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The novel coronavirus in a few words

The infectious agent

Coronaviruses are infectious agents originating from humans or animals (depending on the strain) that have been known for a long time. In humans, they cause acute respiratory disease.


The new coronavirus, called SARS-CoV-2, appeared at the end of 2019 in China. It is generating a global epidemic of a disease (called COVID-19) as it is highly contagious and the general population still has little immunity to this new virus.


The new coronavirus is transmitted mainly through close and prolonged contact, that is, staying within 1.5 meters of an infected person for at least 15 minutes. 

The virus is spread via saliva droplets from an infected person, transmitted through coughing, speaking or even breathing, or when left on surfaces that are touched shortly thereafter. It is not transmitted without direct contact with micro droplets of saliva, as it is not suspended in the air.


The time from contact with the virus and the onset of the first symptoms is usually between 2 to 14 days. 50% of people have symptoms within five days of infection. When a person has a viral infection of the respiratory tract (cough, fever), it is probable to be more contagious when symptoms are more evident.

A patient can be contagious several days before symptoms appear.


The disease, called COVID-19, most commonly manifests as a flu-like condition (fever and/or cough) that lasts for a few days to 2 or 3 weeks. The illness is usually mild in young and healthy people (especially children) but can sometimes be severe in older people or those with chronic diseases. At present, its lethality is estimated to be about 10 times greater than that of seasonal flu.

Populations at risk

People over the age of 65, or those with a chronic illness such as high blood pressure (only if poorly controlled despite treatment), diabetes (if advanced disease with complications or HbA1c>8), cardiovascular disease, chronic respiratory disease, severe obesity (BMI>40kg/m2), immunosuppression due to a disease, treatment or cancer are at greater risk of developing a severe complication that can lead to death. Well treated allergic asthma is not considered a risk factor.

Being pregnant can, in rare cases, put you at risk of complications. Pregnant women must therefore strictly follow preventive measures.


Children are probably less likely to be infected with the new coronavirus as compared with adults. They generally have milder symptoms (cough and/or fever) than adults, or no symptoms at all. Albeit very rare, severe complications are also possible.


Currently, there are two types of tests available to diagnose acute COVID-19 infection, both of them require a nasopharyngeal swab: the PCR test, used since the beginning of the epidemic, and the antigen rapid test, introduced on the 2nd of November 2020. Rapid tests are very reliable and give a result in 15 minutes. They make it possible to increase the number of people tested and more rapidly implement isolation. The decision between a PCR or rapid test is at the discretion of the health care provider. There are blood tests, called serological tests, which detect whether a person has been exposed to the virus in the past, but cannot be used to diagnose acute infection. Serological tests can detect whether one has produced antibodies in response to a previous resolved infection. Serology can be useful in assessing the level of immunity in the population and in deciding whether to suspend quarantine measures in previously infected individuals.


Dexamethasone is currently the only recommended treatment for COVID-19 in Switzerland but only has an effect on the most severe cases.


Several studies have failed to demonstrate a reduction in mortality for chloroquine, remdesivir or lopinavir/ritonavir. 

Antivirals like favipravir or monoconal antibodies anti-SARS-CoV-2 as well as drugs that affect the mechanisms of inflammation (tocilizumab, anakinra) are under investigation and may have a modest effect in some patients.


In the case of a proven COVID-19 infection (positive test result) in the 3 past months, the risk of re-infection is highly unlikely. If symptoms reappear within this interval, a new test is not necessary. However, we do not yet know whether this protection persists beyond 3 months.


If the official hygiene recommendations are properly applied, the risk of catching the virus is greatly reduced.

It is therefore necessary to keep a distance of more than 1.5 meters from other people, wear a face mask when this is not possible and wash your hands before and after touching your face or objects used by other people.

Adequate ventilation also helps reducing the risk of viral transmission in closed spaces. It is thus necessary to regularly ventilate rooms where several people gather.

The CoronaCheck tool

Created in March 2020, CoronaCheck is the product of a close collaboration of experts from the Policlinic of Tropical, Travel and Vaccinal Medicine and engineers from the IT team of Unisanté. Thanks to their long experience in the development of clinical decision support algorithms, these experts in infectious disease, general medicine, public health and informatics could create a digital reference tool that help orient the population and health professionals based on recommendations tailored to their situation. The CoronaCheck algorithm follows the official recommendations of the Federal Office of Public Health as well as scientific literature and the latest medical knowledge.

Unisanté, a pioneering center in digital health

Coronacheck is part of the development of clinical decision support algorithms and other digital health tools, in which Unisanté is a pioneer. The work that Unisanté has been carrying out for 15 years in primary care medicine, has enabled it to develop effective tools for clinical management, promoting modern and personalized medicine.

The translation of this site into eleven languages was made possible thanks to the work of medical students, and the help of doctors from Unisanté and CHUV.

The logic behind coronacheck

Our algorithm is an adaptation of the official recommendations of the Federal Office of Public Health. The logic behind our tool is freely accessible at this link.