Laboratory tests out of South Africa has revealed that Johnson & Johnson's vaccine produced some antibodies but demonstrated "no detectable" neutralization of the Omicron coronavirus variant in a laboratory experiment.
Laboratory tests were conducted on blood plasma samples from those who received two doses of the Pfizer Inc. and BioNTech SE vaccine and those who had the J&J single-shot inoculation, according to Penny Mooe, a professor at Johannesburg's University of The Witwatersrand. The virologist said the vaccine appears to provide some protection against Omicron, maybe through other mechanisms such as immune cell activation.
Geometric mean titers, a measure of antibody levels, dropped from 1,419 against the original coronavirus strain to 80 against Omicron in those who had Pfizer shots. Moore said in an online presentation on Tuesday that the same metric plummeted from 303 against the original strain to undetectable levels against omicron in individuals who had received J&J's shot.
"Omicron does indeed exhibit substantial immune escape from antibodies," she said. "The situation, I think, is even more alarming for the J&J vaccine -- there was no detectable neutralization in our assay."
J&J did not comment on the findings, instead citing to an earlier statement in which the company stated that it is analyzing serum from participants in its booster studies for omicron neutralizing activity while pursuing a variant-specific vaccine that it will advance as needed.
The company is "confident in the robust humoral and cell-mediated immune responses elicited" by its vaccine, Mathai Mammen, head of research & development for J&J's pharma unit, said in a statement.
Moore's yet-to-be-published research ties up with early tests by South Africa's Africa Health Research Institute and Pfizer's own research, which was presented at an African health conference. South African scientists announced the finding of Omicron on Nov. 25.
Moore emphasized, however, that the body has other defenses against the virus.
"Reduced antibody titers will likely result in a decreased ability of vaccines to prevent infection but protection against severe disease likely to be preserved," she said on one of her presentation slides.
In a research involving hundreds of thousands of South African health workers, J&J's vaccine appears to be preventing severe disease, and no one on the study has died after contracting the Omicron variant, said Glenda Gray, the project's co-lead, in an earlier presentation on Tuesday.
A two-shot course of Pfizer's vaccine looked to offer 70% protection against being hospitalized after infection with the omicron strain, according to Discovery Health Ltd., the country's largest medical insurance provider. Pfizer's and J&J's injections are the two that are now being used in South Africa.
