Coronavirus: What is the UAE's 'R rate' and what does it mean when it falls below 1?

The number is used to estimate how many people will be infected by someone with Covid-19

A tourist waits to have her papers checked on arrival at Terminal 3 at Dubai airport. AFP

A tourist waits for her luggage at Dubai airport. AFP

An Emirati policeman directs a tourist to get a medical screening on arrival in Dubai. AFP

A tourist takes a selfie before he gets a medical screening at Dubai airport. AFP

A woman has her temperature checked as she enters the Ramada by Wyndham in Dubai. Thermal scanning for guests entering the property and restaurant is compulsory. Antonie Robertson / The National

Strict check-in procedures in place at a hotel in Dubai. The emirate reopened for tourist in July. Antonie Robertson / The National

Housekeeping staff go to great lengths to disinfect rooms, surfaces, items within the room. Antonie Robertson / The National

A beauty technician wears a face shield and mask while giving a facial at ShuiQi Spa & Fitness at the Atlantis hotel. Spas and massage salons in Dubai have received the green light to resume services. Chris Whiteoak / The National

The gym at Towers Rotana hotel in Dubai is cleaned after each use as part of measures to keep guests safe from Covid-19. Pawan Singh / The National

A thermal scanning camera checks peoples' temperatures as they enter through Gate Avenue at Dubai International Financial Centre. Reem Mohammed / The National

Room sanitation procedures conducted in the rooms at Marriot Hotel Downtown, Abu Dhabi. Victor Besa / The National

Thermal scanners at the entrance of Marriot Hotel Downtown, Abu Dhabi. Victor Besa / The National

QR code menus at the lobby of Marriot Hotel Downtown, Abu Dhabi. Victor Besa / The National

Staff wear face masks and gloves as part of safety measures at Towers Rotana hotel in Dubai. Pawan Singh / The National

Safety plexiglass set up in the reception of Marriot Hotel Downtown, Abu Dhabi. Victor Besa / The National

A cleaner disinfects the lobby of Marriot Hotel Downtown, Abu Dhabi. Victor Besa / The National

An aerial view of a Golf course in the Emirates Hills area of Dubai. AFP

An aerial view of the pedestrian Tolerance Bridge across Dubai Creek. Dubai reopened its doors to international visitors on July 7 after a nearly four-month closure. AFP

A number that tracks the spread of Covid-19 fell in the UAE, confirming what new case numbers have shown for days – the pandemic is now on the decline in the Emirates.

Scientists use the R0, or reproduction number, to track the infectiousness of a disease.

Studies have shown the natural R0 rate of the coronavirus is about 2.2. This means each person with the virus goes on to infect about two other people and those two infect another two each, in the absence of any controls to limit the spread such as face masks and physical distancing.

An R0 rate of 1 means an epidemic is stable – one person infects one other. A disease with a value of less than one will eventually peter out and die because not enough people are passing the infection on.

Countries are striving to keep the R0 below one because once it goes higher, the epidemic begins to grow exponentially again.

The R0 in the UAE is now 0.74, the National Emergency Crisis and Disaster Management Authority said.

"The basic rate of reproduction of the virus reflects how quickly the virus spreads," the authority tweeted.

“The latest figure for Covid-19 rate in the UAE [has reached] 0.74, less than 1, which reflects the efficiency of the health sector and its ability to reduce the rate of infection and the ability to break the chain of transmission, in addition to the efficiency of the policies and measures taken.”

Scientists agree the accuracy of the figure improves the more tests are carried out in a country and the UAE conducted more than 4.8 million tests since the outbreak.

In recent weeks the UAE has been able to shut many of the temporary field hospitals it set up to respond to the outbreak.

In mid-July, the field hospital at Dubai Parks and Resorts discharged its final coronavirus patients, the second such centre in the emirate to do so.

Abu Dhabi has also closed several of its temporary medical centres, including the field hospital at Abu Dhabi National Exhibition Centre it set up to cope with a surge in cases.

This month, the capital announced that all private hospitals in Abu Dhabi were also clear of Covid-19 cases.

Governments around the world use the R0 as a measure of when to tighten or impose additional restrictions.

However, experts say it is difficult to measure and is not recorded the same way universally.

Countries such as France have recorded an increase in the R0 rate, where it was said to be 1.2 last week.

Once the number begins to climb, it increases quickly.

On July 10, the R0 was calculated to be 0.92 in Brittany, France, but jumped to 2.6 in only a matter of days.

The R0 is on the increase elsewhere in Europe, including Spain.

At present, the R0 in the England is under 1 but last week scientists warned it could be increasing again. It was already almost at or above 1 in some parts of the country, including the South West, East Anglia and the North West.