J&J PAUSE: What does it mean if you've had the Johnson & Johnson vaccine?

Have you had the single-shot Johnson & Johnson COVID-19 vaccine within the last month?

If you experience a severe headache that doesn't get away, significant abdominal or leg pain that doesn't subside, or increasing shortness of breath, health officials want you to call your doctor immediately

Those might be signs of a particularly rare, severe sort of clot which will be linked to the Johnson & Johnson vaccine -- so rare that only six cases are reported within us out of the approximately 7 million Johnson & Johnson doses administered so far.

However, if you received the J&J vaccine quite a month ago, the danger is "very low," said Dr. Anne Schuchat, principal deputy director of the US Centers for Disease Control and Prevention, during a virtual briefing on Tuesday.

The CDC announced six women between the ages of 18 and 48 had developed a cerebral sinus thrombosis (CVST) -- a clot within the area of the brain that collects and drains oxygen-depleted blood. When this happens, "blood cells may break and leak blood into the brain tissues, forming a hemorrhage," consistent with Johns Hopkins Medicine.

The women all exhibited symptoms of this "light and severe sort of blood clot" between six and 13 days after their J&J vaccination, the CDC said.

One of the ladies died 12 days after receiving the vaccine and entering the hospital with "dry heaving, sudden worsening of headache and (left) sided weakness," consistent with a record within the US Department of Health's Vaccine Adverse Event Reporting System. Another woman is in critical condition.

The cases prompted the CDC and therefore the US Food and Drug Administration to recommend that administration of the J&J Covid-19 vaccine be paused to permit a further investigation.

"What does an interruption mean? It allows both the US Food and Drug Administration and CDC to further investigate these cases to undertake and understand a number of the mechanisms of what it's, some more details about the history of the individuals that were involved," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, during a White House briefing on Tuesday.

In response, Johnson & Johnson decided to pause vaccinations altogether of its clinical trials while the corporate updates "guidance for investigators and participants," consistent with a news release posted Tuesday afternoon.

The CDC's Advisory Committee on Immunization Practices command meets Wednesday and shares its subsequent analysis with the FDA for action, the agency said.

What does this mean if I've had the J&J vaccine?

"Don't freak out, I will be happening with my life, but I might be very attuned to my body," Dr. Carlos Del Rio, executive associate dean at Emory University School of Drugs, told CNN's Poppy Harlow Tuesday.

"If I develop shortness of breath, if I develop leg pain, if I develop a headache and I am within two to 3 weeks of getting had Johnson & Johnson's vaccine, I might immediately notify my health care provider," Del Rio continued.

The key here is unrelenting pain, said Dr. Mark Crowther, a member of the American Society of Hematology who is an expert in CVST.

"Many people get headaches, many of us have abdominal pain but (CVST) is sustained, it's very severe and it gets worse. it isn't pain that gets better by itself," said Crowther, who chairs the department of drugs at McMaster University in Ontario, Canada.

While CVST isn't a stroke, people can experience stroke difficulty speaking or moving an arm or leg, he added.

"If patients get any of that sort of stuff, they ought to seek medical attention immediately. it isn't the type of thing that you simply wait until your physician's office opens on Monday before you affect it," Crowther said.

The CDC is functioning on "aggressive" outreach to clinicians so that they are conscious of the possible risks and the way to spot symptoms, Schuchat said within the briefing.

"Physicians wouldn't see very many of those in their career so that they might not recognize it as quickly," Crowther said. "We have some highly effective treatments for this therefore the problem is getting physicians to acknowledge this extraordinarily rare problem and treat it appropriately."

In some cases, physicians might not realize that the common anticoagulant drug heparin shouldn't be wont to treat CVST, Dr. Peter Marks, director of the US Food and Drug Administration's Center for Biologics Evaluation and Research, said during a virtual briefing on Tuesday.

"With cerebral sinus thrombosis, heparin could also be dangerous and alternative treatments got to tend, preferably under the guidance of physicians experienced within the treatment of blood clots," Marks said.

The need to speak proper treatment to doctors was a part of the rationale the FDA and CDC moved so quickly to pause the J&J rollout in the week, health officials said.

This development shouldn't deter Americans or anyone else from continuing to be vaccinated with the Pfizer-BioNTech and Moderna two-shot vaccines, or maybe the J&J vaccine once the govt signs off, Crowther stressed.

"COVID is related to a risk of blood clots that's thousands of times higher" than blood clots caused by any vaccine, he said.

"it's important people not miss that," Crowther added. "Get vaccinated!"

How do low platelets factor in?

Cerebral sinus thrombosis affects about five people in 1 million annually, consistent with Johns Hopkins Medicine, occurring mostly in young adults and youngsters.

"CVST has been known about for many years, and there are many conditions during which you'll see CVST, " Crowther said. "Meningitis, which is that the bacterial infection around the brain, causes CVST. In infants, an explanation for CVST is severe dehydration."

The CVST clots in six people within the US occurred together with thrombocytopenia, a condition during which people have a coffee blood count of platelets, the sticky, colorless blood cells that help grume, consistent with the J&J statement.

A rare immune reaction that caused blood clots and low platelets also occurred in 16 European patients who received AstraZeneca's COVID-19 vaccine, consistent with two papers published last week within the New England Journal of Drugs.

In those papers, doctors describe clots within the patients' brains and abdomens that would indicate an abnormal immune reaction in 11 patients in Germany and Austria and five patients in Norway.

There appear to be similarities between the rare blood coagulation events possibly related to Johnson & Johnson's coronavirus vaccine and therefore the AstraZeneca coronavirus vaccine, FDA's Marks said Tuesday, pointing to "an immune reaction that happens very, very rarely after some people receive the vaccine."

One possibility, Crowther said, is that vaccines trigger an overreactive immune reaction that attacks blood platelets. The platelets become active, and as a result, cause blood coagulation, whilst their numbers drop.

But that does not mean that vaccines always cause this phenomenon, Crowther stressed. many of us have lower platelet counts and do not know it, he said, so once they get any vaccine and are later diagnosed with thrombocytopenia it's going to be attributed to the vaccine "even though (they) may have had it for 10 years and just never known about it."

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