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Clalit’s preliminary analysis demystified:
I want to elucidate the preliminary data we made public 10 days ago.
By now we have much better data and inferences, but until the publication is out, the previous interim analysis continues to draw much attention.
Thus - a thread:
>
I want to elucidate the preliminary data we made public 10 days ago.
By now we have much better data and inferences, but until the publication is out, the previous interim analysis continues to draw much attention.
Thus - a thread:
>
Inclusion in the analysis:
200,000 vaccinees age 60+ with at least 11-days of follow-up post vaccine 1st dose. Few had >18 days follow-up.
were compared with a matched group (age and other covariates) of 200,000 unvaccinated individuals.
Clalit members= >50% of Israelis.
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200,000 vaccinees age 60+ with at least 11-days of follow-up post vaccine 1st dose. Few had >18 days follow-up.
were compared with a matched group (age and other covariates) of 200,000 unvaccinated individuals.
Clalit members= >50% of Israelis.
>
Outcome measured:
Proportion of PCR tests that were positive.
These tests are routinely performed in Israel for multiple indications, including symptomatic illness, contact with known case, quarantine shortening etc). ~100k tests per day.
Proportion of PCR tests that were positive.
These tests are routinely performed in Israel for multiple indications, including symptomatic illness, contact with known case, quarantine shortening etc). ~100k tests per day.
Analysis results:
Positivity rates remained relatively constant on days 1-12 following vaccination, and same for the unvaccinated.
Yet on day 14 post-vaccine, a statistically significant drop of 33% in PCR positivity was witnessed in the vaccinated but not unvaccinated.
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Positivity rates remained relatively constant on days 1-12 following vaccination, and same for the unvaccinated.
Yet on day 14 post-vaccine, a statistically significant drop of 33% in PCR positivity was witnessed in the vaccinated but not unvaccinated.
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The decline was maintained in the next days post vaccination, at which point numbers became too small for statistical inference.
Note 1:
These results were preliminary, and released as such for use of local decision makers
The visible decline and its timing were encouraging
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Note 1:
These results were preliminary, and released as such for use of local decision makers
The visible decline and its timing were encouraging
>
Note 2:
Those who know the Pfizer/Biontech clinical trials can recognize the differences between this real-world data and the clinical trial:
* age: 60+ vs 16+
* outcome: composite infection (sympt & astmpt) vs sympt only
* follow-up time: we could not account for full 21 days
Those who know the Pfizer/Biontech clinical trials can recognize the differences between this real-world data and the clinical trial:
* age: 60+ vs 16+
* outcome: composite infection (sympt & astmpt) vs sympt only
* follow-up time: we could not account for full 21 days
Any inference re: implications on the potential of the Pfizer/Biontech vaccine to eventually achieve the same impact in real-life as was witnessed in the trial - is on the interpreter’s responsibility.
Same for the debate of the risk/benefit trade-off of a 1-dose protocol.
Same for the debate of the risk/benefit trade-off of a 1-dose protocol.
We remain optimistic @ClalitResearch as >26% now vaccinated, 80% at age 60+
Updated analysis with full time horizon, multiple outcomes and careful methodology - to follow soon in peer-reviewed sci publication, open for all.
@BBCNews
@SkyNews
@ynetnews @Nadav_Eyal
@EricTopol
Updated analysis with full time horizon, multiple outcomes and careful methodology - to follow soon in peer-reviewed sci publication, open for all.
@BBCNews
@SkyNews
@ynetnews @Nadav_Eyal
@EricTopol
