Hacker News new | ask | show | jobs
by johnisgood 1651 days ago
Well, a reply (from cudgy) to my comment says this:

> The vaccine does not prevent spread of Covid. Period. The smallest amount of research proves this to be the case.

So what is the truth?

1 comments

The commenter cudgy who posted that clearly did not do nontrivial research on this question from reliable sources. The statement is flat out false.

The vaccines significantly reduce the chance of infection given identical exposure. For those who still get infected, the vaccines reduce the viral load throughout the infection, eliminate or ameliorate symptoms, and shorten the time during which an infected person is contagious.

They do not completely prevent any spread of the virus (nor does any other vaccine ever created for any disease), but they make a significant beneficial impact on the rate of spread. They both cut the rate of secondary infections within each household, and reduce the amount of inter-household spread in the community.

> Vaccination reduces the risk of delta variant infection and accelerates viral clearance. Nonetheless, fully vaccinated individuals with breakthrough infections have peak viral load similar to unvaccinated cases and can efficiently transmit infection in household settings, including to fully vaccinated contacts. Host–virus interactions early in infection may shape the entire viral trajectory.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3...

That doesn’t contradict what I wrote, though obviously there is a lot more detail and nuance that could be added here.

A few months after the second dose, 2 doses of the mRNA vaccines is insufficient to reduce peak viral load for breakthrough infections by the delta variant of the virus, making the vaccine less effective over time at preventing basic transmission and mild illness (the 2-dose vaccine was more effective with previous variants). However, a booster dose seems to make a significant improvement:

> By analyzing viral loads of over 16,000 infections during the current, Delta-variant-dominated pandemic wave in Israel, we found that BTIs in recently fully vaccinated individuals have lower viral loads than infections in unvaccinated individuals. However, this effect starts to decline 2 months after vaccination and ultimately vanishes 6 months or longer after vaccination. Notably, we found that the effect of BNT162b2 on reducing BTI viral loads is restored after a booster dose. These results suggest that BNT162b2 might decrease the infectiousness of BTIs even with the Delta variant, and that, although this protective effect declines with time, it can be restored, at least temporarily, with a third, booster, vaccine dose.

https://www.nature.com/articles/s41591-021-01575-4

* * *

For the omicron variant, there is still further reduced effectiveness of these vaccines on basic transmission and mild illness (only 70% effectiveness after a 3 shots; I don’t think there’s much data yet about viral loads), though protection against severe illness should still be robust (but reliable data about this will not be available for another few weeks or months).

I am not saying it contradicts, just thought it is worth noting. I am not having a battle here. :)

In any case... from what I heard, the omicron variant is somewhat close to common cold, and that it causes mild symptoms. If that is the case, then this is good news, especially if this applies to everyone, or most.

If this omicron variant is indeed much less severe, then would it not be a good thing for as many people as possible to go through it and develop immunity?

Some recent findings and whatnot:

> How SARS-CoV-2 evolves over the next several months and years will determine what the end of this global crisis looks like — whether the virus morphs into another common cold or into something more threatening such as influenza or worse.[1]

> Yet researchers expect such gains to become ever smaller. Scientists measure a virus’s inherent ability to spread in an immunologically naive population (that is, unvaccinated and not exposed to the virus previously) by a number called R0, which is the average number of people an infected person infects. Since the start of the pandemic this figure has jumped as much as threefold. “At some point, I would expect that increased transmissibility will stop happening,” says Bloom. “It’s not going to become infinitely transmissible.” Delta’s R0 is higher than seasonal coronaviruses and influenza, but still lower than that of polio or measles.[1]

Might be of interest:

> That evolutionary path, towards immune evasion and away from gains in infectivity, is common among established respiratory viruses such as influenza says Adam Kucharski, a mathematical epidemiologist at the London School of Hygiene and Tropical Medicine. “The easiest way for the virus to cause new epidemics is to evade immunity over time. That’s similar to what we see with the seasonal coronaviruses.”[1]

and

> A more likely, but still relatively hopeful, parallel for SARS-CoV-2 is a pathogen called respiratory syncytial virus (RSV). Most people get infected in their first two years of life. RSV is a leading cause of hospitalization of infants, but most childhood cases are mild. Waning immunity and viral evolution together allow new strains of RSV to sweep across the planet each year, infecting adults in large numbers, but with mild symptoms thanks to childhood exposure. If SARS-CoV-2 follows this path — aided by vaccines that provide strong protection against severe disease — “it becomes essentially a virus of kids,” says Rambaut.[1]

and

> Influenza offers another scenario — in fact two. The influenza A virus, which drives global seasonal influenza epidemics each year, is characterized by the rapid evolution and spread of new variants able to escape the immunity elicited by past strains. The result is seasonal epidemics, propelled largely by spread in adults, who can still develop severe symptoms. Flu jabs reduce disease severity and slow transmission, but influenza A’s fast evolution means the vaccines aren’t always well matched to circulating strains.[1]

> But if SARS-CoV-2 evolves to evade immunity more sluggishly, it might come to resemble influenza B. That virus’s slower rate of change, compared with influenza A, means that its transmission is driven largely by infections in children, who have less immunity than adults.[1]

That said:

> “There may be multiple directions that the virus can go in,” Rambaut says, “and the virus hasn’t committed.”[1]

So I suppose we will see. I am hoping for something like common cold. Mild symptoms. I am also hoping to get rid of some of these mandates and this COVID-19 pass stuff in the future, but once it is in place, do you think it is likely that they will revert it? I do not know, but I hope they will.

I cannot get the vaccines for health reasons, but I am unlikely to get a medical exemption as my country is full of idiots. Other countries do give exemption to immunocompromised people, whereas my country prioritizes them. I wonder if I could get a religious exemption. But yeah, the vaccines might give me a flare-up of whatever I have, and I would rather not risk it. My immune system is in a tough spot with all the inflammations going on, on top of some autoimmune disease. I hope to treat some I can.

[1] https://www.nature.com/articles/d41586-021-03619-8 (Beyond Omicron: what’s next for COVID’s viral evolution, 07 December 2021)

> the omicron variant is somewhat close to common cold, and that it causes mild symptoms

No, we don’t have anywhere near enough data yet to draw that conclusion.

What we know for sure is that it generally doesn’t cause hospitalization/death among people that have previously been infected by Covid or vaccinated. Which is generally true for every variant. And we also know that it has a significant degree of immune escape, causing a much higher rate of reinfections / breakthrough infections than previous variants.

It may be that it turns out to cause less severe disease even for the immunologically naïve, and many observers are hopeful that that turns out to be the case.

> cannot get the vaccines for health reasons

I would recommend you consult a physician who is an expert in your condition before making this decision.

> don’t have anywhere near enough data yet to draw that conclusion

For more explanation, https://cdn1.sph.harvard.edu/wp-content/uploads/sites/2623/2...