I've seen infographics such as this, that compares the efficacy of Sinovac and Pfizer.

'Keberkesanan Vaksin COVID-19 SINOVAC dan PFIZER/ translated: Effectiveness of SINOVAC and PFIZER COVID-19 Vaccines'

In the infographic it says that, according to New England Journal of Medicine :

  1. Sinovac prevents 65.9% of the disease, Pfizer 64% (Yes, the efficacy of Sinovac is higher in this regard)
  2. Sinovac reduces hospitalization by 87.5%, Pfizer 93%
  3. Sinovac reduces ICU cases by 90.3%, Pfizer by 93%
  4. Sinovac prevents 86.3% death, as for Pfizer, no data on this.

Malaysia Health Department is promoting this to reinforce people's confidence in Sinovac, after the country decided to phase out China’s Sinovac Vaccine.

  • Where do the numbers come from?
  • Did New England Journal of Medicine (7/7/2021) really claim this?
  • Are the numbers truly compatible?

Note: My opinion about the efficacy of both vaccines is edited out of the question to avoid unnecessary trolls and flame wars.

  • 1
    1. My brother lives in Malaysia so I actually did some research into the Chinese vaccines they had there (as I already knew about the others) and from what I could find on Sinovac was that the data around it was, to say the least, "spotty". For example, in the Turkey trial, which they claimed 91.25% efficiency, I found that the finding was based on preliminary results from a small clinical trial and none of the data was published in a journal or posted online.
    – Brett
    Jul 27, 2021 at 8:15
  • 2. Something else weird was that how they calculated this data: "A total of 7,371 volunteers were involved in the Turkish trial, but the efficacy data presented by Serhat Unal, an infectious diseases expert, was based only on 1,322 participants, 752 of whom got a real vaccine and 570 of whom received the placebo." "Dr. Unal said that 26 of the volunteers who received the placebo developed Covid-19, while only three of the vaccinated volunteers got sick. He and his colleagues did not share their data in written form."
    – Brett
    Jul 27, 2021 at 8:17
  • 3. nytimes.com/2020/12/25/health/…
    – Brett
    Jul 27, 2021 at 8:17
  • 1
    I believe so - that's why I didn't post an answer, I just found it curious why the data I was finding was a bit spotty. That Chile study seems more recent. They did a Brazil study that only showed 50.65% efficiency, but it was stated that "it showed stronger protection against severe forms of the disease. No one in the Brazil trial who received Sinovac had to be hospitalized" nytimes.com/interactive/2020/science/…
    – Brett
    Jul 27, 2021 at 8:24
  • 1
    The title has been changed to something that is not in the infographic. Nowhere does the infographic claim that (according to the NEJM) Sinovac is more effective than Pfizer. Two percentages are higher for Pfizer, one is higher for Sinovac. Also, nowhere is it claimed on the infographic that these differences are statistically interesting. The only two claims this infographic makes is that these numbers are correct and that they were published in the NEJM.
    – Schmuddi
    Jul 27, 2021 at 17:41

1 Answer 1


There is an article in the NEJM from July 7 that is about a SARS-CoV2 vaccine:

Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Chile

This is about Sinovac, it is named CoronaVac in this paper but those are two names for the same vaccine. The numbers for Sinovac from the graphic match exactly the numbers in table 2 in this paper for fully immunized persons. This study was performed in Chile from February to the end of April, so the predominant variant was likely not the Delta variant we are facing now.

So one half of this graphic is true, there is a study published in the NEJM that found Sinovac to be as efficient as stated in the graphic.

What this paper does not contain is any data on the Biontech/Pfizer vaccine. That part of the graphic is a lie. The study in NEJM did not determine that Sinovac is more effective than the Pfizer/Biontech vaccine, it solely looked at Sinovac.

There are plenty of studies available for the Biontech vaccine (also including data on deaths), I'm not adding any here in the answer because it is very difficult to compare efficacy values from different studies. They have different study designs, different populations and different prevalent virus strains.

  • 2
    The other numbers seem to come from around this news gov.il/en/departments/news/06072021-04 // So, according to your last para, ('don't directly compare numbers from different studies in this way') the entire info graphic 'is a lie'? // Any case: please add the info like: date range i& 'in Chile' for NEJM as well. Jul 25, 2021 at 10:54
  • 23
    @LangLаngС That Sinovac works very well against hospitzalization and death is not a lie. The comparison with the Biontech vaccine is pretty much one, it's at best a cherry-picked data point that is not comparable, and the implication that the data on death is not know for the Biontech vaccine is extremely misleading.
    – Mad Scientist
    Jul 25, 2021 at 11:26
  • 8
    Given this Q's title and the impression the poster gives: "The NEJM" did just not make this comparison for the whole graphic at all; and the Pfizer data seems to be based on a mere shallow copying/extract of some press release (from a source that very recently downgraded these numbers again.). So, the word "is" alone is misleading in any context, as it's a snapshot of a moving target dependent on many factors ('was found to be in this study…'). ('More recent IRL-data, Sinovac looks even better'/but: “We cannot accept [deaths among vaccinated health care workers] as high as we see now,”) Jul 25, 2021 at 13:33
  • 2
    @user1271772 A strict answer to the question in the title is "no" (keep in mind the title changed since I posted my answer). But in general I don't like to boil down answers to a simple yes/no, I prefer to just note the facts and let people draw their own conclusions.
    – Mad Scientist
    Jul 26, 2021 at 21:39
  • 3
    @user1271772 The infographic cites NEJM. The implication is that the source for the numbers in the figure are from NEJM. Jul 26, 2021 at 21:49

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