Pfizer Covid-19 Vaccine Works Against Mutations Found in UK, South Africa Variants, Lab Study Finds

Researchers have strained to assess whether Covid-19 vaccines and drugs will still work against new variants, as governments roll out shots they hope can reopen schools, businesses and other institutions.

Pfizer’s findings are consistent with other preliminary results reported in recent weeks by various research groups looking at the effectiveness of available vaccines against the new variants.

However, the investigation is still preliminary. Pfizer’s research was conducted in a lab and tested only a subset of mutations found in the variants, but not the variants themselves. Also, the researchers did not assess whether their results were statistically significant.

Still, these and other results suggest that the impact of the variants on the shots “will be relatively modest, which is good news for the vaccines,” said Jason McLellan, a structural biologist at the University of Texas at Austin who has studied how coronavirus proteins interacted with antibodies and was not involved in the Pfizer study.

Pfizer said the “findings do not indicate the need for a new vaccine to address emerging variants.” However, the company said it and partner BioNTech SE BNTX -0.30%

were willing to respond to a vaccine-resistant version of the virus.

The Pfizer-BioNTech vaccine uses a new technology called messenger RNA, after the molecular couriers of genetic instructions, allowing developers to make faster changes to their vaccines than more traditional techniques. The other vaccine licensed in the US, from Biotech Moderna Inc.,

also uses mRNA technology.

A recent preliminary study by Moderna, in collaboration with scientists at the US National Institutes of Health, showed that antibodies generated by the vaccine were less effective at binding the mutated South African variant spike proteins. The researchers found no difference for the spike proteins of the British variant. The coronavirus uses its spike proteins, which cover its surface, to invade and infect cells. The proteins are the main targets of antibodies.

As a precaution, the company said it was developing a booster shot for the South African variety.

The new Pfizer study found that antibodies generated by the vaccine were slightly better at binding versions of the virus with some of the mutations found in the British variant.

That could be because the scientists tested their UK variant-like viruses against a variant that lacked an older but important mutation that increases transmittance but makes the virus more susceptible to antibodies, said Dr. McLellan.

The gold standard would be to test antibodies against the variants themselves, he and others said, to understand how their unique constellation of mutations could affect natural immunity or protection against a vaccine.

These studies take place in laboratories all over the world.

Pfizer researchers, working with scientists at the University of Texas Medical Branch, did not conduct statistical significance tests, an important way scientists judge whether their results are due to chance and are really important, another major limitation, uninvolved scientists in the study said.

Rafael Casellas, a molecular immunologist at the NIH, said it was important to continue to monitor the evolution of the coronavirus to assess whether vaccines and other therapies need to be updated, or whether booster shots will be needed. “We cannot take this virus lightly,” he said. “We just don’t have enough information, so we have to be careful.”

Write to Daniela Hernandez at [email protected]