There are at least four variants of Covid-19, all of them international concern, circulating among Mexicans.
These are the SARS-CoV-2 variants that first emerged in UK (B 1.1.7), South Africa (B.1.351), Brazil (P.1) e India (B.1.617), confirmed to Tec Review the Mexican Consortium for Genomic Surveillance (CoViGen-Mex).
These variants were renamed by the World Health Organization (WHO) as Alpha, Beta, Gamma Y Delta, respectively as they were cited.
⚠️Confirmed— # DeltaVariant is by far the * most contagious ** variant found to date, with a transmissibility that is ~ 2x faster than older strain. # P1 is 2nd fastest, says @WHO study.🧵
📍 # B117 # Alpha — 29% faster
📍 # B1351 # Beta — 25%
📍 # P1 # Gamma — 38%
📍 # B16172 # Delta — 97% # COVID19 pic.twitter.com/qZUdwYhvNF
– Eric Feigl-Ding (@DrEricDing) June 17, 2021
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Variants of Covid-19 that are of concern
The information resulted from the positive sample sequencing of people symptomatic of Covid-19, carried out by the CoViGen-Mex group of researchers.
Of the four variants identified, at least two attract the attention of specialists.
“At this moment those who are growing nationwide, that is to say, their proportion is increasing, they are: Alpha and Gamma (English and Brazilian variant, respectively) ”, said in an interview the virologist, Carlos Arias Ortiz.
The scientist, who is part of the recently CoViGen-Mex, abounds that the Covid-19 variants now identified as Alpha and Gamma are widely distributed in the country.
“The Alfa has a presence throughout the country and the Gamma in three quarters of the territory. Where they have appeared they are beginning to predominate ”.
Delta and Beta variants
The renamed Covid-19 variant Delta (Indian variant) is already present in the country.
However, it cannot yet be said that distributed broadly, the virologist said.
According to the latest CoViGen-Mex report, the variant Delta It was identified for the first time in Mexico on April 21 of this year. To date they have registered 25 cases in five states from the country.
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Located in the north
From the Beta variant, emerged in South Africa, CoViGen-Mex has “very few” reports.
This variant of Covid-19 has been located in San Luis Potosi Y Sinaloa.
Mazatlan It is the city in which it was originally detected, from the arrival of a ship that came from India.
Dominant variant in Mexico
Although other variants of Covid-19 gain ground, in Mexico the one it dominates is identified as B.1.1.519, informally known as mexican variant.
It has spread throughout practically the entire country and is the dominant one in sites with high levels of contagion like Mexico City.
According to research led by virologist Arias Ortiz, variant B.1.1.519 dominates in 60% of the national territory.
“There is an increase, at a general level in the country, of the Alpha and Gamma variants. In addition, the presence of the Delta variant, which has higher transmission capacity, even more than the Alpha, suggests that it could increase its presence in the country ”, he points out.
Changes to avoid discrimination
The WHO announced at the end of May the new naming system for Covid-19 variants.
Maria Van Kerkhove, Covid-19 technical leader of this international organization, announced the new names for the variables of “interest” and “worry”.
Variants of concern
The variants of concern were classified as such because they have different characteristics, several of them are much more transmissible than the original virus that emerged in Wuhan, China.
Due to studies carried out by scientists around the world, it is now known that “Alpha is 70% more transmissible than the original Wuhan virus and Delta is between 40-70% more transmissible than Alpha.”
Therefore, the detection of these mutations should increase the epidemiological alerts, because in the areas or regions where they have been detected it is very possible that there will be more intense outbreaks.
“Outbreaks are going to vary regionally, both because of how and where the outbreak started, the number of vaccinated people, the type of vaccine that was used, and so on ”.
Arias Ortiz, also a researcher attached to the Institute of Biotechnology of the UNAM; explains that the variants of concern have, to some extent, the ability to decrease the potency of immunity induced by a natural infection or by vaccines.
Sequencing in Mexico
The quantity of samples that are sequenced in Mexico represents a “reasonable quantity” to carry out the monitoring in the country.
“We are not Denmark or England, where high percentages of positive case samples are sequenced.”
However, he considers that good monitoring is done, since currently there are between 3,000 and 4,000 daily cases of Covid-19.
He adds that among all the Mexican groups, 2,000 samples are being sequenced per month.
“When there were many cases the proportion was lower, but now more is being sequenced. The quantity is very reasonable and we are at a good pace of sequencing, in step with countries like Brazil and Chile ”.
What does it mean that they are variants of concern?
The SARS-CoV-2 variants of concern are classified this way because they present major changes for global public health.
According to the WHO, the Alpha, Beta, Gamma and Delta variants fall into this category because they increased their transmissibility, their virulence or changed in the clinical presentation of the disease.
They could also be in this classification because they reduce the effectiveness of social and public health measures or diagnoses, vaccines and available therapies.
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“Until now it is not clear how each vaccine protects against each variant, and this is something that is being studied in the country and in the world, there is a lot of interest in knowing this. It is a knowledge that is under construction, the answers to this question are still limited “
Why is it important to monitor them?
I agree with you Centers for Disease Control and Prevention (CDC) viruses are constantly changing and diversifying.
By studying them carefully, scientists can learn how changes in the virus affect how it spreads and how people get sick.
If we think of a virus as a tree that grows and branches, each branch of the tree is slightly different from the others.
By comparing the branches, scientists can label them according to the differences.
These small differences or variants have been studied and identified since the beginning of the pandemic.
In support of the efforts of the Ministry of Health to identify the variants of Covid-19 that circulate in the country, as well as their dispersion and evolution, it was established
CoViGen-Mex has been sequencing 1,000 human samples positive for the system since February IMSS, all symptomatic and presenting the type of mild, moderate or severe disease.
It is made up of researchers and specialists from the IMSS, the National Institute of Respiratory Diseases, the National Genomics Laboratory for Biodiversity of CINVESTAV and the Institute of Biotechnology of the UNAM.
This organism is a key epidemiological watchdog to explain the behavior of the virus and the development of the pandemic in the country.
It seeks to detect Covid-19 variants with mutations that have the potential to increase their transmissibility or virulence.
The Consortium’s activities began in February 2021 and are framed within the National Strategic Research and Incidence Project in Virology CONACyT, and have the additional support of the Secretariat of Education, Science, Technology and Innovation of Mexico City.
The samples it monitors come from all over the country, are provided by the IMSS, and are sequenced in three institutions: the UNAM Institute of Biotechnology, the National Institute of Respiratory Diseases and the Langebio del Cinvestav, located in Irapuato.
Sequencing is also carried out at the Food and Development Research Center (CIAD), on the Mazatlán campus, but their samples come from health units other than the IMSS.
A prepandemic initiative
In January 2020, the Ministry of Health formed a group to analyze what was Mexico’s ability to make genetic sequences, follow the diversity, distribution and evolution of the virus, once SARS-CoV-2 arrived in Mexico .
From the first case of Covid-19, Mexican scientists were able to sequence that first sample, detected on February 27, 2020.
The researchers published in ASM Journals the complete genome sequence of 17 isolated SARS-CoV-2 samples corresponding to the first cases sampled in Mexico.
The sequencing program in Mexico is carried out in coordination with the National Epidemiological Reference Institute (InDRE), which is part of the Regional Covid-19 Genomic Surveillance Network.
CoViGen-Mex has a budget to continue genomic surveillance of the virus for one year.