Viruses eventually mutate, that is, undergo changes. This is also true for the SARS-CoV-2 virus which is responsible for the coronavirus disease (COVID-19). In most cases mutations do not lead to changes in the properties of the virus concerned. However, some mutations affect certain properties of the virus, such as its ability to spread and therefore the level of its contagiousness (ability to infect), the disease burden as well as the effectiveness of therapeutic, social and sanitary measures.
WHO and international researchers have been tracking and evaluating the SARS-CoV-2 virus since January 2020. According to them, there are already about 16,000 mutations of the coronavirus infection. Most variants don’t differ much from each other and don’t affect the course of the pandemic. But there are some quite aggressive versions.
WHO is currently studying several strains of COVID-19. They are classified into two groups — “Variants of Concern” and “Variants of Interest”. The first one includes the strains called Alpha, Beta, Gamma and Delta, while the second one numbers Iota, Kappa, Lambda and Mu.
What is the most common way to know which coronavirus variant a person is infected with? Researchers and experts in this area have identified the main symptoms of different coronavirus variants.
Original Version of COVID-19: Typical Symptoms
The most common symptoms include:
- temperature rise;
- dry cough;
- fatigue.
Less common symptoms are:
- muscle and joint pain;
- sore throat;
- diarrhea;
- conjunctivitis;
- headache;
- loss of sense of taste or smell;
- skin rashes or skin discoloration on fingers or toes.
The serious symptoms may be:
- difficult breathing or shortness of breath;
- pain or tightness in the chest;
- speech disturbance or impaired motor function.
The British Alpha: Symptoms and Characteristics
The Alpha variant, known among specialists as B.1.1.7, first appeared in Great Britain in September 2020, according to reports.
Experts of the UK Office for National Statistics reviewed the symptoms suffered by those who became ill during the week before they got a positive test result for the new COVID-19 variant. They also compared them to the symptoms of those people who were infected with the original strain.
Some of the main symptoms observed include:
- cough (35%),
- severe fatigue (32%),
- muscle and whole-body pain (25%),
- sore throat (21.8%),
- fever.
These figures appeared to be higher than those found in people infected with the original COVID-19 strain. At the same time statisticians claim that those infected with the British strain less frequently lose their sense of taste (16%) and smell (15%).
Contagiousness
Cases of the Alpha variant of the coronavirus have been reported in at least 197 countries worldwide. It spreads much faster and easier than the original SARS-CoV-2 virus, and the rate of its transmission is estimated to be 29% on average.
Hospitalization
This variant is on average 59% more likely to cause hospitalization than the original coronavirus.
Vaccine Effectiveness
According to researchers, the Pfizer/BioNTech vaccine is more than 95% effective against hospitalization or death and 92% effective against the symptoms of the disease.
Lethality
Compared to the original SARS-CoV-2, the Alpha variant is believed to be more life-threatening. The estimated mortality rate is 59% on average.
The South African Beta: Symptoms and Characteristics
Researchers from the Republic of South Africa were the first to detect the Beta variant, often referred to as B.1.351. It was in May 2020.
No specific symptoms are associated with the Beta variant; the symptomatology is typical for the coronavirus disease:
- high temperature,
- cough,
- loss of the sense of taste and smell, and so on.
The distinctive feature of this coronavirus version is that it binds to the cells of the body more strongly. It is common in young people, often causing complications in them.
In addition, this virus variant is more resistant to medications. Because of its constant changes, antibodies don’t always “see” it and therefore can’t fight back.
Contagiousness
Of all the other strains, the Beta variant is considered to be the least contagious, however, it spreads faster than the original coronavirus. The transmissibility of this strain is assessed at about 25% on average. By December 14, 2021, the Beta variant had been diagnosed in at least 146 countries.
Hospitalization
The Beta variant is almost twice as likely to cause hospitalization as the original coronavirus.
Vaccine Effectiveness
The Pfizer/BioNTech vaccine is almost 100% effective against hospitalization and death, and 88% effective against the symptoms of the disease.
Lethality
This variant of coronavirus is more life-threatening than the Alpha and Gamma ones.
The Brazilian Gamma: Symptoms and Characteristics
The Gamma variant, often referred to as B.1.1.28 (P.1), made its first appearance in Brazil in November 2020.
This variant of coronavirus caused a second wave of the disease in the city of Manaus. Even though about 70% of the local residents had already had the original variant of COVID-19 and had antibodies.
With the Gamma variant, the disease runs with the classic symptoms of COVID-19. However, this strain is much more transmissible compared to the original version from Wuhan. Young people and pregnant women are more likely to become ill with this infection. Another danger of the Brazilian strain is that it can overcome the natural immunity of people who have already had the disease.
Contagiousness
The Gamma variant is considered more contagious than the Alpha and Beta variants. Transmissibility is estimated at an average of 38% compared to the original SARS-CoV-2. By December 14, 2021, it had been found in 103 countries.
Hospitalization
The Gamma variant is about 30% more likely to lead to hospitalization as compared to the original virus. It stands out of the other variants due to the increased risk of reinfection.
Vaccine Effectiveness
The Pfizer/BioNTech vaccine proves to be equally effective against the Gamma variant as it is against the Beta one. That is, it is 100% effective against hospitalization and mortality, and 88% effective against the symptoms.
Lethality
On average, the Gamma variant causes 50% more deaths than the original coronavirus.
The Indian Delta: Symptoms and Characteristics
The Delta variant, otherwise called B.1.617.2, came from India where it was first reported in October 2020. In addition to the characteristics related to its spread and ability to escape immunity, the Delta variant has also proven to be peculiar in terms of symptoms. Infected people often do not lose their sense of smell as is common with coronavirus disease patients.
Here are the specific characteristics of COVID-19 caused by the Delta variant:
- at the beginning of the disease the body temperature frequently rises above 38.5°C;
- headaches, sore throat and running nose;
- diarrheal syndrome (at any time of the disease);
- loss of sense of smell is less frequent;
- rapidly progressive disease state;
- sharp deterioration of the patient’s condition;
- bacterial infection is more common.
Contagiousness
The Delta variant is considered to be 97% more transmissible than the original SARS-CoV-2 and 60% more transmissible than the Alpha strain. Researchers have found that this variant is also more resistant to vaccines, especially after the first dose. It also affects young people more often. By December 14, 2021, cases of the Delta variant had been reported in 196 countries.
Experiments conducted in hamsters at NIV in the spring of 2021 showed that Delta causes more severe cases of pneumonia than infection with other variants of the virus.
Hospitalization
Of all known strains, it is the Delta variant that most often leads to hospitalization. Compared to the Alpha variant, the chance of being hospitalized with Delta is 85% higher.
Vaccine Effectiveness
According to Pfizer/BioNTech, their vaccine is 96% effective against hospitalization and mortality and 83% effective against the symptoms.
Lethality
The Delta variant is considered the most life-threatening one. In comparison with the original SARS-CoV-2, it is on average 137% more lethal.
A subvariant of the Indian Delta strain is the Delta plus strain that is considered even more contagious.
The South African Omicron: Symptoms and Characteristics
The Omicron variant, sometimes called as B.1.1.529, showed itself first in South Africa and Botswana in November 2021. Throughout the pandemic, experts had been waiting for a coronavirus strain that would be more infectious but less virulent, meaning it could spread far and fast, but would have less severe consequences. The idea is that if a less virulent strain becomes dominant, more people will be infected, but the effect on the infected people will be less critical.
Experts believe that the symptoms of the new coronavirus strain are similar to those of respiratory infections. Their prevalence among the affected, according to experts, is as follows:
- body temperature above 37.5 °C — more than 90%;
- cough, dry or with little mucus — 80%;
- breathlessness — 30%;
- tiredness — 40%;
- tight feeling in the chest — more than 20%.
When infected with the new strain, patients also experience:
- muscle pain and headache;
- nasal stuffiness or mild rhinorrhea (discharge);
- a sore and scratchy throat;
- conjunctivitis;
- skin rash;
- SpO2 (oxygen saturation) — at 95% or lower.
Loss of sense of smell is rare with the new strain. Loss of sense of taste, decreased appetite, vomiting and diarrhea are also less common.
Some patients have low body temperatures and in children there are rashes. Young patients have symptoms of croup, bronchial obstruction, and bronchiolitis (injury to bronchioles accompanied by respiratory failure).
Most people who fall ill have a mild infection. However, the specific features of the new variant of the virus not only contribute to its more rapid spread among people, but also enable it to affect the bronchi and lungs more quickly and aggressively, which, according to experts, justifies the importance of taking Omicron no less seriously than the previous variants.
The main difference between the Omicron variant and the previous ones is that its incubation period is shorter (three to five days once a person is infected) and is much more transmissible. A person infected with it can become contagious in just a few hours.
Omicron is rapidly excreted from the body. Unlike other variants of COVID-19, it does it in about a week.
Still, experts believe that it is premature to draw conclusions, since the existing data are very recent. According to CDC, some cases of infection caused by the new variant of the coronavirus may become more and more serious over the course of several days or weeks.
Contagiousness
There are no exact figures available to compare the rate of spread of the Omicron strain compared to other variants of SARS-CoV-2. Yet, scientists in Africa have concluded from preliminary studies that Omicron is more contagious than Delta. By December 2021, the strain had been detected in 38 countries.
Hospitalization
Scientists are still assessing the risk of hospitalization with the Omicron strain.
Vaccine Effectiveness
According to preliminary data, the Pfizer/BioNTech vaccine has proven to be 70% effective against hospitalization and 33% effective against the symptoms.
Lethality
No reliable data are yet available regarding mortality rates from the Omicron variant. This strain is estimated to be less lethal than Delta.
So, which of the “mutants” is the most dangerous one?
- Currently, the Delta variant is recognized as the most dangerous strain for human life.
- The Beta variant, discovered in Brazil, is the least contagious.
- There are not enough data on Omicron yet, but it is currently regarded as the most contagious but less life-threatening strain.
In any case, a person with characteristic symptoms should seek medical attention.