Johnson & Johnson and AstraZeneca are studying a possible modification of their vaccines against COVID-19 to prevent thrombosis

Aside from scientific hurdles, modifications may require changes in property rights or regulatory approvals (REUTERS)

Johnson & Johnson and AstraZeneca are conducting early research to determine whether modifications to their COVID-19 vaccines could reduce or eliminate the risk of rare but serious blood clots associated with inoculations,said sources close to the case according to statements collected by The Wall Street Journal.

The WSJ reported Tuesday that independent scientists and AstraZeneca's partner, the University of Oxford, were also involved in the efforts. Both vaccines have been linked to the risk of thrombi, although regulators have said that the benefits of vaccines far outweigh the risks.

A Johnson & Johnson spokesperson said the company supports "ongoing research and analysis as we work with medical experts and global health authorities." And from AstraZeneca they assured that they are "actively working with regulators and the scientific community to understand these extremely rare blood clotting events, including information to promote early diagnosis and intervention and appropriate treatment."

Both companies and the University of Oxford assured that the benefits of vaccines generally outweigh the risks, echoing the guidance of government officials (REUTERS)

Aside from the scientific hurdles, modifications may require changes in property rights or regulatory approvals. Still, the unprecedented scale and urgency of the COVID-19 vaccine launch could accelerate scientific research and legal problems, the researchers say, just as it accelerated development of the vaccines in the first place.

The risks of clotting combined with low blood platelets - a rare disease called Vaccine-Induced Immune Thrombocytopenia, or VITT - after injection of AstraZeneca are approximately 1 to 2 per 100,000 vaccines, based on UK case counts. Kingdom and Europe.

Data from the United States government shows a lower rate of about 0.3 cases of the clotting condition per 100,000 doses of Johnson & Johnson vaccine. The risk of severe clotting is generally higher due to COIVD-19 itself and has also long been associated with the use of heparin , a common blood-thinning drug, say researchers and regulators.

Johnson & Johnson's single-dose COVID-19 vaccine is approved in the US, but its deployment was temporarily halted in April due to concerns about a link to blood clotting (REUTERS)

Johnson & Johnson's single-dose COVID-19 vaccine is approved in the US, but its deployment was temporarily halted in April due to concerns about a link to blood clotting. After investigating, US health regulators recommended that use of the vaccine be resumed, saying that its protection against the disease outweighed the rare clotting risk for most people. They added a warning about the risk of clotting.

The AstraZeneca vaccine is not licensed in the US, but is widely used in the rest of the world, with more than 600 million doses distributed. In the UK and across the European Union, regulators have recommended alternative vaccines for younger adults, who are considered more vulnerable to blood clotting than COVID-19.

Johnson & Johnson 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 vaccine recipients to the small increase in risk. They said jabs remained valuable tools in the pandemic.

For both injections, Minimizing or eliminating rare blood clotting problems could be key to increasing confidence in vaccines and opening the doors to wider use.Both formulas can be stored for months at normal refrigeration temperatures, in contrast to the ultra-cold temperatures required for long-term storage of the major vaccines from Pfizer Inc. and Moderna Inc. Johnson & Johnson's single-dose regimen is also considered a advantage.

Modifications to eliminate clotting reactions, if such changes are possible, could help make injections cost-effective in the long term, especially if booster vaccines are widely adopted (REUTERS)

Modifications to eliminate clotting reactions, if such changes are possible, could help make injections cost-effective in the long term, especially if booster vaccines are widely adopted. The two companies could try to profit from 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, modified and harmless viruses that carry genetic instructions to human cells, causing a build-up of antibodies and immune defense tools against COVID-19.

"Companies are moving fast, and I think their desire to alter the vector or the vaccine runs in parallel with the clot explanation ," said Mortimer Poncz, chief of the pediatric hematology division at Children's Hospital of Philadelphia.

AstraZeneca and the team of Oxford scientists who developed the injection are investigating how the vaccine, in very rare cases, triggers the immune response that sustains clots, according to Sarah Gilbert, an Oxford vaccinologist and co-inventor of the vaccine. The specialist cautioned that Oxford and AstraZeneca are exploring possible changes in the vaccine delivery mechanism and said she cannot yet predict when a modified vaccine might be ready.

Symptoms of vaccine-induced immune thrombotic thrombocytopenia or thrombosis with thrombocytopenia syndrome (STT) closely resemble a condition called heparin-induced thrombocytopenia (HIT) (Europa Press)

But what is vaccine-induced immune thrombotic thrombocytopenia or thrombosis with thrombocytopenia syndrome (TTS)? The symptoms  closely resemble a condition called heparin-induced thrombocytopenia (HIT) , a rare autoimmune reaction triggered by heparin, a blood thinner. Despite decades of research, doctors cannot predict who is at risk for HIT; it seems to affect men and women, old and young alike.

By definition,  thrombosis isa disorder that involves the formation of thrombi or clots in the circulatory system .They can be arterial or venous thrombi. Many diseases present with this phenomenon that can affect any internal organ or the general circulation.

"The process by which  the blood that circulated in liquid form becomes a solid element, changes its structure and becomes an obstacle  for the exit of blood from the vessels is a physiological mechanism that humans have in order not to die when we we cut, for example. What happens is that  when the clot forms in places where it should not, it becomes a problem ”. The hematologist doctor member of the Argentine Society of Hematology  José Ceresetto  (MN 74596) explained to  Infobae  that “what was observed to happen with Johnson's vaccine and that had already been seen with AstraZeneca's is that small clots are formed in places where they should not normally exist ”.

“The mechanism by which this occurs  was very well described by the German Andreas Greinacher at the time of what happened in the first place with the AstraZeneca vaccine and called it  vaccine-induced immune thrombocytopenia ; It is not that the clot occurs spontaneously, but rather that the virus that is inoculated in the modified vaccine so that it is harmless to humans and generates defenses against COVID-19 generates this effect on the immune system ”, explained Ceresetto , for whom “ it is a rare combination that occurs immediately after the vaccination of low platelet count and thrombus generation  and that which has already been seen to occur induced by heparin is an immune response that occurs by the presence of antibodies against a clotting factor (platelet factor 4) that is activated and causes platelets to form thrombi ”.

With information from Reuters