Protecting the most vulnerable has been one of the great objectives of society in this pandemic. Severe cases of covid they have been concentrated in some groups, especially the elderly. To top, at first there were doubts about the effectiveness of vaccines in them because their immune system is more deteriorated with the passage of time. However, the response has been magnificent: clinical trials first and reality second show that vaccine protection is excellent. The unknown, now, is elsewhere.
With success in the elderly, doubts remain for people whose immune system is weakened by health issues. The clinical trials did not include immunosuppressed patients for safety and to expedite the investigation, so the answer must be sought among the real population that is already being immunized. Some indications are worrying, because there are studies in USA e Israel, countries with a very advanced vaccination process, which indicate that patients with some types of cancer or those who have received a transplant generate very few antibodies. However, immunology is very complex and experts do not rule out that a little protection is enough to rule out a serious coronavirus infection.
EFE
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“We know that our oncohematological patients develop fewer antibodies when they receive the usual vaccines, such as pneumococcus, hepatitis or flu,” says José Luis Piñana, an expert from the Spanish Hematopoietic Transplant Group of the Spanish Society of Hematology and Hemotherapy (SEHH). “So, we had the suspicion that the same thing would happen with the SARS-CoV-2 vaccines and we are seeing that the first publications confirm it ”, he adds.
An example is a Israeli study published in the journal ‘Blood’ which showed how patients of Chronic lymphocytic leukemia they only developed antibodies in 39.5% of the cases (167 participants with this disease were included). In contrast, all healthy people included in the control group than the control group had achieved this immune response. However, those who were in full treatment responded much worse than those who had already completed it. For this reason, the researchers consider that “the moment in which you administer the vaccine can be very important”, in the case of cancer patients, according to the expert.
As for people who have received a transplant, something similar happens according to the first analyzes. An investigation published a few days ago in the magazine ‘JAMA’ showed that 46% of a total of 658 patients had no antibody response to COVID. The study, conducted by Johns Hopkins University, included American patients who had already received both doses of one of the messenger RNA vaccines, Pfizer or Moderna.
In any case, experts believe that different circumstances and diseases related to immunosuppression should not be put into the same bag because there are many variables that can influence the response to the vaccine. Therefore, the SEHH is developing a study to record the data of patients who have been vaccinated throughout Spain and have data from serological tests (antibody level). “When we have a significant volume of patients, we can analyze what the vaccine response has been depending on each pathology, each procedure and each treatment, ”says Piñana. This research may also show differences between some vaccines and others. “Although these data do not help us for this pandemic, in the future we will have much clearer ideas,” he says.
On the other hand, although there is less seroconversion (less antibodies), “we suspect that there is a possibility that they achieve immunity by cells, that the vaccine achieves that the lymphocytes are able to recognize the virus thanks to the proteins of the vaccines and they can defend us even if no antibodies are made ”. It is a hypothesis that will have to be studied, but it is supported by experience. On vaccines against other diseases “this cellular immunity is produced in some patients who did not have antibodies, but not in all”. However, most of the studies that exist in this regard are very limited, explains the specialist, due to the small number of patients they usually include.
In this sense, experts reject the idea of trying to assess what the real protection of a patient is at a particular level through the performance of post-vaccination antibody tests. “An antibody test is part of the movie, but not all”, Comments Ignacio Molina, professor of Immunology at the University of Granada. If the generation of antibodies (humoral response) is strong, “it is expected that the cellular response is also strong, but a low humoral response does not necessarily mean that you are at risk.”
The relationship between covid and immunosuppression
These types of questions illustrate very well the complexity of the immune system. According to this immunologist, it is always expected that the effect of vaccines will be less in patients with a primary immunodeficiency or associated with some diseases. The same occurs in the event that the immunosuppression is due to medical treatment, as in the case of transplants, in which the aim is to avoid rejection of the new organ. However, “the fact that that response is less does not mean that the vaccine does not work enough to protect them from serious disease.” In that sense, remember that the ultimate goal of covid vaccines is to avoid hospitalizations and deaths. So it is possible that they only work partially in some patients, but that this is enough so that they do not suffer a severe coronavirus infection.
On the other hand, “immunodeficient patients, when passing the disease, do not have a special risk”, recalls the expert. Precisely, having a weaker immune response works in your favor, because severe cases of covid are characterized by an overreaction of the immune system to the invasion of the virus. This causes the hyperinflammation characteristic of the most severe cases. To what extent is this balance between being little protected by the vaccine, but having a lower risk than other people enough to consider that they would be protected? The solution to this complicated equation is to conduct more studies and collect more information.
Some of these patients could live with the virus for longer
Another example that the immunodeficiency situation has a double face is the suspicion that some of the these patients could live with the virus for longer and facilitate mutations to occur. “It is pure speculation, but this could be the origin of the british variant, according to the work that made it known. To explain how so many changes had been caused in the virus, they raised the possibility that it had been in some immunodeficient patient, who would have been in contact with the virus for a long time, enough to accumulate mutations and be transmitted ”, points out Molina. Although it is only a theoretical possibility, it is one more argument to protect these patients.
Solutions
The question is how to do it if it is confirmed that the vaccines do not offer sufficient protection. One of the possibilities is these patients receive more booster doses than the general population. For flu, hepatitis, or pneumococcal vaccines, studies show that booster doses are successful in “rescuing” patients who have not had an initial response. Even so, “it does not work for everyone,” warns the SEHH expert.
So one of the fundamental keys is “that the entire environment of the patients is vaccinated, in particular, the cohabitants. If they do not have diseases, they will respond to vaccines and will prevent the virus from entering the home of an immunosuppressed person, ”says Piñana. In fact, the SEHH has claimed that it is not only given priority in vaccination to certain vulnerable patients but, given the possibility that their response is poor, their relatives should be immunized as a priority. The increasingly clear evidence that vaccines, in addition to preventing disease, prevent the possibility of disease transmission reinforces this idea. Likewise, “despite being vaccinated, it is essential that these patients continue with protection measures, social distancing and mask“, He states,” other respiratory viruses have disappeared from circulation in this pandemic, evidently thanks to these measures against covid. ”
“Despite being vaccinated, it is essential that these patients continue with protective measures”
On the other hand, regardless of individual solutions, anyone who is not sufficiently immunized would also be protected by the whole of society if we achieve the famous group immunity. “As there are a high number of community members who are protected and who do not develop the disease, the virus’s ability to circulate is much lower, with which, this indirectly protects unvaccinated individuals ”, recalls the immunologist from the University of Granada. In this case, that protection would refer to individuals in whom the vaccine has not worked as well as would be desirable. In this sense, group immunity with respect to covid is not only desirable and necessary as a country “but also at the global level,” he points out.
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