The evidence assessments - but not the WHO decisions - for Sinopharm's Beijing vax & Sinovac's CoronaVac are going up on the WHO website… HT @lutl88 @hvasquezhg ...1/n
...Sinopharm Beijing: WHO assessment. 45,000-participant trial in UAE/Bahrain/Egypt/Jordan, doses 21 days apart, efficacy:

- Overall: 78.1% (CI 65-86)
- For people with no previous infection: 80.8% (67-89) (the usual efficacy rate for others)… ...2/n
...- Efficacy against hospitalization: 78.7% (CI 26-94)
- 1 death only, in the placebo group

But this is only up to age 60: negligible people over 60, & none had Covid-19 (in vax or placebo group)
... Safety data for 16,671 people who got Beijing vax (45,000 includes an arm for Wuhan vax, not reported here). The rate of severe adverse events (grade 3) wasn't higher in the vax group - nor was the rate of serious adverse events (SAEs). Only 2 SAEs possibly vax-related...4/n
... Although can't assess vaccine efficacy for older people, they cite safety data from China in older people, where 1.1 million have been injected. (That doesn't really substitute for clinical trial data, though)...5/n
...Not much data here, but this is impressive. It's a test-negative control study from Bahrain. Vaccine efficacy 14 days after 2nd dose:

- All adults: 90% (88-91)
- 60+: 91% (87-94)

...Another thing to take into account for the phase 3 trial: lacked people with co-morbidities (except BMI over 30).

Conclusion on variants of concern: laboratory study showing protection but reduced signs of immunity for B.1.351 ("SA"), but no clinical data on variants ...7/n
..Summary of what's missing from the evidence: hospitalization data, but not data on severe disease.
Conclusion: "High level of confidence" that 2 doses protect against Covid-19 in people aged 18 to 59, with "moderate level of confidence" that adverse events are low for them..8/n
... Side note: Just in case anyone gets confused by this - they have the wrong description on a link that says it's for China National Biotech Group (Sinopharm subsidiary) - in fact, that leads to a Sinovac presentation...9/n
... So there's nothing more on the Sinopharm Beijing vax so far then. Bottom line? The trial plus the Bahrain case-control study add up to results that are actually better than we've been led to expect for this vaccine. & we sure could use *that* good news...10/n
...On to WHO evidence assessment for Sinovac's CoronaVac… (And also note, that incorrectly labeled file has "confidential" on it, so I for one have downloaded it!… ) ...11/n
...They say 260 million doses have been distributed.

Here's the efficacy data they're going on: most of this is already public. Again, negligible data for 60+ in the trials: Brazil, Indonesia, Turkey - with a 2-week dosing interval...12/n
... As well as the trials, they're taking 2 other studies into account. The Chile study (which I tweeted about here ) & a test-negative case control study from Brazil, which is a first sighting...13/n
..Efficacy for symptomatic Covid-19 (previous table) is range we already know: 14 days between doses, ~50% in healthcare worker trial in Brazil & when P1 ("Brazil" variant of concern dominates, 84% in general population in Turkey. Closer to 70% for 28 day interval in Chile...14/n
...High rate of co-morbidity in the healthcare worker trial in Brazil: they put it at 56%

High rate of protection against hospitalization, but not enough data for certainty on how high that is

Definitions of symptomatic Covid-19 differed between the 3 trials unfortunately..15/n
...Safety profile good again. Again, as you'd expect from an inactivated vaccine, low rate of adverse events: severe & serious adverse events weren't increased in the vax group in the trials. Again, though, usage in older people is outside the trials ...16/n
...Results shown from several community studies in Chile & Brazil - none of these are new. Summary on variants of concern: for this vaccine, we've seen it up against P1 in those countries recently...17/n
...They formulated the evidence gaps a little differently - but really the data presented here doesn't seem all that different to Sinopharm's Beijing vax
Same level of confidence on the evidence for people aged 18 to 59 as for Beijing vax ...18/n
...On to the Sinovac presentation marked confidential. And that logo, hey?… ...19/n
...There's brief summaries of conclusions of preclinical data on reproductive safety that I don't think has been published (but my memory could be failing me on this)...20/n
...This is definitely new: phase 1/2 trial data on neutralizing antibodies, showing the results for the 3-17 yr age group: up to now, we've just seen the conclusion that their immune response was higher...21/n
...This is also new: a bit more detail from the trial in Turkey (though it might all have been in the WHO's assessment). ...22/n
... I think this is new - there have been a couple of publications on variants of concern, but I don't think this is in there ...23/n
...Ah, they say that of the 260m doses that have been shipped out, 160m have been administered.
...Very thin assessments from WHO, considering these vaxes haven't been through a major agency like EMA or FDA. But these vaccines work - & CoronaVac has been shown to still offer protection against P1 (another vax that maybe didn't bank on the right interval between doses) 25/25

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Hilda Bastian, PhD

Hilda Bastian, PhD Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @hildabast

5 May
Sinopharm's presentation on their Beijing vaccine to WHO's expert committee is now online:… 1/n HT @AlejandrodeBar1
...Includes this overview of preclinical toxicity studies. (Note, they've also published this study on some preclinical work…) ...2/n Image
...The phase 3, #4Humanity trial in the Middle East - here are the blood collections taken across all the countries. (No answer here to the question of whether there were regular tests for Covid-19 in the UAE part of the trial)...3/n Image
Read 12 tweets
29 Apr
Anvisa (Brazil's drug regulator) just held a press conference on Sputnik V, including responding to the developers' allegations about their assessment & decision. You can see it here Live-tweeted (in Portuguese) by @jasonptodd ..1/n
...They confirmed the presence of replication-competent adenovirus in Ad5 (2nd shot) batches wasn't a finding of their own batch testing - it was reported to them by Gameleya (developers of Sputnik V), who had apparently set a high level of acceptable replication-competence...2/n
...for the Ad5 shot (but not for the 1st, Ad26, dose). They pointed to the US FDA standard for this, here:… That's what they expected Gamaleya to certify. However, apparently Gamaleya set the level at 300, not 3 ...3/n
Read 10 tweets
26 Apr
Anvisa (Brazil's drug regulator) has just announced it has denied the request to import Sputnik V vaccine because of absence of data & issues with the development of the vaccine, including vax quality.… Meeting still streaming ..1/n
...Unanswered questions about the vaccine include basic biological data about its actions in the body, data on adverse events (including questions about thromboembolic events) ...2/n
...I think with all the focus on Lancet paper for phase 3, people forget how little study there had been of this vax: eg only 38 people in phase 1/2 trial version with lots of problems. (…) Assessing a vaccine isn't only about the phase 3 trial results...3/n
Read 13 tweets
17 Apr
Woke up to see this BBC graphic & claim doing the rounds. It's a great example of how data can come with a variety of biases & why perspectives on Covid vaccines is dramatically skewed in entire countries because of national/media bias. Here's why...1/n
..First the claim about AZ being the cheapest: it's on the cheaper end, but it's not the cheapest.

There are 2 aspects to this: the costs of a dose & the costs of vaccinating. Eg vaccinating with a single dose is far cheaper; needing super-freezers is far more expensive...2/n
...Out of vaxes on the BBC list, cheapest per person are Covaxin & CanSino (single dose).

J&J not far off AZ in real costs: manufactured in richer countries so doses more expensive, but it's one of several non-profit vaccines & it's a single dose ...3/n…
Read 15 tweets
16 Apr
Sinovac's CoronaVac in Chile: for Feb-Mar, during major outbreak. Data from National Health Fund, comparisons adjusted for age, gender, region, income, nationality. Fully vaccinated after 14 days was effective; 1 dose wasn't ...1/n… (TY for all the alerts!)
...Data doesn't report dosing interval. Covers about 10.5 million aged 16+. 34% of the group was fully vaccinated, but only the CoronaVac data reported here. Comparisons are for people with positive PCR tests: no info on how good that coverage is...2/n
...5.1m had 2 doses, 7.6m, 1; 90% are CoronaVac, reported here. Partially vaxed = 14 days after 1 dose; fully = 14 days after 2.

Symptomatic Covid-19:
- Partial: 16.1% (CI 14-18)
- Full: 66.96% (CI 65-69)

- Partial: 36.7% (CI 32-39)
- Full: 84.8% (CI 83-87)

Read 5 tweets
15 Apr
Sinovac's CoronaVac, in healthcare workers in Uni of São Paulo hospital vs the city: considerable uncertainty, but suggests ca 50% effective despite high level of variants of concern 2 wks after dose 2, rising to around 70% some weeks later...1/n… Preprint
.For the healthcare workers, "cases" = Covid-19, symptomatic & confirmed. Around 22,000 healthcare workers were vaccinated. If they had symptoms, they left work & got tested... 2/n
...The data are compared with the officially published rates of Covid-19 in the city (presumably not necessarily all symptomatic). Early testing was inadequate as the rate of confirmed cases didn't track with deaths. Later on though the estimates for the city more reliable...3/n
Read 6 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!