Corona-viruses are a large family of viruses that are known to cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome(SARS).

What is SARS-CoV-2?

Severe Acute Respiratory Syndrome Corona-virus-2 (SARS-CoV-2) is the name given to the 2019 novel corona-virus. COVID-19 is the name given to the disease associated with the virus. SARS-CoV-2 is a new strain of corona-virus that has not been previously identified in humans.

Where do corona-viruses come from?

Corona-viruses are viruses that circulate among animals with some of them also known to infect humans.Bats are considered as natural hosts of these viruses yet several other species of animals are also known to be a source. For instance, the Middle East Respiratory Syndrome Corona-virus (MERS-CoV) is transmitted to humans from camels, and the Severe Acute Respiratory Syndrome Coronations-1 (SARS-CoV-1) is transmitted to humans from civet cats. More information on corona-viruses can be found on the ECDC fact-sheet.

Is this virus comparable to SARS or to the seasonal flu?

The novel corona-virus detected in China is genetically closely related to the SARS-CoV-1 virus. SARS emerged at the end of 2002 in China, and it caused more than 8 000 cases in 33 countries over a period of eight months. Around one in ten of the people who developed SARS died.

The current COVID-19 outbreak caused around 7 000 reported cases in China during the first month after initial reports (January 2020), with a further 80 000 cases reported globally during the second month (February 2020). Of these first 87 000 cases, about 3 000 died. Cases are now being detected in Europe and across the globe. See the situation updates for the latest available information.

While the viruses that cause both COVID-19 and seasonal influenza are transmitted from person-to-person and may cause similar symptoms, the two viruses are very different and do not behave in the same way. ECDC estimates that between 15 000 and 75 000 people die prematurely due to causes associated with seasonal influenza each year in the EU, the UK, Norway, Iceland and Liechtenstein. This is approximately 1 in every 1 000 people who are infected. By comparison, the current estimated mortality rate for COVID-19 is 20-30 per 1 000 people.

Despite the relatively low mortality rate for seasonal influenza, many people die from the disease due to the large number of people who contract it each year. The concern about COVID-19 is that, unlike influenza, there is no vaccine and no specific treatment for the disease. It also appears to be as transmissible as influenza if not more so. As it is a new virus, nobody has prior immunity which in theory means that the entire human population is potentially susceptible to COVID-19 infection.

Can humans become infected with a novel corona-virus of animal source?

Detailed investigations found that SARS-CoV was transmitted from civet cats to humans in China in 2002 and MERS-CoV from dromedary camels to humans in Saudi Arabia in 2012. Several known corona-viruses are circulating in animals that have not yet infected humans. As surveillance improves around the world, more corona-viruses are likely to be identified.