Scientists working at computers, wearing masks.
Scientists working at computers, wearing masks.
Scientists working at computers, wearing masks.

COVID Variants: What You Should Know

Featured Experts:

Updated on April 8, 2022

Since December 2020, several coronavirus variants have been identified and are under investigation. Each new variant raises questions: Are people more at risk for getting sick? Will the COVID-19 vaccines still work? Are there new or different things you should do now to stay safe?

Lisa Maragakis, M.D., M.P.H., senior director of infection prevention, Stuart Ray, M.D., vice chair of medicine for data integrity and analytics, and Robert Bollinger, M.D., M.P.H., the Raj and Kamla Gupta Professor of Infectious Diseases, all of Johns Hopkins Medicine, are experts in SARS-CoV-2, the virus that causes COVID-19. They talk about what is known about these new variants, and answer questions and concerns you may have.

COVID Omicron Variant: What You Need to Know

Masked researchers analyzing medical samples

What is the omicron variant? Our experts share what we know about this new coronavirus variant.

Coronavirus Mutation: Why does the coronavirus change?

Variants of viruses occur when there is a change — or mutation — to the virus’s genes. Ray says it is the nature of RNA viruses such as the coronavirus to evolve and change gradually. “Geographic separation tends to result in genetically distinct variants,” he says.

Mutations in viruses — including the coronavirus causing the COVID-19 pandemic — are neither new nor unexpected. Bollinger explains: “All RNA viruses mutate over time, some more than others. For example, flu viruses change often, which is why doctors recommend that you get a new flu vaccine every year.”

What is a variant of concern?

Coronavirus variants are classified in different categories by organizations such as the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC).

A variant of interest is a coronavirus variant that, compared with earlier forms of the virus, has genetic characteristics that predict greater transmissibility, evasion of immunity or diagnostic testing, or more severe disease.

A variant of concern has been observed to be more infectious, and is more likely to cause breakthrough infections or reinfections in those who are vaccinated or previously infected. These variants are more likely to cause severe disease, evade diagnostic tests, or resist antiviral treatment. Alpha, beta, gamma, delta and omicron variants of the SARS-CoV-2 coronavirus are classified as variants of concern.

A variant of high consequence is a variant for which current vaccines do not offer protection. As of now, there are no SARS-CoV-2 variants of high consequence.

Will the COVID-19 vaccines and boosters work on the new variants?

Ray says, “There is evidence from laboratory studies that some immune responses driven by current vaccines could be less effective against some of these variants. Those eligible for COVID-19 boosters should obtain them for added protection against infection and severe disease.

“The immune response involves many components, including B cells that make antibodies and T cells that can react to infected cells, and a reduction in one does not mean that the vaccines will not offer protection.

“People who have received the vaccines should watch for changes in guidance from the CDC, and continue with coronavirus safety precautions to reduce the risk of infection, such as mask-wearing, physical distancing and hand hygiene.”

“We deal with mutations every year for flu virus, and will keep an eye on this coronavirus and track it,” says Bollinger. “If there would ever be a major mutation, the vaccine development process can accommodate changes, if necessary,” he explains.

The Omicron Variant

In November 2021, a variant of the SARS-CoV-2 coronavirus emerged and was named omicron by the WHO, which lists it as a variant of concern. Cases of the highly contagious variant, including a subvariant called BA.2, or “stealth omicron,” have caused surges of COVID-19, particularly in areas where safety precautions have been relaxed.

“The omicron variant is responsible for the largest surge since 2019,” says Maragakis.

“Omicron has a large number of mutations that all appeared at once. It’s very different from previous versions, including delta. It has over 50 mutations, many in the spike protein, which is how it gets into our cells in the first place. The spike protein is also one of the most prominent exterior features of the virus that our immune system recognizes, responds to and uses to develop antibodies.

“Unfortunately, omicron is a perfect storm: Mutations gave it the ability to escape weak immune responses AND become more transmissible from person to person.

Omicron and BA.2: Do they cause more severe illness?

Bollinger says, “The answer appears to be no. In fact, there is evidence that omicron may cause less severe disease than the delta variant.”

“What we see is that omicron may have more of an affinity for our upper airways than our lower airways, and can be more easily spread through talking, coughing or breathing, especially from people without masks on. Omicron also may have more potential for airborne aerosolization of the virus, hanging in the air in indoor settings,” Maragakis says.

Are omicron and BA.2 more contagious than other variants of the coronavirus?

Omicron and especially its subvariant, BA.2, are very contagious, more so than the original coronavirus or the delta variant.

Do the COVID vaccines work on the omicron variant and BA.2?

Data shows that being up to date on vaccines and boosters can spare most people from the worst of COVID-19. “Being fully vaccinated and getting a booster as soon as you are eligible provides excellent protection against hospitalization and death,” says Bollinger.

Current data indicates that even if you are exposed to omicron or BA.2, being up to date with your COVID-19 vaccines and boosters will protect you and prevent severe disease.

According to the CDC, research from January 2022 shows that coronavirus vaccine boosters are effective in preventing severe COVID-19. The CDC encourages boosters for those who are eligible, and recommends staying up to date on all COVID-19 vaccines.

“During both Delta- and Omicron-predominant periods, receipt of a third vaccine dose was highly effective at preventing COVID-19-associated emergency department and urgent care encounters (94% and 82%, respectively) and preventing COVID-19–associated hospitalizations (94% and 90%, respectively).”

A March 2022 study from the CDC found that getting two or three doses of an mRNA COVID-19 vaccine was associated with a 90% reduction in risk for COVID-19–associated invasive mechanical ventilation or death. Protection of three mRNA vaccine doses during the period of omicron predominance was 94%.

Could a new coronavirus variant affect children more frequently than earlier strains?

Ray says that widespread infection with the delta and omicron variants has resulted in an increased number of cases in children, including uncommon severe infections and deaths.

“There is no convincing evidence that any of the variants have special propensity to infect or cause disease in children. We need to be vigilant in monitoring such shifts, but we can only speculate at this point,” he says.

Will there be more new coronavirus variants?

Yes. As long as the coronavirus spreads through the population, mutations will continue to happen, and the delta and omicron variant families continue to evolve.

“New variants of the SARS-CoV-2 virus are detected every week,” Ray says. “Most come and go — some persist, but don’t become more common; some increase in the population for a while, and then fizzle out. When a change in the infection pattern first pops up, it can be very hard to tell what’s driving the trend — changes to the virus, or changes in human behavior. It is worrisome that similar changes to the spike protein are arising independently on multiple continents.”

Regarding coronavirus variants, how concerned should we be?

“Most of the genetic changes we see in this virus are like the scars people accumulate over a lifetime — incidental marks of the road, most of which have no great significance or functional role,” Ray says. “When the evidence is strong enough that a viral genetic change is causing a change in the behavior of the virus, we gain new insight regarding how this virus works. The virus seems to have some limitations in its evolution ― the advantageous mutations are drawn from a relatively limited menu ― so there is some hope that we might not see variants that fully escape our vaccines.

“Updated versions of the current vaccines are being evaluated, but there is no clinical trial evidence yet that variant-specific vaccines would provide significantly greater protection. Though SARS-CoV-2 is changing gradually, it’s still much less genetically diverse than influenza.”

“As far as these variants are concerned, we don’t need to overreact,” Bollinger says. “But, as with any virus, changes are something to be watched, to ensure that testing, treatment and vaccines are still effective. The scientists will continue to examine new versions of this coronavirus’s genetic sequencing as it evolves.”

COVID Variants: Safety precautions still work

“In the meantime, we need to continue all of our efforts to prevent viral transmission, by practicing safety precautions, vaccinating as many people as possible as soon as we can and encouraging boosters among those who are eligible,” says Bollinger.

Ray concurs. “Vaccines and boosters are the medical miracle of 2020, but we also need to reemphasize basic public health measures. We have tools at hand that enable individuals to manage risk, including wearing high-quality masks or respirators. Those rated FFP2 or FFP3 are more protective than cloth masks, and often easier to wear. Hand-washing and avoiding large indoor gatherings, especially with unmasked people, are other ways to mitigate the risk of infection.”

Maragakis says, “The basics work, and everyone should be aware that anyone can have this virus now. If you get yourself into that mindset and act accordingly, then if you get that call that someone you know is positive, if you’ve been vigilant, you can know you’re safer.”

She adds, “It’s entirely possible that yet another variant could emerge. Immunity seems to decline after a number of months, but boosters dramatically improve immunity. I encourage everyone who is eligible to get their booster. We are all in this together.”

“New variants are a reminder that we should be using multiple tools for the safety of ourselves and those for whom we care,” agrees Ray.

COVID-19 Vaccine

syringe close up - covid19 coronavirus vaccine
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