Pfizer Vaccine Likely to Work Against New Coronavirus Variants

  • A new study finds that the Pfizer COVID-19 vaccine is likely effective against new variants of SARS-CoV-2.
  • Mutations to the spike protein in SARS-CoV-2 have concerned researchers because COVID-19 vaccines are designed to identify and go after the viral spike protein.
  • Researchers suspect that as long as COVID-19 is spreading readily, more mutations will come.

New evidence suggests that the Pfizer-BioNTech COVID-19 vaccine will likely be effective against the variants of the coronavirus detected in the United Kingdom and South Africa.

Both of the variants contain a mutation within the spike protein, called the N501Y mutation, that’s thought to improve the virus’s ability to bind to our cells, making it more infectious.

In a new study conducted by scientists from Pfizer and The University of Texas Medical Branch at Galveston, the Pfizer vaccine proved to be effective on strains with the N501Y mutation.

The variant first detected in South Africa contains other mutations within the spike protein, which raises concern these mutations could undermine the vaccines.

However, infectious disease experts remain confident that the vaccines will work against these variants and new ones that come our way.

The mutations that concern scientists

Mutations to the spike protein have concerned researchers because the vaccines are designed to identify and go after the viral spike protein.

“The Moderna and the Pfizer RNA vaccines — the two that are approved for emergency use in the U.S. — those are both vaccines that immunize you against the spike protein,” said Dr. Ellen F. Foxman, an immunologist and Yale Medicine Laboratory Medicine physician.

Foxman said they want to ensure any changes to the spike protein don’t impact the high efficacy reported in the vaccine clinical trials.

Why the vaccines will likely work

Researchers have been studying how the COVID-19 vaccines will respond to the variants, and the findings are promising.

In the new study the researchers looked at postvaccination sera from 20 participants and found it successfully neutralized the coronavirus.

This suggests the variants identified in the United Kingdom and South Africa with the N501Y mutations won’t diminish the effectiveness of the vaccines.

The variant in South Africa contains several other mutations, one of which is also located in the spike protein.

It’s called the E484K mutation, and preliminary evidence suggests convalescent sera and monoclonal antibodies don’t work as well on variants with this mutation.

The spike protein is thousands of amino acids long, so a mutation would alter only a minor piece of a large protein.

The vaccine produces a broad immune responseTrusted Source that involves various antibodies and cell-mediated immune responses working on various sites of the spike protein.

“The mRNA vaccines (both Pfizer and Moderna) generate a number of proteins, and humans’ antibody responses target multiple regions (called epitopes) of these proteins,” said Dr. Dean Winslow, infectious disease physician at Stanford Health Care.

“The antibody response is broad and even in the presence of certain protein substitutions like E484K, antibodies may still be able to neutralize and prevent attachment/entry of the virus,” Winslow said.

Consequently, scientists believe these variants won’t evade the vaccine.

“It is unlikely that single mutations would render a vaccine ineffective. Vaccines induce a whole host of antibodies directed at various parts of the spike protein as well as T-cell immunity so it’s not surprising to see these results,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security and an infectious disease expert.

Vaccine expected to work against other variants

Researchers suspect that as long as COVID-19 is spreading readily, more mutations will come.

Every time a new person gets infected, there’s fresh opportunity for the virus to mutate.

“Mutations, like small changes in the genetic code, are the rule not the exception for viruses,” Foxman said.

Adalja believes the vaccine will work well against most if not all of these variants.

“I expect current vaccines to be robust against variants of COVID. It’s not the case that viruses easily evade vaccine-induced immunity, ” Adalja said.

It would take multiple mutations accumulated over time to render a vaccine useless, Adalja added.

For now, however, it seems highly unlikely that we’ll see variants that will completely escape our vaccines, Foxman said.

Researchers will need to continue tracking and testing for new variants so they can act fast and tweak the vaccines if any seemed to undermine the inoculations, Winslow said.

It will be important to “track mutations and assess what they do to the virus from a functional status standpoint,” Adalja said, “but I am confident in the vaccines at this time.”

The bottom line

New evidence suggests the COVID-19 vaccines will likely be effective against the variants of the coronavirus detected in the United Kingdom and South Africa.

Scientists who recently tested the Pfizer vaccine on the mutations say the vaccine holds up against the N501Y mutation.

Moderna is still testing its vaccine against the variants, but expects it to remain effective given the broad immune response the shot produces.