After the Oxford / AstraZeneca vaccine (THE), it was Johnson's exclusive vaccine & Johnson (J&J), announced the suspension of its administration in the US after the occurrence of six cases of thrombosis (of a lethal) among about 7,2 millions of people who have been vaccinated in the country.
However, even if a relationship is proven –something that has not been done yet– the proportion is less than one case per million vaccinations with J&J, much less likely to get sick with Covid-19.
It was preceded by similar and equally rare cases of thrombosis with the AstraZeneca vaccine, resulting in disruptions to vaccination programs in several countries and age restrictions on its use (e.g. in Greece is granted to those over 30 years).
Suspension of a vaccine is not uncommon and research often concludes that rare medical events are coincidental and unrelated to the vaccine..
Nevertheless, if found, indeed, some correlation, then new instructions are issued as to who should get the particular vaccine and who should be careful.
THE European Medicines Agency (EMA) considers that in the case of AZ this is a contingency, very rare side effect after the first dose vaccine, while it is still too early to assess whether something similar is likely to be true of the J vaccine&J.
In each case, according to the New York Times and the New Scientist, scientists agree that if there are any risks, they are too small and certainly much smaller than the risk of coronavirus, γι’ this people have no reason to hesitate to be vaccinated.
According to the National Vaccination Committee of Greece, "The risk of serious illness and death from Covid-19 is overwhelmingly higher than the risk of thrombocytopenia after vaccination, especially at ages older than 30 years".
This is an unusual type of vascular thrombosis, usually in the brain, which is associated with low platelet counts (thrombocytopenia) and possibly bleeding.
It is presented, mainly, to people under 60 years, more common in women than,what men, although in part this is probably due to the fact that more women than men may have just been vaccinated, as e.g.. in many countries they make up a larger proportion of healthcare staff and caregivers.
It is unknown at this time what he will do after leaving the post,what the elderly.
In the case of J&J thrombosis occurred in women 18 to 48 years, within a time "window" of six to 13 days after vaccination, according to Dr. Anthony Fauci, Chief Scientific Adviser to the Biden Government.
There is still no definite explanation for the occurrence of thrombosis and thrombocytopenia, nor has a safe way been found to predict who may manifest it.
In the case of AZ, many of those who had such a problem tested positive for antibodies, which attach to a molecule (PF4) released from platelets.
There is a possibility, according to Dr. Andreas Greinacher of the German University of Greifswald, the vaccine to trigger - in a way- in very few people the production of such antibodies, which cause multiple small clots in the blood, in a similar way that similar antibodies can be triggered by heparin therapy.
Recently, Some countries have issued instructions to perform a platelet antibody test in case someone has symptoms reminiscent of thrombotic syndrome within two weeks of being vaccinated.
If someone comes out positive, should do the same treatment given to anyone who has experienced something similar after heparin administration.
So far, such a very rare side effect has only been associated with vaccines that use a harmless adenovirus as a "vehicle" to pass on genetic instructions to the vaccinated person in order to trigger the immune process. (AZ contains chimpanzee adenovirus and J&J by man) and not with mRNA vaccines, such as Pfizer / BioNTech and Moderna.
The Food and Drug Administration (FDA) The United States has said no cases of brain thrombosis have been reported, in combination with low platelets, after the above two mRNA vaccines.
«What we see with the J vaccine&J looks very similar to the AZ vaccine. The possible cause, we can guess, is a similar mechanism that probably occurs with vaccines that use adenovirus», noted Paul Marks of the FDA.
According to the FDA, a reason for suspending the single-dose vaccine of J&J is to give doctors time to better understand how to diagnose and treat this very unusual thrombotic syndrome, if presented.
However, thrombotic syndrome is so rare, that those who display it, they probably have someone else - unknown until now- temperamental or biological factor that makes them vulnerable, according to Greinacher.
«There must be individual factors that coexist and trigger it. Otherwise we would see the problem in many more people, which fortunately does not happen», he stressed.