SARS-CoV-2 Variants

In the natural life of a virus, it is common to talk about how it mutates to better adapt to its environment. The more a virus circulates, the more it can modify and, when multiple mutations are made, it is considered a "variant" of the original virus.

In this case, mutations seek to increase the impact of the virus on the environment, either to spread more quickly, impact other population groups or even cause more severe diseases.

Speaking of SARS-CoV-2 and its variants, before getting alarmed, it is crucial to know that this is a scenario expected by scientists, that it was going to occur naturally, but that for the same reason, it is closely monitored based on the changes the virus generates.

Since January 2020, these variants have been monitored by the WHO and associates worldwide, classifying them as "variant of interest" (VOI) and "variant of concern" (VOC). Priority is given to follow-up and research them to respond to the COVID-19 pandemic by adapting existing vaccines. Some other institutions use other classifications and follow-up methods; for example, the CDC (Centers for Disease Control and Prevention in the USA) describes it as "Variant of Major Consequence."

To name the variants, we have worked on a new nomenclature looking for easy-to-pronounce names that do not generate stigmas since it was common to call the variants by their place of origin. For now, experts have recommended the use of the letters of the Greek alphabet to name them.

Let's talk about Variants of Interest (VOI)

All SARS-CoV-2 variants are classified as variants of interest if:

• They have changes in their genome, which have been shown or at least expected to affect critical characteristics such as:
  • Higher contagion rate
  • Greater severity in the development of the disease
  • It can elude the immune system's response, the diagnostic means, or the drugs currently used to combat the disease.
• Evidence of an increase in cases in a country or several countries, causing relative prevalence among the rest of the variants. 

There are 7 variants VOI identified:

Let’s talk about worrying variants (VOC)

A variant of SARS-CoV-2 is determined to be of concern when, in addition to meeting the criteria to be a Variant of Interest (VOI) * see above, it meets any of the following changes to the degree that may have an impact on the world's public health:

• It is transmitted more easily among the population
• Increases the virulence of the disease (severity or even death)
• Faced with the variant, the prevention, diagnosis, vaccination, and available treatment measures are reduced.

A Variant of concern is more contagious, and it can cause disease with greater force and/or reduce the effectiveness of the treatments and vaccines developed so far.

So far there are 4 variants classified as VOC:

With information from the Pan American Health Organization (PAHO) in Mexico, we have 24 variants of SARS-CoV2, being the Alpha, Gamma, and Delta variants the ones with the most significant presence, and, with information from July 14, 2021, it is estimated that the Gamma variant is the one that predominates in our country; however, we must not lose sight of the fact that the Delta variant is highly contagious and that the Alpha variant is the most virulent.

More data on the Gamma VOC. 

• The effectiveness of antibodies either from previous Covid-19 infection or from the vaccine decreases.
• Most typical symptoms of the variant:
  • Fever
  • Dry cough or tiredness

More data on the Delta VOC. 

• Greater transmission, at least twice as fast as the original virus.
• Greater ability to enter the respiratory tract, and therefore if a person could infect two people, now they can infect 6 to 8 people. 
• The protection spectrum of the Pfizer vaccine for the Delta variant is 33% after one injection and 88% after the two doses.
• Most common symptoms of the variant:
  • Headache
  • Sore throat
  • Nasal discharge
  • Fever or diarrhea
  • Vomit

Until not long ago, the Alpha variant was the one with the highest transmission in the world, but today that the Delta variant has occupied its place, it reminds us that, in an ongoing pandemic, new variants are born that impact the different ways the virus evolves and the best way to combat it is still the same measures that we already know:

• Hand washing and use of gel with at least 70% alcohol, both with the correct technique
• Cleaning of surfaces
• Healthy distance
• Use of face masks
• Respiratory Etiquette
• Avoid crowded places
• Do not touch your eyes and face if you do not wash your hands first.

Vaccination is also one of the combat measures for these variants and the original virus. They are effective in preventing the most aggressive form of COVID-19.

It is very important to emphasize that vaccines are not the cure for COVID-19, that is, you can still get it while being vaccinated, but you give your body additional protection, and if you do get infected, the impact will be less than if you were not vaccinated.

Bibliography

• https://www.who.int/es/activities/tracking-SARS-CoV-2-variants
• https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html
• https://www.who.int/es/news-room/q-a-detail/sars-cov-2-evolution
• https://coronavirus.onu.org.mx/gamma-sera-la-variante-de-covid-19-predominante-en-mexico-ops
• https://coronavirus.onu.org.mx/esto-es-lo-que-sabemos-de-la-variante-delta-y-su-nueva-mutacion
• https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1001354/Variants_of_Concern_VOC_Technical_Briefing_17.pdf
• https://www.mayoclinic.org/es-es/diseases-conditions/coronavirus/expert-answers/covid-variant/faq-20505779
• https://www.redaccionmedica.com/secciones/sanidad-hoy/sintomas-especificos-de-cada-variante-covid-delta-se-desmarca-del-resto-9678