The development of the omicron variant — and its differences compared to earlier coronavirus variants — has raised countless questions and concerns. From how variants form to the effectiveness of the currently available COVID-19 vaccines and what comes next in the pandemic, Dr. Nancy Greengold, chief medical officer of Sharp Grossmont Hospital, shares her thoughts.
How do virus variants form?
All viruses mutate because copying errors can randomly occur whenever a virus is replicating itself. Some of these errors, or mutations, give the virus a survival advantage and others don’t. Different variants emerge, and those that lack a competitive edge drop out of the picture.
The virus that causes COVID-19 is reported to have had thousands of mutations since its first appearance. Sometimes the mutations have resulted in infectious agents called “variants of concern,” which have included delta and omicron. Omicron has shown itself to be highly transmissible — or contagious — but does not appear to be as virulent — or severe — as its predecessor, delta.
Will the coronavirus continue to mutate?
Mutation is a key fact in the virus’s own survival because some of the mutations help the virus circumvent people’s existing immunity to previous variants. Basically, we are witnessing natural selection taking place in real time, with the virus continually morphing into altered forms that the immune system is less prepared to fight.
The omicron variant appears to be more infectious but less deadly than previous variants. The most hopeful scenario would be for the coronavirus to evolve to a point where it’s causing milder illness, like some of the other so-called seasonal coronaviruses that have been with us for years and cause relatively minor cold-like symptoms.
How have we been able to eradicate or control past epidemics?
With the Spanish flu, or H1N1 influenza, we did not have vaccines, and so the infection raged throughout the world until immunity became widespread and the virus’s virulence subsided. The virus is believed to have diminished in potency over time and to be present today as seasonal flu.
By contrast, we were able to eradicate polio in the U.S. with a two-dose vaccination, and we have nearly eliminated it globally. Over the course of time, smallpox actually was eradicated from all global populations by vaccination.
In a very different manner, the severe acute respiratory syndrome (SARS, or SARS-CoV-1) outbreak was shut down. Although it was caused by a coronavirus similar in many ways to the one that causes COVID-19, it was contained through swift international cooperation in response to a WHO (World Health Organization) global alert, before it had the chance to become a pandemic.
Unfortunately, we were not able to contain COVID-19 at the outset and we are currently coming to expect that it will become an endemic infectious disease.
When does a pandemic become endemic?
When a virus is no longer circulating wildly throughout an entire population but is concentrated in particular areas or among certain groups, it is considered to be endemic. Essentially, the case numbers of an endemic disease are less overwhelming than those seen during a pandemic, though the seriousness of the disease may not necessarily decline.
It’s hard to say when exactly COVID-19 will become endemic — that is, when the level of immunity in the population and the contagiousness of the disease will reach a steady state. Unless the virus becomes distinctly milder, we will have to continue to maintain strong protective measures, such as masking and distancing, while targeted vaccines and treatments, such as antiviral medications, will remain crucial tools for the management of endemic disease.
Could vaccines become ineffective in protecting against future variants?
It’s definitely possible that our original vaccines can become ineffective if the virus evolves — that is, mutates — to the point where it is no longer recognized by the immune cells that developed in response to those original vaccines. It does appear as if some of the coronavirus mutations that have already occurred have decreased the capability of the body’s “neutralizing antibodies” that were stimulated by vaccination, infection with a prior variant, or both.
At present, it appears that the effectiveness of our original vaccines has been “blunted” over time but not entirely lost. And most people who experience waning immunity are still protected against severe illness and death.
As with vaccination against seasonal flu, it may become necessary to develop annual COVID-19 vaccines that target as many variants of concern as possible. Ideally, the next vaccine will target omicron as well as its previous variants.
Will we need booster shots for every variant?
I think the need for a booster will really depend on the severity of disease caused by a given variant, along with that variant’s ability to break through preexisting immunity. Nobody knows yet how serious the next variants will be. If an endemic COVID-19 happens to behave as a mild illness, like the common cold, there may be less need for a booster shot.
For the news media: To talk with Dr. Greengold about the development of coronavirus variants, contact Erica Carlson, senior public relations specialist, at email@example.com.