WASHINGTON — Federal health agencies on Tuesday will call
for an immediate pause in use of Johnson & Johnson’s single-dose
coronavirus vaccine after six recipients in the United States developed a rare
disorder involving blood clots within about two weeks of vaccination, officials
briefed on the decision said.
اضافة اعلان
All six recipients were women between the ages of 18 and 48.
One woman died and a second woman in Nebraska has been hospitalized in critical
condition, the officials said.
Nearly 7 million people in the United States have received
Johnson & Johnson shots so far, and roughly 9 million more doses have been
shipped out to the states, according to data from the Centers for Disease
Control and Prevention (CDC).
While the move is framed as a recommendation to health
practitioners in the states, the federal government is expected to pause
administration of the vaccine at all federally run vaccination sites. Federal
officials expect that state health officials will take that as a strong signal
to do the same.
Scientists with the Food and Drug Administration and CDC
will jointly examine possible links between the vaccine and the disorder and
determine whether the FDA should continue to authorize use of the vaccine for
all adults or limit the authorization. An emergency meeting of the CDC’s
outside advisory committee has been scheduled for Wednesday, officials said.
An FDA spokeswoman declined to comment.
The move could substantially complicate the nation’s
vaccination efforts at a time when many states are confronting a surge in new
cases and seeking to address vaccine hesitancy. Regulators in Europe and
elsewhere are concerned about a similar issue with another coronavirus vaccine,
developed by AstraZeneca and Oxford University researchers. That concern has
driven up some resistance to all vaccines, even though the AstraZeneca version
has not been approved for use in the United States.
Most of the nation’s vaccine supply comes from two other
manufacturers, Pfizer-BioNTech and Moderna, which together deliver more than 23
million doses a week of their two-shot vaccines. There have been no significant
safety concerns about either of those vaccines.
But while shipments of the Johnson & Johnson vaccine
have been much more limited, the Biden administration had still been counting
on using hundreds of thousands of doses every week. In addition to requiring
only a single dose, the vaccine is easier to ship and store than the other two,
which must be stored at extremely low temperatures.
It is unclear to what degree the pause in the use of the
Johnson & Johnson vaccine will set back the Biden administration’s plans to
deliver enough vaccine to be able to inoculate all adults in the United States
by the end of May.
In the United States alone, 300,000 to 600,000 people a year
develop blood clots, according to CDC data. But the particular blood clotting
disorder that the vaccine recipients developed, known as cerebral venous
thrombosis, is extremely rare. All of the women developed the condition between
six and 16 days of vaccination, and government experts are concerned that an
immune system response triggered by the vaccine was the cause.
The decision is a fresh blow both to Johnson & Johnson
and to the administration’s plans. Late last month, the company discovered that
workers at a Baltimore plant run by its subcontractor had accidentally
contaminated a batch of vaccine, forcing the firm to throw out the equivalent
of 13 million to 15 million doses. That plant was supposed to take over supply
of the vaccine to the United States from Johnson & Johnson’s Dutch plants,
which were certified by federal regulators earlier this year.
The Baltimore plant’s certification by the FDA has now been
delayed while inspectors investigate quality control issues, sharply reducing
the supply of Johnson & Johnson vaccine. The sudden drop in available doses
led to widespread complaints from governors and state health officials who had
been expecting much bigger shipments of Johnson & Johnson’s vaccine this
week than they got.
States have been using the vaccine in a broad range of
settings, including at mass vaccination sites and on campuses. Officials have
also directed it to transient, rural and isolated communities where following
up with a second dose is more complicated.
It is common for regulators to investigate so-called “safety
signals” in new vaccines and other medical products. Very often, the signals
prove not to be of concern. But the concerns about Johnson & Johnson’s
vaccine mirror concerns about AstraZeneca’s, which European regulators began
investigating last month after some recipients developed blood clots.
Both AstraZeneca and Johnson & Johnson use the same
platform for their vaccine, a virus known as an adenovirus. On Tuesday, the
Australian government announced it would not purchase Johnson & Johnson
vaccines. They cited the fact that Johnson & Johnson, like AstraZeneca,
used an adenovirus as the basis of its vaccine. But there is no obvious reason
adenovirus-based vaccines in particular would cause rare blood clots associated
with low platelet levels.
AstraZeneca has not yet applied for an emergency use
authorization in the United States.
In addition to Johnson & Johnson’s vaccine, the FDA has
authorized the vaccines developed by Moderna and Pfizer-BioNTech. Those two
vaccines use a different technology to produce immunity.
The first sign of concern about Johnson & Johnson’s
vaccine came on April 9, when the European Medicines Agency announced that they
were investigating reports of four cases of blood clots in people who received
the Johnson & Johnson vaccine in the United States. One case occurred in
the clinical trial that took place before the vaccine was authorized. Three
occurred in the vaccine rollout. One of them was fatal, the agency said.
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