Should individuals who already had a SARS-CoV-2 infection receive 1 or 2 shots? [pdf] | Hacker News Reader

Should individuals who already had a SARS-CoV-2 infection receive 1 or 2 shots? [pdf]

medrxiv.org

23 pointstosh42 comments

While "zero" obviously isn't the answer long term, I do think it's a reasonable one in the short term: The re-infection rate is clearly less than 1% given we only have a few anecdotal edge-cases there, so "being infected" clearly establishes solid protection. The first peak of the pandemic was 9 months ago, and we're still not seeing re-infections rise, so there's no reason to think this infection-based immunity is short-lived.

Obviously there might be long-term benefits to still vaccinating such people, but right now we're dealing with a very limited resource. Giving the vaccine to someone who hasn't been infected is a huge gain (say, 0% to 60% protection), while the second shot is a smaller gain (say, 60% to 90%), and someone who already has natural immunity is probably even smaller yet (say, 90% to 99%)

(Numbers are off-the-top-of-my-head and meant to indicate magnitude not an exact value)

What is your source for reinfection rate less than 1%? It seems much higher based on the recent second wave in Manaus [0].

[0] https://www.cidrap.umn.edu/news-perspective/2021/01/variant-...

Isn’t that an antibody-escaping variant? Existing vaccines aren’t very efficacious for that variant either.

My comment is being downvoted by an emotional crowd, it seems, but read this: https://www.biorxiv.org/content/10.1101/2021.01.15.426911v1

"Our experiments indicate that these variants, and potentially others that carry K417N/T, E484K and N501Y mutations, can reduce the neutralization potency of vaccinee plasma."

Preprint, not peer-reviewed, but still concerning.

TL;DR: It doesn't currently seem like a problem, but it is definitely a topic worth keeping an eye on.

"The vaccine generated a weaker immune response against the South African strain, but the antibodies remained above levels that are expected to be protective against the virus, the company said, adding the findings may suggest “a potential risk of earlier waning of immunity to the new B.1.351 strains.”

“Out of an abundance of caution and leveraging the flexibility of our mRNA platform, we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic to determine if it will be more effective to boost titers against this and potentially future variants,” Moderna CEO Stephane Bancel said in a statement."

Source: https://www.cnbc.com/2021/01/25/covid-vaccine-moderna-workin...

Source for my source, because he posts a pretty solid round-up of recent research and well-cited sources every Friday: https://thezvi.wordpress.com/2021/01/28/covid-1-28-muddling-...

Here's a source for the reinfection rate. I've seen a few studies that all came to the < 1% conclusion:

https://www.medrxiv.org/content/10.1101/2021.01.15.21249731v...

The Manaus data is interesting. The basis for assuming there's reinfection happening seems to be a seroprevalence survey done over the summer which estimated 76% of the population had antibodies to the virus. The accuracy of that survey has been called into question for a variety of reasons. The survey was done through blood donors and apparently they incentivized blood donation by offering people the results of their antibodies test as part of donation. Since testing capacity during peak infection was limited, this would give people who thought they might have had the virus (and likely did) incentive to donate blood and made the sample not nearly as random as it was presented to be.

> The basis for assuming there's reinfection happening seems to be a seroprevalence survey done over the summer which estimated 76% of the population had antibodies to the virus. The accuracy of that survey has been called into question for a variety of reasons.

This is exactly correct. Extrapolating from the Manaus seroprevalence paper is scientifically tenuous, at best. They say so in the Lancet commentary cited in the CIDRAP piece cited by OP:

"In the Lancet report, experts said four factors may be at play, some possibly related. First, scientists might have overestimated the attack rate for the first surge, and infections might have been below the herd immunity threshold"

> The survey was done through blood donors and apparently they incentivized blood donation by offering people the results of their antibodies test as part of donation. Since testing capacity during peak infection was limited, this would give people who thought they might have had the virus (and likely did) incentive to donate blood and made the sample not nearly as random as it was presented to be.

Not just that, but if you read the paper carefully, you'll see that they've applied a number of fairly arbitrary "corrections" to the data, which pull the seroprevalence from an observed 20% range up to the cited "76%" number (Figure 2A in this link):

https://science.sciencemag.org/content/371/6526/288

While any of these adjustments might be individually merited, when you see a >300% aggregate "adjustment" to the raw data, it should make you very skeptical about any claims made with that data. Particularly when the raw data is below the likely herd-immunity threshold, and has been "corrected" to be above it.

More simply: the most likely conclusion is that the original paper was wrong.

This is perfect example of bad science being propagated by journal title and headline. Whomever wrote that (IMHO, terrible, editorialized) CIDRAP piece didn't bother to read the original data, and just took the first paper's claim at face value. Journalists have been (and continue to be) insufficiently skeptical when it comes to Covid science -- except when it suits the narrative they're trying to create. If a paper supports their desired narrative, any half-baked, highly implausible claim is treated as worth serious consideration. If a paper conflicts with their claim, no counterargument is too implausible to be considered.

Your body throws the kitchen sink at SARS-CoV-2, it may generate spike-based antibodies, but it also might generate core-shell-based antibodies, which might mutate more (and therefore bypass acquired immunity in the future).

That’s one reason why spike-based mRNA vaccines are so exciting...

It is certainly of scientific interest to know these things. But I suspect the logistics of finding out who already have been infected, and only giving them one/zero doses, is not going to be worth it. And even then, only a small portion of the population have a confirmed infection.

In the coming months a very large amount of vaccines is going to arrive in most (western/rich) countries. It is then no longer going to be important to optimize exactly who gets the vaccine, but instead to increase the vaccination rate.

Yes. "Using quantitative serological assays that measure antibodies to the spike protein could be used to screen individuals prior to vaccination if the infection history is unknown." So it's possible, with enough testing, to see if someone really needs a second shot of vaccine. Then, of course, follow up after a month, and probably again later, to see how it worked.

That is the logistics I'm talking about. Testing was incredibly slow to scale up last spring, and scaling up tests for antibodies as well seems like unnecessary complication. We need fewer moving parts, not more.

Titers are measured before, after first jab and before second, so logistically this is pretty easy. The methods are described in the paper. It’s basically a couple of blood draws and quite simple to get a cohort based on questionnaire given that there’s 20M confirmed cases in the US.

This seems like an efficient study that could increase vaccination rate since people are more likely to get one dose rather than two. For many people, traveling to a vaccination appointment is a big deal.

This also serves to help convince people who have had COVID the value in getting a vaccine.

the gist

> In this short report, we show that the antibody response to the first vaccine dose in individuals with pre-existing immunity is equal to or even exceeds the titers found in naïve individuals after the second dose. We also show that the reactogenicity is significantly higher in individuals who have been infected with SARS-CoV-2 in the past. Changing the policy to give these individuals only one dose of vaccine would not negatively impact on their antibody titers, spare them from unnecessary pain and free up many urgently needed vaccine doses.

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