# Johnson & Johnson vaccine pause: What to know if you got or scheduled the shot

The background: The Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) released a joint statement on April 13 recommending a temporary halt in the distribution of Johnson & Johnson’s
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COVID-19 vaccine while they examined six severe cases of rare blood clots that were reported in people who have received the shot. On Friday, an advisory committee to the CDC voted to recommend lifting the pause, and federal health officials are expected to follow suit and recommend that states resume getting the J&J vaccine into people’s arms soon.

Read more: CDC committee votes to lift pause on Johnson & Johnson COVID-19 vaccine

Health officials called for this short-term stoppage in the first place out of “an abundance of caution,” they said, emphasizing that these blood clots were “extremely rare,” and have only happened in one in a million vaccinated people. Specifically, just 15 cases of these rare blood clots have been reported among the 7.9 million Americans who have received the J&J single-dose vaccine. But the CDC wants to ensure that healthcare providers are prepared to treat blood clots if they occur. Health officials were concerned that the clots could be mistreated, the Wall Street Journal reported, as these cases suggest that common blood thinners like heparin could worsen the condition.

Read more: U.S. recommends pausing use of J&J’s COVID-19 vaccine after reports of rare blood clots

And: CDC committee votes to extend the ‘pause’ for J&J’s COVID-19 shot

So what happened? In these cases, all of them women, a type of blood clot called a cerebral venous sinus thrombosis (CVST) was seen in combination with low levels of blood platelets (aka thrombocytopenia). Three women died from the rare clots, a CDC scientist said Friday, and seven women remain hospitalized, with four in the intensive care unit.

Dr. Reynold Panettieri, a pulmonary physician and a professor of medicine at Rutgers University, explained to MarketWatch that a CVST manifests as a stroke. “Blood clots form in the draining veins of the brain, and that backs things up and causes bleeding into the brain,” he said. They’re rare, occurring in five in a million people each year, and can be caused by certain cancers or sickle cell disease.  

Most of the recorded cases of CVST and low blood platelet levels amongst the J&J vaccine recipients  involved women between the ages of 18 and 48, with symptoms presenting six to 13 days after vaccination. But health officials noted that the number of these cases is so small, that they cannot generalize yet on whether this is something women of a certain age, or other demographic groups, could be at a higher risk of developing. This is why the CDC’s Advisory Committee on Immunization Practices, which recommends use of vaccines after the Food and Drug Administration authorization, met to review the cases. 

Coronavirus Update: U.S. COVID vaccine program faces setback with J&J jab, as experts say there is no cause for alarm

The AstraZeneca
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COVID-19 vaccine, which has not been authorized in the U.S. yet, has been halted in some European countries over similar rare blood clot concerns. The Johnson & Johnson and AstraZeneca COVID vaccines are both adenovirus viral vector-based vaccines, which differs from the Pfizer and Moderna shots, which are mRNA vaccines. No thrombotic syndrome cases have been reported in people who have received either the Pfizer or Moderna jabs, although there were earlier concerns about allergic reactions occurring in people who received those shots.  

Read more: Rare blood clots tied to J&J’s COVID-19 shot are similar to issues with AstraZeneca’s vaccine, FDA official says

This news could understandably raise alarm in those people who have already received their J&J vaccine, however, or those who are scheduled to get their shots soon. But there’s no need to panic; just pay attention to whether you have symptoms such as a severe headache, abdominal pain, leg pain or shortness of breath. If you do, seek medical attention. 

“I would tell them to just, first of all, don’t get an anxiety reaction because remember, it’s less than one in a million,” said Dr. Anthony Fauci, the government’s top infectious disease expert, during a White House press conference when the pause was first announced.

So this is what we know about these J&J cases so far, what symptoms people should watch out for, and what you should do about any upcoming J&J vaccine appointments. Keep in mind that this information is subject to change as we learn more, so these guidelines will be updated as health officials update their recommendations. 

I’ve already received my J&J shot. What should I watch out for? 

The CDC and FDA say that if you suffer a severe headache, feel abdominal pain or leg pain, or start experiencing shortness of breath within three weeks after getting your J&J vaccine, you should seek medical attention or speak to your health care provider. 

These blood clot symptoms should not be confused with the flu-like symptoms (fever, body aches, chills, fatigue and nausea) or swollen lymph nodes under your arms and near your collarbone, which can be a normal response to getting any of the COVID vaccines from J&J, Pfizer
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or Moderna
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It should be noted that the blood clot events usually occurred about a week after the J&J vaccine, and no longer than three weeks after vaccination, with a median of about nine days. So if it’s been almost a month since you got your shot, then you should be in the clear.

I’m scheduled to get my J&J shot. Should I cancel my appointment, or get the Pfizer or Moderna vaccine instead? 

There is no need for you to rush to cancel your upcoming appointment, although your state or vaccination site may have already canceled or rescheduled J&J appointments for now while the recommended pause is in effect. Retailers and drugstores such as Walgreens, Rite Aid
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CVS
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and Wegmans have canceled their J&J appointments for the time being, for example. 

Or some states, including New York and Texas, have switched to giving those people scheduled to get the J&J shot one of the other available COVID vaccines from Pfizer and Moderna, instead. Check your local health department or your vaccination site for guidance. And the pause “will not have a significant impact” on the White House’s vaccination plan, according to Jeff Zients, the White House’s COVID-19 response coordinator.

What’s more, doctors and vaccination sites can still give you the J&J vaccine. “This is a recommendation, and it’s not a mandate. It’s out of an abundance of caution,” Dr. Peter Marks, the director of the FDA’s Center for Biologics Evaluation and Research, said in a press conference last week. “If an individual health care provider has a conversation with an individual patient, and they determined that the benefit risk for that individual patient is appropriate, we’re not going to stop that provider from administering the vaccine.” 

Keep in mind that most of the almost 8 million people who have already received the J&J vaccine did not develop this severe side effect. Indeed, half of all adults in the U.S. have received at least one COVID-19 shot, the government announced Sunday. “We have to put this into context,” said Panettieri. “It’s very important to realize that millions of people have gotten Johnson & Johnson vaccines, and have reaped the benefits of the vaccine. This is an incredibly uncommon and rare event. You’re more likely to get COVID-19 and have a serious COVID infection [if you don’t get vaccinated] than to get this complication from the vaccine.”  

Who is most at risk of developing this rare blood clot/low platelet reaction from the J&J vaccine? 

There are still too few cases to make any concrete connections. Six cases were recorded initially, and “review of six is difficult to make generalizations from. We’re going to have our expert committee take a careful look,” Dr. Anne Schuchat, principal deputy director of the CDC, said during a press briefing last week. “The numbers are quite small, small enough that it’s hard to generalize, but large enough that we wanted to take the action with the pause.” While the total number of cases has increased to 15, again, that number is an extremely small percentage of the almost eight million Americans who have received the J&J vaccine.

Some things the cases do have in common so far, however: All 15 cases occurred in women, and 13 cases involved women between the ages of 18 and 48 years old, while two cases were seen in women who are over 50. They developed the clots within six to 13 days of getting the J&J shot. And additional details were shared about the first six cases during the emergency ACIP meeting last week. All six cases were in white women. Three were considered obese, and none were pregnant or postpartum. The median time to symptoms appearing was eight days, and five of the six reported headaches as an initial symptom. Four of them were treated with the blood thinner heparin, which could have worsened their condition, people familiar with the matter told the Wall Street Journal.

It’s far too soon to say that women of a certain age are at higher risk than anyone else, however. Women have been more likely than men to report adverse reactions to COVID-19 vaccines, including post-vaccination lymph node swelling and short-term changes to their menstrual cycles. But the majority of the side effects have been minor.

Read more: What we know about COVID vaccine side effects in women

But again: these blood clots are still extremely rare, and it is not clear yet whether the vaccine caused these clots. Some people have a family history of blood clots. Using oral birth control pills, becoming pregnant, long airplane flights and smoking cigarettes can also raise the risk of clots, although it should be noted that the latter types of clots differ from the rare clots seen in the six J&J patients.

Read more: Why comparing blood clot risks from COVID-19 vaccines and birth control pills doesn’t work

“The likelihood of you having a CVST could occur from many, many more factors that people are exposed to than just this vaccine,” said Panettieri. “And remember, this kind of thrombosis occurs in five in a million people anyway. So when you’re starting to vaccinate millions and millions of people, you’re going to get some people who would have just developed this in any case.” 

How long will the J&J shot be on pause? What happens next? 

Dr. Janet Woodcock, the FDA’s acting commissioner, said that this pause should only last “a matter of days” during a press briefing last Tuesday morning. This could change depending on “what we learn in the next few days,” she noted at the time, and the pause has been upheld for more than a week. 

But that could change now that the CDC’s Advisory Committee on Immunization Practices has voted to recommend lifting the pause. The New York Times reported that federal health officials are expected to respond quickly and formally recommend that states lift the pause.

Dispatches from a Pandemic: Johnson & Johnson saga reveals critical strengths in the U.S. COVID-19 mass-vaccination strategy — and its weaknesses

The bottom line: If you’ve received the J&J vaccine, keep an eye out for symptoms of this rare blood clot, including a severe headache, abdominal or leg pain, and shortness of breath within three weeks of getting your shot. But these blood clots are so rare — being recorded in less than one in a million people who’ve received their J&J shots — that there is no need to panic or rush to cancel an upcoming J&J vaccine appointment. Your vaccination site or local health department may be rescheduling appointments or swapping J&J vaccines for other vaccines, however, so check with your vaccination site to see how this could impact your future appointment. 

“The takeaway message here is, the single most important thing people can do is get vaccinated,” said Panettieri. “Not to get vaccinated would put you at such an enhanced risk of death from COVID, or serious risk from COVID, that I would not be worried about these isolated and very rare cases of blood clots.” 

This story has been updated with the CDC committee vote and the increased number of cases.