The safety committee of the European Medicines Agency Ema (PRAC) concluded today that unusual blood clots with low platelets should be listed as very rare side effects of Vaxzevria (AstraZeneca’s vaccine) and speaks of a strong link with the vaccine. The frequency difficult to assess, the agency says, but mentions the figure of approx 1 case its 100mila, or more. Based on this, explains EMA, national authorities will be able to decide how they would like to vaccinate and with what type of vaccine. The use of the AstraZeneca vaccine could be recommended above 60, learns theAnsa from qualified sources. The indication could be accepted by all EU countries in a unitary position currently under discussion.
There are no risk bands
EMA believes the vaccine could trigger a immune response leading to an atypical disorder similar to heparin-induced thrombocytopenia (called HIT). It is currently not possible to identify specific risk factors, EMA writes and adds at the press conference: Age, gender or previous medical history of coagulation disorders have not been able to be confirmed as rare events are observed in all ages and in men and women. Likewise there is no way to say that pregnancy or oral contraceptives could be risk factors for specific cases, the committee said. The PRAC will require AstraZeneca, the vaccine manufacturer, to carry out a series of studies to ensure reliable data to further evaluate this safety concern.
In the UK AstraZeneca over 30
In the United Kingdom, the Regulatory Agency for Medicinal Products (Mhra, in English acronym) has decided that it will advise to administer to those who have less than 30 years, Pfizer and Moderna vaccines, instead of that of the Anglo / Swedish pharmaceutical company. As of 31 March, 79 rare cases of blood clotting had been recorded in the UK (51 women and 28 men), of which 19 people died, three of whom were under 30 years old.
The analyzes: incidence 1 in 100 thousand
The EMA Committee carried out an in-depth analysis of 62 almost of cerebral venous sinus thrombosis e 24 almost of splanchnic vein thrombosis reported in the EU drug safety database (EudraVigilance) as of 22 March 2021, 18 of which were fatal. The cases were mainly from EEA and UK spontaneous reporting systems, where approx 25 million people they had received the vaccine. The PRAC noted that blood clots occurred in the veins of the brain (cerebral sinus thrombosis, CVST) and abdomen (splanchnic vein thrombosis) and arteries, along with low platelet levels and sometimes bleeding. As of April 4, 2021, the new drug safety database had received a total of 169 cases of cerebral thrombosis and 53 of splenic vein thrombosis. And at that moment they counted 34 million of people vaccinated in the European Economic Area and the United Kingdom.
The reported combination of blood clots and low platelets was judged to be a very rare side effect and it has been confirmed that the overall benefits of the vaccine in the prevention of Covid (linked to serious risks of thrombosis) outweigh the risks of side effects.
With the Johnson & Johnson anti-Covid vaccine, 3 cases of rare and abnormal thrombosis have been reported after the marketing of the shield product out of 4.5 million vaccinated. This was reported by Sabine Straus, head of the Prac Pharmacovigilance Committee of the European Medicines Agency EMA.
The mechanism at play
The EMA also confirms the possible explanation of rare thromboses, resembling the syndrome sometimes seen in patients treated with heparin (heparin-induced thrombocytopenia, HIT): This is a mechanism of autoimmunity. If you give the vaccine, the vaccine is supposed to stimulate the production of antibodies with the spike protein. In some people, fortunately not in all, it also stimulates the production of so-called auto-antibodies, that is, antibodies aimed at the cells that are part of our body, in this case the platelets and coagulation factors, explains Courier service Pier Mannuccio Mannucci, researcher at Fondazione IRCCS Ca ‘Granda Ospedale Maggiore Policlinico di Milano, one of the coagulation experts appointed by Aifa to support decisions on thrombosis.
How to deal with problems
EMA recommends healthcare professionals to pay attention to the signs and symptoms of thromboembolism and thrombocytopenia so that affected people can be treated promptly in line with available guidelines and remind them of the information on the package insert (which will be further updated): See a doctor if they develop: symptoms of blood clots such as shortness of breath, chest pain, leg swelling, persistent abdominal pain neurological symptoms such as severe and persistent headache and blurred vision petechiae beyond the vaccination site after a few days. If the mechanism similar to that of the HIT, it could be treated with immunoglobulins and some blood thinners (without heparin) which can help dissolve clots.
In recent days, some European countries (Germany, France, the Netherlands, Sweden, Iceland, Estonia, Finland) had decided to limit the use of the vaccine only to elderly people (generally over 60 years) precisely because of the slight increase in episodes thrombotic observed in young women not seen in the older population.
Not the first time that EMA has expressed itself on this issue: the first suspension of the AstraZeneca vaccine for rare adverse events dates back to mid-March. EMA had judged the vaccine to be safe, always stating that its benefits outweighed the risks, then the package insert was changed, where warnings regarding disseminated intravascular coagulation were added.
April 7, 2021 (change April 7, 2021 | 19:41)