COVID-19 variants have caused a surge of new cases and deaths across the globe, placing enormous strain on the healthcare system in certain countries.
What is a variant and how does it occur?
All viruses including COVID-19 evolve over time and may change its properties. Mutations of a virus are referred to as a “variant” of the original virus. Depending on where the changes are located in the virus genetic material, mutations may affect a virus properties such as transmission or severity.
How are variants classified?
The WHO (World Health Organisation) and US Centers for Disease Control and Prevention (CDC) classifies variants into three categories:
Variant of Interest (VOI)
A variant with mutations that may help it evade antibodies or bind more tightly to human cells. They have not yet been shown to be more infectious.Variant of Concern (VOC)
A variant that appears to be more infectious or cause more severe disease than other circulating coronaviruses.Variant of High Consequences (VOHC)
A variant of high consequence with clear evidence that prevention measures or medical countermeasures (MCMs) have significantly reduced effectiveness compared to previous variants.
Major types of COVID-19 variants (as of May 2021)
| | Variants of Concern (VOC) | |||
|---|---|---|---|---|
| |
B.1.617 (Delta) |
P.1 or B.1.1.28.1 |
501Y.V2 or B.1.351 (Beta) |
202012/01 or B.1.17 |
|
First
detected | India | Brazil and Japan | South Africa | United Kingdom |
| Features | "Triple mutant" of three prominent mutations: E484Q: Helps the virus evade antibodies
L452R: Enhances virus replication and latches on
P681R: Makes the virus more infectious | Mutations near the tip of the spike protein: N501Y: Helps the virus latch on more tightly to human cells K417T: Similar to the K417N mutation, it may help the virus to latch on tighter E484K: Helps the virus evade some kinds of antibodies | Mutations near the tip of the spike protein: N501Y: Helps the virus latch on more tightly to human cells K417N: Helps virus bind more tightly to human cells E484K: Helps the virus evade some kinds of antibodies | Mutations in the spike protein: N501Y: Helps the virus latch on more tightly to human cells. But not likely to help virus evade current vaccines P681H: May help infected cells create new spike proteins more efficiently |
| Effect compared to original strain | More transmissable than original strain in preliminary studies | Studies suggest that P1 is 1.7 to 2.4 times more transmissible than the previous strain | Thought to be up to 50% increased transmission | Thought to be up to 50% increased transmission and potentially increased severity |
Will the COVID-19 vaccine cover against all strains of COVID-19?
Ministry of Health (MOH) states that current evidence suggest that the Pfizer-BioNTech and Moderna vaccines continue to offer good protection against the various COVID-19 variants. MOH will continue to monitor the evolving situation and global studies of vaccine efficacy against various COVID-19 variants.
How to stay safe from COVID-19 variants?
Stopping the spread of the virus remains key. Steps that you (and your loved ones) can take to stay safe from COVID-19 include:
Frequent hand washing
Wear a well-filtered mask (at least 95 per cent bacterial filtration efficiency)
Physical distancing
Avoid crowded places
See a doctor if you feel unwell and stay at home
Being vaccinated. Vaccination can prevent disease and minimise transmission. To protect yourself and your loved ones (including those who cannot be vaccinated due to medical reasons), you are strongly encouraged to go for vaccination.
To learn more about COVID-19 vaccination, visit www.vaccine.gov.sg
References:
https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/
https://www.who.int/news-room/feature-stories/detail/the-effects-of-virus-variants-on-covid-19-vaccines
https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/variant-surveillance/variant-info.html
Ref: K21
Check out other articles on vaccines:
COVID-19 Vaccine Myths Busted!
COVID-19 Vaccine: Is It Safe for Pregnancy, Breastfeeding or Starting a Family?
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