U.S. health officials recommended pausing administration of the Johnson & Johnson COVID-19 vaccine on Tuesday amid reports of rare but serious blood clots.
"Hitting pause doesn't mean there is a danger, it just means let's step back and make sure everything is OK," explained Dr. Doug Green, the chair of Immunology at St. Jude Children's Research Hospital.
The Centers for Disease Control and Prevention (CDC) and U.S. Food and Drug Administration (FDA) announced officials are investigating six cases in women between 18 and 48-years-old.
"No association, no actual risk has been found as of yet," Green explained. "These blood clots are occurring at the frequency that would be expected in the whole population."
Considering the 6.8 million J&J doses administered, these cases represent a very small percentage.
"Now look at the risk of getting really sick from COVID-19. I don't have to tell you that those risks are pretty scary, so balance risk with possible adverse effect," Green said.
The CDC estimates up to 600,000 blood clots are reported in the U.S. each year or around 1,600 a day.
The type of clot in the six cases the CDC is investigating is very rare.
"It's the vein that's in the brain that drains the blood from the brain. That's very different than the blood clots, we hear in the legs that can travel to the lung and called pulmonary embolism that's deep venous thrombosis (DVT), which is more common," explained Dr. Sahar Amery, a cardiovascular specialist at the Amery Vein and Wellness Center in Raleigh.
Amery also reminding people that the clots are not currently linked to the J&J vaccine.
"We don't know if these six cases where this event has happened, do these individuals have some underlying common underlying issue that reacted to the vaccine or not," said Amery.
Outside the vaccine, other factors like birth control and smoking increases individuals' odds of blood clots.
It's estimated one out of every 1,000 women on birth control and one of every 1,000 smokers develop a blood clot a year.
Twenty percent of blood clots are linked to cancer and cancer treatments, according to the National Blood Clot Alliance.
Hospitalizations, immobility for extended periods of time and pregnancy can also increase a person's chances of developing a blood clot.
AstraZeneca's COVID-19 vaccine that's being administered in Europe has also had concerns raised over blood clots that developed after the shot. The odds of those reactions about four for every 1 million.
Beyond blood clots, many vaccines carry small risks for potentially adverse reactions.
The CDC estimates one out of every one million flu shots administered annually lead to a rare disorder that causes nerve damage, called Guillain-Barre Syndrome.
A study into the MMR vaccine for measles, mumps and rubella found a fever induced seizure for one of every 2,000-3,000 doses.
"There is always some risk, there is always some potential for adverse effects with anything that's being put into your body," said Green.
Green explained that vaccines are very safe and adverse risk is extreme low.
"The risks associated with getting that vaccine are trivial compared to the risks of daily life and the risk of what could happen if you get one of these infections and have not been vaccinated are so much greater. Don't put yourself in that position that you are sorry that you didn't do it," Green said.
Amery said common symptoms for blood clots include one leg being swollen, skin discoloration, pain and headaches. She recommends if you do see a doctor for these symptoms you mention if you've recently received a vaccine.
The CDC reported symptoms occurred in the six individuals 6-13 days after vaccination.