10 ms·

How do vaccinated people spread Delta? What the science says

80 points by kaczordon 5y ago

nanis 5y ago
> vaccinated people who become infected with Delta SARS-CoV-2 can carry as much virus in their nose as do unvaccinated people. This means that despite the protection offered by vaccines, a proportion of vaccinated people can pass on Delta, possibly aiding its rise. Which seems in line with I had speculated about earlier[1]. [1]: https://news.ycombinator.com/item?id=28003932 https://news.ycombinator.com/item?id=28003932
- kaczordon 5y ago
  It looks like viral load diminishes faster which is a plus. However, I’d be willing to bet that almost all transmission happens when people are at their peak viral load. And so if peak viral loads are not differing between vaccinated and unvaccinated I’d guess we’re pretty much going to see unabated transmission amongst vaccinated.
  - maddyboo 5y ago
    I don’t have data or evidence to back this up, but my hunch is that vaccinated people are less likely to take precautions and more likely engage in the “riskiest” (for others) behaviors like attending packed indoor gatherings. That’s why I think it’s so important this message gets out, and even then only a percentage of people will care.
  - klipt 5y ago
    At this point are the symptoms among vaccinated people any worse than other common colds?
  - h0l0cube 5y ago
    > It looks like viral load diminishes faster which is a plus Here's a graph from one such study that backs your claim https://twitter.com/DrEricDing/status/1421874289398194187 https://twitter.com/DrEricDing/status/1421874289398194187
- koheripbal 5y ago
  No, because this is a biased sample set. It is comparing vaccinated people and unvaccinated people who have been admitted to the hospital. The vast majority of vaccinated people who get sick, do not get sick enough to go to the hospital.
rdtwo 5y ago
Vaccine passports are dumb for this reason. Somebody choosing to be at higher risk does not increase the risk to other other than clogging up hospital resources
- Uberphallus 5y ago
  > Somebody choosing to be at higher risk does not increase the risk to other other than clogging up hospital resources So it doesn't have an impact except for when it does?
  - totony 5y ago
    Do you have a "obese passport", "health score"? You can't use a logic only when it's convenient. Implementing a health score and precenting unhealthy people (or even old people) from going outside would alievate hospital use. Do we want that? Although the vaccine seems to somewhat lessen the chance of transmission, it IMO is not enough to stomp on people's freedom. I would maybe consider it if it was the black plague.
    - Uberphallus 5y ago
      Yeah, obesity isn't contagious nor causes immediate and simultaneous need of health services, but nice try.
- ViViDboarder 5y ago
  > other than clogging up hospital resources Which is significant. Also, most of these polices were created based on research prior to Delta becoming prevalent which showed that the vaccines indeed did reduce spread. Since Delta is more transmissible, this benefit is reduced.
ianai 5y ago
Are there any numbers for long covid amongst breakthrough Delta infections?
- HWR_14 5y ago
  As far as I can tell, there are many numbers. Unfortunately, they are contradictory.
mattkrause 5y ago
In vaccinated people who become infected. Since the vaccines cause fewer people to be infected, the unconditional viral load is lower.
- InvertedRhodium 5y ago
  Wait, I thought the general consensus is that the current vaccines reduce the severity of the infection but provide little defense against contacting and spreading it? At least, this has been used to explain why infection rates are still increasing even among vaccinated populations.
  - mattkrause 5y ago
    They're certainly less effective vs variants, but I haven't seen any convincing data suggesting that vaccines are totally ineffective against them. In fact, the article also quotes one of the authors as saying: "The bottom line is, this can happen — it can be true that vaccinated people can spread the virus. But we do not yet know what their relative role in overall community spread is."
    - kaczordon 5y ago
      Looks like against delta the vaccines could have as low as 39% efficacy against preventing symptomatic COVID. https://www.cnbc.com/2021/07/23/delta-variant-pfizer-covid-vaccine-39percent-effective-in-israel-prevents-severe-illness.html https://www.cnbc.com/2021/07/23/delta-variant-pfizer-covid-v...
      - otherme123 5y ago
        We keep using percentages as if they had a true meaning. All the values that keep flying around cannot be compared, as they all measure slightly different things. That 39% number (protection against symptoms) wasn't checked at the trials, or at least wasn't reported. In that same article, they state that protection against being hospitalized/ICUed is still around 90%, which are the same values we heard before. Guess that doesn't sell clicks.
mensetmanusman 5y ago
At least we can protect ourselves now, N95s are available, vaccines are available, this is very different than a year ago.
- musha68k 5y ago
  Not true for very young children though, we can only protect them by proxy (us/others wearing masks plus social distancing).
  - rejectedandsad 5y ago
    Children are not at risk like adults are. I say get back to normal and let the unvaccinated adults suffer the consequences of their own actions.
    - musha68k 5y ago
      Unfortunately there is increasingly more data that shows that SARS-CoV-2 is not benign in children. For example this rather early analysis from 2020 included more than 2,000 children who got infected. 10.6% of infants under 1 year of age had severe or critical symptoms. All of these infants survived but a small number of infants in the United States have died following diagnosis with COVID-19 even then before Delta (or even Lambda and other variants). https://pediatrics.aappublications.org/content/pediatrics/early/2020/03/16/peds.2020-0702.full.pdf https://pediatrics.aappublications.org/content/pediatrics/ea... I have rolled too many d10 not to worry a lot about this.
      - oxymoran 5y ago
        People under the age of 1 is not even close to equaling “kids”. Come on.
        musha68k 5y ago
        Your point being what exactly? Apart from more severe outcomes for babies than what we thought there are children that increasingly have to be treated for pneumonia at hospitals. Also long covid is on the rise. This has been widely reported recently. https://www.nationalgeographic.com/science/article/long-covid-afflicts-kids-too-heres-what-we-know-so-far https://www.nationalgeographic.com/science/article/long-covi... https://www.google.com/amp/s/www.nytimes.com/2021/08/09/health/coronavirus-children-delta.amp.html https://www.google.com/amp/s/www.nytimes.com/2021/08/09/heal...
mint2 5y ago
This title is editorialized to be misleading. It’s specifically the nose not in general. It does not mean the viral load in the lungs is the same. And studies indicate vaccinated ppl may stay infectious a shorter timespan.
- oxymoran 5y ago
  Why is nobody recommending a highly saline nasal irrigation as a prophylactic? Or even a lower saline nasal irrigation with a very diluted amount of hydrogen peroxide???
  - velcii 5y ago
    Probably because Trump suggested something similar...
    - exogeny 5y ago
      Yeah, poor guy. He earned so much credibility with his no-nonsense, straight-shooting communication style full of poignant truths that it’s such a mystery why no one took him seriously on a subject in which he was so clearly well-versed and knowledgeable!
      - velcii 5y ago
        Yea, he was so "not credible" that for anything he said, the opposite has to be the "real" truth. /s
  - blamestross 5y ago
    You need to have well sterilized water for that just not to lead to a sinus infection which will leave you more susceptible. Tapwater isn't good enough, and is going to be rather harsh out of most taps in the US. Clean water in general isn't a solved problem. If you decide to do this with tap water, leave it out for a day or so to let the chlorine evaporate and then boil it for at least 5 minutes. Netti pots are also basically waterboarding fyi. Have fun!
walterbell 5y ago
Vaccines delivered to the arm deltoid muscle never promised mucosal immunity. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733922/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733922/ > The mucosal immune system is the largest component of the entire immune system, having evolved to provide protection at the main sites of infectious threat: the mucosae. As SARS-CoV-2 initially infects the upper respiratory tract, its first interactions with the immune system must occur predominantly at the respiratory mucosal surfaces, during both inductive and effector phases of the response. However, almost all studies of the immune response in COVID-19 have focused exclusively on serum antibodies and systemic cell-mediated immunity including innate responses. That's why vaccinated people can still get infected (upper respiratory tract) and have no symptoms (serum antibodies). They can infect others (upper respiratory tract) when they are infected but don't have symptoms or a temperature check saying they should stay at home. Hence the CDC now recommends tests for vaccinated people who are exposed to Covid. It was stated by Fauci and others in 2020 that current Covid vaccines are non-sterilizing. There are new Covid vaccines in development which provide sterilizing immunity, delivered via nasal inhaler instead of deltoid arm muscle. The MMR (measles, mumps, rubella) vaccine is sterilizing, i.e. prevents infection and transmission.
- Zababa 5y ago
  Thank you for that clear summary.
- drno123 5y ago
  Thank you for the clear explanation. Here in Europe we have Covid passports - if you are vaccinated or tested negative, you are allowed admission to, for example, shopping malls and no need to wear a mask indoors. Does this mean that Covid passports actually help spread Covid from vaccinated to non-vaccinated people who mix together without masks?
  - adrianN 5y ago
    It looks like infected vaccinated people can transmit the disease just as much as unvaccinated people, so yes.
  - 5y ago
furstenheim 5y ago
The article is way more nuanced than the title. That said, if the virus spreaded the same with the vaccine, the advantaged would be that the virus wouldn't have as much evolutionary pressure to change and become resistant. For example, it could make it harder for lambda variant, which might be symptomatic, to become prevalent

80 points by kaczordon 5y ago

> vaccinated people who become infected with Delta SARS-CoV-2 can carry as much virus in their nose as do unvaccinated people. This means that despite the protection offered by vaccines, a proportion of vaccinated people can pass on Delta, possibly aiding its rise. Which seems in line with I had speculated about earlier[1]. [1]: https://news.ycombinator.com/item?id=28003932 https://news.ycombinator.com/item?id=28003932

kaczordon 5y ago
It looks like viral load diminishes faster which is a plus. However, I’d be willing to bet that almost all transmission happens when people are at their peak viral load. And so if peak viral loads are not differing between vaccinated and unvaccinated I’d guess we’re pretty much going to see unabated transmission amongst vaccinated.
- maddyboo 5y ago
  I don’t have data or evidence to back this up, but my hunch is that vaccinated people are less likely to take precautions and more likely engage in the “riskiest” (for others) behaviors like attending packed indoor gatherings. That’s why I think it’s so important this message gets out, and even then only a percentage of people will care.
- klipt 5y ago
  At this point are the symptoms among vaccinated people any worse than other common colds?
- h0l0cube 5y ago
  > It looks like viral load diminishes faster which is a plus Here's a graph from one such study that backs your claim https://twitter.com/DrEricDing/status/1421874289398194187 https://twitter.com/DrEricDing/status/1421874289398194187
koheripbal 5y ago
No, because this is a biased sample set. It is comparing vaccinated people and unvaccinated people who have been admitted to the hospital. The vast majority of vaccinated people who get sick, do not get sick enough to go to the hospital.

rdtwo 5y ago

Vaccine passports are dumb for this reason. Somebody choosing to be at higher risk does not increase the risk to other other than clogging up hospital resources

Uberphallus 5y ago
> Somebody choosing to be at higher risk does not increase the risk to other other than clogging up hospital resources So it doesn't have an impact except for when it does?
- totony 5y ago
  Do you have a "obese passport", "health score"? You can't use a logic only when it's convenient. Implementing a health score and precenting unhealthy people (or even old people) from going outside would alievate hospital use. Do we want that? Although the vaccine seems to somewhat lessen the chance of transmission, it IMO is not enough to stomp on people's freedom. I would maybe consider it if it was the black plague.
  - Uberphallus 5y ago
    Yeah, obesity isn't contagious nor causes immediate and simultaneous need of health services, but nice try.
ViViDboarder 5y ago
> other than clogging up hospital resources Which is significant. Also, most of these polices were created based on research prior to Delta becoming prevalent which showed that the vaccines indeed did reduce spread. Since Delta is more transmissible, this benefit is reduced.

ianai 5y ago

Are there any numbers for long covid amongst breakthrough Delta infections?

HWR_14 5y ago
As far as I can tell, there are many numbers. Unfortunately, they are contradictory.

mattkrause 5y ago

In vaccinated people who become infected. Since the vaccines cause fewer people to be infected, the unconditional viral load is lower.

InvertedRhodium 5y ago
Wait, I thought the general consensus is that the current vaccines reduce the severity of the infection but provide little defense against contacting and spreading it? At least, this has been used to explain why infection rates are still increasing even among vaccinated populations.
- mattkrause 5y ago
  They're certainly less effective vs variants, but I haven't seen any convincing data suggesting that vaccines are totally ineffective against them. In fact, the article also quotes one of the authors as saying: "The bottom line is, this can happen — it can be true that vaccinated people can spread the virus. But we do not yet know what their relative role in overall community spread is."
  - kaczordon 5y ago
    Looks like against delta the vaccines could have as low as 39% efficacy against preventing symptomatic COVID. https://www.cnbc.com/2021/07/23/delta-variant-pfizer-covid-vaccine-39percent-effective-in-israel-prevents-severe-illness.html https://www.cnbc.com/2021/07/23/delta-variant-pfizer-covid-v...
    - otherme123 5y ago
      We keep using percentages as if they had a true meaning. All the values that keep flying around cannot be compared, as they all measure slightly different things. That 39% number (protection against symptoms) wasn't checked at the trials, or at least wasn't reported. In that same article, they state that protection against being hospitalized/ICUed is still around 90%, which are the same values we heard before. Guess that doesn't sell clicks.

mensetmanusman 5y ago

At least we can protect ourselves now, N95s are available, vaccines are available, this is very different than a year ago.

musha68k 5y ago
Not true for very young children though, we can only protect them by proxy (us/others wearing masks plus social distancing).
- rejectedandsad 5y ago
  Children are not at risk like adults are. I say get back to normal and let the unvaccinated adults suffer the consequences of their own actions.
  - musha68k 5y ago
    Unfortunately there is increasingly more data that shows that SARS-CoV-2 is not benign in children. For example this rather early analysis from 2020 included more than 2,000 children who got infected. 10.6% of infants under 1 year of age had severe or critical symptoms. All of these infants survived but a small number of infants in the United States have died following diagnosis with COVID-19 even then before Delta (or even Lambda and other variants). https://pediatrics.aappublications.org/content/pediatrics/early/2020/03/16/peds.2020-0702.full.pdf https://pediatrics.aappublications.org/content/pediatrics/ea... I have rolled too many d10 not to worry a lot about this.
    - oxymoran 5y ago
      People under the age of 1 is not even close to equaling “kids”. Come on.
      - musha68k 5y ago
        Your point being what exactly? Apart from more severe outcomes for babies than what we thought there are children that increasingly have to be treated for pneumonia at hospitals. Also long covid is on the rise. This has been widely reported recently. https://www.nationalgeographic.com/science/article/long-covid-afflicts-kids-too-heres-what-we-know-so-far https://www.nationalgeographic.com/science/article/long-covi... https://www.google.com/amp/s/www.nytimes.com/2021/08/09/health/coronavirus-children-delta.amp.html https://www.google.com/amp/s/www.nytimes.com/2021/08/09/heal...

mint2 5y ago

This title is editorialized to be misleading. It’s specifically the nose not in general. It does not mean the viral load in the lungs is the same. And studies indicate vaccinated ppl may stay infectious a shorter timespan.

oxymoran 5y ago
Why is nobody recommending a highly saline nasal irrigation as a prophylactic? Or even a lower saline nasal irrigation with a very diluted amount of hydrogen peroxide???
- velcii 5y ago
  Probably because Trump suggested something similar...
  - exogeny 5y ago
    Yeah, poor guy. He earned so much credibility with his no-nonsense, straight-shooting communication style full of poignant truths that it’s such a mystery why no one took him seriously on a subject in which he was so clearly well-versed and knowledgeable!
    - velcii 5y ago
      Yea, he was so "not credible" that for anything he said, the opposite has to be the "real" truth. /s
- blamestross 5y ago
  You need to have well sterilized water for that just not to lead to a sinus infection which will leave you more susceptible. Tapwater isn't good enough, and is going to be rather harsh out of most taps in the US. Clean water in general isn't a solved problem. If you decide to do this with tap water, leave it out for a day or so to let the chlorine evaporate and then boil it for at least 5 minutes. Netti pots are also basically waterboarding fyi. Have fun!

walterbell 5y ago

Vaccines delivered to the arm deltoid muscle never promised mucosal immunity. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733922/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733922/ > The mucosal immune system is the largest component of the entire immune system, having evolved to provide protection at the main sites of infectious threat: the mucosae. As SARS-CoV-2 initially infects the upper respiratory tract, its first interactions with the immune system must occur predominantly at the respiratory mucosal surfaces, during both inductive and effector phases of the response. However, almost all studies of the immune response in COVID-19 have focused exclusively on serum antibodies and systemic cell-mediated immunity including innate responses. That's why vaccinated people can still get infected (upper respiratory tract) and have no symptoms (serum antibodies). They can infect others (upper respiratory tract) when they are infected but don't have symptoms or a temperature check saying they should stay at home. Hence the CDC now recommends tests for vaccinated people who are exposed to Covid. It was stated by Fauci and others in 2020 that current Covid vaccines are non-sterilizing. There are new Covid vaccines in development which provide sterilizing immunity, delivered via nasal inhaler instead of deltoid arm muscle. The MMR (measles, mumps, rubella) vaccine is sterilizing, i.e. prevents infection and transmission.

Zababa 5y ago
Thank you for that clear summary.
drno123 5y ago
Thank you for the clear explanation. Here in Europe we have Covid passports - if you are vaccinated or tested negative, you are allowed admission to, for example, shopping malls and no need to wear a mask indoors. Does this mean that Covid passports actually help spread Covid from vaccinated to non-vaccinated people who mix together without masks?
- adrianN 5y ago
  It looks like infected vaccinated people can transmit the disease just as much as unvaccinated people, so yes.
- 5y ago

furstenheim 5y ago

The article is way more nuanced than the title. That said, if the virus spreaded the same with the vaccine, the advantaged would be that the virus wouldn't have as much evolutionary pressure to change and become resistant. For example, it could make it harder for lambda variant, which might be symptomatic, to become prevalent