How is the coronavirus transmitted? What are the symptoms of COVID-19, and how might the illness progress? And where did the coronavirus first appear? Find out here.
Transmission of the coronavirus
Cases of coronavirus infection most frequently occur indoors. If you are in close and protracted contact with an infected person in a poorly-ventilated indoor environment, you will have a high risk of infection.
The virus can be transmitted in any of various ways:
- Directly via droplets: When an infected person breathes, talks, sneezes or coughs, droplets containing the virus can get directly onto the mucous membranes in the nose, mouth or eyes of other people in the immediate vicinity (i.e. less than 1.5 metres away). The longer and closer the contact you have with an infected person, the greater the risk of infection.
- Via aerosols in the air: The virus can be transmitted via aerosols over both short and longer distances. In small and poorly-ventilated indoor spaces where aerosols can accumulate over longer periods, the risk of infection via aerosols is particularly high. The risk of infection via aerosols is also high during activities that require increased breathing (such as physical work, sports, loud talking and singing). You’ll find more information on aerosols on the Frequently Asked Questions (FAQ) page.
- Via surfaces and the hands: When infected persons cough or sneeze, infectious droplets get onto their hands or nearby surfaces. Another person can then become infected if they get these droplets onto their hands and subsequently touch their mouth, nose or eyes. With the coronavirus, this form of indirect transmission is thought to play only a minor role. But maintaining good hand hygiene is still a simple and important way to protect yourself from the transmission of the coronavirus and of other germs (such as the flu virus).
The relative extents to which droplets and aerosols are involved in the transmission of the coronavirus will depend (among other things) on the distance between the persons concerned, and cannot be firmly quantified. The difference between droplets and aerosols is a matter of size, and the distinction is a fluid one.
Symptoms of coronavirus disease
There is a very wide range of symptoms caused by the coronavirus.
The most common symptoms are:
- Symptoms of an acute respiratory illness (sore throat, cough (usually dry), shortness of breath, chest pain)
- High temperature
- Sudden loss of sense of smell and/or taste
- Headache
- General weakness, feeling unwell
- Aching muscles
- Gastrointestinal symptoms (nausea, vomiting, diarrhoea, stomach ache)
- Head cold
- Skin rash
Symptoms can be more or less severe and can vary depending on the virus variant. They can also be mild and even cold-like symptoms can indicate an infection. Complications, such as pneumonia, are also possible.
You’ll find information on post COVID-19 condition (long-term effects of COVID-19) on the page Post COVID-19 condition.
Range of illness severity
The way the coronavirus disease progresses can vary widely. Some people may have no symptoms or barely notice that they are ill. Others require intensive care in hospital.
No symptoms
People with no symptoms are unaware that they have become infected. They can therefore pass on the coronavirus to others without realising it.
Mild cases
A significant majority of people who become infected experience a mild form of the disease. This means they experience mild symptoms for just a few days.
Serious cases
In serious cases, the symptoms are mild at first, but deteriorate after around five to ten days. Patients may develop a persistent temperature, feel unwell and/or develop shortness of breath. This may lead to pneumonia. In such cases, the person requires hospital treatment, in many cases with supplemental oxygen.
In serious cases, the illness generally lasts two to four weeks. With proper medical treatment, patients usually make a full recovery. However, they may still feel tired, short of breath and generally weak for a long time afterwards. Scientists currently assume that a person who has had COVID-19 is immune from renewed infection for a time, although it is unclear for how long.
People can become seriously ill at any age, although it is extremely rare in children and young people. People at especially high risk are more likely to experience serious illness.
Critical cases
Some people become critically ill and are in an acute life-threatening state that necessitates intensive care to ensure their survival., This requires highly specialised personnel and drugs.
Treatment
If you develop symptoms of a cold and are in an especially high risk group, contact your medical specialist. They can then consider whether prompt treatment is required in case you have contracted the coronavirus.
A coronavirus infection cannot be treated with antibiotics because antibiotics are only effective against bacteria, not against viruses.
Prevention
Vaccination can help protect you from a severe case of COVID-19. You can find more information on the Vaccination page.
Protecting from infection
Find out more on the page Protect yourself and others.
COVID-19
On 11 February 2020 the WHO gave the disease caused by the coronavirus an official name: COVID-19, short for coronavirus disease 2019.
What is the coronavirus?
The coronavirus epidemic in China probably originated at a market in the central Chinese city of Wuhan where bats, snakes and other wild animals were traded alongside fish. The virus was transmitted to humans via animals, probably bats or indirectly via pangolins. Since then the virus has been transmitted from person to person. The Chinese authorities closed the market at the beginning of January.
The coronavirus, known as SARS-CoV-2, belongs to the same family of viruses as six other known coronaviruses that we have known about for years or even decades. Four of these are human coronaviruses, which generally cause mild winter colds.
Other known coronaviruses include:
- the SARS virus, SARS-CoV-1, identified in southern China in 2003 and transmitted to humans from civets and
- the MERS virus, identified in 2012 on the Arabian peninsula and transmitted to humans from dromedaries.
Coronaviruses are enveloped RNA viruses (RNA = Ribonucleic acid). This means that they have a lipid membrane (greasy film), which can be dissolved with soap and water or disinfectant, thereby inactivating the virus.
Variants of the coronavirus
It is normal for viruses to constantly change, resulting in random mutations. The term ‘mutation’ describes the process of change undergone by a virus. If a number of mutations arise with sufficient properties that differ from the original virus, we talk of a new variant.
While most newly emerging mutations have no great influence on the spread of a virus, some mutations or combinations of mutations can put the virus at an advantage. This could be greater transmissibility (infectiousness), for example. Variants of this sort can pose a threat to people’s health, and are therefore classified as variants of concern.
Frequently Asked Questions (FAQs)
Answers to frequently asked questions concerning disease, symptoms and treatment can be found here.
Last modification 05.07.2023