SARS history
Severe Acute Respiratory Syndrome (SARS) is a severe pneumonia caused by viruses belonging to a branch of the Coronaviridae family, which were first identified in 2003, when one of these made its appearance in China and caused a first fatality in Vietnam.
Within a few months, the disease had spread to North America, South America, Europe and Asia, before the global outbreak could be contained.
According to the World Health Organization (WHO), a total of 8.098 people worldwide fell ill with SARS during that outbreak. Of this figure, 774 people died. In the United States, only eight people have been infected with SARS-CoV based on laboratory confirmation. All of these people had traveled to other parts of the world where SARS was present.
SARS usually begins with a high fever (a fever greater than 100.4°F [>38.0°C]). Other symptoms may include a headache, a general feeling of discomfort, and body aches. Some people experience mild respiratory symptoms early in the illness. About 10 to 20 percent of patients suffer from diarrhea. After 2 to 7 days, SARS patients may develop a dry cough. Most patients get pneumonia.
ALPHA (lineages B.1.1.7 and Q)
The Alpha variant, commonly known as the British variant after the country where the first outbreak originated, or scientifically as lineage B.1.1.7, is a mutated variant of SARS-CoV-2, the virus that causes COVID-19 .
It made its appearance in September 2020 and on December 18 of the same year, the World Health Organization included it in its list of “worrying variants”.
According to the same organization, 1,153,877 infections worldwide can be attributed to this variant.
Alpha’s runaway success has scientists wondering how this variant took the world by storm. A recent study mentions one of the secrets of its success: Alpha disables the first line of immune defense in our body, so the virus has more time to multiply.
Alpha has 23 mutations that distinguish it from other coronaviruses.
BETA (lineages B.1.35 and descendants)
The B.1.351 variant or South African variant is one of the most risky due to its ability to evade the immunity of certain vaccines. It is believed that it generates a reduction of up to twelve times the effectiveness of the vaccine developed by Moderna. In an article published in the scientific journal Science Mag, reference is made to the results of an in vitro study that showed how several monoclonal antibodies were not capable of neutralizing this variant.
The results also reflected a decrease in the neutralization capacity of convalescent sera, up to nine times. The first results of the phase II trials with a booster dose of the vaccine specifically designed against this variant, achieved high levels of neutralizing antibodies against both the B.1.351 variant and the Brazilian variant (P.1).
Its virulence is such that South Africa, where it was detected for the first time, technically entered the third wave of the coronavirus.
DELTA (lineages B.1.617.2)
The Delta variant of COVID-19 is one of the “variants of concern” according to the WHO, due to its high contagiousness (more than 60% of the original virus) and not because of its lethality. It is currently present in more than 180 countries, and today it is one of the items of this SARS-COV-2 virus pandemic that most worries the scientific community because, to prevent its transmission, societies that are fully vaccinated with the immunization protocol are needed.
The World Health Organization (WHO) warned that the mutation that already represents more than three quarters of new cases of COVID-19 in many countries, will be the predominant one throughout the planet in the coming months.
The US Centers for Disease Control and Prevention (CDC) themselves admitted that their latest studies have determined that vaccinated people can become infected and infect others.
ÓMICRON (B.1.1.529)
The European Center for Disease Prevention and Control (ECDC) said it expects Omicron to become the dominant variant in the EU, accounting for more than 50% of cases, between January and March 2022. The variant has spread in a month to more than 89 countries.
For specialists, more than the number of mutations, the important thing would be to analyze the effect of all the variants together. One thing is the mutation in the genome and quite another the impact on the biology of the virus. The effect does not have to be cumulative, there can be compensation phenomena: the effect of one mutation can be compensated with that of another.
The General Director of the WHO, Tedros Adhanom Ghebreyesus, warned that there is “robust evidence” that people who have been vaccinated against COVID-19 or those who have become infected, “can contract the Omicron variant” whose spread is accelerating day after day around the world. From Geneva, he said information on Omicron indicates that this variant circulates “faster than the previous ones” and that “those vaccinated and those who have been cured of COVID 19 are likely to become infected or reinfected.”
