COVID-19 pandemic is the third recorded outbreak of a coronavirus
Nobody is unknown to coronavirus and the havoc it has wreaked on humanity since 2020. Considered to have been one of the biggest pandemics in the history of humankind, the coronavirus induced COVID-19, is still infecting millions of people worldwide with its emerging variants.
As per an NCBI paper, the COVID-19 pandemic is the third recorded outbreak of a coronavirus, with the 2002 sudden acute respiratory syndrome (SARS, SARS-CoV-1 or SARS-CoV) and the 2012 Middle East respiratory syndrome (MERS or MERS-CoV) epidemics preceding it.
​Coronavirus variants
Viruses change over time. While most viruses do not change their properties, in many others important properties associated with the severity, performance of vaccines, therapeutic medicines, and diagnostic tools change drastically, posing a threat to mankind.
This is how variants are formed.
Depending on their risk to public health, the World Health Organisation (WHO) classifies coronaviruses as either variants of concern or variants of interest.
The variants of concern have a detrimental effect on the infected people. These variants have increased transmissibility, and virulence.
Coronavirus variants of concerns
So far, five variants of coronavirus have been labelled as variants of concern:
Alpha, Beta, Gamma, Delta, and Omicron.
The Alpha variant, B.1.1.7, was first found in the United Kingdom in September 2020, as per WHO. The Beta variant, B.1.351, was found in South Africa in May 2020. The next highly transmissible variant, Gamma, P.1, was found in Brazil in November 2020.
"These three ‘variants of concern’ share some mutations, particularly in key regions of the spike protein involved in recognizing the host-cell ACE2 receptors that the virus uses to enter cells. They also carried mutations similar or identical to those spotted in SARS-CoV-2 in people with compromised immune systems whose infections lasted for months," says a Nature article.
The fourth variant, Delta, B.1.617.2, or the super-Alpha, as researchers call it, was identified in India in October 2020. Epidemiologists say it was 60% more transmissible than the alpha variant. "Compared with other variants, including Alpha, Delta multiplies faster and to higher levels in the airways of infected individuals, potentially outpacing initial immune responses against the virus," the article says.
The Omicron, B.1.1.529, variant was traced in November 2021. Compared with other variants, Omicron contains more mutations, in the spike that recognizes host cells, thus accounting for its transmissibility.
The coronavirus variants which are variants of interest as per WHO are Lambda and Mu.
​What do research studies say about the next one?
A Nature article citing evolutionary biologist Jesse Bloom says that the new pathogen would not be eradicated. Rather, it would become endemic and establish itself in humans.
On the aggressive mutation of the virus, and in view of the mild severity of the Omicron, Andrew Rambaut, an evolutionary biologist at the University of Edinburgh, UK told Nature that expecting the next variant to be milder "is bit of a myth. The reality is far more complex."
The WHO calls for following COVID appropriate behaviour in order to stop the transmission of the infection from the current as well as future variants.
WHO expert Maria Van Kerkhove says, "Omicron will not be the last variant that you will hear us discuss, and the possibility of future emergence of variants of concern is very real. And more variants that emerge, we don't understand what those the properties of those variants may be."
"Certainly, they will be more transmissible because they will need to overtake variants that are currently circulating. They could become more or less severe, but they could also have properties of immune escape. So we want to reduce the risk of future emergence of variants of concern," the WHO expert adds.