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What to Know About Variants

Many people are getting a crash course in variants as they learn more and more about COVID-19 variants.

COVID-19 variants are here, especially the B.1.1.7 variant.

This isn’t the first time most have heard about these types of variants though.

What to Know About Variants

Wait, other viruses can have variants?

Of course!

“When humans are infected with influenza viruses that normally circulate in swine (pigs), these viruses are call variant viruses and are designated with a letter ‘v’ (e.g., an A(H3N2)v virus).”

Types of Infuenza Viruses

Remember when we used to be worried about variant flu viruses?

And polio virus variants?

In 2005, there was an outbreak of vaccine derived polio among a group of unvaccinated Amish in Minnesota.

Global efforts to immunise children with the oral polio vaccine (OPV) have reduced wild poliovirus cases by 99.9% since 1988.”

Fact Sheet: Vaccine-Derived Poliovirus

And while there have been very few cases of wild polio virus infections in 2021 (one case in Pakistan and one case in Afghanistan), we are still seeing sporadic vaccine-derived poliovirus type 2 (VDPV2) isolates, a variant of the wild polio virus, in a few more countries.

Hopefully we won’t be seeing them for much longer though, as countries have switched to bOPV that doesn’t include the type 2 polio strain. That switch was made possible by the eradication of the type 2 wild polio strain.

Do other viruses have variants?

Yes, although instead of variants, some other viruses have multiple strains, including:

  • the varicella-zoster virus that causes chickenpox and shingles (multiple strains)
  • the measles virus (multiple strains)
  • HPV (multiple strains)
  • HIV (multiple variants)
  • HHV-6 (variants) – causes roseola
  • CMV (variants)
  • rabies virus (variants)
  • norovirus (variants)
  • RSV (variants)
  • Ebola (variants)
  • West Nile Virus (multiple strains)
  • hepatitis B (variants)

And some have both…

Wait, what’s the difference between variants and strains?

“Although mutation, variant and strains can be used interchangeably when describing the SARS-CoV-2 epidemiology, it is important to understand the distinctions. Mutation refers to the actual change in the genetic sequence. Viruses whose genetic sequences differ are called variants. Variants with a few mutations belong to the same lineages. Lineages are important for showing how a virus spreads through communities or populations. Strictly speaking, a variant is a strain when it has a different characteristic.”

Seven things to know about COVID-19 variants in Africa

The measles virus, for example, might have multiple strains, but they all basically act the same. Measles, and a few other viruses, like rubella, yellow fever, and polio are genetically very stable and are actually considered mostly invariant.

In contrast, a variant of a virus might be more or less contagious or more or less deadly. Or in the case of a vaccine preventable disease, a variant virus might become capable of vaccine escape, leading to vaccine failure.

“Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. Sometimes new variants emerge and disappear. Other times, new variants emerge and persist. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic.”

About Variants

The concern with the COVID-19 variants is that they will be more contagious and more deadly. Vaccine escape is also a concern. As is the possibility that some people who have already had a natural COVID-19 infection might again become susceptible to one or more of these COVID-19 variants.

“The SARS-CoV-2 B.1.1.7 variant, which is more transmissible and virulent than previously circulating strains, threatens to reverse the current downward COVID-19 trends in the United States (US) and could lead to a significant surge in cases in the next 4 to 12 weeks.”

Reassessing COVID-19 Vaccine Deployment in Anticipation of a US B.1.1.7 Surge: Stay the Course or Pivot?

Viruses with variants aren’t anything new though.

“The variants of concern that have arisen to date, including B.1.1.7, B.1.351, and P.1, have done so in a human population that has largely been without any vaccine-derived protection. Variants will continue to mutate wherever ongoing transmission occurs.”

Reassessing COVID-19 Vaccine Deployment in Anticipation of a US B.1.1.7 Surge: Stay the Course or Pivot?

And the best thing we can do is continuing to work to stop the spread of COVID-19 by wearing masks, practicing social distancing, and getting as many people vaccinated and protected as quickly as possible.

More About Variants

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