The variants that emerged in the United Kingdom and India have a high rate of spread.
There are at least four variants of Covid-19, all of international concern, circulating in the Mexican population.
The Mexican Consortium for Genomic Surveillance (CoViGen-Mex) has confirmed to Tec Review that these are the variants of SARS-CoV-2 which first emerged in the United Kingdom (B 1.1.7), South Africa (B.1.351), Brazil (P.1), and India (B.1.617).
These variants have been renamed by the World Health Organization (WHO) as Alpha, Beta, Gamma, and Delta, respectively.
— Eric Feigl-Ding (@DrEricDing) June 17, 2021
The CoViGen-Mex group of researchers obtained the information by sequencing positive samples from symptomatic Covid-19 cases.
Of the four variants identified, at least two have caught the attention of the specialists.
“At the moment, the ones that are increasing at national level, i.e. increasing in proportion to the others, are Alpha and Gamma (the UK and Brazilian variants, respectively),” said virologist Carlos Arias Ortiz in an interview.
The scientist, who is part of the newly formed CoViGen-Mex, says the Covid-19 variants now identified as Alpha and Gamma are widely distributed in the country.
“Alpha has a presence throughout the country and Gamma is in three quarters of the country. Where they’ve appeared, they’re beginning to dominate.”
The Covid-19 variant renamed Delta (the Indian variant) is already present in the country.
However, the virologist warns that it can’t yet be said to be widely distributed.
According to the most recent report from CoViGen-Mex, the Delta variant was identified in Mexico for the first time on April 21 of this year.
To date, 25 cases have been recorded in five states across the country.
CoViGen-Mex has “very few” reports of the Beta variant, which emerged in South Africa.
This Covid-19 variant has been identified in San Luis Potosí and Sinaloa.
Mazatlán is the city where it was originally detected, from a ship that had arrived from India.
Although other Covid-19 variants are gaining ground, the dominant one in Mexico is identified as B.1.1.519, informally known as the Mexican variant.
It has spread throughout practically the entire country and is dominant in places with high infection levels, such as Mexico City.
According to research led by virologist Arias Ortiz, variant B.1.1.519 dominates in 60% of the country.
“The Alpha and Gamma variants are increasing at a general level nationwide. What’s more, the presence of the Delta variant, which is even more transmissible than Alpha, suggests that it could increase its presence in Mexico.”
The WHO announced the new naming system for Covid-19 variants in late May.
Maria Van Kerkhove, Covid-19 technical lead for the international body, announced the new names for variants “of interest” and “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 done by scientists around the world, it’s 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 raise epidemiological warning levels because it’s very possible that there’ll be more intense outbreaks in the areas or regions where they’ve been detected.
“Outbreaks are going to vary regionally because of how and where the outbreak started, the number of people vaccinated, and the type of vaccine that was used.”
Arias Ortiz, who is also a researcher at UNAM’s Institute of Biotechnology, explains that variants of concern can, to some extent, weaken the immunity induced by a natural infection or by vaccines.
The number of samples that are sequenced in Mexico is a “reasonable amount” to monitor the country.
“We’re not Denmark or England, where they sequence high percentages of positive case samples.”
However, he believes that good monitoring is being done since there are currently between 3,000 and 4,000 daily Covid-19 cases.
He adds that 2,000 samples are being analyzed per month from all Mexican groups.
SARS-CoV-2 variants of concern are classified as such because they imply important changes for global public health.
According to WHO, the Alpha, Beta, Gamma, and Delta variants fall into this category because they have increased their transmissibility, their virulence, or they have changed the disease’s clinical presentation.
They could also be classified as such because they reduce the effectiveness of social and public health measures or tests, vaccines, and available therapies.
CoViGen-Mex was established to support the Ministry of Health’s efforts to identify Covid-19 variants circulating in the country, as well as their spread and evolution.
Since February, it has sequenced 1,000 samples of positive cases for the Mexican Social Security Institute (IMSS) system, all of which presented mild, moderate, or severe symptoms of the disease.
It consists of researchers and specialists from IMSS, the National Institute of Respiratory Diseases, the National Laboratory of Genomics for Biodiversity at CINVESTAV, and the Institute of Biotechnology at UNAM.