BOSTON (CBS) — The Massachusetts Department of Public Health on Tuesday told all providers in the state to stop administering the Johnson & Johnson coronavirus vaccine after federal health officials called for a “pause” as they investigate “rare and severe” blood clots in six people who received the single-dose vaccine.

“Today the Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) issued a statement regarding the Johnson & Johnson COVID-19 vaccine recommending a pause in its use out of an abundance of caution,” DPH tweeted. “The Department of Public Health is notifying all Massachusetts providers to pause administration of the Johnson & Johnson COVID-19 vaccine, effective immediately.”

According to state data released Monday, 181,034 doses of the Johnson & Johnson vaccine have been administered in Massachusetts. More than 6.8 million have been administered nationwide.

The Department of Public Health is notifying all Massachusetts providers to pause administration of the Johnson & Johnson COVID-19 vaccine, effective immediately. @CDCgov @US_FDA (2/2) pic.twitter.com/65ueAZIV2E

— Mass. Public Health (@MassDPH) April 13, 2021

A spokesman for CVS said the pharmacy chain would also immediately pause administration of Johnson & Johnson vaccines.

All the U.S. blood clot cases have been in women under the age of 50, and have happened 6-to-13 days after vaccinations, according to CBS News medical contributor Dr. David Agus. One woman died from the blood clots, according to Dr. Agus. The women all had pain in the abdomen or a headache.

None of the six cases were in Massachusetts, a spokesperson for the state’s COVID-19 Response Command Center said.

Those who have already received the Johnson & Johnson vaccine should talk to their doctor if they have any concerns. Anyone who has scheduled a Johnson & Johnson vaccine should reach out to the provider they booked with directly.

The Pfizer and Moderna vaccines, which are made using a different technology, have not had any blood clot issues.

BOSTON (CBS) – The CDC and FDA are recommending a pause in the use of the Johnson & Johnson COVID-19 vaccine in the United States “out of an abundance of caution.” The federal agencies issued a joint statement Tuesday morning saying they are reviewing six reported cases of a “rare and severe” type of blood clot in people who have received the single dose vaccine.

Today FDA and @CDCgov issued a statement regarding the Johnson & Johnson #COVID19 vaccine. We are recommending a pause in the use of this vaccine out of an abundance of caution.

— U.S. FDA (@US_FDA) April 13, 2021

As of Monday, more than 6.8 million doses of the J and J vaccine have already been administered in the U.S. Researchers say these blood clots appear to be “extremely rare.”

None of the six cases are linked to Massachusetts, according to the state’s COVID-19 Response Command Center.

According to state data released Monday, 181,034 doses of the Johnson & Johnson vaccine have been administered in Massachusetts. The state’s Department of Public Health said it is “notifying all Massachusetts providers to pause administration of the Johnson & Johnson COVID-19 vaccine, effective immediately.”

CVS said it is also pausing in its use of the Johnson & Johnson vaccine at Massachusetts pharmacies “per the recommendation from federal health agencies.”

All the U.S. blood clot cases have been in women between the ages of 18 and 48 and have happened 6-to-13 days after vaccinations. According to CBS News medical contributor Dr. David Agus, one woman died from the blood clots. The women all had pain in the abdomen or a headache.

“People who have received the J&J vaccine who develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider,” the agencies said in their statement.

“At present, no clear causal relationship has been established between these rare events and the Janssen COVID-19 vaccine,” Johnson & Johnson said in a statement Tuesday.

“CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance. FDA will review that analysis as it also investigates these cases,” the agencies said.

“Until that process is complete, we are recommending this pause. This is important to ensure that the health care provider community is aware of the potential for these adverse events and can plan due to the unique treatment required with this type of blood clot.”

A similar issue has been seen in the AstraZeneca vaccine, which is not yet approved for emergency use in the U.S.

“When you’re seeing it with two different vaccines that have some similarity we get really worried,” Dr. Agus said on CBS This Morning.

“Tomorrow morning there’ll be an advisory meeting where they’ll review these six cases and see whether they think they are related to the vaccine or not and what to do.”

The FDA will hold a news conference at 10 a.m. Tuesday to reveal more information.

“It’s horrible, absolutely horrible. I wish it hadn’t happened. it’s going to put a wrench in what’s going on with the vaccines, all of the vaccines, and we need to to figure this out and develop a national plan to move forward,” Dr. Agus said.

The Pfizer and Moderna vaccines, which are made using a different technology, have not had any blood clot issues.

If you’ve had the J and J vaccine, Dr. Agus says “listen to your body” if you have concerns.

“If you have any symptoms where you have pain and it’s unexplainable, go to an emergency room right away. And doctors around the country are now aware of this and they know how to treat it,” he told CBS This Morning.

PHILADELPHIA (CNN) — The US Centers for Disease Control and Prevention and the US Food and Drug Administration are recommending that the United States pause the use of Johnson & Johnson’s Covid-19 vaccine over six reported US cases of a “rare and severe” type of blood clot.

The city and all partner clinics in Philadelphia have paused the use of this vaccine until we receive further guidance. Details on the specific changes to clinics will be forthcoming, but some clinics will be closed today and others will be switched to other types of vaccine.

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Today FDA and @CDCgov issued a statement regarding the Johnson & Johnson #COVID19 vaccine. We are recommending a pause in the use of this vaccine out of an abundance of caution.

— U.S. FDA (@US_FDA) April 13, 2021

The six reported cases were among more than 6.8 million doses of the Johnson & Johnson vaccine administered in the United States. All six cases occurred among women ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination, according to a joint statement on Tuesday from Dr. Anne Schuchat, principal deputy director of the CDC and Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.

“CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance,” the statement said. “FDA will review that analysis as it also investigates these cases. Until that process is complete, we are recommending a pause in the use of this vaccine out of an abundance of caution. This is important, in part, to ensure that the health care provider community is aware of the potential for these adverse events and can plan for proper recognition and management due to the unique treatment required with this type of blood clot.”

This is a breaking news story.

(CNN) — US health agencies are taking concerns about blood clots and the Johnson & Johnson Covid-19 vaccine “seriously” and are working to assess whether the shot is associated with a very small increased risk of rare blood clots, a federal official told CNN.

“The CDC and the FDA are taking these concerns about blood clots and the J&J vaccine seriously and are diligently assembling data,” the official said.

An expert outside the government who is familiar with the situation agreed that health officials are taking the matter seriously.

“The CDC is very concerned and they’re very working hard on this and monitoring this closely,” said the expert, who spoke on the condition of anonymity due to the sensitive nature of the issue.

There have been “four serious cases of unusual blood clots” reported after people received the Johnson & Johnson vaccine, according to European health authorities. Like their US counterparts, the European authorities say they’re still investigating these cases and that “it is currently not clear” whether there’s a causal association between the vaccine and the clots.

The concern in the United States isn’t just about the Johnson & Johnson shot per se. At a time when US health officials are encouraging Americans to get vaccinated as soon as they can, there’s a worry that news coverage about clots being studied in relation to Johnson & Johnson’s vaccine might make some Americans more hesitant to get any Covid-19 vaccine.

Vaccine hesitancy is already an issue in the US, and officials at the US Centers for Disease Control and Prevention and the US Food and Drug Administration are “thinking through how to communicate about the issue without creating the impression that something might be wrong with the [Johnson & Johnson] vaccine,” the federal health official said.

Another expert familiar with the situation said that was the right approach, stressing the importance of communicating without scaring people.

“I would hope that HHS is having a confab about this right now,” the expert said, referring to the US Department of Health and Human Services.

In a statement, Johnson & Johnson said its tracking of side effects revealed “a small number of very rare events following vaccination. At present, no clear causal relationship has been established between these rare events and the [Johnson & Johson] COVID-19 vaccine.”

The FDA released a statement last week that it was aware of reports of “serious thromboembolic events” in the US that occurred “in a few individuals following receipt of the [Johnson & Johnson] COVID-19 vaccine” and that “at this time we have not found a causal relationship with vaccination.”

J&J study participant’s illness revealed

Publicly, the nature of the participant’s illness remained a mystery until February, when the FDA revealed that a 25-year-old male study participant with no past medical history and who wasn’t taking any medications received the vaccine and experienced a transverse sinus thrombosis.

About 3 to 4 people per 1 million experience this blood clot each year, and 75% of the adult cases are women, according to a 2005 study in the New England Journal of Medicine.

During Johnson & Johnson’s clinical trial, there were reports of other types of blood clots, too. Some are relatively common, such as deep vein thrombosis, so it wasn’t surprising that among roughly 20,000 participants who received the vaccine, some would experience those clots.

What made FDA scientists take note, however, is that in the trial, about the same number of people received a placebo — a shot of saline that does nothing — as received the vaccine. However, when comparing the two groups, more study participants developed clots after receiving the vaccine than the placebo.

Calling it a “slight numerical imbalance,” the FDA noted that there were 15 events in 14 participants who received the vaccine, compared to 10 events in 10 participants who received the placebo.

The FDA report concluded that given this imbalance, “vaccine cannot be excluded as a contributing factor,” and that the FDA would recommend “surveillance” for blood clots once the vaccine was rolled out.

The Johnson & Johnson vaccine was rolled out March 3, a few days after the FDA issued that report. Since then, more than 6.8 million people in the US have received it, according to the CDC.

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That’s a small number compared with Pfizer and Moderna, which were authorized in December. Since then, more than 36 million have been fully vaccinated with two doses of the Pfizer vaccine and more than 31 million have received two doses of the Moderna vaccine, according to the CDC.

Following manufacturing challenges, allocations of J&J’s vaccine are expected to drop 84% this week, according to a CNN analysis of CDC data.

In this context, Andy Slavitt, White House senior adviser for Covid-19, said at a news briefing on Monday that the United States is still on track to reach its Covid-19 vaccination targets even without additional doses from Johnson & Johnson.

Scrutiny over blood clots

The AstraZeneca vaccine, which has not been authorized in the United States, has been authorized in more than 70 countries. The J&J vaccine and the AstraZeneca vaccines are similar — they both use adenovirus vectors to make them work.

By March, doctors in several European countries had begun to notice “very rare” cases of unusual blood clots among people who received the AstraZeneca vaccine.

The European Medicines Agency noted that most of these people experienced a type of blood clot in the brain called cerebral venous sinus thrombosis. Transverse sinus thrombosis — the clot experienced by the young participant in the Johnson & Johnson trial — is a type of cerebral venous sinus thrombosis.

The agency noted that its safety committee reviewed 62 cases of cerebral venous sinus thrombosis and 24 cases of splanchnic vein thrombosis, a type of blood clot in the abdomen, 18 of which were fatal. The cases were reported at a time when 25 million people in Europe and the UK had received the vaccine.

The European agency concluded that unusual blood clots with low blood platelets should be listed as “very rare side effects” of the AstraZeneca vaccine. While advising the public to look out for the signs of clots, the regulators said the benefits of the shot were still worth the risk.

The European Union authorized J&J’s vaccine last month, and it’s expected to be rolled out there in the next few weeks.

A ‘vaccine-induced’ condition

But the people who received the AstraZeneca vaccine and developed the clots hadn’t taken heparin.

Writing about AstraZeneca’s vaccine in the New England Journal of Medicine last week, European doctors invented a new term: “vaccine-induced immune thrombotic thrombocytopenia.”

“It’s actually very interesting,” said Dr. Peter Kouides, immediate past president of the Thrombosis and Hemostasis Societies of North America. “The risk is very, very low, but it does seem to be a true disorder triggered by the vaccine.”

He said there are treatments for this “very serious condition,” but they don’t always work.

“When you have [this] happen, all bets are off,” said Dr. Hanny Al-Samkari, a hematologist and instructor at Harvard Medical School. “You can get clots anywhere. You can get them in your brain, in your belly, in your extremities, in your heart — it doesn’t matter. They can happen just about anywhere and obviously that’s often problematic and/or fatal.”

Harsh words for Johnson & Johnson

“We are aware that thromboembolic events including those with thrombocytopenia have been reported with all COVID-19 vaccine,” according to the Johnson & Johnson statement.

The company included a footnote to a study published in February that looked at 20 case reports of thrombocytopenia among people who had taken the Moderna and Pfizer vaccines as of February 2. By that time, more than 30 million people had received at least the first dose of one of those vaccines, according to the CDC.

Considering that’s such a large number, it’s not surprising some in this group would experience thrombocytopenia, a condition where there are low levels of platelets in the blood, said Dr. Paul Offit, a member of the FDA’s Vaccines and Related Biological Products Advisory Committee. The issue, he said, is whether that number of people exceeded what would be expected if they had not been vaccinated.

He pointed to a CDC presentation in January that showed people who received the Moderna and Pfizer vaccines were actually less likely to experience thrombocytopenia or certain types of blood clots compared to those who were unvaccinated.

“That is a really irresponsible thing to say,” Offit said, referring to the J&J statement. “It will unnecessarily scare people about Moderna and Pfizer when not only is there no evidence it’s a problem — there’s evidence there is not a problem,” added Offit.

A J&J spokesman declined to comment on Offit’s criticism.

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