On Monday, a team of Israeli scientists publicized research showing that even a second booster dose of the Moderna or Pfizer mRNA vaccines doesn't bestow complete immunity from the omicron variant.
Now, just days later, their conclusion appears to have been corroborated by a team of South African researchers from the University of Cape Town and Stellenbosch University who observed seven individuals who had been infected with the omicron variant despite having been "boosted". The patients represented the first known cases of breakthrough infection by omicron, the researchers told the Lancet, the British medical journal where their findings were published.
Keep in mind, the South African team used a very different approach. First of all, the patients they examined had only received a single booster dose (unlike with the Israeli study, which focused on patients who had received two doses).
As for the study's subjects, all of them were white, and four were participating in medical training at Cape Town hospitals. The other three were on vacation. They were all between the ages of 25 and 39, and none of them could be classified as "obese", or had any other relevant medical history. All of them had tested negative before arriving in Cape Town, and none of them had reported a prior bout of COVID infection.
Five of them had received three doses of the COVID vaccine made by Pfizer and BioNTech. One had received a dose of the Moderna jab followed by Pfizer for the next jabs. Another received the AstraZeneca jab then switched over to Pfizer.
All of the subjects reported respiratory symptoms starting between Nov. 30 and Dec. 2; they ultimately experienced mild or moderate disease. The presence of the group of Germans presented a "unique opportunity" that researchers quickly jumped on, since the seven individuals represented the first known cases of omicron breakthrough infection involving patients who had already been boosted.
"The presence of this group from Germany presented a unique opportunity to study omicron breakthrough infections in individuals with mRNA vaccine boosters," the researchers said.
"Robust CD4 and CD8 T-cell responses" were detected in the subjects, the researchers said in reference to an additional line of the human immune system’s defenses aside from the production of antibodies. "The mild to moderate course of illness suggests that full vaccination followed by a booster dose still provides good protection against severe disease caused by omicron," they said.
The news hit shares of Pfizer and Moderna, the two biggest producers of mRNA jabs.
The findings ultimately demonstrated "insufficient prevention of symptomatic infection in otherwise healthy individuals who had received three doses of COVID-19 mRNA vaccines." Furthermore, the findings supported the need for "updated vaccines to provide better protection against symptomatic infection". Pfizer and Moderna have already promised to roll out retooled versions of their jabs specifically designed to protect against omicron. But at this point in the pandemic, it's unclear if the new jabs will be available before COVID finally makes the jump from "pandemic" to "endemic".
Readers can read more about the team's findings below: