Q & A on the Novel Coronavirus

What are coronaviruses?

Coronaviruses are a family of viruses causing infection in humans and a variety of animals including birds and mammals such as camels, cats and bats. Coronaviruses are zoonotic, which means they can transmit between animals and humans.

To date, seven coronaviruses have been shown to also infect and cause illness in humans. When animal coronaviruses evolve, infect people and then spread between humans, it can lead to outbreaks such as what happened with MERS-CoV and SARS.

Novel coronavirus 2019-nCoV infections 

Why are the cases in Asia worrying?

The  2019-nCoV identified in China is a new strain of coronavirus that has not been previously identified in humans. Outbreaks of novel virus infections among people are always of public health concern, especially when there’s little knowledge about the characteristics of the virus, how it spreads between people, how severe are the resulting infections  and how to treat them.

How severe are the infections caused by 2019-nCoV?

This novel coronavirus detected in China is genetically closely related to the 2003 SARS virus and appears to have similar characteristics, although the data available to ECDC for assessing this is very scarce at this stage. From what we know so far, the virus can cause mild, flu-like symptoms as well severe disease. People with existing chronic conditions seem to be more vulnerable to severe illness. Pre-existing conditions reported so far include hypertension and other cardiovascular disorders, diabetes, liver disorders, and other respiratory disease.

What is the source of the outbreak?

Although the most likely primary source of this outbreak is of  animal origin investigations are ongoing to determine the source and mode of transmission of the 2019-nCoV virus.

What is the mode of transmission? How easily does it spread?

Authorities in China confirmed human-to-human transmission of this virus, including healthcare workers. ECDC doesn’t  have enough epidemiological information to determine the extent of this human-to-human transmission. However, we can expect case numbers and numbers of deaths in China to increase over the coming days. Further global spread is likely.

What is the difference between limited human to human and sustained human to human transmission?

Limited human to human transmission happens when people get infected after close contact with the bodily fluids (blood, stool, urine, saliva, semen) of infected persons. When there is sustained human to human transmission, the virus spreads easily from one person to another and further onward, and is not limited to limited groups or people living or working in close proximity to one another, such as family members or co-workers.

What is the significance of health workers being affected?

The fact of healthcare workers being exposed to sick people poses them at a particular risk of being affected. In that sense, Infections among these professionals are one of the early indicators of human to human transmission.

What is ECDC doing?

ECDC is monitoring this event and providing risk assessments to guide EU Member States and the EU Commission in their response activities.


  • Guidance on how to identify suspected cases and when to initiate testing.
  • Risk assessment guidelines for Infectious diseases transmitted on aircraft (RAGIDA) for Middle East Respiratory Syndrome Coronavirus (MERS-CoV). There are no specific guidelines for assessing the risk of 2019-nCoV transmission during a flight. However, the MERS-CoV recommendations can be applied for 2019-nCov

Working on:

  • Case definitions for the European Region, with WHO Regional Office for Europe.
  • Mathematical modelling to support the prediction of scenarios of the evolution of the outbreak.