Since a year and a half ago the new coronavirus began to hit the planet with virulence and doctors were thrown into a frantic race to decipher the characteristics of SARS-CoV-2, one of the biggest unknowns of the pandemic has been the immunity generated by the illness. Until now, the record of symptomatic infections in people who have already suffered from COVID-19 it is scarce, and the same happens with those who have completed the vaccination regimen. However, they do occur and raise the uncertainty of whether there is most susceptible groups to be affected.
Although COVID-19 serums have been shown to be very effective in protecting against serious illness and death and reinfections are very rare, the vaccine does not exempt from suffering a mild or moderate form of the illness. Thus, it is explained by the vice president of the Spanish Immunology Society, Eva Martínez, who points to the immunosuppressed people and the elderly such as those immunized most likely to present a clinical picture caused by the coronavirus.
“These are people undergoing chemotherapy or immunosuppressants, transplant patients, individuals with primary immunodeficiencies … They can make a much less potent response to the vaccine and it is possible that they develop a slightly more severe form of the disease, “says Martínez.
“People who generate fewer defenses may be more susceptible to having a symptomatic form”
Nor does he forget the elderly, at risk for having an immune system “less powerful than young people” and to which, on occasions, other pathologies are added, such as “hypertension, diabetes or obesity”. “People who generate fewer defenses may be more susceptible to having a symptomatic form, with clinical manifestations; but of those that existed before, which caused ICU admissions and deaths, it is now being seen a drastic decline“, he emphasizes.
In a similar vein, Alfredo Corell, the immunologist and professor at the University of Valladolid, emphasizes the duration of protection against COVID-19. “We still don’t know how long immunity lasts of the vaccine or that acquired by the infection. It is proven that the first reaches at least six or seven months and the second, ten. However, it is probably higher, “he details, and highlights that in the elderly it may be lower than in the rest of the population.
“We are always going to be more aware of people whose immunity is worse and in this case they are the elderly, because their immune system is more worn by age and they may stop having defenses sooner“, he says, more concerned about the future than the present, since currently there are hardly any severe conditions in vaccinated and reinfected elderly people.
“We are always going to be more aware of the people whose immunity is worse and in this case they are the oldest”
In this sense, one of the clearest examples of the effectiveness of vaccines to date are senior centers, whose users no longer die from COVID-19 or enter hospitals like a little over a year ago. In fact, screenings in these places have shown that some of the residents were infected after the punctures, but they ignored it as they did not present symptoms.
The vaccinated and the cured infected can infect
There are many studies that have tried to shed light on infections in vaccinated and cured patients and have placed the percentage of people at this juncture between 10% and less than 1%. A recent analysis in Chicago senior centers published by the US CDC detected 8 positives with different clinical pictures among patients and users of these residences, of which 3 suffered pneumonia and another died. Similar figures have offered published works The New England Journal of Medicine, The Lancet Y British Medical Journal.
These studies have also shown how infected and reinfected vaccinates can transmit the virus to their contacts. This is because the virus enters the respiratory tract and, for a few hours or days, It can multiply even in immunized people, until the defenses existing in the blood reach that area to neutralize it, explains Corell. During this time, the person can breathe it out and spread it.
“The time that they can transmit is much less and the viral load that they can transmit is much smaller”
“Why is this happening? Because intramuscular vaccines are boosting an immune response especially in our blood, not the route of entry, in the respiratory tube. When there are vaccines that are inhaled, the reverse effect is likely to occur: there will be no so much strength in the defenses in blood, but there will be many defenses in the airway, and these will prevent infection and transmission“, Add.
In this way, the period in which these people have the ability to spread the virus is two or three days, much less than that of non-immunized people, clarifies José Luis Barranco, spokesman for the Spanish Society of Preventive Medicine Public Health and Hygiene . “The time they can infect is much less and the viral load that they can transmit, the infective load, is much smaller, “he adds.
What about the variants?
On the role of variants in the infections of those already immunized, Barranco highlights that there is nothing to support that the different versions of the coronavirus may be behind. “Vaccines are all effective, the four that we have. It does not have to affect, “he assures.
A statement supported by the vice president of the SEI, who deepens: “If a new variant appears against which vaccines are not so sensitive, even people would be infected. It will depend on the severity of the variants. “