If You Have 1 of These 8 Side Effects, the CDC Says "Seek Medical Care Urgently"

Shortness of breath and a severe headache are just some of the side effects of concern.

Since December, when the U.S. Food and Drug Administration (FDA) first approved a COVID vaccine from Pfizer for emergency use, experts at the Centers for Disease Control and Prevention (CDC) have been explaining which vaccine side effects people should expect. But now, in the wake of the Johnson & Johnson vaccine being put on pause due to concerns of very rare, severe blood clots, the CDC has listed a new set of side effects to be aware of, even though the risk of experiencing this adverse reaction is very low. "We do not know enough yet to say if the vaccine is related to or caused this health issue," the CDC says, but they're playing it safe by pausing use of the vaccine. As the CDC and the FDA conduct a full investigation into the unusual reaction, the CDC is advising that if you notice specific changes to your body within three weeks of getting the Johnson & Johnson vaccine, you "seek medical care urgently."

Keep reading to learn about the eight vaccine side effects the CDC wants you to pay attention to if you got the Johnson & Johnson vaccine recently. And for more recent vaccine side effect news, check out Pfizer Caused This Reaction in Half of Recipients, New Study Says.

Severe headache

Lonely sad woman deep in thoughts sitting daydreaming or waiting for someone in the living room with a serious expression, she is pensive and suffering from insomnia sitting on couch (Lonely sad woman deep in thoughts sitting daydreaming or waiting fo

As the CDC and FDA learn more about these rare blood clots—which were found up to two weeks after the shot and in women between the ages of 18 and 48—the agencies are urging people to recognize any serious side effects that might otherwise be overlooked. For example, one symptom that shouldn't be ignored is a severe headache or migraine, the CDC says. While headaches are an expected vaccine side effect, if they're severe, they can be a sign of a blood clot in the brain, WebMD points out.

And for more post-vaccine advice, beware that Doing This After Your Vaccine Can Make Side Effects Worse, Doctors Say.


man with backache and muscle pain

While muscle aches and pains tend to come with the COVID vaccine, a bad backache is another vaccine side effect that could be linked to blood clots, the CDC notes. According to Healthily, chest or upper back pain (a sharp or stabbing pain that may get worse when breathing in) could be a sign of a pulmonary embolism, which is a blood clot in your lungs.

New neurologic symptoms

woman trying to smell half an orange
DimaBerlin / Shutterstock

Despite COVID behind primarily a respiratory disease, the virus has caused specific neurological symptoms in many patients. And now, the CDC is warning that the Johnson & Johnson vaccine could also provoke new neurological side effects. Neurological symptoms could range from loss of smell or taste, to muscle weakness, to tingling or numbness in the body's extremities, according to Harvard Health Publishing.

And for more up-to-date vaccine news delivered straight to your inbox, sign up for our daily newsletter.

Severe abdominal pain

Woman curled up on cough with abdominal pain

You could have severe abdominal pain for a wide range of reasons, like a stomach virus, constipation, or food poisoning. But the CDC is warning anyone with this symptom after the Johnson & Johnson vaccine to seek medical attention as it could be a sign of a blood clot.

And for more facts about this rare reaction, learn about The One Thing People Who Get Blood Clots After the Vaccine Have in Common.

Shortness of breath

man holding his chest in pain indoors.

Difficulty breathing or shortness of breath must also not be ignored, especially if the vaccine side effect arises within three weeks after your Johnson & Johnson jab, the CDC says. Shortness of breath is not only a symptom of COVID itself, but it's also one of the vaccine side effects that could be an early sign of a blood clot, according to UChicago Medicine.

Leg swelling

woman holding her leg in pain
BEAUTY STUDIO / Shutterstock

The CDC is warning that leg pain or swelling is cause for concern after getting the Johnson & Johnson shot. Deep vein thrombosis, a blood clot that occurs in the leg, likely is accompanied with leg pain or swelling, but it's also possible to be asymptomatic, according to WebMD. Additionally, swelling could be seen where the blood clot has formed.

And for more concerning vaccine reactions, check out If 1 of These 3 Body Parts Starts Swelling Up After Your Vaccine, Call a Doctor.

Tiny red spots on your skin

young woman studying skin on her arm
Anatoliy Karlyuk / Shutterstock

Tiny red spots on your skin, also known as petechiae, are another reason to contact your health provider after getting vaccinated with the Johnson & Johnson shot, the CDC says. The small round spots show up on the skin as a result of bleeding and can appear red, purple, or brown, Mayo Clinic explains.

New or easy bruising

Woman who bruises easily with arm bruise

Lastly, if you've noticed an unusual or unexplainable bruise, the CDC says you shouldn't hesitate to call your doctor. Bruise-like discoloration, which is likely to be red, could be spotted on the affected body part due to a blood clot, according to Prevention.

And if you're curious as to why some people react differently post-vaccination, This Is Why Half of People Have Stronger Vaccine Side Effects, CDC Says.

Filed Under