Sunday, November 28

New Zealand in ‘uncharted territory’ trying to keep Delta R number below 1 – Covid-19 modeler


New Zealand is in “somewhat unfamiliar territory” as it attempts to reduce the R-number of the Delta variant outbreak below 1 for an extended period, says a Covid-19 modeler.

Blurred illustration of Corona Covid-19 virus

The R number (reproduction number) is the average number of people infected by someone with the virus. If the R number is greater than 1, the sprout increases. If it is less than 1, the number of cases decreases.
Photo: 123rf.com

The Ministry of Health reported 75 new cases in the community yesterday, a figure that is not a cause for alarm, according to the Director General of Health, Dr. Ashley Bloomfield, despite being above the 49 reported the previous day.

Bloomfield said the R-value, based on the latest model, was still promising. There was a 90 percent chance that it would stay below 1, showing that the lock was still working and the drive chains were breaking.

The R number (reproduction number) is the average number of people infected by someone with the virus. If the R number is greater than 1, the sprout increases. If it is less than 1, the number of cases decreases.

University of Canterbury Covid-19 modeling professor Michael Plank said Morning report the R number was “probably” below 1, but that alone was not enough.

“We really need to put it way below 1 to start reducing cases quickly, because if the R number is .9 that means the cases are decreasing, but they will do so very slowly and you know the blockage could drag on for weeks or months. .

“So we really need to lower that R number to make it look more like .7 and start to see the cases decline more quickly and hopefully we can eliminate the outbreak.”

When asked if anyone had lowered the R-number for Delta as low as .6 from .7, Plank said: “Queensland removed, or appears to have removed an outbreak of the Delta variant. It wasn’t as big as this one, and it’s difficult estimate these R numbers when you have a small number of cases, but we know that it is possible to control Delta that way.

“New Zealand is here in a bit of unexplored territory. Not many countries have managed to get Delta under control and get an R number less than 1 for a sustained period, but we know that what we are doing is effective and we have a good chance of achieving that. .

“It is a good sign that you know that three quarters of new cases are not in the community while they are infectious, because that means they are not at risk of spreading the virus to other bubbles, but this is a key number, so “It will be important to monitor over time the number of new cases that are in the community while they are infectious, and obviously we will want that number to decrease.”

Regarding daily case numbers, Plank said: “We never want to read too much into single day numbers. What matters is the trend, I think it looks like we are seeing the beginning of a downtrend, but it is very in the early days, and we’ll have to see how that trend plays out and how fast it goes down in the next few days.

“One of the reasons the numbers will bounce is that people will have to be tested on different days, and that can certainly contribute to, you know, when exactly cases are reported.”


www.rnz.co.nz

Leave a Reply

Your email address will not be published. Required fields are marked *