COVID-19 Symptoms: New Variants and What to Watch For

Aaron S. Weinberg MD, MPhil
February 15, 2022
8 mins

We’ve been fighting COVID-19 for more than two years now — acting together, through lockdowns, social distancing, mask mandates, and vaccines. And although these actions have helped immensely, the virus continues to be a serious threat to public health. 

Part of the reason for this is that COVID-19 is an RNA-based virus; these viruses are known for their ability to mutate and create new variants (or “strains”). Mutation is especially common when these viruses are subject to geographic separation as time passes. This explains why we have seen several COVID-19 variants appear during the course of the pandemic. Variants of an infectious virus may have symptoms, effects, and other characteristics that differ greatly. In recent months, the COVID-19 Omicron variant has become the dominant strain in much of the world. In this post, we will answer frequently asked questions about Omicron and other variants.

What Are the Symptoms of the COVID-19 Omicron Variant?

Does the new COVID-19 variant have symptoms that are different from previous strains? Yes and no. Many symptoms of the Omicron variant are the same as those of previous variants, though they tend to be milder and can more often be treated at home (though Omicron can lead to hospitalization and death). Even in people who are vaccinated, Omicron can cause breakthrough cases. Symptoms to watch for with the COVID-19 Omicron variant are:

     • Fever and/or chills

     • Aching muscles

     • Sore or scratchy throat

     • Congestion and/or runny nose

     • Shortness of breath

     • Muscle and/or body aches

     • Fatigue

     • Headache 

     • Cough

     • Nausea and/or vomiting

     • Diarrhea

     • Loss of taste and/or smell (this is rarer than with previous variants)

What Is Omicron?

Also known as B.1.1.529, the Omicron strain of COVID-19 was first detected in South Africa. It was later classified by the World Health Organization (WHO) as a “variant of concern.” It has quickly replaced Delta as the most prominent strain in the United States. This new strain of COVID-19 spreads more easily than previous variants, but the symptoms have been reported to be less severe in most vaccinated people (most hospitalizations and deaths from Omicron have been among unvaccinated people). We also saw an increase in pediatric hospitalizations due to the Omicron strain. 

How Is Omicron Different from Other Strains?

Omicron shares many symptoms with other strains, but they tend to be less severe than those of the previous variant, Delta. Omicron has also proved to be more contagious than previous strains. Although many “breakthrough” cases have been recorded, vaccines greatly reduce symptom severity (or prevent symptoms altogether) in most cases. Being fully vaccinated (which means completing your initial vaccinations and receiving a booster shot) is very effective against preventing severe infection, hospitalization, and death from Omicron. Omicron has also rendered most of the monoclonal antibodies ineffective (except for sotrovimab). Luckily, we have oral antiviral therapies (from Pfizer and Merck), which are effective against this variant for higher-risk individuals.

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What Are the Other Covid-19 Variants and Their Symptoms?

The original COVID-19, which is the Alpha strain, has mutated into four other notable variants aside from Omicron: Lambda, Epsilon, Delta, and Delta Plus (a subvariant of Delta). (The WHO has been using Greek letters to name COVID-19 variants.) Here are some details on each strain. 

+ Delta Variant

Delta is the variant that preceded Omicron and is considered by the WHO to be a “variant of concern.” One reason for concern is that Delta seems likelier to present with severe symptoms in unvaccinated people. It also seemed to cause more illness in younger people than other COVID-19 strains.

But even asymptomatic people may spread the virus to others. When compared with the original strain, Delta has been found to be two times more contagious. 

Symptoms of Delta are similar to those of the Alpha and Omicron strains of COVID-19 but seem to cause more cold-like symptoms such as fever, runny nose, headache, and sore throat. 

As with other strains, vaccines have proven to be very effective at preventing serious illness, hospitalization, and death. 

+ Delta Plus Variant

First seen in India, Delta Plus is a subvariant of Delta. It has mutations that allow it to more easily attack the cells in a person’s lungs. Delta Plus isn't thought to be any deadlier than Delta, but it could be better at evading vaccines. 

+ Epsilon Variant

First detected in California, the Epsilon variant has a greater ability to both evade COVID-19 vaccines and resist COVID-19 treatments. This is probably due to three mutations that have taken place in the virus’s spike protein. These particular mutations make it easier for the virus to penetrate the host cells. It is currently a “variant of interest,” as cases have started to diminish. 

+ Lambda Variant

Considered to be a "variant of interest,” the Lambda variant is responsible for a very small number of cases in the United States. It was first detected in Peru, and although it shares many similar mutations with other contagious variants, it has not had a large impact on the U.S. population. 

Why Does the COVID-19 Virus Mutate?

Simply put, RNA viruses mutate naturally. More infected people lead to more copies of the virus, which means more opportunities for mutations to occur. Another common virus that mutates quickly is the virus that causes the flu. (This is the reason that new flu vaccinations are recommended every year.) Variants that are more contagious can spread faster and are then able to displace other variants. 

Are There Additional Precautions That I Should Take for COVID-19 Variants?

All the currently recommended precautions should be sufficient: social distancing, wearing masks, and frequently washing your hands are crucial. Getting vaccinated (including getting a booster shot) remains the best way to protect yourself against severe outcomes from COVID-19. Some people are not able to be vaccinated due to other health concerns, so it’s important to follow all precautions as a way to keep everyone around us safe. 

Are Vaccines Effective for All COVID Variants?

According to the CDC (U.S. Centers for Disease Control and Prevention), vaccines are effective against most variants found in the United States. In the case of Omicron, the vaccine helps protect infected people from severe symptoms, hospitalizations, and death. Children who are five years old or older are now able to receive the vaccine, which will help to prevent the spread. As more variants arise, research will be done to determine the effectiveness of the vaccine against them. 

How Effective are Masks Against COVID-19 Variants?

Masks are very effective in helping to protect yourself and others from all COVID-19 variants. It is recommended that anyone spending time indoors in public wear a mask. If you are outdoors in a crowded public space, it is also a good idea to put on a mask. 

N95 masks are recommended as the best defense against COVID-19, even for vaccinated people.

Carbon Health’s medical content is reviewed and approved by healthcare professionals before it is published. But note that our knowledge and understanding of COVID-19 are developing and changing very rapidly; if you have questions or concerns about COVID-19 precautions, treatments, and vaccinations, please talk to your healthcare provider.


Aaron S. Weinberg MD, MPhil

Aaron S. Weinberg, MD, MPhil, is Director of Program Development at Carbon Health and triple board-certified in Pulmonary, Critical Care, and Internal Medicine.


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