Page 15 - MONTT LATIN AMERICAN MAGAZINE, MAY 2021, (English)

Increase in Contagions
In parallel, the country continues to vaccinate quickly but the rise in infections generates uncertainty. Chile is the second territory in the world with the highest percentage of the population inoculated with two doses, only behind Israel, which surpasses other vaccination giants such as the United States and the United Kingdom and all other Latin American countries, according to data from the University of Oxford
However, Chile registered 8,680 daily cases on Friday, May 28th, the second highest number of the pandemic after the 9,117 infections reported on April 9th. The occupancy of critical beds at the national level was 95,4 percent, the daily report showed, but in the Metropolitan and Coquimbo regions it was 98 percent, all of which is leading experts to take progress with caution. of vaccination. “We still have many uncertainties to think that the pandemic will end soon. 50 percent is still a low gure, we need to vaccinate at least 75 percent of the population to achieve herd immunity, “said Nicolás Muena, an expert in vaccines and virologist at the Science and Life Foundation.
According to a study released by the Chilean government, the Sinovac vaccine, which is virus-inoculated and requires two doses, prevents 67 percent of infections, compared to 95 percent effectiveness of Pfizer / BioNTech or 80 percent by AstraZeneca. Late the authorities are understanding that Chinese immunization is not enough and that although in four months, more than 60 percent of the population has been vaccinated, the country is still at risk and with a false sense of security.
It is not enough to have a reasonable number of adequate doses, if you do not get quality. In fact, four of the ve countries that have vaccinated the most in the world, are struggling to contain the coronavirus outbreaks that are, per capita, higher than the increase that devastates India, a trend that makes experts intensify their questioning. on the type of immunization used.
The Seychelles, Israel, the United Arab Emirates, Chile and Bahrain are the ve countries with the highest number of
immunizations in the world; only Israel is not ghting to contain a dangerous rise in covid-19 infections.
Studies conducted on millions of people in Israel immunized with the Pfizer- BionTech vaccine showed that mRNA doses prevented more than 90 percent of asymptomatic infections.
Herd Immunity
That’s important, said Raina MacIntyre, an epidemiologist at the University of New South Wales in Sydney, because the ability of a vaccine to stop asymptomatic infection “is the determining factor of whether herd immunity is possible or not.” This is generally accomplished when the virus can no longer nd a vulnerable host in which it can continue to spread. Therefore, which vaccines will be applied in a country could a ect everything from policy on mask use and social distancing, to lifting of border restrictions and economic reactivation, given the in uence that daily case counts have on Government decisions. For individuals, it means how soon they can regain the freedoms they enjoyed before the pandemic. But apparently and despite the vaccination e ort, we are far from that. The initial so-called “heady hopes” when mass vaccination began is giving way to a much more di icult reality. First, while there is so much inequality in the capacity of vaccines, it will be di icult if not impossible to achieve the desired herd immunity; then for governments, the appearance of new variants is causing problems in their plans to reopen economies and return some normalcy to life.
Furthermore, scientists tracking the pandemic are seriously questioning the idea that societies will ever achieve herd immunity, even when there is an abundant supply of vaccines. At the beginning of the pandemic, some specialists expected that the threshold could be as low as 60 percent. For most of the past year, Washington DC Vaccine Research Foundation executive director Peter Hale argued that US health agencies informally set herd immunity at about 75 percent.
Test results for the messenger ribonucleic acid (mRNA) vaccines developed by BioNTech / P zer and Moderna seemed
likely to help achieve that goal, at least for developed nations. But since the B.1.1.7 “UK” variant, which is now dominant in the United States, is more transmissible than the prevalent strains in the country, the threshold for herd immunity may now be closer to 80 percent, he said.
In the United Kingdom the possible spread of the Indian variant, which is believed to be even more contagious, further complicates calculations on this matter.
The director of the covid-19 modeling consortium at the University of Texas, Lauren Ancel Meyers, argues that: “I would not say that herd immunity is out of the question, but I would add that herd immunity is quite unlikely in the foreseeable future, in the most communities and in most cities in the United States and around the world”.
Incomplete Protection
The professor of the Chair of Medicine at the University of East Anglia, England, Paul Hunter, doubts that herd immunity can be achieved today, given the levels of hesitation and incomplete protection that even the best vaccines provide, something that however, it is likely to decrease over time. “For me, there are two reasons why the misuse of the term ‘herd immunity’ can be harmful. The rst is that some people may mistakenly think that they do not need to be vaccinated because they are protected by all the people around them who have been vaccinated. The second is that people are using herd immunity as an argument to relax social distancing restrictions too quickly. “ If, as now, large swaths of the world remain unvaccinated, travel between regions runs the risk of triggering new outbreaks in areas where uptake of the vaccine has been erratic and important variants that can evade vaccination.
“Cities can serve as reservoirs where the virus can continue to thrive and continue to evolve, and it is very likely that we will see variants emerging and spreading throughout the world,” Meyers says.
To this must be added that there are several groups of people who are averse to vaccines, skeptics or even entrenched anti-vaccines. More recently, concerns about a rare side e ect of the Oxford / AstraZeneca vaccine have hit con dence: After the injection was stopped in March, the number of people who perceived it to be safe dropped substantially in France, Germany, Italy and Spain.
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