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COVID Q2- Can these vaccines give me COVID? NO. Truly not possible. The vaccines do not contain any particles of the actual COVID virus (SARS-CoV-2). But I get why some folks are worried about this! Some past vaccines for other diseases could actually give you the disease! 1/
Some (mostly older) vaccines were made with live virus that was weakened in some way so it couldn’t make someone truly sick. The weakened virus could produce a strong, durable immune response, conferring immunity. 2/
In fact, the earliest form of vaccine- “variolation”- used smallpox virus (from patient pus or scabs) that had been weakened, for example through sun exposure, smoking, or aging. This typically produced a mild infection and provided durable immunity to smallpox. 3/
But sometimes variolation produced severe infections that could maim or kill. As a result, the concept of vaccination was controversial from the earliest days. Soon, newer techniques replaced variolation, which improved safety. But history did repeat. 4/
The Sabin polio vaccine for example is a mix of live attenuated polio virus strains. In about 1 in every ~3 million cases, the three strains of virus “recombine” (mix their genetic material) in a way that makes a stronger virus, thereby causing polio. 5/
The realization that this recombination could occur led to the eventual adoption of a fully inactivated polio vaccine instead. Since then, much has been learned that has informed vaccine design principles. Still, how can I be sure this won’t happen with the COVID vaccines? 6/
Bc none of the approved covid vaccines have ANY actual virus! Instead, they use different tricks to deliver a tiny PIECE of the virus– just a single protein. This protein is not a living, infectious thing and cannot make more copies of itself, so it cannot give a person COVID. 7/
The main difference between most of the covid vaccines is HOW they deliver that little protein. The Pfizer and Moderna vaccines don’t even contain the protein itself! Just some instructions that tell the cells of your own body how to make that protein for a little while. 8/
As a result, there is truly no physical way the vaccines can give anyone COVID19! BUT… there is a way the vaccines it could make you THINK they caused COVID… 9/
Vaccines don’t work immediately. For the Pfizer vaccine, it takes 12 days for immunity to kick in. During those 12 days, if you become infected from another source, the vaccine will NOT stop you from getting COVID. 10/
Now, the chances that any one person gets COVID19 in the exact 12 day period after being vaccinated is very low. But if we are vaccinating hundreds of millions of people… then this is definitely going to happen on occasion. 11/
In fact, it already has! In the Phase 3 trial of the Pfizer vaccine, the rate of new COVID cases in the vaccine arm was identical to the placebo arm for the first 12 days. (Polack etal, 202 DOI: 10.1056/NEJMoa2034577) 12/
So I guarantee you will soon see impassioned posts on social media saying THE VACCINE GAVE ME COVID!!! The evidence will seem very convincing. "I felt feverish within hours and 2 days later I had trouble breathing"! But it's a combo of normal side effects + bad timing. 13/
We need to build awareness of the concept of delayed protection NOW in order to combat this misperception! More to come soon other common vaccine misperceptions, as well as how each of the approved vaccines actually work. Please RT! 14/14
