Lit the alarms from the authorities around the world due to its high contagion capacity and in a few months it became the dominant variant in the world, however, the Delta has remained until now a minority phenomenon in a large part of the Latin American countries.
The competition between strains, diversified vaccination or biological and cultural factors are some of the hypotheses that experts consider to explain this phenomenon, which still has the region between caution and calm.
With almost 44 million cases and 1.46 million total deaths, Latin America, one of the regions most affected by covid-19 in health and economic terms, has been with sprouts isolateds of this variant originated in India and even countries such as Chile, Uruguay or Colombia enjoy a pandemic truce.
Except for Mexico, where the Delta does predominate over the rest, the situation is far from that experienced in Europe or Asia, where in a matter of weeks it spread like wildfire leaving behind millions of infections.
Climate and culture
Since the first case of Delta was reported in Chile last June, the country has registered a sustained decrease in infections and is now enjoying one of its best pandemic moments, with more freedom than ever since the arrival of the virus.
For the director of the Institute of Public Health of Chile, Heriberto García, one of the hypotheses that would explain that the Delta has not penetrated so much it has to do with the weather, since in Europe it spread rapidly in summer, while in the southern hemisphere it was winter.
“Another reason would be cultural factors. In South America we have an idiosyncrasy and a way of relating that is different from other parts of the world and that might not accommodate the Delta,” said the expert.
Competition between variants
Other reasons why it has grown at a slower rate is the “competition” between the different variants of the region, according to the director of the National Center of Public Health of the National Institute of Health of Peru, Fernando Donaires.
In Peru, which has more than 2 million infections, the Delta has left 244 cases and has a frequency of 20%, while the lambda -of Andean origin and found in April- came to suppose 80% of infections.
In Chile, gamma is the majority, with a 41% frequency, compared to 18% for Delta.
“It is one of the possibilities that could be delaying the transmissibility of this variant, but it is feasible that in the course of time can somehow be increased“Donaires said.
An “intriguing” affair
Along the same lines, the infectologist Unaí Tupinambás, from the Federal University of Minas Gerais (Brazil), added that the low spread of the Delta is an “intriguing” issue that could be related to “having a cross reaction “with other strains.
This could partially explain why the Delta “failed to reach Brazil with great force and even reduced its prevalence” from 61% in early August to 35% two weeks later, he warned.
“The expectation was that the cases would increase, but now we are seeing a reduction, “added Tupinambás about the South American giant, which has 21 million infected but where the averages have been falling for weeks.
The importance of vaccination
Although it has been done unevenly and with a late start in some countries, vaccination is advancing in Latin America.
Chile and Uruguay are among those who vaccinate the fastest in the world, with more than 70% of their population with the complete scheme; Ecuador exceeds 50%, and Colombia, Brazil or Argentina are above 30%, according to the University of Oxford.
For Dr. Flavio Salazar, vice-rector for Research at the University of Chile, immunization has been “essential” to prevent outbreaks, as well as the use of vaccines from different laboratories.
When the doses of Pfizer or AstraZeneca did not arrive at the beginning of the year, some countries chose to diversify vaccination with the acquisition of Sputnik V (not authorized by WHO) and Sinovac (approved last June), which served to speed up the process.
In addition, the Chinese serum, which is virus inoculated and complete, it is “shallower but broader” that others like the one of Pfizer, of messenger RNA and that “they do not contain the sufficient varieties to detect some variants”, detailed to Efe Salazar.
This would explain why Delta caused outbreaks in Israel, where only the American-German vaccine was administered, despite having a high percentage of immunized population, he specified.
The advance of the strain “Mu”
While the Delta seems to stagnate, a new variant is beginning to gain ground in some countries: the Colombian Mu, recently considered “of interest” by the WHO.
During the third peak of the pandemic in Colombia, between April and August, the National Institute of Health (INS) blamed this strain for what happened, which in Chile has a frequency of 29%, and has already overtaken the Delta (18 %).
For Carlos Trillos, coordinator of Epidemiology at the Universidad del Rosario, in Bogotá, this does not mean that the Delta variant should be lost sight of, whose first case was identified in the country last July.
“From that moment we have seen how in other regions reports of a Delta variant detected in Bogotá, Antioquia or Huila have begun to appear. It will continue to grow, as we know Delta is a much more contagious variant,” he said.
With 3,017 new infections and another 176 deaths from coronavirus, in the last 24 hours, as of this Tuesday, Argentina already has cases of the Delta variant, of community transmission, but like other countries it is not the predominant strain.
The country has been going through the lowest point of the contagion curve since the first wave, registered in the middle of last year.
Although the impact of the Delta variant in the country is still unknown, this strain of the coronavirus forced local health authorities to focus attention on the community of a renowned school in the Belgrano neighborhood, where several were detected cases.
Clarín newsroom with information from EFE