File photo shows Central Rome on March 19, 2020. (Photo: AFP)

The World Health Organization (WHO) warned that while it was “happy to see slowdown in COVID-19” in the hardest-hit European countries, lifting restrictions on movement must be based on protecting human health: "we can't replace lockdown with nothing."

The warning from Geneva on Monday comes as Spain, once of the countries worst hit by COVID-19, started to reopen sectors of its economy this morning, sending some employees back to work for the first time since the country introduced strict lockdown measures.

With other European countries eyeing similar options as rates for hospitalization and confirmed cases decreased in some nations over the weekend, the executive director of the WHO Health Emergencies Programme, Michael J. Ryan was unequivocal:

"By no means does that mean it is over. Now is the time for vigilance. Now is the time to double down. Now is the time to be very, very careful."

"In the past week, we've seen a welcome slowing in some of the hardest-hit countries in Europe, like Spain, Italy, Germany and France," said WHO director-general Tedros Adhanom Ghebreyesus as he opened the briefing.

"Some countries are considering when they can lift these restrictions; others are considering whether and when to introduce them. In both cases, these decisions must be based first and foremost on protecting human health," he added.

"We know that COVID-19 spreads fast, and we know that it's deadly, 10 times deadlier than the 2009 flu pandemic… However, while COVID-19 accelerates very fast, it decelerates much more slowly. In other words, the way down is slower than the way up."

He stated that called for a very careful easing of measures and more testing:

"That means control measures must be lifted slowly... it cannot happen all at once. Control measures can only be lifted if the right public health measures are in place, including significant capacity for contact tracing."

Michael J. Ryan went on to warn that countries could not simply unlock their economies and go back to normal overnight:

"You can't replace lockdown with nothing. You must replace lockdown with a very deeply educated, committed, empowered and engaged community. We are going to have to change our behaviors for the foreseeable future."

He added that from the WHO's perspective, testing and isolating victims was still the only way to move away from lockdown measures. The way out was "to find the virus. The only way we find the virus is to identify those people who may be infected and test and isolate."

Although Ryan commended health care services around the world for their work fighting the virus, he added that front line workers would have to remain on emergency footing for the foreseeable future:

"We're going to have stay in that capacity and health workers are going to have to continue to have protective equipment and we're going to have to continue to have intensive care beds on standby because as we come out of these lockdown situations, we may see a jump back up in cases, and we don't want to lurch from lock down to nothing."