Health & Wellness

When will 2nd vaccine doses be given @ 21-28 days due to very low efficacy of 1st dose against UK and Indian variant?

[OP]
Newbie
Feb 26, 2021
62 posts
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When will 2nd vaccine doses be given @ 21-28 days due to very low efficacy of 1st dose against UK and Indian variant?

I just saw latest news on CTV that moderna, pfizer and AZ were only 33% effective against symptomatic disease from the Indian variant and 50% effective against symptomatic disease from the UK variant.
PHE said a first dose of both vaccines was 33% effective against symptomatic disease from B.1.617.2 after three weeks, lower than its 50% effectiveness against B.1.1.7.
Two Pfizer COVID-19 shots effective against variant first identified in India: U.K. study

Since UK strain is the most dominant variant in Canada, when will we see the 2nd vaccine doses given at 21days (pfizer) - 28days (moderna & AZ) days as per manufacturer guidelines which the world follows, to reduce number of cases between doses and increase effectiveness against symptomatic disease to 93% (mRNA) / 66% (AZ) against the UK variant and 88% (mRNA) / 60% (AZ) against the Indian variant?
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[OP]
Newbie
Feb 26, 2021
62 posts
26 upvotes
Ah thanks! Looks like CTV is a bit behind in reporting.

But doesn't look like that post answered the most important question in the subject line, which is:

When will we see the 2nd vaccine doses given at 21days (pfizer) - 28days (moderna & AZ) days as per manufacturer guidelines which the world follows, to reduce number of cases between doses and increase effectiveness against symptomatic disease to 93% (mRNA) / 66% (AZ) against the UK variant and 88% (mRNA) / 60% (AZ) against the Indian variant?
[OP]
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Feb 26, 2021
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mr_raider wrote: That news article is grossly misleading.

Here is the original trial:

https://www.bmj.com/content/373/bmj.n1088
I don't think that's the exact same study as the one recently reported by CTV because:

a) The results for the B.1.617.2 variant from India is not mentioned in the bmj article anywhere.
b) The one dose 33% effective against symptomatic disease from the Indian variant and 50% effective against symptomatic disease from the UK variant is not mentioned in that article.

So the question remains:

When will we see the 2nd vaccine doses given at 21days (pfizer) - 28days (moderna & AZ) days as per manufacturer guidelines which the world follows, to reduce number of cases between doses and increase effectiveness against symptomatic disease to 93% (mRNA) / 66% (AZ) against the UK variant and 88% (mRNA) / 60% (AZ) against the Indian variant?
Deal Expert
Feb 29, 2008
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DealsinThe6ix wrote: I don't think that's the exact same study as the one recently reported by CTV because:

a) The results for the B.1.617.2 variant from India is not mentioned in the bmj article anywhere.
b) The one dose 33% effective against symptomatic disease from the Indian variant and 50% effective against symptomatic disease from the UK variant is not mentioned in that article.

So the question remains:

When will we see the 2nd vaccine doses given at 21days (pfizer) - 28days (moderna & AZ) days as per manufacturer guidelines which the world follows, to reduce number of cases between doses and increase effectiveness against symptomatic disease to 93% (mRNA) / 66% (AZ) against the UK variant and 88% (mRNA) / 60% (AZ) against the Indian variant?
Then I suggest we wait for the full study.

My guess is that those estimates include the first 14 days.

UK's own health data suggest that Pfuzer gives about 70-75% protection against the B1.117 variant after 1 dose 21 days out and further. So the 50% estimate doesn't seem congruent unless they used a different metric.

The only thing I would take from this is that Indian variant protection is lower than UK, but not dramatically so after 2 doses. 1 dose efficacy was clearly not properly studied here.
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Feb 29, 2008
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As a side note, be very, very careful of news headlines of scientific studies. They rarely capture the nuances of the data.

For example the early headlines of colchicine hailed it as a life saving drug, yet the actual publsihed data showed a marginal benefit in a small sub group of patients.

Another example is the Qatar study that was interpreted as 1 dose vaccination having minimal protective effect by news agencies. The author of that study was forced to reply by stating that their study could not evaluate the effects of prolonged dosing interval since all recipients received their 2nd dose in 21-28 days.
[OP]
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Feb 26, 2021
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mr_raider wrote: As a side note, be very, very careful of news headlines of scientific studies. They rarely capture the nuances of the data.

For example the early headlines of colchicine hailed it as a life saving drug, yet the actual publsihed data showed a marginal benefit in a small sub group of patients.

Another example is the Qatar study that was interpreted as 1 dose vaccination having minimal protective effect by news agencies. The author of that study was forced to reply by stating that their study could not evaluate the effects of prolonged dosing interval since all recipients received their 2nd dose in 21-28 days.
Thanks for the advise. will keep a close eye in the next few days of any updated news from CTV, based on doctor devilla and doctor williams and doctor tams interpretation of this recent news.

Edit: in anycase I hope they reduce the interval to AZ's guidelines of 28 days before those vaccines expire, especially if some of those prioritized from March do not want it, then give it to those who do instead of wasting it.
Last edited by DealsinThe6ix on May 23rd, 2021 12:15 pm, edited 1 time in total.
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I don't think any first dose studies are reliable unless it can be determined the contamination occured at least 3-4 weeks after the first dose was given. Else, there is no mean to know exactly when the infection occured, which has a very high chance of being when there was still no immunity, or very limited immunity. This is aggravated by the fact that people tend to engage in risky behavior early after receiving a first dose, such as meeting people again, which skews the numbers further.

33% for the Indian variant or 50% for the UK variant is simply an impossible number.
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Feb 20, 2015
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This is the demand for the second shot... so much so that people are willing to go to the USA for it, as it's that abundant and going in the trash bin when it expires. Too much red tape at the border, they're not letting people over just for the shot and you'll have to quarantine for 2 weeks coming back to Canada - after getting fully vaccinated - that doesn't make sense.
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Here's a local story on it, where I live:

https://windsor.ctvnews.ca/windsor-mayo ... -1.5436589

We are literally, this close:
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It's too bad they can't make this work, doses are being wasted and it would take some strain off of the supply here in Canada. It seems that "what makes sense" will never happen, however.
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Gibsons wrote: This is the demand for the second shot... so much so that people are willing to go to the USA for it, as it's that abundant and going in the trash bin when it expires.
For those going to trash bin vaccines, there are a lot more places in the world which desperately need those vaccines.
Canada has plenty enough for everyone to get 2 doses.
I recommend US sending those excessive ones to India or 3rd world countries who need it more (and so far US has failed to do so).

By the way, the definition of "fully vaccinated" means 2 weeks after the second dose - so the 2 weeks quarantine makes perfect sense.
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Apr 13, 2017
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nosnoop wrote: For those going to trash bin vaccines, there are a lot more places in the world which desperately need those vaccines.
Canada has plenty enough for everyone to get 2 doses.
I recommend US sending those excessive ones to India or 3rd world countries who need it more (and so far US has failed to do so).

By the way, the definition of "fully vaccinated" means 2 weeks after the second dose - so the 2 weeks quarantine makes perfect sense.
US announced they are sending 20 million US approved vaccines + 60 million AZ doses by end of June through COVAX initiative. None coming to Canada.
[OP]
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Feb 26, 2021
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Does anyone have any links to studies how effective a fully vaccinated individual is against the delta variant 2 weeks after 2nd mRNA dose, which was given 8 weeks or more after

A) AzteaZeneca 1st dose?

B) mRNA 1st dose?

The 88% after 2nd mRNA dose is based on manufacture 21 and 28 day guidelines but Canada uses on average 8 weeks or more after 1st dose.
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Dec 1, 2008
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I am going to have to dig for those links as I posted in a different thread. It looks really, really, really good.

Ireland just announced that covid is "virtually eliminated" among their fully vaccinated folks.

I have been extra cautious and now feel like 3 weeks post second dose I will loosen up a whole lot more. I am only hearing very, very good news (after digging through most of the doom and gloom headlines and reading the actual stats).
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Feb 29, 2008
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m2m wrote: I am going to have to dig for those links as I posted in a different thread. It looks really, really, really good.

Ireland just announced that covid is "virtually eliminated" among their fully vaccinated folks.

I have been extra cautious and now feel like 3 weeks post second dose I will loosen up a whole lot more. I am only hearing very, very good news (after digging through most of the doom and gloom headlines and reading the actual stats).
And Delta has not taken over.

https://www.rte.ie/news/primetime/2021/ ... lip-nolan/

I'm still not convinced the UK's delta problems are all related to the virus mutations themselves. Behavioral and socio economic factors clearly play a role.
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Aug 12, 2007
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DealsinThe6ix wrote: Does anyone have any links to studies how effective a fully vaccinated individual is against the delta variant 2 weeks after 2nd mRNA dose, which was given 8 weeks or more after
A) AzteaZeneca 1st dose?
B) mRNA 1st dose?
There is not enough data on mixed dose.
But the latest analysis from England found that either is very effective to prevent hospitalization.

Vaccine effectiveness in preventing hospitalization for Delta (Indian) Variants:
Pfizer - after 1st dose - 94%
Pfizer - after 2nd dose - 96%

AZ - after 1st dose - 71%
AZ - after 2nd dose - 92%

I can imagine mixed doses should have similar results as single Pfizer dose is already so effective.

Interestingly, single dose of Pfizer is more effective against the Delta/Indian variant than against Alpha/UK variant in preventing hospitalization.
[OP]
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Feb 26, 2021
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nosnoop wrote: There is not enough data on mixed dose.
But the latest analysis from England found that either is very effective to prevent hospitalization.

Vaccine effectiveness in preventing hospitalization for Delta (Indian) Variants:
Pfizer - after 1st dose - 94%
Pfizer - after 2nd dose - 96%

AZ - after 1st dose - 71%
AZ - after 2nd dose - 92%

I can imagine mixed doses should have similar results as single Pfizer dose is already so effective.

Interestingly, single dose of Pfizer is more effective against the Delta/Indian variant than against Alpha/UK variant in preventing hospitalization.
Thanks for the link!

But I think England is using the recommended interval of 21 days for Pfizer and 4weeks to 8weeks for Astrazeneca, and these numbers are for vaccine effectivness against hospitalization.

What about after vaccine effectiveness against symptomatic disease after 8weeks or more after 1st dose, which is what Canada is doing, at least for mRNA vaccines?

We know after 1 dose for Pfizer, it's 33% effectiveness against symptomatic disease for delta variant, and 2nd dose 21 days after 1st dose, effectiveness is 88%, but this is not the reality in Canada. The reality is 8weeks or more after 1st dose.

I think we all need clarity for mRNA effectiveness against symptomatic disease 8 weeks or more after 1st dose against this delta variant.
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Dec 12, 2009
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With appointments opening up in hot spots for those that got their first dose by May 30, we are getting close to having some at the 21-28 day schedule.
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Mar 23, 2011
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I made an appointment today for tomorrow which puts me at 42 days between doses. I would have liked it to be less than 30 days but it's a ton better than the 4 months it was going to be.
Since most have already had a 1st dose (75% or so) the reality is that the only people that are going to be in that window are ones that haven't gotten their 1st dose yet.
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