A senior German disease control expert has warned that the coronavirus pandemic could continue for two years, depending on how long it takes for an effective vaccine to be developed and if people develop immunity after illness.

Speaking on Tuesday, the Robert Kock Institut's (RKI) president, Prof. Lothar Wieler, said pandemics tend to run their course in waves, and factors influencing how it unfolds from this point include how many people become immune to it after contracting the virus – and how quickly a vaccine is made.

The RKI, a German federal agency responsible for disease control and prevention, on Tuesday raised the country’s threat level from the ongoing coronavirus pandemic from ‘moderate’ to ‘high’.

It said the revision comes in light of the continuing increase in new infections of the rapidly-spreading virus, which originated in China late last year and whose symptoms range from fever to serious respiratory illness. Germany has recorded over 7,900 cases of Covid-19 to date, with 20 deaths.

New research from RKI scientists and the Helios clinic group also says that the novel coronavirus can more seriously afflict adults aged under 60 who have no underlying health conditions than similar patients suffering severe pneumonia in the regular flu season.

Although countries around the globe have largely stepped up measures to counter the spread of the virus, including border closures, shutting schools and limiting mass gatherings, Covid-19 cases outside of China recently surpassed the total figure recorded inside the country that had, until now, suffered the worst of the outbreak. Italy, in particular, is struggling with the pandemic and recorded a larger single-day number of deaths last weekend than China did at the worst of the peak there.

On Monday, the World Health Organization’s chief described the novel coronavirus as the “defining global health crisis of our time.” He also urged countries to “test, test, test” for the virus, saying: “You cannot fight a fire blindfolded. And we can’t fight this pandemic if we don’t know who is infected.”

There have been over 87,700 confirmed cases globally, and almost 7,500 deaths.