Why the delta variant is not spreading in the region as fast as it has in Europe | Various strains and diverse vaccination

The arrival of the delta variant in Latin America raised the alarm of the authorities due to its great contagion capacity, which led it to become the predominant variant almost all over the world. However, thThe advance of the delta so far in the region was not explosive as we have seen in the old continent. Competition between different strains and diversified vaccination are some of the hypotheses considered by experts to explain this phenomenon, which is still under observation.

The region has nearly 44 million cases and 1.46 million deaths in total.

Several variants in competition

One of the reasons that the Delta variant might grow 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 adds more than 2 million infections, the delta left 244 cases and has a frequency of 20 percent, while lambda – of Andean origin and found in April – accounted for 80 percent of infections.

In Chile, gamma is the majority, with 41 percent frequency, against 18 for the delta. “This is one of the possibilities that could delay the transmissibility of this variant, but it’s possible that over time it could increase one way or another, ”Donaires said.

Similarly, infectologist Unaí Tupinambás, Federal University of Minas Gerais (Brazil), added that the low spread of the delta is an “intriguing” problem that could be linked to the fact that “cross-reacted” with other strains.

This could partly explain why the delta “failed to reach Brazil with great force and even reduced its prevalence” from 61 percent in early August to 35 percent two weeks later.

“The cases were expected to increase, but now we are seeing a reduction,” Tupinambás added on the panorama of Brazil, which has 21 million people infected but where the averages have been falling for weeks.

The role of vaccination

Although unevenly and with a late start in some countries, immunization rates are increasing across the region.

Chile and Uruguay are among the fastest vaccinated in the world, with over 70 percent of its population on the full diet; Ecuador is above 50 percent, and Colombia, Brazil and Argentina are above 30 percent on the full diet, according to the University of Oxford.

For Dr Flavio Salazar, Vice-Rector for Research at the University of Chile, vaccination was “essential” to prevent epidemics,yes like the use of vaccines from different laboratories.

When at the beginning of the year the doses of Pfizer or AstraZeneca did not arrive, some countries chose to diversify the vaccination with the acquisition of Sputnik V and Sinovac, which served to speed up the process.

The Chinese vaccine, which is an inoculated and complete virus, is “shallower but wider” than others like Pfizer’s, messenger RNA and which “do not contain enough varieties to detect certain variants,” explained Salazar.

That would explain why delta caused epidemics in Israel, where only the American-German vaccine was administered, despite a high percentage of the population vaccinated, he said.

The advance of the Colombian variant Mu

A new variant is starting to make its way in some countries: Mu, recently deemed “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 the responsibility for what happened to this strain, which in Chile, it has a frequency of 29 percent and has already exceeded the delta.

For Carlos Trillos, epidemiology coordinator at the Universidad del Rosario de Bogotá, this does not mean that we should lose sight of the delta variant, the first case of which was identified in the country last July.

“From that moment we saw how in other regions reports of a delta variant detected in Bogotá, Antioquia or Huila started to appear. It will continue to grow, because we know that the delta is a variant a lot more contagious, ”he said.