COVID Illinois

Feel sick after your COVID shot? Cook County Health official explains why

Vaccine side effects are a positive signal from your body’s immune response, according to Dr. Sharon Welbel, the chief of Epidemiology and Infection Control for Cook County Health

If you’ve gotten vaccinated before, you might remember experiencing side effects that felt very similar to the symptoms of the illness you were trying to avoid, but don't fret, because that's a good thing.

Dr. Sharon Welbel, Chief of Epidemiology and Infection Control for Cook County Health, says some people experience side effects after vaccination as an immune response to the injection of foreign bodies. 

“For those people who do get sick, it indicates that our immune system has been stimulated by this vaccine, which is a foreign protein or antigen,” Dr. Welbel said. “And so our body sees something that's different and it gets stimulated, which makes our cells release certain materials that create fevers, headaches and muscle aches.”

In other words, a strong immune response to the vaccine is correlated with high antibody production. This should mean that a patient should be well-prepared to face exposure to the virus. 

Those with weaker responses to the vaccine shouldn’t be worried either. Anyone who gets vaccinated will have increased antibody levels to fight the virus, experts say.

Welbel said taking care of yourself while experiencing post-vaccination side effects depends on your different needs. 

“People should do what makes them feel good,” Dr. Welbel said. “Whether it's resting, putting an ice pack on one's head for headaches. One can also take acetaminophen or a non-steroidal anti-inflammatory.” 

The length of time a vaccinated person might experience side effects varies widely, but that duration is nothing to worry about, Welbel added. 

The FDA and CDC recommend the COVID vaccine for all individuals six months and older. Cook County Health offers free vaccines to all of their patients who last received the shot more than two months ago. You can visit your doctor’s office or find the phone number of your health provider here.

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