What Is a COVID-19 Variant?
Viruses are always changing, and that can cause a new variant, or strain, of a virus to form. A variant usually doesn’t affect how the virus works. But sometimes they make it act in different ways.
Scientists around the world are tracking changes in the virus that causes COVID-19. Their research is helping experts understand whether certain COVID-19 variants spread faster than others, how they might affect your health, and how effective different vaccines might be against them.
How Many Coronaviruses Are There?
Coronaviruses didn’t just pop up recently. They’re a large family of viruses that have been around for a long time. Many of them can cause a variety of illnesses, from a mild cough to severe respiratory illnesses.
The new (or “novel”) coronavirus that causes COVID-19 is one of several known to infect humans. It’s probably been around for some time in animals. Sometimes, a virus in animals crosses over into people. That’s what scientists think happened here. So this virus isn’t new to the world, but it is new to humans. When scientists found out that it was making people sick in 2019, they named it as a novel coronavirus. Experts call this strain SARS-CoV-2.
How Do Variants Happen?
Coronaviruses have all their genetic material in something called RNA (ribonucleic acid). RNA has some similarities to DNA, but they aren’t the same.
When viruses infect you, they attach to your cells, get inside them, and make copies of their RNA, which helps them spread. If there’s a copying mistake, the RNA gets changed. Scientists call those changes mutations.
These changes happen randomly and by accident. It’s a normal part of what happens to viruses as they multiply and spread.
Because the changes are random, they may make little to no difference in a person’s health. Other times, they may cause disease. For example, one reason you need a flu shot every year is because influenza viruses change from year to year. This year’s flu virus probably isn’t exactly the same one that circulated last year.
If a virus has a random change that makes it easier to infect people and it spreads, that variant will become more common.
The bottom line is that all viruses, including coronaviruses, can change over time.
Alpha (B.1.1.7) . In late 2020, experts noted gene mutations in COVID-19 cases seen in people in southeastern England. This variant has since been reported in other countries, including the U.S. Scientists estimate that these mutations could make the virus up to 70% more transmissible, meaning it could spread more easily. Some research has linked this variant to a higher risk of death, but the evidence isn't strong.
The mutation on the alpha variant is on the spike protein, which helps the virus infect its host. This is what COVID-19 vaccines target. These vaccines make antibodies against many parts of the spike protein, so it’s unlikely that a single new mutation in the alpha variant will make the vaccine less effective.
Beta (B.1.351). Other variants of the virus have been found in other countries, including South Africa and Nigeria. The beta variant appears to spread more easily than the original virus but doesn’t seem to cause worse illness.
Gamma (P.1). In January 2021, experts spotted this COVID-19 variant in people from Brazil who’d traveled to Japan. By the end of that month, it was showing up in the U.S.
The gamma variant appears to be more contagious than earlier strains of the virus. And it may be able to infect people who've already had COVID-19. A report from Brazil confirms that a 29-year-old woman came down with this variant after an earlier coronavirus infection a few months before.
Some early research suggests that the variant’s changes might help it evade antibodies (made by your immune system after an infection or a vaccine) that fight the coronavirus. A lab study shows that the Pfizer-BioNTech vaccine can neutralize the fast-spreading Brazil strain. But more research is needed.
Delta (B.1.617.2). This variant was spotted in India in December 2020. It caused a huge surge in cases in Mid-April 2021. The highly contagious variant is now found in 43 countries including the U.S., U.K., Australia, and Singapore.
The delta variant has now become a dominant strain in the U.K. due to travel to India and community spread. An added cause for concern: It’s causing more cases of COVID-19 in young people. However, the fast-spreading variant isn’t likely to cause much harm in the U.S. due to overall vaccination rates.
A study of the COVID-19 vaccine’s effectiveness against this variant found that:
- 2 doses of the Pfizer-BioNTech vaccine were 88% effective 2 weeks after the second dose.
- 2 doses of the AstraZeneca vaccine available in the U.K. were 60% effective.
- Both vaccines are only 33% effective 3 weeks after the first dose.
Given the difference in protection between doses, experts recommend getting the second shot as soon as you’re eligible.
Research suggests that changes to the spike protein may make the delta variant up to 50% more transmissible than other COVID-19 variants. Experts have concerns about how the mutated delta variant affects immune response, but say they need more research to know for sure.
Earlier Coronavirus Variants
Earlier in 2020, when the pandemic was new, you might have heard that there was more than one strain of the new coronavirus. Is it true? The answer appeared to be yes.
The theory about different variants of the new coronavirus came from a study in China. Researchers were studying changes in coronavirus RNA over time to figure out how various coronaviruses are related to each other. They looked at 103 samples of the new coronavirus collected from people, and they looked at coronaviruses from animals. It turned out that the coronaviruses found in humans weren’t all the same.
There were two types, which the researchers called “L” and “S.” They’re very similar, with slight differences in two places. It looks like the S type came first. But the scientists say the L type was more common early in the outbreak.
What to Expect
The virus that causes COVID-19 will probably keep changing. Experts may find new variants. It’s impossible to predict how those virus changes might affect what happens. But change is just what viruses do.