Ask HN: Effects of Covid Vaccination on R0?

2 points by complexworld 4 years ago | 6 comments

I searched for medical studies on how vaccination affects the spread of COVID-19 (aka R0). But it has been surprisingly hard to find good information!

I'm having a discussion about vaccination with a family member, and I'd like to have some evidence that I can show them.

aurizon 4 years ago |

The R number is a complex beast. When viruses reproduce they are in race with their own death - the immune system is in a counter race, to neutralise all loose virus particles in the blood and to kill all the cells making particles. If you have been vaccinated or have survived the virus you will mostly have a mild case, your immune system wins. A person with no vaccination or immunity has to raise his immune antigen levels ASAP to be able to kill new viruses and the cells that make them so he quells the infection. If not, he is at risk of death. Death via Covid comes in many ways. All the antigenic warfare creates a huge burden of dead cells, fragmented viruses and cellular innards - all in the blood stream creating many destructive situations. You may have heard of the Covid cascade, a cytokine storm induced by the interactions of these cellular by products. https://www.thelancet.com/journals/lanres/article/PIIS2213-2...

I said earlier that the virus was in a race, well it is, and it is a badly run and badly maintained factory. If the viral RNA used only perfect virus parts, and used them in the exact numbers needed for every stage - all the viruses would be infective. In truth, some people say less that 10% of the viruses made are correctly made and are infective - this varies with the virus. Measles virus make infective virus particles over 90% of the time = a very high R0, almost 20. A virus below 1 will die out. The first covid was about 2 to 2.5. The new Delta variant is said to be around 15. So more perfect particles coupled with a more efficient viral factory = the highest possible R0

There is an old saying, the wind my tear and the wind may roar, but you will never drown on Lac St Pierre - so long as you stay on the shore, that applies to covid. Get vaccinated, wear a mask, avoid groups/crowds etc. We criticise China, but their attention to isolation in detail has allowed them to crush the infection. These whining idiots of anti vaxxers/maskers - they are going to drown in the virus - unless they stay on the shore. That is from the Wreck of the Julie Plante - a French Canadian poem in argot. https://www.poemhunter.com/poem/the-wreck-of-the-julie-plant...

complexworld 4 years ago | |

Yes I agree with you. I wish I could find a study that clearly shows that unvaccinated people are more likely to transmit the disease than vaccinated people.

There are studies, but the ones I have found compare only people are infected. And when you have COVID you're contagious, vaccinated or not. This is then used as a basis for claiming: "See vaccinated are just as, or even more, contagious as unvaccinated!". That's what I'm trying to disprove.

Example of what I have found: https://www.thelancet.com/journals/laninf/article/PIIS1473-3...

nojokes 4 years ago | | |

If your likelihood to get infected is lower then you are less likely to retransmit but it is even more nuanced as this because viral load dynamics are a little different for vaccinated and non-vaccinated.

jstx1 4 years ago |

If I were you, I would look at efficacy and effectiveness of the vaccines. The effect on R0 is more difficult to estimate because you can't run a controlled study on it and you have a bunch of confounding factors.

complexworld 4 years ago | |

The person I'm talking with is young, healthy, and believes he is at very low risk of a serious case of COVID.

For society in general, the crux of his argument comes down to:

"Unvaccinated people are just as contagious as vaccinated, so why should I get vaccinated?"

I'm finding it surprisingly difficult to find unassailable evidence that vaccinated people are less likely to pass the virus on to someone else.

jstx1 4 years ago | | |

> I'm finding it surprisingly difficult to find unassailable evidence that vaccinated people are less likely to pass the virus on to someone else.

Then search for the studies that look into this; my point is that they won't be using R0 as a measure.