Updated:10/31/22

Information regarding COVID-19 and vaccines are continually evolving, new details may be available since this content was developed. Please visit the CDC's website for the most up to date information.

Uncertainty about the COVID-19 vaccines has been common since they were first introduced. 

Cristina Cicogna, M.D. an infectious disease specialist at Hackensack University Medical Center, answers the latest viral topic in question, can the booster shot make you test positive for COVID? 

No, the COVID-19 booster shots will not make you test positive for COVID. 

“The COVID-19 vaccines, which includes the boosters, can not make you sick with COVID,” says Dr. Cicogna. “In order to get COVID, you need to come in contact with the live virus. None of the brands of the vaccine have the live virus that causes COVID.”

The COVID-19 vaccines do not include the live COVID-19 virus as an ingredient. Learn more about the vaccine ingredients. 

“The mRNA vaccines, Moderna and Pfizer, show your body how to make a specific viral protein found on the surface of the COVID virus called the spike protein. Your body will then recognize that that particular protein is not supposed to be there, triggering an immune response. This is very similar to a natural infection,” explains Dr. Cicogna. “The Johnson & Johnson vaccine uses a modified viral vector that carries the specific spike protein and presents it to the immune system. The modified virus cannot replicate and cause infection.”

Possible side effects of the COVID booster may make you feel sick.

If you feel sick after the booster shot, it is normal and those symptoms should relieve themselves in a few days. 

Common side effects of the booster are similar to the vaccine:

• Fatigue 
• Fever
• Chills
• Headache 
• Pain at the injection site 

Side effects from the vaccine can be a sign that the vaccine is working.

“Some patients worry that side effects after the booster or vaccine is actually illness from the COVID-19 virus, however symptoms from the vaccine should clear up in a day or so, if it was symptoms from the virus you wouldn’t bounce back as quickly,” says Dr. Cicogna.

“The thing to understand is, side effects to the virus or the vaccine are your body’s way of responding to it. In both cases, your body has acknowledged an intruder, either the live virus from infection or the spike protein from the vaccine, and is fighting back,” says Dr. Cicogna. 

“You will not get a false-positive test result because you received the booster shot. If you get tested for the virus and results are positive, then you have COVID-19 because you were exposed to the virus at some point” adds Dr. Cicogna.

The COVID-19 vaccines and boosters are safe and effective. 

The COVID-19 vaccines and boosters help prevent severe illness, hospitalization and death from COVID.

“While getting boosted is a critical tool to help prevent infection and serious illness, it does not make you invincible or completely immune to the virus. It’s still important to take proper precautions like mask wearing and hand washing,” advises Dr. Cicogna. 

Next Steps & Resources: 

• Meet our source: Cristina Cicogna, M.D.
• To make an appointment with a doctor near you, call 800-822-8905 or visit our website.
• CDC - Possible Side Effects
• CDC - How Vaccines Work 

The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.