[1] A glaring counterexample to your hypothesis is Brazil (Manuas) where prior infections (as high as 60%) didn't stop the P1 variant from ripping through.
The prior infection estimates for Manaus were simply wrong. They were based on a paper that "adjusted" the observed seroprevalence rates upward by a factor of ~3x. The parsimonious conclusion is that these corrections were too aggressive and ended up over-estimating infections. See Figure 2a in the paper, here:
https://pubmed.ncbi.nlm.nih.gov/33293339/#&gid=article-figur...
It is a "glaring" example only of how the low editorial standards of major journals during this pandemic has led to a wave of confusion amongst the public.
Apparently they're using 40% Astra Zeneca, 60% Sinopharm; hopefully the issue is simply the latter being ineffective. But as all the success stories with vaccination have also had very significant numbers of deaths with covid, we may need significant levels of natural immunity in conjunction with vaccine immunity to actually get cases to decline.
New Zealand had zero community cases without vaccination, during 2021 its vaccination programme has only covered some front line workers and very high risk people, and it still has zero community cases. Is that "success"? Is it "not success" ? How would you tell?
Whereas in my own country about two thirds of adults have had at least one jab, but still people are dying every single day from COVID-19, just much fewer than an the height of the pandemic here. Is that a success? Not a success?
One of the reasons New Zealand was so slow? With zero cases they had no reason to do Emergency Authorization. So they didn't. The Pfizer vaccine they picked got the full (albeit accelerated) approval process that any other medicine would get. This behaviour would be crazy in a country like the US with thousands dying, but it made sense in a country where most citizens have negligible risk day-to-day.
I think you're reading my comment incorrectly. I'm not promoting a criteria. I'm just stating the facts: we may find out that vaccines alone simply can't stop covid from infecting - and maybe even killing - large numbers of people.
Obviously, if that is true to a sufficient degree, lockdown may prove to have been pointless.
> How would you tell?
New Zealand will most likely find out how successful their vaccination program was when they open their borders to the rest of the world.
The Seychelles is still 40% unvaccinated. Even people who are vaccinated have some chance of getting infected, though if they get infected, their chance of showing symptoms is lower, and their chance of ending up in the hospital is much lower. It looks like the people testing positive in the Seychelles are mostly unvaccinated, and that the people ending up in the hospital are even more likely to be unvaccinated. But there's not enough information in the BBC article to judge just how effective the vaccines have been in the Seychelles.
The BBC article does contain one falsehood:
> In April, China's top disease control official said the efficacy of the country's Covid vaccines was low, although he later insisted his comments had been misinterpreted.
George Gao did not say this. He gave a talk at a conference on vaccines which was blatantly misconstrued by a "researcher" at an American think tank, the Council on Foreign Relations. That misrepresentation then got spread by the media. All George Gao actually said was that researchers should consider ways of increasing the efficacy of vaccines that have lower efficacy. He didn't name any specific vaccine or any specific country. He proposed the same sorts of measures that are being considered for other vaccines, such as the AstraZeneca shot: delaying the second dose, mixing vaccine doses, etc. This got twisted into an "admission" that Chinese vaccines have low efficacy. It's too bad to see that the BBC is still repeating this false claim, weeks later.
Seychelles just reported 1800 cases for the last week or 1.8% of its total population. This equates to 6 million cases in the US or more than 800k per day, a number never approached.
> It looks like the people testing positive in the Seychelles are mostly unvaccinated
It stated that 1/3 were in fully vaccinated and the rest were in partially vaccinated or unvaccinated. There are now 60k that are fully vaccinated, leaving just 8.5k first-dose only. The article was written before the 1800 cases dropped a couple days ago.
More data is needed for hospitalizations and deaths, but as it stands now, it does not look convincing for the vaccine. It's likely more cases will continue to come over the next few weeks, even more than the record breaking prior week.
Seychelles and other island nations that had no major covid outbreaks before vaccine launch (only 500 cases prior and 7.5k since) are the best real life settings we have for vaccine efficacy. For much of the rest of the world, a huge number of people were already infected before vaccine launch, making it difficult to separate out the effectiveness of the vaccine.
I see 67% effectiveness of preventing symptomatic cases for Sinovac. I'm not sure where the 80% comes from, they could be talking about AstraZeneca.
> A large multi-country Phase 3 trial has shown that 2 doses, administered at an interval of 21 days, have an efficacy of 79% against symptomatic SARS-CoV-2 infection 14 or more days after the second dose.
There are two different Sinopharm vaccines, but I think that BIBP is the one being used in the Seychelles. And yes, as you note, the Phase III studies were conducted outside of China. In order to conduct a Phase III study, there has to be community transmission of the virus, meaning that Phase III trials are impossible in China right now. You would get the same result for the vaccine and placebo arms of the trial: no infections.
1. https://www.who.int/news-room/feature-stories/detail/the-sin...
> The rest had either had a single dose or were unvaccinated.
So ~66% of the cases were from partially or unvaccinated people.
Do you have a source for that?
"Natural exposure induces a dominant Ab response against the nucleocapsid protein (NP), but since NP is not in the vaccine, there is no vaccine induced response against it. In this way vaccinated people who had a prior natural exposure can be classified because they have Abs to NP."
Simply looking at one aspect of immunity - detectable antibodies in the blood - is a very incomplete way of looking at the overall level of protection. For example, it's well known that mucosal immunity is important, and injected vaccines have a hard time inducing that kind of immunity: https://theprint.in/opinion/why-a-mucosal-covid-vaccine-has-...
It's also concerning that there is evidence that while people who have been vaccinated are much less likely to be infected. If they do get infected, they are more likely to be infected with one of the variants than unvaccinated: https://www.ncbi.nlm.nih.gov/bioproject/PRJNA728463
The immune response developed to our vaccines is quite specific - they only generate the spike protein - which leads to a much less diverse response than a natural infection.
Finally, the study you quoted can't really compare apples to apples anyway, as it's defining prior infection as simply having some level of antibody response, without considering how mild or severe those infections actually were.
I'm nowhere near as concerned about a variant infecting my upper respiratory tract as I am with being unvaccinated and having any of the variants attack my heart, kidneys, lungs and blood.
The use of spike was also not a mistake. Attempts to produce vaccines against NP for SARS-CoV-1 produced signs of ADE, so that is why everyone is using spike-only (other than the few inactivated virus vaccines).
I have not seen an actual credible claim that injectable vaccines can’t produce mucosal immunity. IIRC the HPV vaccines seem to generate strongly protective mucosal immunity. The opinion piece you linked seems off, too: the mRNA vaccines and (possibly to a lesser extent) the viral vector vaccines do seem to prevent most infections.
But it’s definitely true that antibodies in the blood are an incomplete picture. There are also memory B cell and all kinds of T cells.
That's not "concerning"...it's a truism. You've made those people immune to the wild-type strain. If they're going to get infected, it's going to be to a variant. You're still missing the denominator (i.e. how often does it happen?) and the most important question: how serious is it when they do get infected?
So far, the answers are "not often", and "not serious", respectively.
>Simply looking at one aspect of immunity - detectable antibodies in the blood - is a very incomplete way of looking at the overall level of protection
You seem to have no idea what you are reading. Of course vaccines aren't going to have antibodies against the nucleocapsid -- they only generate antibodies against the spike! The vaccines only ask the human body to develop immunity to the spike!
And you know what actually neutralizes the virus? Mostly antibodies against the spike because that is where all the important parts of infecting a cell originate from.
>For example, it's well known that mucosal immunity is important
You are right about mucosal antibodies -- but your statement is also proving to be false as more research comes out. The latest research shows IgG antibodies from vaccination in the mucosal regions too. Apparently our nose is not just waiting for IgA from a natural infection (https://www.medrxiv.org/content/10.1101/2021.05.06.21256403v...)
>It's also concerning that there is evidence that while people who have been vaccinated are much less likely to be infected. If they do get infected, they are more likely to be infected with one of the variants than unvaccinated
You also completely misrepresented this (and frankly, it's disappointing you couldn't even link to the actual publication -- it's https://www.medrxiv.org/content/10.1101/2021.04.06.21254882v...). The framing of this is disingenuous. Vaccines provide nearly complete protection against the non-variant form of COVID-19. They provide a little less protection against variant COVID-19s. Your non-protected human body is the same way -- it's more likely to get a variant too. It isn't that if you get infected after vaccination, it's because you were more susceptible to variants, it's that everyone is more likely to get one of the variants. Your risk is still minimized way more than than if you weren't vaccinated!
> The immune response developed to our vaccines is quite specific - they only generate the spike protein - which leads to a much less diverse response than a natural infection.
Which tells me that your response of:
> You seem to have no idea what you are reading. Of course vaccines aren't going to have antibodies against the nucleocapsid -- they only generate antibodies against the spike!
is wholly inappropriate as they clearly know what you are using as a rebuttal and makes me wonder if you are the one with no idea of what you are reading!
Perhaps take a second to read the person's comment more thoroughly before being rude, which I see you've continued with in the rest of your comment. It's a discussion, not a fight, try to add your thoughts in a better way, please.
This says nothing about the strength of a previous infection. It very plausibly just says that R > 1.7, ie it is infecting the remaining 40%.