The variants of the coronavirus that predominate in Argentina: which are the most contagious despite being vaccinated
Since December 2020, the Argentina carry out a vaccination plan in order to slow down the Coronavirus pandemic. Almost 60 million dose against him Covid-19 and some 25 million Argentines have completed their projects. With a decrease in infections over 19 weeks and a comparable intensive care bed occupancy rate at the end of July, the infections registered for him government national provides details on predominant variants in the country and what is their behavior.
“With two doses, there is sufficient protection for all the variants circulating in Argentina.. There is a need to complete the vaccination schedule in each population at risk, reach 70 or 80% of the population and start vaccination in pediatric patients at risk for persistent diseases first, then assess how this continues “, did he declare. Ricardo Teijeiro (MN 58065), infectologist at Pirovano hospital, in dialogue with TN.com.ar.
In this sense, Victor Romanowski, director of the Molecular Virology Laboratory at IBBM-Fac. by Cs. Exactas (UNLP / CONICET) and Vice President of the Argentine Society of Virology (SAV), said: “Vaccinees can become infected, but the immune system built after the vaccine significantly reduces the risk of hospitalization, serious illness and death. Vaccinees infected and studied show the situation of circulation of variants at each location, but vaccines are still very effective as a preventive tool”.
What are the variants present in Argentina
According to the latest genomic surveillance report published in October by the Ministry of Health, from January to September 27, 2021, “5,977 samples were analyzed for the identification of variants of SARS-CoV-2”, of which 5,177 corresponded to people. without travel. history and 800 to travelers and individuals with import links.
In the case of Travelers, so far this year they have been detected 462 infected with the Delta variant (India, including 337 travelers and 125 related), 137 by Gamma (Manaus), 69 by Alpha (British), 28 by Lambda (Andean), 12 by Mu (Colombian) and only one for Beta (South Africa).
In case of contagion no connection with travelers, they found 3,236 cases of Gamma variant infection, 1087 for the Lambda, 327 for the Alpha, 99 for the Delta and 12 cases for the Mu.
With which, according to the report, over the past three weeks, the proportion of priority variants among non-travelers continues to be more than 70% for Gamma, a constant decrease for Alpha and an increase of 5% to around 13% for Delta. Meanwhile, Lambda posted a drop from 23% to 11%.
What are the characteristics of each variant present in Argentina
For the World Health Organization (WHO), there are three stages for mutations that have occurred during a pandemic: Variants of concern (VOC, for its acronym in English), Variants of interest (VOI) and the Variants under surveillance (VUM or enhanced alert), according to their height within this podium this will be the importance they will have for the international health situation. That is, to what extent they are “evaded” from the immune system, their degree of transmissibility or lethality.
- Gamma (Manaus): This mutation has been classified as VOC because it is associated with a higher rate of transmission and rapid spread, up to 2.0 times compared to the first variants. In addition, there was a correlation between infection with this variant and a higher viral load; and there is growing evidence of an association with greater severity.
- Lambda (Andean): This variant is considered VOI and was detected at the end of 2020 in Peru, where it remains prevalent. While in Argentina and Chile it is shown in a high proportion. Its mutations give it characteristics which link it to an increase in infectivity and resistance to neutralizing antibodies.
- Alpha (British): it is a mutation classified as VOC and associated with a higher transmission rate (30-90%) than the variants of the first wave. In addition, it was linked to an increased risk of hospitalizations, ICU admissions and death.
- Delta (India): When this variant called COV appeared, in October 2020, there was a strong epidemiological epidemic and a health crisis. This mutation is associated with a higher transmission than the first wave lines and even higher than the other VOCs. This variant has at least two mutations which have been associated with greater transmissibility, a reduction in neutralization by certain monoclonal antibodies and a moderate reduction in neutralization in post-vaccination sera. But that’s not all, it would also have a more efficient entry of the virus into the cell and a greater capacity for the virus to spread, in addition to presenting greater risks of hospitalization, admission to intensive care and death. . Meanwhile, in people vaccinated with a full regimen, it was detected that they would have similar viral loads as unvaccinated people, albeit with disease resolution in less time.
- Mu (Colombian): this mutation, which was identified in January of this year, is called VOI. In July 2021, this variant already represented 80% of the coronavirus viruses circulating in Colombia and is now identified in at least 39 countries. The mutations in this variation have already been detected in other VOCs and VOIs, implying a higher level of infectivity and evasion / evasion of the immune system.
“Variants have constellations of mutations, some of which would result in an increase in the ease of entry of the virus into cells (cleavage of the S protein and change in conformation), while others would reduce the possibility of recognition by neutralizing the monoclonal antibodies ”, summarized Romanowski.
How the vaccines given in Argentina behave against the variants
Argentine scientists Carolina Torres, Humberto Debat and Mariana Viegas conducted a study on vaccines administered in Latin America and their performance against the mutations present. That’s why they rated AstraZeneca, Spuntik V, Moderna, Pfizer, as well as Janssen and Sinovac.
For the case of the variant Gamma, the trial assessed that they had “shown neutralization reductions with regard to SARS-CoV-2 of early epidemic», Which varied between 2.8 and 13.8 times for the vaccines: Sputnik V, SinoVac, Pfizer, Moderna and Janssen. While “an increase in the neutralization power was observed over time for individuals vaccinated with Sputnik V”. On the other hand, for the SinoVac and AstraZeneca vaccines, the effectiveness in preventing death it was 70% and 90% respectively (with complete diagrams).
“The levels of protection by vaccination are very satisfactory, even taking into account the fact that in general terms a significant increase in efficacy has been observed against severe cases, hospitalizations and deaths,” said they pointed out. For transfer Lambda, the neutralization reductions with regard to the viruses of the first wave, they were between 1.5 and 6.1 times for those vaccinated with Sputnik V, Pfizer, Moderna and Janssen, while the drop compared to the “original” virus was 2 , 3 times in those immunized with SinoVac.
Meanwhile, before the variant Delta the reduction of neutralization it was between 1.6 and 11.3 times compared to the viruses present in the first wave for those immunized with Sputnik V), Pfizer, Moderna, AstraZeneca and Janssen. While in the protection against serious illness, hospitalization and death Values greater than 80 or 90% were recorded for people vaccinated with complete schedules and greater than 70% for those immunized with a dose of AstraZeneca, Sputnik V, Pfizer and Moderna vaccines.
As noted in the genomic surveillance report, out of 2,777 cases with a history of vaccination. Of the 1,197 analyzed who were infected after one dose, 65.5% corresponds to the Gamma variant, 23.5% at Lambda, 6.2% at Alpha, 2% at Delta and 0.2% at Mu. Now for the 1158 who completed the program, the numbers were: one 64% a gamma, 22% a Lambda, 5.3% an Alpha, 2% a Delta and 0.2% a Mu.
“The vaccinated can be infected, but the immune system strengthened after the vaccine decrease in particular the risk of needing hospitalization, serious and fatal illness. The vaccinated people who become infected and are studied show the situation of circulation of the variants in each place, ”said the vice-president of the Argentinian Society of Virology (SAV).
Third doses and variants in sight
WHO has positioned six mutations at the highest rungs of its ladder and, despite advances in national and global vaccination, the threat of further changes remains linked to the high viral circulation. This is why specialists emphasize the the importance of completing immunization schedules to stop these chains of infections and prevent the most serious conditions.
“When you take a single dose, you have less protection for all the variants and some have shown immune breakout, which would mean the vaccine is not as effective. This is the Mu variant, but it still has no impact in our country ”, underlined Teijeiro and added:“ The variants that really had more impulses after the first wave were the Gamma and the Lambda. which predominated and continue to do so in our country. “
While Romanowski added: “The variants present constellations of mutations, some of which would result in an increase in the ease of entry of the virus into cells, others reduce the possibility of recognition by neutralizing the antibodies, but the vaccines induce a humoral and cellular response, which matures over time even if the titers of neutralizing antibodies decline ”.
“In our country, the Delta variant It has already been admitted more than eight weeks ago and despite the fact that there have been community cases unrelated to travelers, and more than 500 have been diagnosed in different provinces, so far he could not move the other variants. A situation that did not occur in the northern hemisphere, which quickly displaced the others in four or six weeks. In all cases, we must consider the possibility of a new wave and maintain active preventive measures ”.
Even when asked about the possibility of a third dose To stop these mutations, the two specialists warned that they should only be applied to a small group of the population. “It is a discussion in the world and it has been decided that after six or eight months it should be administered to patients who respond less to vaccines (oncological, immunocompromised, chronic, elderly), in addition to health workers because of the level of exposure, ”said the infectologist.
“Except in special situations of people with deficiencies in the immune system, there is no evidence that it works in the general population at such short vaccination times with the two-dose schedule, ”he added.
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