How well will the COVID-19 vaccine work against new strains? Experts weigh in

·7 min read
A pharmaceutical technician fills a syringe with the Moderna Covid-19 vaccine at the corona vaccination centre at the University hospital in Magdeburg, eastern Germany, on January 22, 2021. (Photo by Ronny Hartmann / AFP) (Photo by RONNY HARTMANN/AFP via Getty Images)
A pharmaceutical technician fills a syringe with the Moderna COVID-19 vaccine at the corona vaccination center at the university hospital in Magdeburg, Germany, on Jan. 22. (Photo by Ronny Hartmann/AFP via Getty Images)

COVID-19 variants have dominated headlines for weeks. But while officials have said that the public shouldn’t worry about the variants, they seemed slightly more concerned over the weekend.

British Prime Minister Boris Johnson said during a recent news briefing that B.1.1.7, the COVID-19 variant that has been circulating in the U.K. and has spread to the U.S., “may be associated with a higher degree of mortality.” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, also said during an appearance on MSNBC that U.S. officials are keeping a close eye on B.1.1.7, as well as the 501.V2 variant, aka the South African variant.

Fauci said that it is “a little bit more concerning” that the South African variant may negatively affect monoclonal antibodies that have been given for treatment of the virus. “It looks like it does diminish more so the efficacy of the vaccine, but we’re still within that cushion level of the vaccines being efficacious against these,” he said.

“These are serious situations that we are following very closely and, if necessary, we will adapt to it,” Fauci continued. He also stated that the vaccines could be altered in the future, if needed. This new information raises a lot of questions about the COVID-19 vaccines in relation to the variants. Here’s what you need to know.

First, it’s important to understand how the COVID-19 vaccines work

Currently, there are two vaccines authorized in the U.S. for use against SARS-CoV-2, the virus that causes COVID-19: One from Pfizer-BioNTech and the other from Moderna. Both use a new technology called messenger RNA (mRNA).

These vaccines work by encoding a part of the spike protein that’s found on the surface of SARS-CoV-2, according to the Centers for Disease Control and Prevention (CDC). The mRNA vaccines use pieces of that encoded protein from SARS-CoV-2 to create an immune response from your body, triggering it to create antibodies to SARS-CoV-2.

After that, your body eliminates the protein and the mRNA, but the antibodies stick around. What’s unclear, at this point, is how long the antibodies last. However, it’s expected that they’ll have staying power, infectious disease expert Dr. Amesh A. Adalja, senior scholar at the Johns Hopkins Center for Health Security, tells Yahoo Life.

How are the variants different from ‘regular’ COVID-19?

There are several variants currently circulating, but the two that are getting the most attention are the U.K. strain (B.1.1.7) and South African strain (501.V2). B.1.1.7 has several mutations in its genetic makeup, and some are in the virus’s spike protein, per the CDC. Some of these mutations seem to make the virus better able to latch on to your cells than “regular” SARS-CoV-2, making this newer strain more infectious, Dr. Thomas Russo, a professor and chief of infectious disease at the University at Buffalo, tells Yahoo Life.

The South African strain also has several mutations in its spike protein, the CDC says. And, as a result, it all seems to spread more easily than the regular SARS-CoV-2.

How effective are the COVID-19 vaccines against the variants?

As of now, they seem to be effective at preventing COVID-19 in people who are vaccinated. Both vaccines have an efficacy rate of up to 95 percent against the traditional form of SARS-CoV-2. “That’s really good, and much better than we expected at first,” Russo says.

Since the U.K. and South African variants have emerged, both Pfizer-BioNTech and Moderna have said their vaccines are effective against the newer strains in lab testing.

“The Moderna COVID-19 vaccine expresses the full-length spike protein of the SARS-COV-2 virus, allowing for the generation of neutralizing antibody responses to multiple domains of the protein,” Moderna explained in a press release in late December. “The full-length spike protein is 1,273 amino acids long, so while recent variants involve multiple mutations, for instance up to eight amino acid changes in the spike protein of the B.1.1.7 strain, these represent less than a one percent difference from the spike protein encoded by Moderna’s vaccine.”

Moderna announced in a press release on Monday that, after actually testing its vaccine against the variants, there was “no significant impact” on neutralizing titers — the concentration of antibodies in the body)—for B.1.1.7. But, the company said, there was a six-fold reduction in neutralizing titers with the South African variant. Despite that reduction, Moderna says that the neutralizing titers “remain above levels that are expected to be protective.”

Still, Moderna announced that it has a strategy to “proactively address the pandemic as the virus continues to evolve.” The company plans to test an additional booster dose of its vaccine to see if it will increase antibodies against emerging strains, as well as an emerging variant booster candidate to target the South African variant. “Moderna expects that its mRNA-based booster vaccine will be able to further boost neutralizing titers in combination with all of the leading vaccine candidates,” the company said in its press release.

So, what happens now?

Based on what is known at this moment, “the vaccines are likely going to be effective against the variants. All the data shows that they’re going to be effective,” Adalja says. The research on the variants and vaccines so far has been in labs — not in people — which makes it hard to know for certain how much a drop in antibodies in a lab setting actually translates to the real world, he says. “Vaccines don’t just induce one type of antibody,” Adalja explains. “There are a whole host of antibodies, as well as T-cell immunity to consider.” And all of that together can help prevent COVID-19, he says.

There’s also this to consider, per Russo: There’s a decent amount of wiggle room, given that the vaccines are 95 percent protective. “We may lose some effectiveness from the 95 percent mark but, even as efficacy decreases, the likelihood is still that the virus will be less severe and less likely to cause a bad outcome in people who get the vaccine,” he says. “The unresolved question at this point is what is going to be our efficacy threshold for changing the formulation and then producing the alternative vaccine? We’re not there yet, and that may never need to happen.”

Dr. David Cennimo, assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School, tells Yahoo Life that it’s “reassuring” to know that the antibodies from the vaccine “still bind well” to prevent COVID-19. But, he adds, “I suspect they do not bind as well as they would in a nonvariant virus. This is why they are talking about the possibility of needing different vaccine in the future.”

As of this moment, Moderna is exploring a booster vaccine “just in case we need it,” Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life. “I hope we don’t,” he adds.

Overall, people should be confident that the vaccine is “so far, so good,” Schaffner says. “I don’t think we should get too excited about this,” he says. “Let’s all get vaccinated now with the vaccine that’s available when we can and, if we need a booster down the road, we’ll deal with it.”

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.

Read more from Yahoo Life:

Want lifestyle and wellness news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.