The vaccinations They are focusing the social, health and even political debate. However, there is still no solution to one of the unknowns that they raise and that is whether they will finally end the total transmission of SARS-CoV-2, and therefore, with the current situation in which we have become used to covering our faces with masks. and get at least two meters away from our friends and relatives. Herd immunity, that is, 70% of the vaccinated population, could make it difficult to pass the virus. However, while this is happening, there is no certainty that a vaccinated person cannot become infected and transmit the virus.
Manufacturers have already warned: “Data are limited to ensure the effect of the vaccine against the transmission of SARS-CoV-2 from individuals who are infected despite vaccination ”. Because that’s right, a person vaccinated with designs that don’t get mucosal immunity can still get infected. “The vaccine does not prevent infection because it does not generate immunity in the upper respiratory tract,” says Agustín Valenzuela, virologist and researcher at the University of La Laguna (ULL). It is precisely in that location that the virus usually uses to begin to multiply and, later, spread throughout the body. Therefore, although immunity has been developed, teaching T and B lymphocytes “by heart” to attack the pathogen before it causes a Covid-19, it is unknown if that will be enough to stop the infections.
This would not happen if the immunity conferred by these vaccines were total, because in this way “the possibility of establishing a viral reservoir in the primary infection is eliminated,” explains the researcher. In other words, “the patient is protected and is prevented from infecting”. And it is categorical: “Moderna and Pfizer do not prevent you from getting infected or from getting infected.” In light of all this, Valenzuela considers that a person, despite being vaccinated, “could infect when the viral load allows it.” As he points out, “to determine the control effect of these vaccines on community transmission, solid scientific data still have to be obtained and work at the level of Israel or China during vaccine administration.” It should also be remembered that there are no data on these vaccines in patients with severe Covid-19 pictures, “who are not going to be vaccinated with these developments.”
“Preliminary studies show that once this memory is generated, we should not transmit the disease “, says the director of the University Institute of Tropical Diseases and Public Health of the Canary Islands, Jacob Lorenzo. However, this theory clashes head-on with what is previously known about the disease. And it is that asymptomatic patients are also contagious, despite not suffering it. Asymptomatic patients have also become the main stumbling block for Pfizer and Moderna, who admit that they could be the main problem in the future pandemic. As they point out, although “the high efficacy demonstrated against Covid-19 in symptomatic people may translate into general prevention of transmission in populations with sufficiently high vaccination,” it is possible that if the efficacy against asymptomatic infection were less than this , “Asymptomatic cases in combination with a reduction in the mask and social distancing could cause significant continuous transmission.”
In this sense, they conclude that it is necessary to carry out “additional evaluations that include data from clinical trials and the use of the vaccine after authorization, to evaluate its effect in preventing the spread and transmission of the virus, especially in asymptomatic people.” This line of research is one of the priorities set by the World Health Organization (WHO) which, in turn, considers it “a gap” in the knowledge of this vaccine.
A recent article published in the scientific journal British Medical Journal by the journal’s physician and editor, Peter Doshi, insisting that concrete data is needed to prove that vaccines are 95% effective. Among his concerns, Doshi noted that a report from the United States Food and Drug Administration (FDA) warned that in Pfizer’s studies there were 3,410 suspected cases of Covid-19 that could not be confirmed. With 20 times more cases of Covid-19 suspected than confirmed and “trials that were not designed to evaluate whether vaccines can interrupt viral transmission,” the expert points out that it is necessary to carry out a study beyond the symptoms, in which assess rates of hospitalizations, ICU cases, and deaths among trial participants. Valenzuela emphasizes, in this regard, that “the cases of asymptomatic infected in the immunized group have not been studied, both in the final Pfizer and Moderna safety and efficacy trials, and their comparison with placebo.” According to the researcher, this data is of great relevance, given that “community transmission is maintained by those infected by SARS-CoV-2 asymptomatically and who spread for time.”