A person wears a face mask as people walk in Westminster, London, Britain, March 24, 2022. REUTERS/Peter CziborraThroughout these two years of the coronavirus pandemic, we learned that it is possible for a person who has already had COVID-19 to become infected again in the short, medium or long term. According to scientific evidence, for some viruses, the first infection can provide lifelong immunity; but for seasonal coronaviruses – it is known – protective immunity is short-lived. And with SARS-CoV-2 the same thing happens, as a coronavirus it is.The latest news that caught the attention of scientists, such as prominent cardiologist Eric Topol, it became known that in the United States, 10 people who contracted COVID-19 from the Delta variant were reinfected with Ómicron in less than 90 days after their first infection. The expert communicated this news via Twitter and cited the scientific study presented by the Centers for Disease Control and Prevention (CDC).Un nuevo estudio científico comprobó que las reinfecciones por COVID-19 pueden ser antes de los 90 días (REUTERS/Kai Pfaffenbach)REUTERSThis report describes 10 patients from four US states (Vermont, Wisconsin, Washington, and Rhode Island) with Omicron variant infections, of which eight were under 18 years of age and one of them was 11. Since most PCR tests do not identify the specific variant of COVID-19 responsible for an infection, and some people may have viral RNA remaining after infection, the study used whole genome sequencing (WGS) of the virus to confirm the variant. The first cases of Omicron re-infection occurred within 90 days of a previous confirmed Delta infection, and the shortest interval between one infection and another was 23 days for the individual from Washington. Of these cases, nine patients showed symptoms for an average of 9 days while infected with the delta variant; however, during re-infection with Omicron, only six were symptomatic in a five-day period.“The findings of this case series may not be generalizable to the US population and are specific to the transition period between the predominance of the Delta variant and Ómicron. However, this study highlights the potential limits of infection-induced immunity against new variants,” the authors of the study indicate. According to the CDC, only one of the patients had received a full series of primary COVID-19 vaccines, but was not yet receiving booster, while the other nine were not up to date with the recommended vaccines, so it was concluded that they may have a higher risk of infection with SARS-CoV-2 due to low rates of vaccination. La vacunación sigue siendo el arma más eficaz para evitar el coronavirus (REUTERS/Agustin Marcarian)REUTERSGiven these facts, the authors of the study indicated that “vaccination remains the safest strategy to prevent future SARS-CoV-2 infections.” While this study does not represent the general population of the U.S. “This study highlights the potential limits of infection-induced immunity against new variants,” the report states.Consulted by Infobae, the infectiologist Lilián Testón (M.N.87.307), coordinator of the Department of Epidemiology and Infection Control of FUNCEI (Foundation of the Center for Infectological Studies of Dr. Daniel Stamboulian), explained: “Reinfection is a highly debated phenomenon during the current pandemic and not yet some concepts are clear. Its diagnosis is difficult, since it requires genomic sequencing techniques to compare both infections and that in the primary infection it has been confirmed by PCR, that there is the disappearance of symptoms of this infection”.“We know that CRP can persist positive beyond the patient’s symptoms and what it is demonstrating is the presence of non-infective particles. Once infected, individuals developed an immune response to SARS-CoV-2, remembering that in more than 80% the infection with COVID is mild. From what we know about the virus, reactivation, relapse or latent infection seems to be less possible and has not been described in coronaviruses,” he added.Todavía el mundo vive en pandemia y los cuidados deben extremarse (REUTERS/Gonzalo Fuentes)REUTERSFor the doctor of virology Laura Palermo, an Argentine professor who lives and teaches at the Faculty of the Human Biology program at Hunter University and at the University of the City of New York, “the scientific definitions of reinfection and recontagion tell us that they are synonymous, and with respect to COVID-19, what is seen until now is that when a patient suffered from this disease and recovered, he usually does not get infected again, that is, there is no re-infection.”There is another exceptional situation, as explained to this medium by Laura Palermo, although it is not precisely addressed in the recent case study: “There are some people who are confused in relation to patients who apparently reinfected themselves, but in general they are cases of symptoms that were never able to eliminate the virus completely and suffer a kind of relapse, they are sick who feel bad for many weeks, at some point they seem to get better and then they relapse. These patients actually suffer from a single infection, the primary one, but that spreads more than usual, and these cases are called “persistent infection”.KEEP READING:Why COVID-19 reinfections become more frequentThe wave by Ómicron generated more reinfected than the entire previous stage of the pandemic