There is no scientific evidence nor is it suggested by regulatory bodies, but many countries have already jumped on the bandwagon of the fourth vaccine. Chile, Israel or the United Kingdom have begun to inject this booster dose and Spain will join them in a few months, when five months have passed since the immunosuppressed population received the third. In this scenario, experts warn that There is no scientific evidence to support the need to re-inoculate this puncture in such a short period of time. and they question that the population should be vaccinated indefinitely against covid-19.
"Given the demonstrated efficacy of current vaccines, there is no evidence to suggest that a fourth dose should be administered in the near future." This is how the Spanish Society of Immunology (SEI) contemplates it, which has also remarked that "It makes no sense to give a third dose to healthy and young people, such as the group between 18 and 40 years old", as proposed by the Ministry of Health. They consider that this reinforcement is even less necessary "when many of them have just been infected with the Omicron variant and have already acquired a natural reinforcement."
The CSIC virologist, Margarita Del Val agrees with them and admits "not understanding" the decision to vaccinate people who have just had the disease which, according to the guidelines of the Ministry of Health, they should be revaccinated 4 weeks after diagnosis. "It doesn't make immunological sense because the system is reinforced by the infection," says the CSIC scientist, who points out that it doesn't make logistical sense either. "Are they going to vaccinate half of the Spaniards in a month?" asks the virologist. Furthermore, it emphasizes that covid should not be treated in any way like the flu, neither in regard to vaccination. To begin with, because "the covid vaccine is more effective than the flu vaccine and because the coronavirus mutates 10 times less." But also because there are so many other viruses living with us for which the population is only protected once without the need to inoculate a booster dose. This is the case of the pneumococcal vaccine for those over 65 years of age, which, as Del Val indicates, "is so powerful that once it is inoculated, it is enough."
García Rojas considers that first the vaccinations must be completed and the laggards must be incorporated
Experts agree that there will be a part of the population that will surely require a booster dose, and that is the one that suffers from some type of immunosuppression. However, they do not believe that, in this case, the inoculation should be done in the short term because, at the moment, there is no data to support this decision. "It is a debate that we should not be opening now," laments the head of epidemiology of the Government of the Canary Islands, Amos Garcia Rojas, who points out that "There is no evidence that it is required, and not even the regulatory bodies are recommending it". "What it is time to complete the vaccination to those who have not finished it and incorporate the laggards", asserts the epidemiologist. In the Canary Islands there are still 287,478 people who have not yet received their first puncture - including children between 5 and 11 years old -, which represents 13.7% of the population.
"People who have immunosuppression respond worse to vaccines, because they develop antibodies against covid worse, but it is not yet known if they are less protected because there is no data," insists, for her part, the virologist from the Higher Council for Scientific Research (CSIC), Margaret of Val. The expert recalls that, before making decisions, "clinical data must be studied to find out if these people are at greater risk or not" against the coronavirus before vaccinating them again. Without this information, she insists, "It doesn't make sense to give a fourth vaccine shortly after the third," because in addition, "the fourth dose can be an improvement, but not tremendous".
A recent study, conducted in Israel, is consistent with the statement of the Spanish virologist. According to the preliminary results of a study by the Israeli Sheba Medical Center, a booster dose from both Pfizer and Moderna is only "partially effective" against the omicron variant, which is currently the absolute dominant in the Islands and much of Spain.. "Despite increased antibody levels, the fourth vaccine offers only partial defense against the virus. Thus, the vaccines (Pfizer/Moderna), which were more effective against previous variants, offer less protection against omicron," said Gili Regev-Yochay, director of the research. "The increase in antibody levels that we saw with both Modern as with Pfizer is slightly higher than what we saw after the third booster vaccine," said Regev-Yochay, director of the Infectious Diseases Unit, who, however, detects less effectiveness with the current dominant variant.