As SARS-CoV-2 — the virus that causes COVID-19 — spreads, it constantly changes. Mutations in the genetic code of the virus create variants. Some of these variants disappear quickly, while others can become more prevalent. Some coronavirus variants can be more contagious and impact the severity of COVID-19 symptoms.

Several variants of the virus that causes COVID-19 have already spread around the world. Researchers are still trying to understand how these variants will affect those living with long COVID. News on variants is rapidly changing as researchers race to learn more.

What Are COVID-19 Variants?

SARS-CoV-2 makes copies of itself when it infects a person’s cells. These copies can then infect more cells or spread the virus to other people. However, SARS-CoV-2 makes some mistakes when it copies itself, leading to new viruses that have genetic changes called mutations.

Some mutations make no difference in how the virus spreads, or they may even make the virus less effective at spreading. Other mutations can allow a virus to spread more easily. Some coronavirus variants can spread quickly throughout the global population.

The U.S. Centers for Disease Control and Prevention (CDC) tracks different variants of SARS-CoV-2 and classifies each one depending on how it might impact public health. As of June 2022, there was one major variant the CDC classified as a “variant of concern” — omicron.

Delta Variant

The delta variant is important to mention even though it is no longer a dominant strain of coronavirus. Delta was first identified in India in late 2020 and became the predominant strain in many parts of the world for several months. The CDC noted that the delta variant caused more than twice as many infections as the original coronavirus strain, and it also caused more severe illness in unvaccinated people. While the initial COVID-19 vaccines were designed for earlier forms of the virus, they were largely effective against the delta variant as well.

Omicron Variant

The omicron variant was first reported on Nov. 24, 2021 by scientists in South Africa. Omicron was likely spreading throughout the world before it was identified and did not originate in South Africa. As of July 5, the CDC reported that the omicron variant was responsible for essentially all COVID-19 cases in the U.S.

Omicron has proved to be the fastest-spreading variant yet, moving from person to person more quickly than the earlier strains of coronavirus. In contrast, scientists believe omicron is likely less severe than previous versions of the coronavirus that causes COVID-19.

However, omicron can still cause severe disease that may lead to hospitalization, need for intensive care, and even death in some people — especially those who are not vaccinated. Given how fast omicron can spread, and the large number of people who have been infected by it, many people have become seriously ill with COVID-19 from this variant despite its general tendency to produce more mild symptoms.

The CDC states that COVID-19 symptoms are generally similar regardless of the variant that causes them. Symptoms include:

• Fever
• Shortness of breath
• Chills
• Tiredness
• Pain in the muscles
• New loss of taste or smell
• Sore throat
• Headache
• Congestion or runny nose
• Nausea and vomiting
• Diarrhea

Omicron Subvariants

You may have heard the term “subvariant,” which describes new versions of the coronavirus variants whose differences are not as dramatic as the differences between major variants like delta and omicron. Scientists are still learning about coronavirus subvariants, but many believe new subvariants of omicron tend to be more contagious than previous versions of the virus.

Some of the newer subvariants have replaced previous versions of omicron in many countries. In the United States, multiple waves of these subvariants have occurred during the pandemic. While major variants are commonly known by letters of the Greek alphabet, subvariants go by a series of numbers and letters. For instance, subvariants BA.4 and BA.5 now make up over 50 percent of coronavirus infections in the United States.

Do Variants Cause a Higher Risk of Long COVID?

Scientists are still learning about the new coronavirus variants circulating throughout the world, but some early research reveals how these variants will affect the development of long COVID. A study comparing people who were infected with omicron to people who were infected with the delta variant suggests that omicron only causes long COVID about half as often as delta does (less than 5 percent compared to over 10 percent of people infected).

However, the coronavirus variants of concern are more contagious, allowing them to infect more people and potentially cause more cases of long COVID. Getting vaccinated against COVID-19 can help protect you from contracting COVID-19, and thereby reduce your risk for long COVID. It is possible to have COVID-19 more than once, so vaccines are important even if you think you have already had COVID-19.

Evidence suggests the omicron variant can evade some of the immune system protection created by vaccines. A small study compared how well the antibodies from people vaccinated with two doses of the AstraZeneca or Pfizer vaccines could neutralize the delta and omicron variants. They found that the ability of the antibodies to neutralize omicron was significantly lower when compared to earlier coronavirus variants, although there was evidence that a booster shot after the two-dose vaccination series provided more protection.

Other studies have found that most people vaccinated with only two doses of a COVID-19 vaccine had minimal protection against the symptoms caused by the omicron variant. However, those who had a booster shot of a messenger RNA (mRNA) vaccine, such as Pfizer, after their two-vaccination series had more protection against omicron. This evidence points to the idea that vaccine boosters can help reduce the number of COVID-19 infections and therefore the risk of developing long COVID.

To counter omicron’s increased ability to spread even in vaccinated people, some vaccine makers are developing omicron-specific COVID-19 vaccines.

Can Variants Affect People Who Already Have Long COVID-19?

Scientists still don’t know exactly what causes long COVID-19 or how reinfection with coronavirus variants may affect people with long COVID.

Researchers think the symptoms of long COVID could have several causes, including:

• Damage to the immune system
• Direct infection of bodily tissues by the virus
• Severe inflammation
• A risk of blood clotting sometimes caused by fighting the virus

Some symptoms of long COVID may also be due to the debilitating effects of prolonged hospitalizations and the medications received during treatment. Reinfection with a COVID-19 variant might make these issues worse, but it’s too early to know for sure.

According to the World Health Organization, people who’ve already had COVID-19 may be more likely to experience a reinfection with the omicron variant than with the other previous variants. Scientists in one study noted that previous coronavirus infections prevented reinfection with delta and earlier variants by 90 percent, but prevented reinfection with omicron only about 60 percent of the time. This means the immune system protection people develop from previously having COVID-19 is less likely to stop infections with new variants.

Fortunately, COVID-19 vaccines and booster doses can provide a higher degree of protection against the current coronavirus variants. This can help protect people with long COVID against reinfection while they are still recovering from long-term symptoms.

If more contagious coronavirus variants arise and infect more people with COVID-19, there is a higher chance for more people to develop the lingering symptoms of long COVID. Preventing infection through vaccines and COVID-19 booster doses remains the best protection against long COVID.

Find Your Team

On myCOVIDteam, the social support network for those recovering from the effects of COVID-19, you can connect with others. Members come together to ask questions, give advice, and share their stories with others who understand.

Are you living with long COVID? Share your insights in the comments below, or start a conversation by posting on myCOVIDteam.