WHO says preliminary evidence indicates an ‘increased risk of reinfection with Omicron’ compared with other coronavirus variants, but information is limited.
On November 24, 2021, scientists in South Africa reported a new coronavirus variant with a higher number of mutations than were found in other variants. Two days later, the World Health Organization (WHO) said the new variant, dubbed Omicron, was a variant of concern (VOC).
The announcement led many countries to impose travel restrictions.
What are mutations?
All viruses mutate, and the SARS-CoV-2 coronavirus has continued to mutate since it emerged in late 2019. A mutation is a change in a virus’s genetic code, and a mutated virus is known as a variant.
Some coronavirus variants spread more easily than others, which can lead to increases in the rate of infection. A surge in infections can put additional strain on healthcare resources, potentially leading to more hospitalisations and deaths.
Experts believe there are at least 50 mutations on the new variant, with 32 mutations on the spike protein, the part of the virus that enters human cells. Scientists have said that similar mutations seen in other variants have been associated with higher transmission and a higher chance of escaping the body’s immune defences, compared with the original strain of the virus.
Mutations are identified by letters and numbers such as D614G – which means an amino acid changed from a D (aspartate) to a G (glycine) at position number 614 of the viral spike proteins.
How variants are named
The WHO has identified five VOCs and eight variants of interest (VOI). Since May 2021, they have been named after the letters of the Greek alphabet starting with Alpha.
According to this, the next assigned letters were supposed to be Nu then Xi but according to the WHO, “Nu is too easily confounded with ‘new’ and Xi was not used because it is a common surname.”
Instead, the 15th letter, Omicron, was used.
How Omicron compares with other variants
The WHO has said the global risk of the Omicron variant is “very high”.
Currently, the Delta variant, first documented in India in October 2020, is the most dominant strain, accounting for more than 99 percent of global sequenced cases.
On Sunday, the WHO said it is not yet clear whether Omicron is more transmissible or causes more severe disease compared with other variants. It added that “vaccines remain critical to reducing severe disease and death”.
Preliminary evidence suggests there may be an “increased risk of reinfection with Omicron as compared with other variants of concern, but information is limited”, it said.
South African epidemiologist Salim Abdool Karim said on Monday that not enough data had been collected to determine the clinical implications of Omicron compared with previous variants, and that reinfections were likely but that vaccinated people had less probability of developing serious symptoms.
Experts say that more information will be available in the coming days and weeks as the virus spreads more widely and researchers study how Omicron’s mutations work together.
How to protect yourself and others
The WHO advises the following steps to protect yourself and prevent the spread of COVID-19.
- Get vaccinated
- Wear a mask
- Maintain physical distancing
- Ventilate indoor spaces
- Keep good hygiene
- Self-isolate if you develop symptoms