[simonh]

Widespread vaccination dramatically reduces the rate at which the virus spreads, by more than 80%. It's not a binary does/doesn't stop spreading.

https://www.nature.com/articles/d41586-021-02054-z

Vaccination rates in the US have been abysmal by developed world status, precisely because so many of you don't think vaccination works. It does work to dramatically slow spreading, but only if enough people take it up.

[spurgu]

No it actually does not really stop spread to any significant degree (which is evident just by looking around what's going on everywhere). It just makes the symptoms milder.

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

https://www.thelancet.com/journals/lanepe/article/PIIS2666-7...

[pfg]

I don't understand how you came to that conclusion based on the articles you linked.

The first study finds that "The SAR [secondary attack rate] in household contacts exposed to the delta variant was 25% (95% CI 18–33) for fully vaccinated individuals compared with 38% (24–53) in unvaccinated individuals" and "Fully vaccinated individuals with delta variant infection had a faster (posterior probability >0·84) mean rate of viral load decline (0·95 log10 copies per mL per day) than did unvaccinated individuals with pre-alpha (0·69), alpha (0·82), or delta (0·79) variant infections." (The study did not determine a meaningful impact on peak viral load and on the SAR in households when the index case was vaccinated.)

The second link is a letter that reiterates the fact that vaccinated index cases are just as likely to infect other household members and concludes with "It appears to be grossly negligent to ignore the vaccinated population as a possible and relevant source of transmission when deciding about public health control measures", which makes sense, but does not mean spread

When you say "which is evident just by looking around what's going on everywhere", it's important to point out that we're now dealing with a variant that is significantly more transmissible than previous ones, so we can't compare the numbers like-for-like.

[spurgu]

> vaccinated index cases are just as likely to infect other household members

> It appears to be grossly negligent to ignore the vaccinated population as a possible and relevant source of transmission

You're going to have to dumb it down for me as to how this doesn't refer to spread.

> we're now dealing with a variant that is significantly more transmissible

And yes, agreed. Many are still focused on data from the previous variants though, whereas the thinking will need to change.

[pfg]

> You're going to have to dumb it down for me as to how this doesn't refer to spread.

Vaccinated index cases infecting others in the same household are only one scenario, and in that particular scenario, the study found no impact on spread. The study did find that vaccinated household members were less likely to be infected (SAR 25% vs. 38%) and that vaccinated cases had a faster rate of viral load decline - both of these findings (especially the first one) also relate to spread.

(It's arguably a bit surprising that the faster rate of viral load decline did not have an impact on the SAR for vaccinated index cases - one could make a (hopefully) reasonable hypothesis that this would matter more outside of household settings and thus still have an overall impact on spread, but that's not backed by any data from this study.)

There's also a world of difference between not "ignor[ing] the vaccinated population as a possible and relevant source of transmission" and saying that it doesn't stop spread to any significant degree. It's not binary.

[spurgu]

WHO is citing that study as well[0], seemingly drawing the same conclusion as I did:

> Prior to the emergence of the delta variant, it was reported that the risk of symptomatic cases in household contacts of vaccinated cases was about 50% lower than that among household contacts of unvaccinated cases(22). However, the impact of vaccination on reducing transmission in the context of the more transmissible delta variant appears to be lower(23).

https://www.who.int/news/item/24-11-2021-interim-statement-o...

[0] The first link I posted, reference 23 in the WHO statement

[pfg]

I'm really not sure if we're on the same page on the conclusion of the study, so I'll repeat it just in case:

Scenario 1: A vaccinated household member (the index case) is COVID-positive. The study finds that other household members are just as likely to get infected regardless of the vaccination status of the index case. There is no reduction of spread.

Scenario 2: Some household member (regardless of vaccination status) is COVID-positive. The study finds that other vaccinated household members are less likely to get infected. Spread is reduced.

That's basically what the WHO is saying - we may have had the positive impact of scenario 1 prior to Delta, but that's mostly gone. Scenario 2 still shows some effect on spread. It may be lower now, but it's still significant.

The article also states that "Vaccinating school-aged children may help minimize school disruptions by reducing the number of infections at school" and "there are benefits of vaccinating children and adolescents that go beyond the direct health benefits. Vaccination that decreases COVID transmission in this age group may reduce transmission from children and adolescents to older adults".

[simonh]

Oh, it 'just' saves your life. Oh well, if that's all...

[spurgu]

Potentially saves your life if you're in a risk group with co-morbidities yes...

Not downplaying anything here. Reducing the symptoms is great. But interesting also to not that we don't even knows why it does that:

> The reason for the efficacy of the new mRNA vaccines is not clear.

https://en.wikipedia.org/wiki/MRNA_vaccine#Efficacy

[simonh]

Where do you get the idea that the vaccines only work on people who have co-morbidities? That’s certainly not the experience here I’m the UK. They seem to reduce the death and serious illness rate in otherwise healthy people just fine.

[spurgu]

> Where do you get the idea that the vaccines only work on people who have co-morbidities?

How do you draw that conclusion? I never said that. Vaccines work across the board. But to illustrate an extreme, they do practically nothing to kids. For 80+ year olds they're miracle drugs.

[adam_arthur]

Yes, of course.

But the virus is endemic and vaccines will not stop it from being caught by everybody at some point.

You can't lockdown the virus away. You can't stop the spread by canceling flights either. Just seems like awful policymaking driven by virtue signaling.

Covid is here forever, and that's life.

[simonh]

We can't stop it dead, but we can dramatically reduce the number of critical illnesses and deaths, and have done so in many countries. I'm a Brit and our lockdown and vaccination policy has been extremely effective. We've largely lived normal lives since the summer, with low case rates and very low mortality thanks to strong vaccine uptake and popular support for protective measures. If we need to lock down again, we will because we have experienced the benefits that this strategy has produced. I'm having my booster shot on Saturday.

I fully expect to contract the virus at some point, and that's fine. I'm well protected by vaccination and the rate of propagation in the country is moderate enough that the hospitals aren't being overwhelmed by huge surges in infections and deaths any more.

Slowing down and limiting the impact of the virus doesn't stop it, correct, but it does massively reduce the damage it causes. That is very much worth doing, as the experience here in the UK clearly shows.

[adam_arthur]

The UK has roughly equivalent covid deaths per capita as the USA, where vast parts of the country never locked down and still by and large don't wear masks or get vaccinated.

Did the stricter lockdowns make a difference in the end?

[simonh]

Were demographically and geographically completely different. Our population is much denser, more like a populous US state than a sprawling continental giant. People used to compare virus control in the US to places like Singapore and New Zealand, as though their ability to control the virus has any lessons that are realistically applicable.

We were hammered early on because we are very highly connected with the rest of the world. London is very international, and Heathrow is one of the busiest airports in the world, out of proportion to our population size. We were always going to take a heavy hit.

Nevertheless as soon as vaccines became available we have had broad adoption, and ever since we've been reaping the rewards. Delta arrived here early, but by then our vaccine take up was enough that it didn't really make as much of an impact on us as it has elsewhere.

It's just amazing to me that in 2021 here on HN the fact that vaccines protect against viruses is an actual question, or in any way political.

[adam_arthur]

Yes, vaccines mitigate the impact of the virus on individual health outcomes.

They likely also have some marginal impact on transmissibility.

But the data shows pretty clearly that the effect on reduction in transmissibility is quite low, or else there would be an obvious relationship in the data in infection rate vs vaccine uptake... Which clearly there isn't. If you believe otherwise, please share data proving some macro effect of reduced case counts correlated with vaccine uptake.

There's nothing political about what I'm saying. I am arguing against policies that are not backed by the data or science.

People proposing policies that are not evidence based are the political ones.

[simonh]

It's true that vaccines are less effective at slowing down delta. They slowed previous variants down by 80% or more. They still slow it down, but not as much. But in the UK we had high vaccination rates before delta hit and in the first 6 months of the year this saved a _lot_ of lives. It's still saving lives by reducing transmission, but now mainly by simply protecting us from the worst effects of the virus.

[junon]

Seems we've already forgotten the whole point of lockdowns the first time: to prevent overloading the hospital systems.

In places where hospitals were under capacity, deaths were significantly lower. Germany is a good example of this.

Overwhelmed healthcare systems, by comparison, saw lots more deaths.

Once it escaped Wuhan the goal was no longer to contain, but to control and soften the impact.

[FourHand451]

> But the virus is endemic and vaccines will not stop it from being caught by everybody at some point.

Plenty of people live their whole lives without catching smallpox or polio. We have/can develop effective vaccines for COVID. Why should it be different?

[beagle3]

No people have gone through their life without catching the cold and very few without catching the flu at least once, despite having flu vaccines for a few decades now.

Not all viruses are the same, and sarscov2 is much more like cold/flu than polio.

Specifically, saracov2 has reservoirs in animals. Unless you had an effective vaccine that also works for cats, dogs, deer etc and the ability to actually deploy it (think wild deer all over the US), it’s here to stay.

[Geezus-42]

Create an animal vaccine, give hunters dart guns and free rein to shoot as many as they can. Then see what happens.

[beagle3]

You are underestimating the geographical spread and numbers of deer in the us. And likely also overestimating the number and ability of hunters.

[taylodl]

> Covid is here forever, and that's life.

Good thing we didn't take that attitude with smallpox. Or polio. We have eradicated disease. It's not like we've never done this before.

[adam_arthur]

Those diseases actually had high mortality rates, unlike covid.

There's something called proportionate response. Personally I think policymakers should consider the actual pros and cons and the weight of them, rather than virtue signal as if everybody can be saved from every ailment, and acting as if second order effects don't exist.

We also could have locked down every winter to save people from dying due to flu. Why do you think we didn't do that before, when it could have saved hundreds of thousands of lives? Why don't we wear masks 24/7 to protect from flu?

[taylodl]

Because flu doesn’t fill our ICU’s to overflowing and burn out our medical staff. The number of deaths aren’t the only metric that should concern us.

[Gibbon1]

Some nurse friends of mine say a bad flu season will strain the capacity of ICU's. Something people that want to 'live with covid' don't seem to consider.

[TheOtherHobbes]

This is nonsense.

Vaccination stopped smallpox and polio. Failure at Zero Covid is the result of poor, anti-realistic policies and attitudes - like yours, for example.

It's not because it's impossible, either economically or scientifically.

[beagle3]

This is nonsense.

Vaccination did not stop measles or whooping cough, and has not even reduced their spread (only their symptoms) despite decades of availability.

Both of their vaccines are leaky - just like the Covid vaccine.

[loeg]

What? Measles is almost entirely constrained to the unvaccinated and we vaccinate babies for pertussis at 2 months.

[beagle3]

Sorry, meant to write flu. Not sure why I wrote measles.

Measles vaccine is, indeed, likely the best vaccine ever in terms of efficiency and safety. It’s also sterilizing rather than leaky.