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"By the fourth week after receiving the initial dose, the Pfizer and Oxford-AstraZeneca vaccines were shown to reduce the risk of hospitalisation from Covid-19
by kop316 6y ago
"By the fourth week after receiving the initial dose, the Pfizer and Oxford-AstraZeneca vaccines were shown to reduce the risk of hospitalisation from Covid-19 by up to 85 per cent and 94 per cent, respectively.
Among those aged 80 years and over - one of the highest risk groups - vaccination was associated with an 81 per cent reduction in hospitalisation risk in the fourth week, when the results for both vaccines were combined."
I wanted to highlight this part for folks reading. My brothers Mother in Law is now hospitalized due to COVID, and there is a high likelyhood that she will not survive COVID due to lung scarring. She got her first COVID vaccination about a week before she got COVID.
You are not out of the woods just because you got your first dose COVID vaccine! It will take time for it to take affect.
- StavrosK 6y agoThe AZ vaccine is more effective than the BioNTech one? That's extremely interesting.
- ageitgey 6y agoI wouldn't read too much into that small difference. This study wasn't really designed to show which one works better. The bigger takeaway is that both show significant protection even with just one dose (which presumably rises after the second dose).
- sgt101 6y agoAgree. I can't find the right information but I suspect that the headline figures from the different vaccine trials may be generated by somewhat different counting methodologies. I think that some of the trials counted from day 1 of the vaccination, and some of them from day 15 - but I am hoping that someone has the actual information!
- turbonaut 6y agoThe vaccines have also been delivered in slightly different contexts that may relate to risk of hospitalisation. Pfizer, for example, often administered in hospitals due to the freezer requirement. You could imagine the risk of hospitalisation of an 80 year old who frequents hospitals and one who doesn’t is different.
- sgt101 6y agoThat's an excellent observation - very challenging to fish that out of the numbers.
- solarkraft 6y agoWith my very little biology knowledge I could imagine it being linked to the much stronger reaction many people seem to have to the AZ vs. the BioNTech one, resulting in more solid immunity.
- Exmoor 6y agoEdit: I'm an idiot who was trying to do too many things at once and misread. Removing my incorrect commentary on 95% CI numbers. I'll leave the excerpt from the study since that's useful info. >Findings: The first dose of the BNT162b2 vaccine was associated with a vaccine effect of 85% (95% confidence interval [CI] 76 to 91) for COVID-19 related hospitalisation at 28-34 days post-vaccination. Vaccine effect at the same time interval for the ChAdOx1 vaccine was 94% (95% CI 73 to 99). Results of combined vaccine effect for prevention of COVID-19 related hospitalisation were comparable when restricting the analysis to those aged ≥80 years (81%; 95% CI 65 to 90 at 28-34 days post-vaccination).` [0] https://www.ed.ac.uk/files/atoms/files/scotland_firstvaccinedata_preprint.pdf https://www.ed.ac.uk/files/atoms/files/scotland_firstvaccine...
- checker659 6y agoAZ had 100% efficacy against severe disease in their 3rd phase interim readout. 0 hospitalization in vaccinated arm, 8 hospitalizations 1 severe and 1 death in the control arm. In contrast, with pfizer, there were 0 covid deaths in the entire trial (vaccinated or unvaccinated).
- zeku 6y agoI could be wrong, but I think that's after just one dose. The pfizer vax requires 2 doses for it's full effect.
- ageitgey 6y agoI sorry to hear about your brother's Mother-in-Law. I just wanted to concur for anyone who is not yet aware: all the data so far (from multiple studies) shows that there is zero or near zero protection for the first two weeks after the first dose. It's not until the third/fourth weeks after the dose that you start to see substantial protection, with higher protection the fourth week.
- xur17 6y agoDo you remember what studies this data was from? I'd be curious to look at it. The fda filing [0] for Moderna seemed to indicate a decent uptick in protection > 14 days after dose 1 (which seems to mirror the studies you are referencing). I see a "Vaccine Efficacy" of 92.1% for > 14 days after dose 1, which seems to be fairly close to the ~95% efficacy I've seen described for 14 days after dose 2. [0] https://www.fda.gov/media/144434/download https://www.fda.gov/media/144434/download (page 28)
- jhayward 6y agoWe should note that the >14-day efficacy is presumed to decay fairly rapidly, thus the need for the 2nd dose to cement the response long-term, as well as eke out the last few percent of efficacy.
- selimthegrim 6y agoThen why is the delay in second doses being encouraged?
- xur17 6y agoI imagine "fairly rapidly" means a few months rather than a few weeks, in which case delaying the second dose from 4 weeks to 8 weeks won't cause any dramatic dips (this is all conjecture though).
- iso1631 6y agoThe idea behind the second dose being delayed in the UK was it was better to give 24 million and 80% coverage to the most vulnerable people with 1 dose over 12 weeks (assuming 2 million per week), then to give 2 doses to 9 million and 1 dose to 3 million over 12 weeks .8 * 24 = 19.2m covered in scenario 1 .959 + .83 = 10.95m covered in scenario 2 Even if it were 60% with 1 dose and 95% with 2 it would be .6 * 24 = 14.4m covered in scenario 1 .959 + .83 = 10.35m covered in scenario 2
- tonyedgecombe 6y agoI think the figures from Israel show you are at increased risk of infection for the first week after the vaccine is administered. Presumably because people are already starting to change their behaviour.
- cnlevy 6y agoIt could also be because people got contaminated IN vaccination centers when coming for their first vaccine dose. Told from a doctor working in Israel.
- merpnderp 6y agoThe vaccination locations are the largest group of people anyone I know how been around in a year. Dozens of people coming in and out of a room every 15 minutes, plus having to sit next to strangers for 15 minutes to make sure you don't have an adverse reaction is a larger risk than most take ever.
- ashtonbaker 6y agoI've worked several full days at a vaccination center in Michigan. It's quite crowded, something like a grocery store. It wouldn't surprise me if there was some spread there.
- mancerayder 6y agoIs it possible the immune response initially from the virus causes strain on the body and temporarily and paradoxically makes it more susceptible ? The immune system can be weakened from a bunch of things, including lack of sleep and stress and other infections.