The biology of coronavirus COVID-19 - including research and treatments

[Yessica]

Most of the vaccinated index patients in our data set (93%) had received only the first dose of vaccine.

 

[Snow Leopard]

There are worrying trends of a "third wave" (or is that fourth) in the UK, with cases per day per million almost ten times higher in the UK compared to the USA on Tuesday. The US death rate is still three times higher (per million), but cases have more than doubled so those rates may well be similar in 2-3 weeks.

https://www.worldometers.info/coronavirus/country/uk/
https://www.worldometers.info/coronavirus/country/us/

Meanwhile in Australia we're freaking out about a handful of local transmission cases per day.

 

[Sean]

Meanwhile in Australia we're freaking out about a handful of local transmission cases per day.

In fairness, it is because we don't want it to turn into the UK and USA, which it easily could seeing as our outbreak is the Delta variant.

 

[Snow Leopard]

seeing as our outbreak is the Delta variant.

So what? All SARS-2 is highly infectious. I think naming these variants is often used to deflect blame from authorities...

 

[ahimsa]

Thanks for your link, @Snow Leopard ! I did notice the line that @Yessica quoted - "Most of the vaccinated index patients in our data set (93%) had received only the first dose of vaccine."

Looking at my question again

...can someone who is fully vaccinated, and then gets infected, transmit the coronavirus to someone else?

I think that this question is too broad.

There may be different answers about post-vaccination transmission (by fully vaccinated people, eg, 2 weeks past the final shot) for each of the different brands of vaccine.

There are different reported effectiveness rates for different vaccines. So it makes sense that there might also be differences when it comes to a fully vaccinated person who gets a breakthrough infection being able to transmit that infection to someone else.

And even when talking about effectiveness for a single brand of vaccine I've seen different rates of breakthrough infections for different strains of the virus.

I can't find the quote right now but it was something like for Pfizer it's 95% effective against one strain of the coronavirus but 88% effective against the delta strain. NOTE - these are made up numbers! And I also can't remember whether it was about Moderna or Pfizer. I just remember that the effectiveness was lower for the delta strain.

Anyway, the point is that the same vaccine can have different rates of effectiveness for different strains. So I think that's one scientific reason why different strains matter? (but this is all way beyond me so maybe I've missed something)

I know this post is a bit rambling, but I hope it makes sense!

I'll end by quoting from a study looking into coronavirus transmission after being fully vaccinated (there's probably more than one, this is just the study that I found) -

“The underlying premise is that we know that vaccines work extremely well at preventing symptomatic disease, keeping people out of the hospital and preventing death, but what’s not translated to most people is that vaccines cannot block us from being exposed to infections like the one that causes COVID-19,” said Fischer, an assistant professor of biostatistics and epidemiology.

Vaccinated individuals can still be exposed to the virus that causes COVID-19 and become infected, she said, and it’s currently unclear if they can still pass the virus on to unvaccinated people, who could have severe or fatal outcomes. The researchers hope to answer whether people who are vaccinated against the virus are in fact stopping transmission.

This is one of the "we still don't know" quotes that I mentioned in my earlier post.

But maybe it's only "we still don't know" when it comes to certain brands of vaccine? Maybe it's "yes, we know that it can be transmitted by fully vaccinated people" when it comes to certain vaccines?

 

[Wits_End]

I think the vaccine (probably AstraZeneca, since that's what most of us had in the UK at that stage) was shown to greatly reduce transmission, but I couldn't quote you chapter and verse on that one.

 

[Sean]

So what? All SARS-2 is highly infectious. I think naming these variants is often used to deflect blame from authorities...

According to Wikipedia the Delta variant seems to be around 50-60% more transmissible than the Alpha variant. Which is not good.

However, it also seems to be less fatal, and a double dose of either Pfizer or AZ vaccines are over 90% effective at preventing hospitalisation.

 

[Snow Leopard]

I can't find the quote right now but it was something like for Pfizer it's 95% effective against one strain of the coronavirus but 88% effective against the delta strain. NOTE - these are made up numbers! And I also can't remember whether it was about Moderna or Pfizer. I just remember that the effectiveness was lower for the delta strain.

That was the (currently most recent) Public Health England data.
https://www.medrxiv.org/content/10.1101/2021.05.22.21257658v1

In prior research, efficacy against symptomatic infection has correlated reasonably well with transmission rates, hence I am willing to bet that the vaccines that have higher efficacy against symptomatic (and asymptomatic) infection also have reduced risk of transmission.

Vaccines have never reduced transmission risk to zero.

According to Wikipedia the Delta variant seems to be around 50-60% more transmissible than the Alpha variant. Which is not good.

However, it also seems to be less fatal, and a double dose of either Pfizer or AZ vaccines are over 90% effective at preventing hospitalisation.

Neither claims are backed by high quality evidence, because behaviour and demographics are not controlled.

The claims of lower fatalities are strongly biased by the fact that countries have been selectively vaccinating the older/most vulnerable populations.

 

[Mithriel]

In Scotland, the numbers have soared to higher than they have ever been since the pandemic started but hospitalization is still low. It is nothing like it was last year. The proportion of hospital cases needing ICU and the number of deaths deaths are also down.

Two thirds of the cases are in men under 40 so distribution of the cases is different from before.

These figures mean that vaccination has been very successful especially in the older population. The numbers have dropped, but are not zero of course.

 

[Trish]

Two thirds of the cases are in men under 40 so distribution of the cases is different from before.

I have heard it suggested that the recent surge of cases among young men is largely due to a recent football match.

 

[Mithriel]

"The fitba' it has robbed them o' the wee bit sense they had"

 

[FMMM1]

There are worrying trends of a "third wave" (or is that fourth) in the UK, with cases per day per million almost ten times higher in the UK compared to the USA on Tuesday. The US death rate is still three times higher (per million), but cases have more than doubled so those rates may well be similar in 2-3 weeks.

https://www.worldometers.info/coronavirus/country/uk/
https://www.worldometers.info/coronavirus/country/us/

Meanwhile in Australia we're freaking out about a handful of local transmission cases per day.

Yea and (to me) ludicrously there are comments here (UK) about not wanting to be like Australia!

 

[Snow Leopard]

Yea and (to me) ludicrously there are comments here (UK) about not wanting to be like Australia!

Life here has been mostly normal, besides mandatory check-ins at retail premises.
Many people in Australia are yearning for the time before (ASAP) and seem to mistakenly think that is the situation in the UK.

 

[Wits_End]

Considering that the UK Government is threatening England with the removal of most restrictions in a couple of weeks, I should think they'd want to avoid that situation at all costs. I don't think the results will be pretty.

 

[Snow Leopard]

But can someone who is fully vaccinated, and then gets infected, transmit the coronavirus to someone else?

Here is a study in India that found that vaccinated people can transmit the virus to other people.
https://www.researchsquare.com/article/rs-637724/v1

 

[Mij]

I plan to wear a mask for at least another year after I'm fully vaccinated.

 

[Mithriel]

I plan on wearing a mask because it will stop me touching my mouth with my glasses keeping my eyes safe. It seems it gives a little bit of protection for the wearer too.

What is worrying for us is that the people making the choice to not wear a mask are not the ones at risk it is everybody in their vicinity.

I am quite upset at the thought because I have ventured out shopping 4 times since the pandemic when numbers were low and I enjoyed the way I could choose my own meals and things, it was fun.

But if the shops are stuffed with people not wearing masks I won't be able to take the risk of becoming ill and my ME making me completely bedridden instead of being able to get up for a time every day. I don't go out often but I don't want to have to give it up.

It will be ironic if people on the tube are allowed to infect everyone with coronavirus but smoking is forbidden because of the problems for other people.

(People who can't wear a mask are presumably taking precautions but someone who decides to risk people's health anyway seems to me more likely to be the same person who doesn't think covid would be a problem for them so they are not diligent about hygiene rules.)

 

[Hoopoe]

I had a discussion with a person who believed that vaccinated people are variant factories because they don't have good antibodies and exert evolutionary pressure on the virus without killing it.

The idea seems to come from Gøtzsche.

Is there some truth to this? I read that vaccine-induced antibodies are not neutralizing antibodies (I'm not sure what that means exactly, but it seems to mean the antibodies aren't as good as those that will be produced in a real infection).

I can't however see why a vaccinated person would be more likely to give rise to dangerous new variants. Surely some protection from non-optimal antibodies is better than none? My mental model of how variants arise is that it's just a matter of random chance resulting in mutations, followed by natural selection of beneficial (for the virus) mutations, so anything that slows or prevents multiplication would be good.

There also seemed to be the idea that vaccinations interfere with the killing of infected cells.

 

[Barry]

I had a discussion with a person who believed that vaccinated people are variant factories because they don't have good antibodies and exert evolutionary pressure on the virus without killing it.

The idea seems to come from Gøtzsche.

Is there some truth to this? I read that vaccine-induced antibodies are not neutralizing antibodies (I'm not sure what that means exactly, but it seems to mean the antibodies aren't as good as those that will be produced in a real infection).

I can't however see why a vaccinated person would be more likely to give rise to dangerous new variants. Surely some protection from non-optimal antibodies is better than none? My mental model of how variants arise is that it's just a matter of random chance resulting in mutations, followed by natural selection of beneficial (for the virus) mutations, so anything that slows or prevents multiplication would be good.

There also seemed to be the idea that vaccinations interfere with the killing of infected cells.

Speaking without any expertise on this at all.

Depends how a mutation arises. Are mutations a function of the transference of the virus from one person to another? Or a function of the virus replicating within a person? Either way it would seem that the rate of increase of the virus within a population must inevitably influence the chance of random mutations appearing.

 

[Keela Too]

I would imagine the selection pressure of having vaccinated people in the population, would simply be that should a variant arise that our vaccine-generated-immunity can’t tackle, then that variant will spread faster than variants to which we are immune.

So if covid becomes endemic (highly likely) the we are likely no need regular vaccine boosters against emerging variants.

Overall though I would think vaccination is likely to suppress the number of new variants that are able to spread rapidly.