Updated January 28, 2022

By James Shea

The UK variant. Delta variant. Omicron. And now, omicron BA.2.

New strains of the SARS-CoV 2 virus, which causes COVID-19, have spread in waves around the world. Some are more deadly. Some infect more people.

Although viruses mutate all the time, new strains of the coronavirus have serious implications when it comes to COVID-19 hospitalizations, deaths and the efficacy of our vaccines.

Dr. Michelle Doll, an assistant professor in the Department of Internal Medicine at the VCU School of Medicine, is an expert in infectious diseases. Here, Dr. Doll addresses the effect these variants have on our health and our vaccines.   

Let’s start by defining terms. Is there a difference between a strain and a variant? 

The terms are often used interchangeably. There is no definite criteria for applying one versus the other. Whether you call it a strain or a variant, you’re talking about a specific genetic signature of that virus.

We know that viruses will mutate over time, steadily accumulating minor changes. Sometimes those changes mean something and sometimes they don’t. If the changes are found to be significant, or the changes begin to vary enough, it is considered a different variant or strain. That just means there is something about that version of the virus that is distinct from the parent virus.

Did scientists expect new strains, or variants, of the coronavirus?

Yes. Viruses are known to mutate over time, so scientists have been discussing the impact of these variations throughout the pandemic. Certainly, this has been on the radar of virologists and other scientists working on our vaccines. Additional variants are expected to appear, which is why surveillance is so important.

Do the variants make you sicker?

Not necessarily. Generally, we see more people sick whenever a more contagious variant emerges because more people are infected at once and so more people are at risk for getting sicker.

The omicron variant was actually characterized by overall less severe infections, with many people minimally symptomatic or even with no symptoms at all. This helps the virus to spread as well. However, we certainly continue to see very ill patients with omicron strains. The experience of the population overall does not mean that someone with vulnerability won’t develop a life-threatening infection. This is why vaccination continues to be so important for the individual as well as the population.

How do variants impact how well our vaccines work?

Our current vaccines continue to offer tremendous protection against the variants we've identified, but the protective antibodies they prompt inside your body may not be quite as potent against future strains.

How potent is potent enough? That is the question on everyone’s mind. What we truly need is protection from severe disease, which is responsible for hospitalizations, death and long-term disability, as opposed to 100% protection against infection. 

Scientists have always envisioned a future in which SARS-CoV-2 continues to circulate in low levels and we are all relatively protected by some form of immunity. The collective population immunity needs to be enough, though, to prevent outbreaks of severe disease.

With that in mind, vaccine developers have been studying the use of boosters to produce better immunity against the new strains. The Centers for Disease Control and Prevention recommends you get a booster in addition to your primary vaccine series. It’s possible we will need additional or annual boosters to maintain good levels of immunity against new strains as they emerge. 

Can one vaccine work on multiple strains?

Yes, many existing vaccines incorporate multiple diseases into the same shot. Consider the DTaP shot (formerly the DPT shot) we get as children. It protects against diphtheria, tetanus and pertussis (whooping cough). So certainly, vaccine developers can incorporate multiple strains into a single SARS-2-CoV vaccine.

Should we take extra precautions because of these variants?

The precautions necessary to combat these variants are the same you’ve been hearing about since the beginning: masking, handwashing and social distancing. Above all, get vaccinated and boosted.

Should people continue to wash surfaces, or do the variants spread mainly through the air?

I think there probably is a surface component based on what we see from other respiratory viruses. Wiping down surfaces is important for infection control, but a bigger component is droplet spread — even from normal speech. Masking makes a big difference in preventing this form of transmission.

The challenge with contact, or surface, spread is that it’s pretty much invisible. Just because you don’t see it doesn’t mean it’s not happening, though. I definitely recommend diligent handwashing as well as masking to protect yourself.

I hear there’s now a COVID pill to treat COVID-19. Will that work against new variants?

The oral medications work against our current strains of the coronavirus. New variants may affect the efficacy of these medications, but how and to what extent we cannot predict.

This story was last updated February 23, 2021. It was completely revised and updated January 28, 2022.

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