• Shortness of breath,

• Loss of appetite,

• Confusion,

• Persistent pain or pressure in the chest,

• High temperature (above 38 °C).

Other less common symptoms are:

• Irritability,

• Confusion,

• Reduced consciousness (sometimes associated with seizures),

• Anxiety,

• Depression,

• Sleep disorders,

• More severe and rare neurological complications such as strokes, brain inflammation, delirium and nerve damage.

People of all ages who experience fever and/or cough associated with difficulty breathing or shortness of breath, chest pain or pressure, or loss of speech or movement should seek medical care immediately. If possible, call your health care provider, hotline or health facility first, so you can be directed to the right clinic.

What happens to people who get COVID-19?

Among those who develop symptoms, most (about 80%) recover from the disease without needing hospital treatment. About 15% become seriously ill and require oxygen and 5% become critically ill and need intensive care.

Complications leading to death may include respiratory failure, acute respiratory distress syndrome (ARDS), sepsis and septic shock, thromboembolism, and/or multiorgan failure, including injury of the heart, liver or kidneys.

In rare situations, children can develop a severe inflammatory syndrome a few weeks after infection.

Who is most at risk of severe illness from COVID-19?

People aged 60 years and over, and those with underlying medical problems like high blood pressure, heart and lung problems, diabetes, obesity or cancer, are at higher risk of developing serious illness.

However, anyone can get sick with COVID-19 and become seriously ill or die at any age.

Are there long-term effects of COVID-19?

Some people who have had COVID-19, whether they have needed hospitalization or not, continue to experience symptoms, including fatigue, respiratory and neurological symptoms.

WHO is working with our Global Technical Network for Clinical Management of COVID-19, researchers and patient groups around the world to design and carry out studies of patients beyond the initial acute course of illness to understand the proportion of patients who have long term effects, how long they persist, and why they occur. These studies will be used to develop further guidance for patient care.

How can we protect others and ourselves if we don't know who is infected?

Stay safe by taking some simple precautions, such as physical distancing, wearing a mask, especially when distancing cannot be maintained, keeping rooms well ventilated, avoiding crowds and close contact, regularly cleaning your hands, and coughing into a bent elbow or tissue. Check local advice where you live and work. Do it all!

Read our public advice page for more information.

When should I get a test for COVID-19?

Anyone with symptoms should be tested, wherever possible. People who do not have symptoms but have had close contact with someone who is, or may be, infected may also consider testing – contact your local health guidelines and follow their guidance.

While a person is waiting for test results, they should remain isolated from others. Where testing capacity is limited, tests should first be done for those at higher risk of infection, such as health workers, and those at higher risk of severe illness such as older people, especially those living in seniors’ residences or long-term care facilities.

What test should I get to see if I have COVID-19?

In most situations, a molecular test is used to detect SARS-CoV-2 and confirm infection. Polymerase chain reaction (PCR) is the most commonly used molecular test. Samples are collected from the nose and/or throat with a swab. Molecular tests detect virus in the sample by amplifying viral genetic material to detectable levels. For this reason, a molecular test is used to confirm an active infection, usually within a few days of exposure and around the time that symptoms may begin.

What about rapid tests?

Rapid antigen tests (sometimes known as a rapid diagnostic test – RDT) detect viral proteins (known as antigens). Samples are collected from the nose and/or throat with a swab. These tests are cheaper than PCR and will offer results more quickly, although they are generally less accurate. These tests perform best when there is more virus circulating in the community and when sampled from an individual during the time they are most infectious.

I want to find out if I had COVID-19 in the past, what test could I take?

Antibody tests can tell us whether someone has had an infection in the past, even if they have not had symptoms. Also known as serological tests and usually done on a blood sample, these tests detect antibodies produced in response to an infection. In most people, antibodies start to develop after days to weeks and can indicate if a person has had past infection. Antibody tests cannot be used to diagnose COVID-19 in the early stages of infection or disease but can indicate whether or not someone has had the disease in the past.

What is the difference between isolation and quarantine?

Both isolation and quarantine are methods of preventing the spread of COVID-19.

Quarantine is used for anyone who is a contact of someone infected with the SARS-CoV-2 virus, which causes COVID-19, whether the infected person has symptoms or not. Quarantine means that you remain separated from others because you have been exposed to the virus and you may be infected and can take place in a designated facility or at home. For COVID-19, this means staying in the facility or at home for 14 days.

Isolation is used for people with COVID-19 symptoms or who have tested positive for the virus. Being in isolation means being separated from other people, ideally in a medically facility where you can receive clinical care. If isolation in a medical facility is not possible and you are not in a high risk group of developing severe disease, isolation can take place at home. If you have symptoms, you should remain in isolation for at least 10 days plus an additional 3 days without symptoms. If you are infected and do not develop symptoms, you should remain in isolation for 10 days from the time you test positive.