Wednesday, October 6, 2021

How to Spot Propaganda Statistics -- COVID Edition

NOTE: This post is also available at as it explains how antivaxxers misuse statistics for propaganda purposes. 

Recently, experts warned that pregnant women are being deliberately targeted with COVID vaccine misinformation. Some claimed that COVID vaccines can affect fertility, while another claimed vaccines cause stillbirths. One even cited a study recently published in the New England Journal of Medicine titled "Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons" to claim the vaccine is unsafe for pregnant persons. But the study actually shows the opposite of it. So how do you spot such misinformation? By always looking for the context. If a statistic is presented WITHOUT context, you cannot trust it. 

Feel free to read the abstract of the summary above, but I'll include a relevant highlight from the Pubmed link above:

... 13.9% resulted in a pregnancy loss...

While the 13.9% pregnancy loss sounds alarming in itself, you cannot say whether the vaccine is bad or good without knowing the context of such a number. What you should be asking here is "so what is the normal pregnancy loss, i.e. pregnancy loss rate without COVID vaccine?" Or to use a statistics term, what is the base rate or background rate, so we can have a proper comparison? 

Turns out, the answer is not that simple, because, in the US, there are actually TWO terms for pregnancy loss: miscarriage (for fetus before 20 weeks), and stillbirth (fetus at 20 weeks or older), and separate statistics are kept. 

For miscarriage, the answer is between 10-20%, according to the Mayo Clinic, but that's reported cases. The actual rate is higher due to unrecognized pregnancies. As high as 33% according to some estimates. 

"About 10 to 20 percent of known pregnancies end in miscarriage."

Once past 20 weeks, the fetal death rate falls off significantly, down to 1 in 100 to 160 pregnancies, according to CDC. 

As the study used the term "pregnancy loss", which encompasses BOTH stillbirth and miscarriage, and 10-20% vastly overshadows the 1/160 rate, 10-20% is the right number to use as a base rate. 

Thus, the 13.9% number is actually somewhat BELOW the known rate, if we take the median, which is about 15%. And the difference is so small it is probably within statistical error margins. 

Thus, there is no known risk to pregnancy by the mRNA COVID vaccine, since the rate of vaccinated pregnancy loss is almost indistinguishable from the unvaccinated pregnancy loss rate. 

But you wouldn't know that if you ONLY heard the 13.9% figure. It sounds scary. And that's what the people who presented those statistics WANT you to feel: FEAR through propaganda, manipulating your thoughts through misinformation and disinformation. 


A similar thing happened with the earlier CDC vaccine reaction tracking that there seems to be a few cases of myocarditis among people who got vaccinated, that they temporarily halted the use of one COVID vaccine for a few weeks, out of an abundance of caution, while the study was re-checked and more data was gathered. Myocarditis is the inflammation of the heart muscles. CDC later put the odds of such at about 4.8 per million.  

As expected, anti-vaxxers started touting this as "COVID vaccines are unsafe". They even got a study that supposedly proves that myocarditis increased after COVID vaccines were added. But again, should you check the studies, what is the base rate, and what are the alternatives? 

Turns out, Reuters had published a full fact-check article on this. The study that was touted by the anti-vaxxers made a huge error. The original study was done by The University of Ottawa Heart Institute. It stated that odds are 1 in 1000 of developing a heart problem after COVID vaccination. It was put on preview on September 16th, before it was peer-reviewed. Turns out, they used the wrong figure in "doses administered". They used a figure of 32379 over the study period of 2 months. It should be about 25X larger at 845930. Instead of 1/1000, the figure is more like 3.78/100000. The paper was withdrawn from preview on September 24th, and the Heart Institute itself had issued an apology. 

So the evidence is not there. There are also TWO MORE factors to consider... 

a) What is the base rate of myocarditis? i.e. what is the possibility of catching it without the vaccine?  

According to Wikipedia, it's about 22 per 100K people per year. And 20% will die in the first year. 

However, this is the overall rate. The rate is much lower for younger people, about 5 per 100K people. 

b) What is the possibility of COVID-induced myocarditis, if you caught COVID instead of vaccinating, but recovered? 

Existing myocarditis data from 2019 (pre-COVID) was compared to 2020 data (during COVID) and the signs are having had COVID suggests you are "15.7 times more likely" to have a myocarditis event. 


Another study involving records of 2 million patients from 40 different hospitals specifically looked for incidents in individuals who had received the COVID vaccine. Guess how many cases they found? Twenty, out of Two Million. 1 per 100000. That's lower than the background rate / base rate. It is of no factor. 

But now you have mothers screaming on Twitter that "my teenager caught myocarditis from the vaccine". 

Except, again, there's no proof from temporal association, i.e. correlation is not causation. It's an anecdote, not data. 

CDC has the data, and it's sharing in the full report from June 2021:

The results now show more children are getting infected and dying because the vaccine isn't available for them until VERY recently, and the unvaccinated are clogging up the hospital beds so people who need normal hospitalization can't get in, and either transfer to a different state... or die. 


When the antivaxxers tell you "do your own research", what they actually mean is "please read our propaganda (where we scare you into supporting us and distrust the doctors)" 

What you should do instead, is REALLY do your research... by spotting other people's propaganda for what it is... intention to manipulate you. 

And yes, I am trying to manipulate you... into REALLY thinking for yourself, not just looking up stuff to confirm your own beliefs.