J&J and AstraZeneca explore modification of Covid-19 vaccine in response to rare blood clots

A spokesperson for J&J said the company supports “further research and analysis as we work with medical experts and global health authorities.” AstraZeneca said it “is actively working with regulators and the scientific community to understand these extremely rare blood clotting events, including information to drive early diagnosis and intervention, and appropriate treatment.”

In addition to scientific hurdles, changes may require changes in property rights or regulatory approvals. Yet the unprecedented scale and urgency of the Covid-19 vaccine deployment could accelerate scientific research and legal issues, scientists say, just as it accelerated vaccine development in the first place.

The chances of coagulation combined with low blood platelet counts – a rare condition called vaccine-induced immune thrombotic thrombocytopenia, or VITT – after injecting AstraZeneca are about 1 to 2 per 100,000 vaccinations, depending on the count. British and European cases.

US government data shows a lower rate of about 0.3 cases of coagulation per 100,000 doses for the J&J vaccine. The risk of severe clotting is usually higher because of Covid-19 itself and has also long been associated with the use of heparin, a common anticoagulant drug, according to researchers and regulators.

Johnson & Johnson’s single-dose Covid-19 vaccine is approved in the United States, but its rollout was temporarily halted in April due to concerns about a link to blood clotting. After investigation, U.S. health regulators recommended resuming use of the vaccine, saying its protection against Covid-19 outweighs the risk of rare clotting for most people. They added a warning about the risk of clotting.

The AstraZeneca vaccine is not licensed in the United States, but is widely used around the world, with over 600 million doses distributed. In the UK and across the EU, regulators have recommended alternative vaccines for young adults, who are considered to be more vulnerable to blood clotting compared to Covid-19.

The two companies and the University of Oxford said the benefits of vaccines generally outweigh the risks, echoing advice from government officials.

J&J and AstraZeneca injections have more recently been linked by US regulators to a slightly increased risk of Guillain-Barré syndrome, a rare neurological disorder associated with other vaccines. US and European officials have alerted doctors and vaccines to the low increased risk. They said the gunfire remained valuable tools in the pandemic.

For both injections, minimizing or eliminating rare blood clotting problems could be key to building confidence in the vaccines and opening the doors to wider use. Both vaccine manufacturers sell their vaccines for no profit. Both can be stored for months at normal refrigeration temperatures, unlike the ultra-cold temperatures required for long-term storage of Pfizer’s major vaccines. Inc.

and Moderna Inc.

J & J’s single dose regimen is also seen as a benefit in protecting hard-to-reach people after a single injection.

Modifications to eliminate clotting reactions, if such changes are possible, could help turn injections into long-term sources of money, especially if booster vaccinations become widely adopted. Both companies could look to cash in on vaccines in richer countries once the pandemic is over.

Scientists say they must first understand whether the culprit is one or more ingredients in vaccines, the purification process, or something mechanical in how vaccines work. Both injections use so-called adenoviruses, altered and harmless viruses that carry genetic instructions into human cells, causing a build-up of antibodies and immune defense tools against Covid-19. In AstraZeneca injection, the vector, or carrier, is an altered chimpanzee cold virus. The J&J shot uses a weakened human cold virus.

“Progress is being quickly continued by companies, and I think their desire to change the vector or vaccine evolves along with the explanation” for clots, said Mortimer Poncz, head of the pediatric hematology division at the hospital. for children of Philadelphia.

AstraZeneca and the team of scientists at Oxford who developed the vaccine are studying how the vaccine, in very rare cases, triggers the immune response at the base of the clots, according to Sarah Gilbert, a vaccinologist at Oxford and co-inventor of the vaccine. According to Professor Gilbert, Oxford and AstraZeneca are exploring potential changes in the vaccine delivery mechanism. She said she couldn’t predict when a revamped vaccine might be ready. An Oxford spokesperson declined to elaborate.

Oxford researchers said they hope to have a new version of the vaccine targeting the variants ready by the fall. This is probably faster than the vaccine could be modified to treat rare blood clots, according to some people familiar with the subject.

Write to Jenny Strasbourg at [email protected] and Parmy Olson at [email protected]