Here's what you need to know about the coronavirus right now:

Masks to prevent a second wave

Population-wide face mask use could push COVID-19 transmission down to controllable levels for national epidemics, and could prevent further waves when combined with lockdowns, a British study showed.

COVID-19 is a respiratory disease and not a blood disease.Courtesy: Reuters

If people wear masks whenever they are in public it is twice as effective at reducing the disease's reproduction rate than if masks are only worn after symptoms appear, the research found.

Hotspot in Arizona

Arizona has again told hospitals to activate the coronavirus emergency plans after cases spiked following reopening, turning it into a U.S. virus hotspot along with neighbouring southwest states.

A "cavalier" exit from the state's successful stay-at-home programme caused the sudden case surge, former state health chief Will Humble said.

University of Washington researchers estimated on Monday that 145,728 people could die of COVID-19 in the United States by August, raising their forecast by more than 5,000 in a matter of days.

Virus disappearing down under

Australia is on course to have largely eradicated the coronavirus by July, as the country's most populous state announced the removal of restrictions on community sports.

New South Wales has gone for two weeks without any cases of community transmission.

New Zealand lifted all restrictions except international border controls after declaring on Monday that it was free of the coronavirus.

Tracing app inspired by U.S. school project

Singapore reached out to a Stanford University student, Rohan Suri, in January to understand his experiences and considerations while developing a prototype for a contact tracing app called kTrace as a high school project in 2014.

Suri developed the prototype with a schoolmate as the Ebola epidemic ravaged western Africa.

He spent February and March volunteering on Singapore's TraceTogether app alongside fellow Stanford students Nikhil Cheerla and Daniel Lee, giving Singapore a roadmap by sharing kTrace's code and providing advice on stronger privacy protections.

Now, Suri has co-founded another app called Zero, which aims to attract users by bundling contact tracing technology with a safety-rating tool for shops and restaurantsbased on measures such as occupancy limits and mask rules.

How Germany's Merkel tamed the virus

A rare inside view of how Angela Merkel handled the pandemic shows how, in Germany as in the United States and elsewhere, Covid-19 is exposing deep tensions between nationalist and collaborative styles of leadership.

A visit to the Chinese city of Wuhan – the ground zero of the pandemic - last September helped shape Merkel's response to Covid-19. If the disease forced a metropolis of 11 million people to quarantine itself and come to a complete stop, people close to her said, she saw that it must be serious.

Quick lockdown and widespread testing are two elements that have been widely credited by epidemiologists for keeping Germany's reported fatalities lower than many countries.