WHEN SHOULD I WORRY ABOUT...

How Worried Should You Be About COVID-19 Variants?

April 27, 2021 - Katie McCallum

Adjusting to life during a pandemic hasn't been easy. It's meant adopting a healthy respect for COVID-19 and changing your daily routine accordingly.

Now, with COVID-19 variants circulating in Houston and elsewhere, you may be wondering if you need to reassess your approach to staying safe from COVID-19.

Understanding how concerned you should be about these variants starts with understanding what COVID-19 variants are and what we currently know about them — including how they're different from the COVID-19 strain(s) we've previously seen spread through the population.

How do COVID-19 variants develop?

"COVID-19 variants arise when the virus collects genetic changes, called mutations. These mutations are part of the normal evolution process that all pathogens undergo in their journey of being transmitted from person to person. Fortunately, the great majority of mutations have no medically relevant effect. However, a few mutations have arisen in this virus that make them better able to spread or change the disease course in individual patients," explains Dr. Jim Musser, chair of pathology and genomic medicine at Houston Methodist Hospital.

"These mutations truly start to be 'of consequence' when they gain special qualities that have a clinical impact, such as leading to the virus becoming more effective at spreading from person to person or better at avoiding detection by the immune system, for instance."

There are currently several COVID-19 so-called "variants of concern," including:

  • B.1.1.7 – first detected in the U.K.
  • P.1 – first detected in Japan/Brazil
  • B.1.351 – first detected in South Africa
  • B.1.427 and B.1.429 – closely related variants first detected in California

"Right now, the most prominent COVID-19 variant circulating here in Houston by far is B.1.1.7, which is often referred to as the U.K. B.1.1.7 variant," says Dr. Musser.

Are COVID-19 variants more deadly?

For a virus that has already caused more than a half-million deaths in the U.S. alone, it's daunting to think that a more deadly variant might be in the community.

"Based on our extensive genome mapping and our ability to match genome sequences with patient outcomes, we've been able to ask and answer very important questions about disease severity and clinical relevance. For the first nine months of the pandemic, we were seeing variants arise, but none that seemed unusually dangerous," says Dr. Musser.

Then, the U.K. variant entered the mix.

"Since it's landed here in Houston, we've learned that the U.K. B.1.1.7 variant does have an increased ability to cause a person to be hospitalized. It's only a slight increase, but it is a significant one. And this is identical to what's been described by U.K. health officials," says Dr. Musser. "However, although a person infected with this variant may be more at risk for hospitalization, there's no evidence in our Houston Methodist data that the U.K. B.1.1.7 variant is more lethal."

Are COVID-19 variants more contagious?

There's another somewhat concerning characteristic of the U.K. variant: It spreads from person to person very successfully.

"In just the last three months, the U.K. B.1.1.7 variant has increased rapidly in Houston — and it now causes approximately 65% to 75% of all new COVID-19 cases in metropolitan Houston. To be clear, this does not mean total cases have increased by that amount, because they have not. It simply means that this new variant has spread well enough to become the predominant strain causing new infections right now," adds Dr. Musser.

Will COVID-19 variants cause another surge?

Although several other COVID-19 variants like the U.K. variant can spread very effectively, Dr. Musser says that these variants won't be the only thing to cause any COVID-19 surges that might occur in the near future. Rather, surges are more likely to occur when there are breakdowns in the preventive measures that keep communities safe.

"None of the variants circulating right now make important protective behaviors — such as wearing a mask, social distancing, avoiding indoor gatherings and getting vaccinated — obsolete. If we keep doing the things that we know are proven to decrease the spread of this virus, we'll be well-protected from these new variants," says Dr. Musser.

And Dr. Musser adds that the more we let this virus spread among us, the likelier new variants become.

"Mutations are a numbers game. If we enter another surge and let this virus spread unchecked, we increase our chances of eventually coming up against a more concerning COVID-19 variant," Dr. Musser explains. "This is why vaccination is so critical. The more people who get vaccinated and are immune to this virus, the better."

Can you get reinfected with a COVID-19 variant?

Infection with COVID-19 produces some amount of natural immunity in most people, and, reinfection with COVID-19 remains relatively rare. However, this doesn't mean reinfection — including reinfection with a different variant — is impossible.

"It's tempting to feel a sense of 100% security after you've had COVID-19, but there are still many questions surrounding how long natural immunity lasts and how protective it is on an individual basis. Those who have had COVID-19 can go on to get vaccinated after a period of time has elapsed," says Dr. Musser.

Can COVID-19 vaccines protect against variants?

One thing that is very clear is that vaccine-induced immunity remains strongly protective against many of these new variants — especially the U.K. B.1.1.7 variant prevalent here in Houston.

"Although it's spreading successfully from person to person in unvaccinated individuals, the U.K. B.1.1.7 variant is totally susceptible to each of the COVID-19 vaccines currently available," says Dr. Musser.

In addition, the durability of vaccine-induced immunity will continue to be closely studied in ongoing clinical trials.

This means that, regardless of whether you've had COVID-19 in the past or you're young and seemingly healthy, vaccine-based immunity is your best bet for staying safe from COVID-19 — variants or not.

"Importantly, widespread vaccination will also help limit spread, which in turn reduces the chance of a more concerning variant eventually arising," adds Dr. Musser.

Which COVID-19 variants are currently circulating in Houston?

The COVID-19 variant landscape varies based on where in the U.S. you're located. And keeping tabs on it takes massive genome sequencing efforts.

Fortunately, Dr. Musser and his team are providing Houston with a huge amount of data about the variants currently circulating here by analyzing the genomes of virus collected from thousands of COVID-19 patients.

"With the more than 40,000 SARS-CoV-2 genomes that we've sequenced, we've learned many different things. About a year ago, we first learned that a COVID-19 variant had arrived in Houston (called the D614G mutant). It spread very rapidly and became the predominant strain here by summer of 2020," explains Dr. Musser.

As Dr. Musser and his team kept sequencing the virus, they saw multiple versions of the virus entering Houston independently. But none of these were variants of concern — meaning that the small changes had no impact on spread of disease severity and/or never took a substantial hold in the infected population.

"Eventually, we began to identify the variants of global concern, and we now have all of the major variants circulating here in Houston. As mentioned, the U.K. B.1.1.7 variant is the most abundant here," says Dr. Musser. "The other variants of concern are here, but not nearly as prominently. Frankly, we don't really understand why the other variants aren't increasing as rapidly and dramatically, but we will continue to track their prevalence through our sequencing efforts."

In the meantime, Dr. Musser continues to stress how very important vaccination and protective behaviors — like wearing a mask and social distancing — are for not only reducing the risk of severe disease and spread throughout the community, but also for limiting the chance of a more deadly variant eventually arising.

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