From Wednesday, Sciensano shares the R-value per province every day, the figure that indicates how many people an infected person infects. Before that, this only happened at national level.
At the moment, the national R value is at 1.27. That means that the epidemic in our country continues to grow at a national level. However, Van Gucht indicated that there are strong regional differences. Moreover, with the exception of the leaders West Flanders (1.37), Walloon Brabant (1.34) and Namur (1.27), all provinces have a lower R-value than the national number.
At the moment the R values at the provincial level are as follows:
Note: if you look at the number of registered infections per 100,000 inhabitants, Antwerp is still in the lead with 76.6 per 100,000 inhabitants. West Flanders is then only in 9th place, but the number of cases has increased the most since last week after Brussels. The number of infections per municipality can be found here.
How is the R value calculated at the provincial level?
The national R-value is currently calculated based on the number of hospital admissions, because that is a stable and fast way, says Van Gucht.
But at the provincial level, that number is too low. Then it is better to look at it number of infections. Hasselt University is already calculating the national R-value in this way, and now Sciensano will do it that way for each province. Van Gucht does indicate that this calculation depends on the test strategy. That could be a disadvantage, but the testing strategy has “evolved a lot since March,” he says.
What is the difference between an R0 value and an Rt value?
‘The reproduction number depends on the biological characteristics of the virus itself, but also on our behavior as humans.’ The base reproduction number, the R0-value, is estimated to be about 3.28 for covid-19. “That means that if you let the virus run its course, 1 infected person will infect 3.28 new people on average,” explains the virologist.
However, there is also it effective reproduction number or the Rt value, says Van Gucht. “This number is determined by the measures being taken to contain the virus and also by an increase in the number of immune people as the virus has spread in the population.” That value is constantly evolving depending on the epidemic. ‘An epidemic grows if the Rt is higher than 1, because then 1 person will infect several people. If the Rt is less than 1, the epidemic will shrink and slowly die out.