ALL ABOUT COVID-19 VARIANTS
Text by Henrylito D. Tacio
Photo courtesy of WHO
Viruses are microscopic parasites, generally much smaller than bacteria. “They lack the capacity to thrive and reproduce outside of a host body,” writes Aparna Vidyasagar, a Live Science contributor.
But how small are viruses compared to bacteria? “With a diameter of 220 nanometers (nm), the measles virus is about 8 times smaller than E. coli bacteria,” explains Vidyasagar. “At 45 nm, the hepatitis virus is about 40 times smaller than E. coli.”
E. coli, if you care to know, is Escherichia coli, a type of bacteria that normally lives in your intestines. It’s also found in the gut of some animals. While most types are harmless, some strains can cause diarrhea if you eat contaminated food or drink fouled water.
But how small is small when it comes to viruses? In an article published in the journal Nature Education in 2010, Dr. David R. Wessner, a professor of biology at Davidson College, provides this analogy: The polio virus, 30 nm, is about 10,000 times smaller than a grain of salt.
“Such differences in size between viruses and bacteria provided the critical first clue of the former’s existence,” Vidyasagar writes.
What concern most countries is the fact that viruses may be used as a weapon of mass destruction.
“The ability of viruses to cause devastating epidemics in human societies has led to the concern that viruses could be weaponized for biological warfare,” Wikipedia points out. “Further concern was raised by the successful recreation of the infamous 1918 influenza virus in the laboratory.”
It must be recalled that smallpox virus devastated numerous societies throughout history before its eradication. Currently, only two centers in the world are authorized by the World Health Organization (WHO) to keep stocks of smallpox virus: the State Research Center of Virology and Biotechnology VECTOR in Russia and the Centers for Disease Control and Prevention in the United States.
“It may be used as a weapon, as the vaccine for smallpox sometimes had severe side-effects, it is no longer used routinely in any country,” Wikipedia reports. “ Thus, much of the modern human population has almost no established resistance to smallpox and would be vulnerable to the virus.”
These days, the most popular virus is called coronavirus, particularly SARS-CoV-2, which causes the dreaded coronavirus disease 2019 (COVID-19).
“Most people infected with the COVID-19 virus will experience mild to moderate respiratory illness and recover without requiring special treatment,” the WHO states. “Older people, and those with underlying medical problems like cardiovascular disease, diabetes, chronic respiratory disease, and cancer are more likely to develop serious illness.”
According to the United Nations health agency, “the best way to prevent and slow down transmission is to be well informed about the COVID-19 virus, the disease it causes and how it spreads.”
All viruses, including SARS-CoV-2, change over time. “Most changes have little to no impact on the virus’ properties,” the WHO says. “However some changes may affect the virus’s properties, such as how easily it spreads, the associated disease severity, or the performance of vaccines, therapeutic medicines, diagnostic tools, or other public health and social measures.”
The WHO, in collaboration with partners, expert networks, national authorities, institutions and researchers have been monitoring and assessing the evolution of SARS-CoV-2 since January 2020.
Just recently, the WHO convened a group of scientists from several countries and agencies to consider easy-to-pronounce and non-stigmatizing labels for variants of concerns (VOC) and variants of interest (VOI). At the present time, this expert group has recommended using labels using letters of the Greek alphabet.
A SARS-CoV-2 variants that meets the definition of a VOC and through a comparative assessment, has been demonstrated to be associated with one or more of the following changes at a degrees of global public health significance:
Increase in transmissibility or detrimental change in COVID-19 epidemiology; or increase in virulence or change in clinical disease presentation; or decrease in effectiveness of public health and social measures or available diagnostic, vaccines, therapeutics.
So far, the WHO has identified VOC. These are Alpha (earliest document samples taken in the United Kingdom in September 2020), Beta (South Africa in May 2020), Gamma (Brazil in November 2020), and Delta (India in October 2020).
A SARS-CoV-2 isolate is a VOI if, compared to a reference isolate, its genome has mutations with established or suspected phenotypic implications, and either: has been identified to cause community transmission/multiple COVID-19 cases/clusters, or has been detected in multiple countries; or is otherwise assessed to be a VOI by WHO in consultation with the WHO SARS-CoV-2 Virus Evolution Working Group.
The Philippine strain is called Theta; it was first reported in January 2021. The other VOI are Epsilon (USA in March 2020), Zeta (Brazil in April 2020), Eta (multiple countries in December 2020), Iota (USA in November 2020), and Kappa (India in October 2020).
“These labels do not replace existing scientific names, which convey important scientific information and will continue to be used in research,” the WHO said in a statement.
“While they have their advantages, these scientific names can be difficult to say and recall, and are prone to misreporting,” the WHO explained. “As a result, people often resort to calling variants by the places where they are detected, which is stigmatizing and discriminatory.”