Preprint of results from the Novavax phase 2 trial in South Africa with efficacy outcomes, with 4,387 participants. Sequencing done for most of the people with Covid-19: 93% were infected with B.1.351 ("SA" variant). ...1/n…
...Small trial, so a lot of uncertainty in efficacy results.

Vaccine efficacy rates:

Overall (not previously infected with SARS-CoV-2): 49.4% (CI 6-73)
HIV- : 60.1% (CI 20-80)*
Against B.1.351 variant: 51.0% (CI 0.6-76)

* 6% of people in the trial living with HIV

...About 30% of people tested positive for previous SARS-CoV-2 infection, & their risk of getting sick with Covid-19 was the similar to people who'd never been infected before. Placebo group: 5.3% vs 5.2%. Previous protection didn't protect against the variant ...3/n
...The trial participants were predominantly young & black: only 4% were 65 or older; 95% were Black-African. Obesity rate: 20% ...4/n
...This is a vaccine that had a high efficacy rate in the larger UK trial (89% overall, 96% against original strain). It's a protein subunit vaccine - so a fairly traditional vaccine type ...5/n
...Adverse event (AE) data for the first week after injections from the early part of the trial: 968 people. There are reactions to the injection; otherwise quite low rate of AEs. The rate of severe systemic AEs was similar to the placebo group...6/n
...There were <210 people living with HIV in this group, so it's far too small to draw conclusions, so need for alarm here. Had such a large impact on efficacy because there were 6 people who got Covid-19 (4 in the vaccinated group)...7/n
...Would have been such a different picture without the variant! But it provided some protection against it (prior infection didn't & nor did the Oxford vaccine in a small trial). There was only 1 person with severe Covid-19 in this trial (but remember, not many older people). /8

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More from @hildabast

1 Mar
Public Health England released leaked study - it's a copy of a manuscript submitted to a preprint server. It's not a study of who was vaccinated, but of vaccination status of people seeking Covid tests for symptoms ...1/n… HT @michael_jshaw @TheGazmanRants
...This study is a test negative case control study - it's a study design that's been used in a variety of vaccines. (Here's an article about this type of controlled study:…)...2/n
...It's data from tests for the general community (called Pillar 2: doesn't include eg hospital testing). Data was linked to the National Immunisation Register, on Feb 22. Vaccination began in the UK on Dec 8 (with BNT-Pfizer), followed soon by Oxford-AstraZeneca vaccine...3/n
Read 7 tweets
25 Feb
ca 600,000 vaccinated with BNT-Pfizer vaccine in Israel, matched on demographic/clinical characteristics of 600,000 unvaccinated (median age 45) showed results similar to the phase 3 trial... 1/n…
...Similar pattern, for infection, symptomatic Covid-19, hospitalization, severe disease, death: 10,561 people infected, 57% of them developed symptoms; 369 in hospital, 229 severe Covid-19, 41 deaths...2/n
...7 days after 2nd dose: 92% efficacy against infection (CI: 88 to 95) - that's a strong result. Hospitalization: 87% (CI: 55 to 100) - wide confidence intervals, so not so certain. Remember, it's a group on the young side...3/n
Read 5 tweets
24 Feb
Away we go. J&J ENSEMBLE trial evaluation has landed - 8am again - thanks, FDA! ....1/n…
...First up, yes, outcome measure was reasonably close to what we're used to. Here it is based on the FDA-harmonized definition (including mild disease) - & keep in mind this is with South Africa &c included: vaccine efficacy 67% (CI: 56-75) (CI is a measure of uncertainty)...2/n
...This is what that looks like. Keeping in mind it's a single shot - and 28 days after it is about similar to the time of 7 days after BNT-Pfizer's second shot (as they're 3 weeks apart). (ENSEMBLE-2 is underway to see a 2nd shot on day 57) ...3/n
Read 21 tweets
24 Feb
It's another ENSEMBLE-watch day! The FDA meets on 26th to discuss the evaluation of the J&J single-shot vaccine - 3rd vaccine for FDA - & they aim to publish report 2 days ahead, which they achieved for the last 2. So 🤞 all will be revealed in a few hours ... 1/n
...This is where reports will be posted:…

Trial protocol:…

Press release with trial efficacy readout:…

My thread on it:

Records on this vaccine:… ...2/n
...Things I'll be watching out for. By far the biggest set of "events" (people with symptomatic Covid-19) of any trial. So it'll be the strongest data yet on questions past that top line efficacy - efficacy in severe disease, for example, which others had too few to answer ...3/n
Read 7 tweets
22 Feb
Report from Scotland with great news on Covid vaccination reducing hospitalization rates. Not enough data released to be sure about much beyond that though, & number of vaccinated people hospitalized appears to be too small (happily!) to draw much beyond that though...1/2
..Some details about the study… BBC says 58 people in hospital who were vaccinated a month before: % by vaccine & for over 80s, but that number seems too small to break it down it by vaccine & age. Overall, ca 90% lower. 🤞… 2/2
...Ah ... preprint tweeted by @jaclark73 - thanks!… Just hunting out the numbers now... 3/n
Read 18 tweets
19 Feb
This Oxford-AstraZeneca vaccine study from a preprint a couple of weeks ago is now published in the Lancet. At first look, there are some additions... 1/n…
...In the original thread, I'd had a question about hospital admissions, but ignore that if you re-read it: the wording is expanded a little in the paper, & it clears it up... 2/n
...The supplementary info includes listing of serious adverse events & unsolicited adverse events, but no data on solicited adverse events - all of that is new...3/n…
Read 5 tweets

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