New Variants

First up, check out the video recently posted with a interesting take on the decline of the South African variant and the UK variant. https://fb.watch/3IiEGutsom/

According to Medpage Today, the new SARS-CoV-2 variant first appearing in southern England has a transmission advantage of 0.4 to 0.7 points higher in reproduction number, also known as R0, compared to the initial strain, British researchers found.

As known from earlier context, the average R0 of Covid-19 is around 2.5, essentially meaning that on average about 2.5 people get infected from every one person who contracts the virus. The R0 is important because the herd immunity threshold is based around the R0 of a virus. For a virus with an R0 of 2.5, the herd immunity threshold, without pre-existing immunity (which we already know we do have with Sars-Cov2), is 60%. Given that we do have pre-existing immunity, this threshold is likely to be much lower. The exact threshold is yet to be known, but we can assume it will be below 60%.

The herd immunity formula is the following 1-1/R0. So now, let’s look at how a new variant might change this threshold. Assuming we multiply the higher 0.7 to our original R0 of 2.5, we get 4.25; therefore, using the formula to determine herd immunity threshold we now get about 76%. Again, we know that people do have pre-existing immunity to this virus; therefore, that actual threshold is likely to be much lower.

Currently, with the case numbers plummeting all over the US, we are seeing our nation achieving herd immunity. That would mean natural immunity plus those vaccinated have contributed to such. Knowing that we are around 10% of the population having already received the vaccine and likely around 50% of the population having been previously infected, that would mean the threshold needed for herd immunity was around 60% (well below Fauci’s current herd immunity estimates).

Another huge factor to consider is just because a virus is more contagious does not equal more deadly. In fact, it general is the opposite. In order for a virus to be more successful at transmission, it typically becomes less deadly so it can infect more people. A good video on the subject can be found below. Please note, I do not fully agree with the author’s explanation, but he does a good job of breaking down the numbers in a helpful way to understand.