60% of the population is vaccinated, but they continue to …

Chile has overtaken 30 thousand dead since the start of the pandemic and in recent weeks new infections reported stood on a high plateau with an average of eight thousand each day. This also has 49,000 active cases and more than 3,200 hospitalized patients in intensive care units. Presents a 97% bed occupancy (only 167 are free) and the pressure on the health system is strong.

As is the case at the national level, the Chilean Society of Intensive Medicine has warned against imminent collapse of the sectorAlthough there are several cities on epidemiological alert, Santiago shows the worst numbers. It recently surpassed four thousand infections in one day, reaching the record it had only reached in June 2020, in the first wave, when diagnosed infections reached 4,421. , it has an intensive care bed occupancy rate of 98.8%.

Chile has the step-by-step plan, a phased system very similar to that established in Argentina, with quarantines targeted to each district, with openings and closings. The landscape is very similar to what is painted in most countries in South America. Even if there is a significant difference: According to the OurWorld in Data site, Chile has already vaccinated 59% of its population. Indeed, it shares the first places with Israel (63%), Canada (61%) and the United Kingdom (59%) thanks to the rhythm acquired by the massive inoculation of its inhabitants. “We have successfully vaccinated more than 8 million people with the two doses, which represents more than 53% of the target population of 15.2 million people,” President Sebastián Piñera said at a recent conference. The vaccination strategy also accumulates a 71.2% of citizens with the first dose, with which the coverage process has already been opened for people aged 23 to 25 years.

The paradox is served: while a priori it would be very close to collective immunity, unlike other experiences such as Israel or the United Kingdom, Chile faces a much more complex present. Of the doses he inoculated, 82% were Sinovac (CoronaVac), which is about 56% effective in preventing the spread of the disease. This way, although it has a greater ability to avoid hospitalizations and deaths, the spread of Sars CoV-2 and its variants does not stop.

Focus on the Sinovac

“Chile applied more doses than the population, I mean they inoculated an average of 102 doses per 100 people. Of course, that doesn’t mean that they have immunized one hundred percent, but there is a very large percentage of society vaccinated with a single dose and another not insignificant percentage who received both, ”explains the virologist. by Conicet. Mario Lozano placeholder image. And he maintains, “However, over the past week, he posted the second highest infection record in the entire pandemic. It’s basically due the low coverage of the technology they mainly use; I mean the Sinovac”. Then, the former rector of the National University of Quilmes continues his reasoning: “It is a vaccine which at the first dose hardly protects and with the complete scheme, that is to say with the two doses, it manages to protect half of the people. If we think that 80% of Chileans have received this formula, 40% of those vaccinated do not have the ability to avoid contagion. Yes, on the other hand, it protects better by avoiding serious cases and deaths due to Covid ”.

In April, the Chilean Ministry of Health published a report on the effectiveness of CoronaVac in order to analyze in real time what was happening with the vaccination process. “In a study referring to mid-April, specialists from the health authority evaluated the effectiveness of the two doses and also what happened with just one. Allí lograron affirmed that 14 días después de recibir la segunda dosis, the eficacia will be of a 67% frente a la enfermedad, of an 85% ante la hospitalización, of 89% frente a ingreso a terapia intensiva y un 80% respecto a muerte ” , precise Daniela Hozbor, Principal Investigator of Conicet at the Institute of Biotechnology and Molecular Biology of La Plata. The problem, however, was the poor protection afforded to individuals who only had the first. “With one dose, after 14 days, the efficiency to avoid infection was 16%, to avoid hospitalization it was 35%, 42% compared to admission to intensive care and 40% compared to death “explains biochemistry.

“Although with two doses the vaccine would work well, with just one the coverage is a bit loose. All the more so if the aspect of avoiding disease is taken into account. Your current situation may be due to this“, says Hozbor. ArgentinaOn the other hand, he uses vaccines which confer greater efficacy with a single dose. A survey conducted by the government of Buenos Aires among 186,581 people demonstrated the “real impact” of the first dose of Sputnik V. The study gave 78.6% effectiveness in preventing cases of covid, 84.7% in preventing death and 87.6% in reducing hospitalizations in people aged 60 to 79 years.

From this point of view, says Hozbor: “This is why in Chile they have made rapid progress in covering a large part of its population with a second dose. The time between the first and the second must be reduced as much as possible in this case ”. Then he ends: “For Sinovac, a strategy of postponing the second dose would not be very convenient”. As Argentina inoculates vaccine options more effectively, the option of postponing the second to protect more people in less time makes more sense. Nations like the UK and Canada have followed a similar path.

Inequalities that worry

The path that each country chooses for the mass immunization process takes place in a context marked by unequal access. “For Chile, the agreement with Sinovac enabled it to rapidly vaccinate its inhabitants and reduce the death rate. We are in a scenario where powerful nations are the ones who monopolize vaccines, for this reason, it is not easy for peripherals to get the best and in the right quantityLozano says. Then he goes ahead with a hypothesis that points against the media and opposition politicians: “All vaccines have their advantages and disadvantages. If our government had agreed with Pfizer, I am sure the media and the political opposition would have caused a scandal by reporting a few cases of serious allergies., as they have been identified in various nations. The sport they practice is the complaint, in any case they would have found the reasons ”.

In addition to Sinovac, Chile has also used other vaccines such as Pfizer (with which he immunized 18.5 of the total vaccinated), AstraZeneca (at 2%) and CanSino (at 0.6)but to a lesser extent. In 2022 the strategy could be oriented towards the incorporation of other more effective formulas, such as Moderna and Sputnik V, or else try to obtain more doses of Pfizer, whose landing in the south of the continent was rather poor. . the variants, like the one in Manaus and the one in the United Kingdom, they also complicate matters, especially in younger patients who, unlike the first wave, require hospitalizations. Hence the difference with strategies like Argentina, whose vaccination process is slower but based on vaccine formulas which have shown greater protection.