It is the ideal to achieve since the pandemic began, almost a year ago. When the majority of the population is immunized, it will be difficult for the virus to find individuals to infect and the epidemiological situation will be – it is believed – controlled.
Now, is the immunity achieved by those who contracted the disease of equal value as those who were vaccinated? What percentage of the population should be protected in order to start thinking about a return to “normality”? How much does the low vaccination rate in Latin America and the early arrival of the fall / winter season affect a second or third wave in the region?
The paradox that COVID-19 brought to the table is that the same questions that “ordinary” people have asked women and men of science since the new virus put the world on edge.
“Without a doubt we have a problem in Latin America; We are the second to last region in the world in access to vaccines – the last one is Africa – and this is not a simple comparison but it is the reality according to which, for the more than 600 million people in Latin America to achieve their immunity from herd have to vaccinate 70% of the population and what is important is that this vaccination is quickly accessed because the variants that are circulating in the world are already being done by some countries in the region ”. For the infectious disease doctor Roberto Debbag (MN 60253) another not less data is that “half of Latin America will enter in the next six weeks in the fall season and has the possibility of a second or third wave ahead and therefore there is an urgent need to access hundreds of millions of doses in the next 8 to 12 weeks and this is not happening ”.
In the words of the vice president of the Latin American Society of Pediatric Infectology, “only Chile, which had generated timely agreements, is ahead in vaccination since it is receiving more doses and achieving a high vaccination rate, which is not what happens in the rest region of”.
“In Argentina, it is necessary that in March and April, between 12 and 15 million people are vaccinated with at least a first dose, who are those over 60 years of age, in addition to all those who have comorbidities -he insisted in dialogue with Infobae-. In this way, four weeks after the first dose, the probability of death would decrease if there is the epidemic peak that would begin when the autumn-winter season begins in the country ”.
Also consulted by this means, the infectologist and president of the Argentine Society of Infectology, Omar Sued (MN 91262) evaluated that “it is very difficult to give a standard definition of herd immunity; one could talk about what happens in most diseases, but in COVID-19 it is still not known. “If one thinks of a herd immunity that occurs after an infection in a large number of people, reality surprises us with the second wave that was seen in Manaus (Brazil), where 70% of the population had positive serology because had suffered coronavirus before But a new strain with mutations that were not recognized by the antibodies that these people had generated a new wave ”, he analyzed, while emphasizing:“ Then a situation could occur in which despite the fact that there are many people who have suffered the disease, as happened for example in the Mujica neighborhood of the City of Buenos Aires, where 52% of people have positive serology, they become infected again ”.
For Sued, “the second topic in herd immunity is talking about vaccinated people, and then To think about herd immunity by vaccines with a vaccine that is sterilizing, that is, that does not produce infection, it would take at least 75/80% of people vaccinated and no country in the world except Israel has achieved this level of coverage of vaccines so it is not yet known how this behaves at the public health level ”.
According to Debbag, “the main problem lies in the non-availability of vaccines, but the problem is not only in the global difficulties that occurred around production, but also that the countries did not make early agreements to guarantee the supply of vaccines.” In that sense, for him “Herd immunity is not going to be achieved this year in the region; more than 400 million people would have to be vaccinated and there is no availability ”.
And he added: “It is a problem of inequity in access to vaccines in the region due to multiple factors; factors that have to do with the health policies of the different governments and also with issues that have to do with the deterioration of the health system in the last 30/40 years in relation to the processes of transparency in the making of agreements and systems of vaccine delivery ”.
– Does it depend only on the number of people vaccinated? What role do people who naturally acquired immunity from contracting the disease play?
– Debbag: It depends on the degree of community immunity, either from the vaccine or from having contracted the disease.
Since most governments do not carry out efficient programs to detect infected people and vaccinate dirty (without knowing which people have natural antibodies), more than 70/80% vaccination of populations is required.
People who acquired the disease have immunity naturally and are protected – at least so far the studies that exist speak of an eight-month immunity – that’s why in countries or regions like Argentina that do not quickly access millions of doses In the meantime, the alternative in the meantime is to find the people who have had the infection and not vaccinate them (postpone the vaccination until three or six months after the infection is acquired since there are studies that show that if they are vaccinated between the third and the sixth month have even higher antibody titer than those who received two doses).
Finally, Sued added bad news: “Vaccines are 100% effective in preventing death but they do not prevent infection. When it is said that they are 80/90% effective, it means that there will be 10/20% of people who may have mild COVID and who have a positive CRP and are surely contagious, although there are no studies yet to see the contagion potential of these people ”.
“We must continue to hope that science advances in conjunction with vaccination plans and continue to appeal to vaccinate as many people as possible as quickly as possible, especially among those who are more likely to die as are the groups of more 60 years old -he argued-. We hope that these people are vaccinated by September at the latest, but that will depend on the provision of vaccines reaching the country on time ”.
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