Vaccinating consists of teaching the immune system what to detect and attack. It consists of making the immune system learn to detect pathogens without having to suffer the disease they produce. However, vaccines are by far the most suspicious clinical therapy in the population.
One of the main misgivings against SARS-CoV-2 vaccines is based on the fact that they have been developed in record time . This reason does not make sense if we take into account that the current technological conditions and the clinical trials that have been carried out, when we find ourselves in a pandemic situation, have allowed it to do so. If vaccines were cars, it would be like comparing the manufacturing process of a Fort T – a 1908 model – with that of any current car.
Any drug accepted by regulatory bodies and already on the market goes to what is called phase IV, or pharmacovigilance. In this situation we find all the vaccines accepted by the European Medicines Agency. And because of that, we are faced with pressure on the Astrazeneca vaccine due to the possibility that it causes thrombi in a very low proportion of the population, only 2-3 cases out of 1 million vaccinated people.
Should we block a vaccine because of this possibility? Many of us are clear that not.
What is a thrombosis and what are its causes?
Thrombosis consists of the formation of clots in the circulatory system that, when they move, block blood flow and cause strokes or cerebral or myocardial infarctions.
Clot formation is a natural process that prevents us from bleeding out when the circulatory system is damaged. The problem arises when clotting occurs without tissue damage.
The Astrazeneca vaccine has been associated with certain cases (222 so far) of deep vein thrombosis. These thromboses are caused by abnormalities that affect blood flow in central veins of the circulatory system. They can be due to sedentary lifestyle or obesity, spending too much time on a plane (economy class syndrome), bed rest, genetic factors, fractures, pregnancy or having given birth, taking contraceptives, etc … That is, multiple activities everyday.
Can activation of the immune system cause thrombosis?
If possible. The production of clots with a low number of platelets (Thrombocytopenia) is a rare phenomenon but it can occur naturally. In fact, in COVID-19 patients it is the most common type of thrombosis. That is, the viral infection already, by itself, produces thrombosis phenomena with reduction of platelets.
Within this category we find immunothrombocytopenia with low platelets, an autoimmune response. That is to say, the cause of thrombi and the drop in platelets is the immune system itself, which, for some reason, generates antibodies that activate platelets, causing thrombi.
Benefit / risk, the normal balance in today’s medicine.
Our body is a set of cells and factors that act harmoniously for most of the time. Problems arise when this balance is broken by any factor.
Under normal conditions, without vaccines or pandemic, the incidence of immunothrombocytopenia is 3-4 cases per 100,000 inhabitants / year. It is what we generally consider a rare disease. In Spain it would be about 1410 cases a year.
So far in vaccination, the EMA has received 222 cases of thrombosis (unspecified) among 34 million vaccinated, a total of 0.65 cases per 100,000 vaccinated. This indicates 4.61 fewer than expected cases of this disease in the adult population. Is there, therefore, cause for concern?
I do not think so. But let’s argue a bit. Vaccines are made up of the antigens that we want the immune system to act against and the adjuvants that help activate the immune system. If thrombus production depended on adjuvants, many more people would have suffered from the same problem, but this has not been the case. We can, therefore, rule out an effect of vaccine adjuvants.
We have the antigen left. In this case, we could think that there is a predisposition of the people most affected by vaccines to respond to the antigen (vaccine or natural) in an exaggerated way and produce antibodies against platelets due to molecular similarity. That is, somehow the antigens of the virus would cause the immune system to generate antibodies that would activate the platelets. If this were the case, these people would still suffer clots when infected with the natural virus. Therefore, not being vaccinated would not be a valid option since their immune response would be more serious against the natural virus.
Be that as it may, the cause-effect relationship is so difficult to establish and may depend on so many factors that we can never arrive at a clear relationship, as is the case with most autoimmune diseases.
To stop getting vaccinated is to put yourself at risk and put others at risk.
The alarms have caused many people to fear being vaccinated with this particular vaccine. This puts these people and those who are related to them at risk, not only because of COVID but also because of the consequences that they can produce. I do not think it is necessary to insist on it.
Risk studies have been carried out with the Astrazeneca vaccine and all of them have indicated the high benefit of vaccination, especially in situations of high risk of infection. In other words, the possibility of becoming ill and dying from infection with SARS-CoV-2 is between 1,000 and 10,000 times greater than that of suffering a thrombosis, which can be clinically solved by the vaccine,
Despite that, scaremongering has spread. Furthermore, patients with immunothrombocytopenia already diagnosed before the pandemic have suffered from deficiencies in adequate healthcare during the pandemic, which have endangered their lives even without being infected or vaccinated.
Vaccination is the only possible strategy against a virus against which we do not have efficient drugs. Let’s be clear about it.
Guillermo López Lluch, Professor of the Cell Biology area. Associate researcher at the Andalusian Center for Developmental Biology. Researcher in metabolism, aging and immune and antioxidant systems, Pablo de Olavide University
This article was originally published on The Conversation. Read the original.
