Updated Variant Guide: Which strains of the corona virus are still threatening us?

Adam Zapel
8 min readOct 22, 2021


The COVID19 virus constantly creates mutations. Some of them manage to spread, infect and even cause serious illness. Which variants managed to survive in the fourth wave as well, which ones disappeared, and what happens to the new variant of the Delta Plus that was recently located in Israel?

If you thought the corona virus was likely to disappear from the world — it will not happen soon: it is one of the most mutant viruses, constantly creating variants (strains) that infect faster and cause more serious diseases, and now also in children. This week (Tuesday), the Ministry of Health announced that a new variant has been identified for an 11-year-old child in Israel, a variant that has already spread in Europe, just at a time when the fourth wave is shrinking.

So why do viruses continue to create variants? Mainly because of their evolutionary goal — to spread around the world, and the way to do that is through genetic diversity that is supposed to overcome the immune system, vaccines and drugs. So does the corona virus, which has, according to estimates, already developed dozens of strains and thousands of different mutations.

The new variants, which contain many mutations, are of great concern in the world. But for now, apart from faster infection, even in healthy people including children and pregnant women — the course of the disease is not necessarily more turbulent than other strains. Most of the mutations that were discovered, the same genetic changes, directed the virus to attach more quickly to the human cell. However, there is still no evidence that the disease is different from the corona we have known so far.

Variants classified as “worrying varieties” are the main varieties of corona today, and they spread rapidly and make up most of the morbidity. Today, the worrying strains are beta, gamma and delta. In the group of “interesting varieties” are the varieties Miu and Kappa, and “varieties under surveillance” — are variants that have been discovered with a relatively low distribution rate or new variants.

The new variant: AY4.2

When it was discovered: The variant was recently located in Israel on an 11-year-old boy who returned from abroad and underwent an examination at Ben Gurion Airport. The sample underwent genetic sequencing in a laboratory in Tel Hashomer while the child was in solitary confinement, and yesterday (Wednesday) five more verifications were discovered that were infected with the sharp variant.

Meaning: This is a sub-strain, one of several sub-strains called “Delta Plus” in which there is a mutation in the “spike” protein of the corona virus (the same “thorny” envelope that binds to the human cell) and it has already been found in 8% of coronavirus viruses in the UK. This is where the variant was first discovered last July. The virus itself was first discovered in India, and has since spread to several European countries.

Not much is known about the “feats” of the variant, but it is clear that he is a “cousin” of the AY.4 virus lineage, which remains the dominant version in most countries of the world. According to estimates by world health organizations, the Delta strain is considered to be much more contagious than other strains, and it tends to cause particularly serious illness in children. But the calming tone comes from the vaccine companies: According to Pfizer and Moderna, the vaccines are effective against all the variants that are common in the world today.

Alpha variant

When it was discovered: October 2020 in the UK, samples taken about a month earlier.

The mutations: The British strain includes 17 mutations, of which eight mutations in the envelope protein S.

Meaning: The variety is spreading around the world and becoming dominant in many countries. It is estimated that it does not cause a more serious disease, but is more easily contagious due to mutations in the shell proteins, which cause it to bind rapidly to body cells. The strain is very common in children, probably because it spread in parallel with the start of vaccination campaigns. According to Modern and Pfizer, their vaccines protect against the British strain

Variant beta

Formerly called: Nigerian Enter B.1.1.207.

When it was discovered: May 2020 in Nigeria.

The mutations: The variant includes a mutation called P681H which was also found in the British strain.

Meaning: Found in about one percent of all corona cases that have been genetically engineered in Nigeria, and probably continues to spread there.

Variant gamma

World Health Organization Classification: A strain of concern
Formerly called: Brazilian Enter P.1.

When it was discovered: January 2021 in Tokyo by four travelers who visited the Amazon. One week later, 13 more cases were found in Brazil.

The mutations: The virus has 17 genetic changes in amino acids that make up proteins, ten of them in envelope proteins.

Meaning: The virus has been detected in Japan, Brazil, South Korea, Germany, the United Kingdom, Italy, the United States and Peru. However, reports of strains in the strain are dwindling.

Delta variant

World Health Organization Classification: A strain of concern
Formerly called: Indian Enter B.1.617.2.

When it was discovered: The strain was first detected in October 2020 in India, and spread rapidly throughout the world, until it became the dominant strain in most countries of the world.

The mutations: The Delta strain has several important mutations in the shell protein, two of which — L452R and D614G — allow the variant to attach very strongly to receptors called ACE2 Saturn in the human body. Other mutations like P681R allow the virus to enter the body cell more easily.

What it means: As far as is known, the Delta strain is the most contagious of all the variants in the world today, but not necessarily the deadliest of them all. The vaccines are still effective against it in preventing disease, but less so in preventing infection: data shown by Israel found that Pfizer vaccines prevent only 64% of infections among the vaccinated. However the vaccine remains powerful in preventing serious morbidity and mortality.

Delta Plus variant

World Health Organization Classification: A strain of concern
When it was discovered: March 2021.

The mutations: The Delta Plus strain differs from the original Delta strain in another mutation (genetic deformity) found in the protein shell of the corona virus, the “Spike Protein”. This location of mutations also exists in previous strains on the envelope protein, and is of great importance because it determines the degree of attachment of the virus to receptors on the cell in the body.
This link between the virus and the infected cell allows the virus to penetrate the lungs, heart, kidneys and intestines very easily. Once the virus attaches to the receptor, it changes it to an “open” or “closed” state. The K417N mutation helps the envelope proteins of the corona virus increase the chance of “opening” the infected cell envelope, thus penetrating the cell.

Meaning: The virus appeared near the Delta strain, most likely in the UK or India. On June 22, the World Health Organization declared the Delta Plus strain a “worrying strain” and noted that it is more contagious, communicates faster to receptors on the cell and overrides the immune system that tries to destroy it without success.
This strain has already spread around the world and also in Israel. The vaccines have been found to protect against severe disease from the Delta and Delta Plus strains. Vaccine companies are updating that the new versions of the vaccines that will be distributed next year will also include updates against the Delta strain.
Variant Atta (IOTA)

What exactly is a mutation?

Unlike a bacterium, a living creature by itself, the virus cannot live outside a living cell. In order for the viruses to multiply one must infiltrate a living cell, take over the hereditary charge, “steal” it and replicate themselves in order to infect more cells. The virus is constantly trying to change the structure of the cell envelope into which it invades, in order to penetrate the body more easily, and also to prevent the body from recognizing it. This makes the virus more contagious, and its ability to reproduce intensifies.

So does the corona virus. Using the same “thorns” in the outer shell, corona viruses attach to receptors on the cells of the respiratory system, called ACE-2. This adhesion transports the corona virus to a second stage, in which additional envelope proteins dissolve the human cell envelope, and thus the virus penetrates into the cell nucleus, replicating itself through the hereditary charge of the human cell — the DNA found in the nucleus.
However, the corona virus is not always successful in its work: many people infected with the virus will not develop any symptoms at all. The virus will be present in their bodies, but the immune system will be able to destroy it even before it has managed to penetrate the cells and cause destruction. In others, the virus will cause a very mild illness that will likely lead to a fever. In this condition, the body raises the temperature to lead to an uncomfortable environment for the activity of the corona virus, while circulating white blood cells that will destroy the virus.
If the virus has managed to penetrate the cells of the respiratory system, it will begin to multiply and infect more cells quickly, creating a condition called an “immune storm.” In this condition the body injects huge amounts of white blood cells towards the viruses, which destroy them while also destroying healthy lung cells. This condition is known as pneumonia in which some patients with coronary heart disease.
In some cases the disease becomes very turbulent. More and more corona viruses are able to replicate rapidly, and the immune system is unable to cope with them. More and more lung cells are damaged, to the point of lung failure and the need for artificial respiration. The virus can also spread to the bloodstream and cause a state of sepsis — a common infection that leads to a drop in blood pressure — and later cardiac arrest and death.

What is the difference between a new strain and a mutation?
There is a terminological confusion between the two. A mutation is a genetic modification. A new strain of virus (“variant”), is a virus in which the same one or more genetic changes occur. A number of mutations have been found in the new corona varieties. For example, 23 new mutations have been found in the British corona strain.

What is the difference between a mutated strain and infection with normal corona strains?
The new strains probably infect faster, especially those aged 20 and under, probably due to mutations in the virus envelope as well, which allow it to bind to the human cell more quickly, penetrate it and reproduce quickly. However, beyond the speed of infection, there does not appear to be a change in the nature of the disease itself that occurs with the same symptoms and complications known from the other strains.

What happens if a vaccine-resistant mutation still emerges?
In such a case, and thanks to the innovative mRNA technology, Pfizer and Moderna announced that within about six weeks they could complete a change in the vaccine so that it would be adapted to any possible mutation.

How can you protect yourself from the mutations in the meantime?
The same Corona guidelines also apply to mutations: masking, social alienation, and vaccination. The faster we get a herd vaccine, in which over 80% of the population is vaccinated, the lower the risk of the mutations spreading and the development of additional mutations.