Covid: United States calls for pause on Johnson & Johnson vaccine after cases of coagulation

Federal health agencies on Tuesday called for an immediate hiatus in use of Johnson & Johnson’s single-dose coronavirus vaccine after six recipients in the United States developed a rare disease involving blood clots about two weeks after vaccination, officials briefed on the decision said.

The six recipients were women aged 18 to 48. A woman has died and a second woman in Nebraska has been hospitalized in critical condition, officials said.

Nearly seven million people in the United States have received injections of Johnson & Johnson so far, and about nine million additional doses have been shipped to the United States, according to data from the Centers for Disease Control and Prevention.

Although the move was intended as a recommendation to health care practitioners in states, the federal government will suspend vaccine administration at all federally administered immunization sites. Federal officials expect state health officials to take this as a strong signal to do the same.

Scientists from 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 allow use of the vaccine for all adults or limit the clearance. An emergency meeting of the CDC’s external advisory committee is scheduled for Wednesday, officials said.

The move could significantly complicate the country’s vaccination efforts at a time when many states face an outbreak of new cases and seek to address the reluctance to vaccinate. Regulators in Europe and elsewhere are concerned about a similar problem with another coronavirus vaccine, developed by researchers at AstraZeneca and the University of Oxford. This concern has resulted in some resistance to all vaccines, although the AstraZeneca version has not been approved for use in the United States.

Most of the country’s vaccine supply comes from two other manufacturers, Pfizer-BioNTech and Moderna, which together deliver more than 23 million doses per week of their two-dose vaccines. None of these vaccines raised significant safety concerns.

But while shipments of the Johnson & Johnson vaccine have been much more limited, the Biden administration still relied on the use of hundreds of thousands of doses each week. In addition to requiring only one dose, the vaccine is easier to ship and store than the other two, which must be stored at extremely low temperatures.

It is not known to what extent the pause in use of the Johnson & Johnson vaccine will delay the Biden administration’s plans to provide 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 develop blood clots each year, according to CDC data. But the particular blood clotting disorder that vaccinees developed, known as cerebral venous thrombosis, is extremely rare. All of the women developed the disease between six and 16 days of vaccination, and government experts fear that an immune system response triggered by the vaccine was the cause.

The move is another blow to Johnson & Johnson and 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 company to throw away the equivalent of 13 to 15 million dollars. doses. This plant was supposed to resume the supply of vaccine to the United States from the Dutch factories of Johnson & Johnson, which were certified by federal regulators earlier this year.

FDA certification of the Baltimore plant has now been delayed as inspectors investigate quality control issues, drastically reducing Johnson & Johnson vaccine supply. The sudden drop in available doses has led to widespread complaints from governors and state health officials who expected much larger shipments of vaccine from Johnson & Johnson this week than they did. have received some.

States use the vaccine in a wide variety of settings, including mass vaccination sites and campuses. Authorities have also referred him to transitional, rural and isolated communities where follow-up with a second dose is more complicated.

It is common for regulators to study so-called “safety signals” in new vaccines and other medical products. Very often the signals are not of concern. But concerns about Johnson & Johnson’s vaccine mirror those of AstraZeneca, which European regulators began investigating last month after some recipients developed blood clots.

Of 34 million people who received the vaccine in Britain, the European Union and three other countries, 222 developed blood clots associated with low platelet counts. The majority of these cases occurred within the first 14 days after vaccination, mainly in women under 60 years of age.

On April 7, the European Medicines Agency, the main regulatory agency, concluded that the disorder was a very rare side effect of the vaccine. German and Norwegian researchers published studies on April 9 suggesting that in very rare cases the AstraZeneca vaccine caused people to make antibodies that activated their own platelets.

Nonetheless, regulators argued that the benefit of the vaccine – preventing people from getting infected with Covid-19 or the few people who release it from the hospital – far outweighed this small risk. Countries in Europe and beyond have continued to administer the vaccine to older people, who face a high risk of serious illness and death from Covid-19, while limiting it in younger people.

AstraZeneca and Johnson & Johnson use the same platform for their vaccine, a virus called adenovirus. On Tuesday, the Australian government announced that it would not buy the Johnson & Johnson vaccines. They cited the fact that Johnson & Johnson, like AstraZeneca, used an adenovirus as the basis for their vaccine. But there’s no obvious reason why adenovirus vaccines in particular would cause rare blood clots associated with low platelet counts.

AstraZeneca has not yet applied for emergency use authorization in the United States.

In addition to the Johnson & Johnson vaccine, the FDA has cleared vaccines developed by Moderna and Pfizer-BioNTech. These two vaccines use different technology to produce immunity.

The first sign of concern over Johnson & Johnson’s vaccine came on April 9, when the European Medicines Agency announced it was investigating reports of four cases of blood clots in people who received the vaccine. Johnson & Johnson in the United States. One case arose during the clinical trial that took place before the vaccine was released. Three occurred during the deployment of the vaccine. One of them was fatal, the agency said.

Regulators have described the reports as a “safety signal” – a set of cases requiring further investigation. But they said it was not clear whether the vaccines caused the clots.

Johnson & Johnson responded with a statement saying, “At this time, no clear causal relationship has been established between these rare events and the Janssen Covid-19 vaccine.” Janssen is the name of the division of Johnson & Johnson that developed the vaccine.