Myth busting thread: Vaccines *do* reduce transmission- even with delta. Anyone who says otherwise (and I've seen many scientists say this recently to rationalise not vaccinating children!) is misinterpreting the evidence. Let me explain
There are two levels of protection against transmission:
1. Protection against infection (if you don't get infected you can't transmit)
2. Protection against transmission *if* breakthrough infection occurs
When many people say there isn't protection against transmission, they're talking about 2. - that is- if you get infected, you can still transmit delta efficiently. But that doesn't account for the fact that you are *less likely* to get infected in the first place.
REACT-1 data from England has shown ~60% protection against infection on average (this changes over time, and protection after 5 months or so may be markedly reduced), but there is substantial protection (even if not complete) for several months.…
Waning makes a difference, and the effectiveness of protection reduces over time with delta, but between 40-70% protection for several months is reasonably good protection in a pandemic where infection can spread over very short periods of time.
If you *do get infected* (the chance of which is reduced), then it seems there is little or no protection against transmission. Transmission can be similar among those who are vaccinated who have breakthrough infections, and those who are unvaccinated.
So vital for those who are vaccinated to take precautions- masking, getting tested, isolating if positive, because the transmission is efficient as this study shows. Thanks for @LongDesertTrain for correcting an earlier error I made reading the study.…
This study also shows that most cases with breakthrough infection were those 3-4 months out from vaccination, again highlighting the significant impact of waning immunity over time on reducing protection against infections. But boosters can massively increase this.
Recent work suggests boosters can boost immunity to give very high protection against infection as well as severe disease - of course we don't know how long this lasts, and it may well wane again over time, but even several months of high protection in a pandemic is important.
Also notable that protection from infection in the above study was ~35% - lower than REACT-1. Potentially several reasons for this. It's possible that household members of those infected were also likely on average a longer period post-vaccine (e.g. partners).
But potentially also lower protection with prolonged household contact than other types of contact. But even these levels of protection from infection would likely have significant impact at population level. We've seen lower infection rates overall among the vaccinated.
So, it's worth trying to separate out protection from infection & onward transmission *if* infection occurs.I worry that the overwhelming messaging that's being put out is that there is no protection from transmission, when there clearly is, even if it's not perfect, and wanes.
Also important to point out that boosting can reverse the waning - at least temporarily (we don't know how long currently) - it can substantially improve protection from infection, and severe disease. So please get your boosters if you are eligible. To protect yourself & others.
Just because protection isn't complete doesn't mean it's *no* protection. Remember, if you don't get infected, you can't transmit. It doesn't mean we don't need to use mitigations with vaccination, but that vaccines provide one layer of multiple layers of protection.
And yes, if you are vaccinated and get infected, you can transmit efficiently, so you do need to take precautions (isolation etc.) to protect the people around you. And although vaccines reduce infection risk, they don't eliminate it, so wear a mask. It'll protect you & others.
Just want to add that the same applies to protection from long COVID. Two layers: -protection against infection -protection against long COVID/long COVID severity/duration Vaccines definitely protect against 1. (potentially also some of 2.), so they provide significant protection
Sorry, deleted an earlier continuation of this thread due to an error. The rest of the thread is here:

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More from @dgurdasani1

23 Nov
More pseudoscience propaganda from the BBC.

We've escaped the 'worst of what's being seen in the continent' because we've already got the highest total death rate, we've already killed 14,000 people since 'freedom day' (more than any other country in Europe) & maimed >1 million
What Nick doesn't tell you could fill a phD thesis.
The UK has one of the lowest vaccine rates in Western Europe totally (just above Austria and Germany but below other countries) because of massive delays in vaccinating children & shambolic roll out. Image
We have twice the cumulative deaths of Germany, and the third highest total deaths in Western Europe- close to Belgium and Italy. Italy seems to have learned it's lessons, and cumulative deaths are now flat, while ours? Still rising! >2 in 1000 people overall have died of COVID Image
Read 10 tweets
22 Nov
What's disturbing is a conference abstract (one of thousands presented-*not* a peer review paper) providing no information on numbers, research methods & correlating immune biomarkers post-vaccination with probability of acute coronary syndrome being disseminated in this way.
We have extensive evidence from the CDC on millions vaccinated on outcomes in patients which very clearly shows that both short and long term impacts from COVID-19 far outweigh any risks from vaccination. Vaccine myocarditis is typically mild & in recovers fully in most.
COVID myocarditis (and other COVID impacts) are far more serious, and more common. Anyone giving warnings about vaccine-myocarditis (with no details of methods, incidence rates or clinical correlates) without talking about impacts of COVID-19 should be treated with scepticism.
Read 5 tweets
21 Nov
So I presume he has access to information that the ACIP at the CDC didn't in their analysis which was made accessible and available publicly?
And the risk of covid myocarditis- both in frequency and severity is greater than vaccine myocarditis which has not results in a single fatality and is typically mild. COVID myocarditis unfortunately has led to death, in children who could be alive had they been vaccinated.
Oh, and on the point that vaccines don't prevent transmission- they definitely do!! Substantially as a single measure in fact- between 50-70%. Perhaps even more so in children. Even real-world data from England backs this up, with drops in teenagers correlating with uptake:
Read 6 tweets
21 Nov
Exceptionalism the scientific community which is justifying exceptional govt policies is killing us. Yet, some of our scientists seem to continue to justify this in the face of overwhelming evidence for failure. Why?
A thread.
I'm seeing actual scientists/medics saying that our govts policy of mass infection through summer was a good one because we've got more 'population immunity' than Europe now, and this will protect us through winter. Let's examine this claim.
A central argument to this claim is that exposure to mass infection over summer - to prevent future infection over winter was a good thing. First, this argument doesn't pass basic scrutiny because vaccines are a much safer and more effective way to get 'population immunity'
Read 22 tweets
21 Nov
This is outrageous and deeply offensive. The fact that Asian and black people have 2-3 times higher death rates than white people doesn't have to do with pulse oximeters. It has to do with structural racial discrimination, deep social and health inequalities. Please stop.
So many of this govts hostile policies already contribute to this structural discrimination, and the anti-immigration rhetoric has stoked so much hate. Please stop denying the painful lived experience of minorities, after having spent decades contributing to that pain.
And I want to say that as a medic I've used pulse oximeters every single day on hundreds of patients, and believe me, medical device bias isn't the reason people die. It's racism and denial of this that kills.
Read 6 tweets
19 Nov
Our commentary on the Smith et al @NatureMedicine paper on child deaths in England up to Feb '21
led by @LawtonTri
Key takeaways:
-their results actually validate ONS data
-ONS data now has >70 deaths in 0-19 yr olds
-population rates are v. misleading!…
The premise of the study is unclear to me- it seems to just recapitulate ONS data from death certification (done by the treating clinician), so not sure why all these cases were reviewed. It's bizarre that the paper doesn't seem to mention ONS data or compare with this at all.
By contrast to the reports from the paper, the vast majority of PHE deaths 'with COVID-19' are currently 'from' COVID-19- unlike during the period covered by the paper. And infection rates in children, and deaths are unfortunately the highest they've ever been.
Read 7 tweets

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