‘Covid Turns Into A Cold’: Understand What CoronaVac’s 50.4% Effectiveness Means

247 – The government of São Paulo released on Tuesday (12) the results of the global effectiveness tests of CoronaVac, a vaccine against Covid-19 developed by the Chinese laboratory SinoVac and brought to Brazil by a partnership with the Butantan Institute.

The global effectiveness is 50.38% in the tests in Brazil, an index considered adequate by the WHO (World Health Organization) to contain infections, the organization announced. But many people were confused, they thought the rate might be low, and they did not understand what 100% effectiveness means for severe cases, 78% for mild cases, and 50.4% for asymptomatic patients. After all, what is the difference? And how was the study done?

The epidemiology specialist Márcio Sommer Bittencourt, cardiologist at the Hospital Israelita Albert Einstein and researcher at the Epidemiological Clinic of the University Hospital of USP, bring a very clear explanation on Twitter. In short, he says that, with the vaccine, “the Covid catches a cold in most cases.”

“For a vaccine developed in a year, that can be produced on a large scale locally, easily distributed without problems, I think it is a spectacle,” said Bittencourt, who has drawn attention on social media for his analyzes of the pandemic. See the sequence of his posts on Twitter:

** URGENT NOTE **

Let’s fix what is spoiling the brilliant communication of the SP government.

CORONAVAC’S RESULTS ARE VERY GOOD!

– They have impacts on the strategy of use, they have limitations, but they are really good. Much better than the official communication brand

– Simply put, a vaccine is made to teach your body to defend itself from an enemy it has never seen. When the enemy arrives you will be (more) prepared than if you had not been vaccinated. There is a vaccine that teaches you everything, there is a vaccine that teaches you less.

– The first question is whether the body learns (produces antibodies) and what dose it needs for that.

Coronavac passed the test, with the best 3 mcg scheme 28 days apart.

Over 90% produced enough antibodies and almost all produced some (green vs. black marbles)

– The next question is whether it is safe. Coronavac is safe (study of butantane on slides). Antibody and safety details posted here.

– The next question is whether what the body has learned helps to defend itself from the enemy (phase 3 study). We took a large population (9242), half trained with the vaccine, half untrained (won a placebo). We let everyone go and see that they catch COVID19 and if those who trained catch less.

– We wait until one person has COVID19 and then we see who entered each group. The confusion begins, because someone takes COVID19 and does not feel anything, since we do not do tests in all, you can pass a case expired.

– In addition, the vaccine can train you more or less, you cannot prevent the virus from entering, but when it enters you are more prepared for battle, so your image of COVID19 is clearer. THAT IS VERY IMPORTANT, I will explain later. But what happened in Coronavac?

– In the placebo group, 3.6% took COVID19 (167/4599). In the vaccine group, 1.8% took COVID19 (85/4653). YOU HAVE 50.38% LESS CHANCE OF TAKING COVID19. You have half the chance of getting COVID19, that’s enough. But there is much better than that.

– As already said, many times COVI19 is just a cold, sometimes it is a cold and sometimes it kills. For this reason, we have created a severity classification in 10 levels that can be grouped into mild, moderate and severe. Source.

** NOW THE SENSATIONAL PART **

In the group that did not train (placebo), 0.7% (31/4653) required medical assistance for COVID19.

The group that trained with the vaccine was better prepared, only 0.15% (7/4599) needed medical assistance.

*** 0.15% vs. 0.7% *** From 78% less.

– And 100% against serious cases? The problem is statistical. We haven’t had enough yet to be sure. With few cases it can happen by chance, we say that it was not statistically significant. But what is the score? 7 X 0 (7 cases in placebo, 0 in vaccine)

– In summary, you have a 50% less chance of contracting COVID19 and a reduction of almost 80% in the cases that need a doctor, perhaps more than that in the most serious ones. Of those vaccinated, yes, the majority only had a cold that did not need a doctor. “COVID19 turns into a cold” in most cases

– In my 7 x 0 accounts with N it should be significant (making Fisher exact or assuming different times in the logarithmic range), I don’t know if they did post hoc adjustment or something else, in my account it was to give significant even to hospitalized patients .

– What I think? For a vaccine developed in a year, which can be produced on a large scale locally, easily distributed without problems, I find it a spectacle. Yes, there is something that was better in the research, but if you can’t distribute it, it doesn’t help.

– Being simplistic, if you vaccinate 1 million with a vaccine that reduces by 95% the maximum that you protected was 950 thousand people. If you vaccinate 200 million with a vaccine that reduces by 50%, you protect up to 100 million people. And the ones that get the most don’t even need a doctor.

– THE BEST VACCINE IS THE FASTEST AVAILABLE VACCINE. THE BEST VACCINE IS THE VACCINE THAT CAN VACCINE MORE PEOPLE. THE BEST THING ABOUT PANDEMIC IS TO HAVE REASONABLY EFFECTIVE AND SAFE VACCINES. And Coronavac is.

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