A summer of infections pending the fourth vaccine

The covid-19 begins, again, to be a problem in hospitals. Before him infection boom, Specially in older than 60 years, Catalonia asks the Ministry of Health put the fourth doses in those over 80. Health had planned to administer them from autumn. There are also experts, such as the CSIC immunologist Margaret of Val, who are committed to giving, to the vulnerable patients who have not obtained a good immune response after the first three doses, drugs such as monoclonal antibodies, in replacement of the fourth puncture.

The pandemic tightens. In just one month, health centers throughout Spain have gone from having some 6,500 patients admitted the first week of June to 10,249 notified by the Ministry of Health this Friday. The cumulative incidence in the last 14 days it has risen to 996 cases per 100,000 inhabitants (a month ago it was 617) and covid-19 causes an average of 40 deaths a day in all Spain. “I am concerned that we have many patients again with coronavirus. There are already enough to stress to the hospital”, certifies the Head of the Infectious Diseases Service of the Hospital Clínic (Barcelona), Alex Soriano.

They are, yes, very old patients, who are admitted “because they decompensate their underlying disease”. “The good part is that, at the moment, we do not have patients in ICUs due to covid. But I am worried that things will change in a week or two. And, also, that at a certain moment the age of admission lowers and the severity increases, “adds the infectologist.

In this situation of spread of the virus (something that is essentially due to the subvariant of the omicron, the BA.5, the most contagious of all), the Ministry of Health urged the Public Health Commission this Friday to reassess the possibility of administering the fourth dose to those over 80 years of age before the fall. “I don’t see much point in having to wait until the fall,” The president of the Scientific Advisory Committee against Covid-19 had already said last week, Magda Campins, on Catalunya Ràdio.

Del Val: “Immunity is not lowering”

However, not all experts agree on the need to give the fourth dose, not even to vulnerable people. “We haven’t seen any indication that immunity has dropped. Immunity is lasting,” said the immunologist of the Higher Council for Scientific Research (CSIC) on Monday. Margaret of the Valley at the presentation of a European study on the Impact of covid-19 on Spanish residences.

“Right now a fourth dose to people who respond well to the vaccine doesn’t make sense,” defended from Val. According to her, the third dose of the vaccine already greatly increases neutralizing antibodies against the virus.

Del Val also focused on the fact that there are people (for example, the very old elderly the patients immunocompromised or transplanted) in which the three doses of the vaccine have not generated a good immune response. For this reason, she advocates administering other drugs to this small group, instead of giving them the fourth vaccine.

“We know there is between 5% and 10% of transplant patients or immunosuppressed patients who will remain unresponsive to the fourth dose. It is possible that these patients would benefit more from other strategies than from a fourth vaccine,” Soriano also points out.

Specifically, he refers to Evusheld, what is a monoclonal antibody (an artificial protein that acts like a human antibody in the immune system). It is already being used in immunocompromised patients. “It can serve as a way to vaccinate. A form of passive vaccination”, says this infectologist.

“Cross-Country Variability”

As explained by the Section Head of the Infectious Diseases Service of the Germans Trias i Pujol Hospital (Can Ruti, in Badalona), Roger Paredes, there are “vulnerable populations”, at higher risk, in which the “usual doses” of the vaccine “are not enough”. According to him, there is “much variability” between different countries. “Some believe that, with the fourth dose, they would achieve a good answer. Others, that, no matter how much vaccine there is, it cannot reach the desired protection” He says. For example, a group of those who do not respond well are the lymphoma patients. “There are monoclonal antibodies that remain in the blood for between three and six months. We consider these people, who are few, do this treatment.

The most vulnerable patients, in addition to monoclonal antibodies that can serve as protection against the coronavirus, also have a series of antiviral drugs that are administered to them once they have already tested positive for covid-19. Are the paxlovid (“the highest priority of all”), the remdesivir (given for three days to newly infected people intravenously) and the molnuparivir (by mouth, but there are studies that show “less efficacy”).

Even so, Paredes remembers that all these drugs are “more expensive” than the vaccine. “That’s why we must first maximize the efficacy of the vaccine. In a specific population, it is not silly to put fourth doses,” defends the Can Ruti infectologist.

Antibody resistance

For his part, the internist and infectologist at the Hospital de la Santa Creu i Sant Pau (Barcelona) Pere Domingo he fears the problems that antivirals can cause. have already been described Mutations of the virus that generate resistance to antivirals. The virus will try to look for mutations that do not allow the drug to act,” Domingo points out. It is not an opinion shared by all his colleagues. “Right now antiviral resistance is not a common problem,” says Dr. Paredes.

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For Sunday, however, it is “sure” that these resistances will occur to drugs. That is why it is important to continue researching and finding new antivirals. “If we had Many, it would be less of a problem. But we don’t have many antivirals.” One option would be, when there is more variety of antivirals, to do “combinations” between them. The high daily transmission of the virus facilitates mutations and escapes, not only to vaccines, but also to drugs.

Domingo warns that the subvariante BA.5, which is already present in 80% or 90% of infections in Catalonia, is “the worst” that there has been so far as far as transmission is concerned. It is less serious than the previous ones and is not causing many admissions to ucis. But, if the patients in hospitals continue to increase, so will the ICUs and, with them, mortality.

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