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 minsal.cl/wp-content/upl… (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.
Death from Covid-19:
- Partial: 40.2% (CI 33-47)
- Full: 80.4% (CI 73-86)
...4/n
...This vaccine is clearly making a major difference. Ministry of Health stresses that given effectiveness rate, though, Chile needs *all* eligible people to get fully vaxed. It's a vax with very low adverse events; it's a country with a strong vax network:🤞 🇨🇱 5/5
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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
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 medrxiv.org/content/10.110… 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
Some things to keep in mind when you see people dumping on "low efficacy" of "Chinese Covid vaccines", particularly based on that single medium-sized trial in Brazil of doses only 2 weeks apart...1/n
...There's the obvious ones: the results of this trial aren't the whole picture - not of the trials that are underway, nor of the way the vaccine is being used (doses more than 2 wks apart)...2/n
...The efficacy against fearsome outcomes was good in this trial - a vaccine that could prevent over 80% of the worst outcomes & reduce the severity in a major way is incredibly needed in a world bereft of enough options...3/n
Preprint on Brazilian trial by @butantanoficial of Sinovac's CoronaVac, 2 weeks apart. Data for 9,823 people who had 2 doses, 12,396 after 1 dose.The P1 ("Brazilian") variant of concern was not circulating in the areas the trial ran...1/n papers.ssrn.com/sol3/papers.cf… HT @josegallucci
...14-day interval seems too close, & immunity may increase over time: they recommend 28 days. Their primary efficacy, unlike other vax trials, includes people who had previous SARS-CoV-2 infection. But this table provides the comparable number: 50.5% (CI 34-63)..2/n
...Their primary efficacy analysis was based on 85 vs 168 people with symptomatic Covid-19. Unfortunately, they don't provide detailed data on symptoms so can't try to see whether this was milder disease than other trials... 3/n
The FDA has said it investigated the blood clot/low platelets cases after J&J vaccine & found no causal association with the vaccine: they're continuing to investigate. abc.net.au/news/2021-04-1… Given the way the EMA's statement of formal investigation is being reported,...1/4
..I went back to EMA press conference to check my tweets. Peter Arlett from EMA said: (at ~40 mins) Since the trial "There have been 3 cases with the J&J vaccine of blood clots associated with low platelets which have some similarities to these cases...2/4
...that we’ve been describing today for AstraZeneca vaccine. However the numbers are extremely small compared to the 4.5 million patients vaccinees that have received the J&J vaccine worldwide.” (~51 mins) "…if you look at those reports of blood clots with thrombocytopenia...3/4
Digging into the detailed EMA report on the AZ vaccine investigation. (The committee vote for their decision was 31 out of 32.) They discuss several hypotheses that have been proposed for the phenomenon, if it's triggered by the vaccine. ema.europa.eu/en/documents/p…
...1/n
..1st was one from researchers in Germany/Austria, based on studying several of the people: that it's similar to heparin-induced thrombocytopenia ("HITT-like"), & related to Platelet Factor 4. assets.researchsquare.com/files/rs-36235… (preprint)...2/n
...EMA conclusion: there are similarities, so still needs to be investigated. But there are differences too: eg HITT doesn't cause a condition that occurred here (DIC). So they called this unproven...3/n