Mice who received more than four Covid vaccine jabs had a collapse in their ability to fight the coronavirus, Chinese researchers have found.
The damage extended past antibodies, the immune system’s front line of defense against viruses and bacteria, to the T-cells that form the crucial backup.
The researchers reported the finding in a peer-reviewed paper published December 22 in the journal iScience. In surprisingly clear language, they warned:
Our findings demonstrate potential risks with the continuous use of SARS-CoV-2 vaccine boosters, providing immediate implications [emphasis added] for the global Covid-19 vaccination enhancement strategies.
Later in the paper, the researchers were even more direct:
We found that the protective effects from the humoral immunity and cellular immunity established by the conventional immunization were both profoundly impaired during the extended vaccination course.
The finding has not been confirmed in humans.
But the mice the researchers used are genetically altered to model accurately the human response to the coronavirus and have “been shown to share profound similarities [emphasis added] with humans in response to SARS-CoV-2 infections,” as the paper explains.
The scientists used a vaccine that has a different mechanism of basic action than the mRNA jabs from Pfizer and Moderna, which turn our own cells into spike protein factories. But like them, the Chinese-tested vaccine causes the immune system to focus on a specific part of the coronavirus spike protein to the near-exclusion of other responses.
The finding may help to explain why large epidemiological studies keep finding that people who have received multiple boosters are at higher risk for Omicron infection than unvaccinated people.
(Highlights: Extended immunizations destroy the immune system’s ability to fight the coronavirus)
The Chinese report comes as Covid deaths are rising again in several highly mRNA vaccinated countries, including Australia, Denmark, and Japan – where they have now reached an all-time high, the population-adjusted equivalent of about 9,000 weekly deaths in the United States.
Meanwhile, large epidemiological studies – which measure real-world vaccine results – keep showing that mRNA jabs have “negative efficacy” against the coronavirus. In other words, people who received them are more likely to become infected than those who were never vaccinated.
Last month, researchers at the Cleveland Clinic reported that they had found “the higher the number of vaccines previously received, the higher the risk of contracting Covid-19.”
And last week a very large French study reported that a second mRNA booster was less effective than the first at every comparable time interval – and that after four months it actually raised the risk for infection compared to people who had not received it. Even worse,
In the chart below, lower dots represent a higher risk of infection. The horizontal axis is time, roughly one dot per month. The blue dots are people who have received a second mRNA booster, or fourth shot. After six months, they have a 30 percent higher risk of infection than they did before they got it. Worse, the negative efficacy appears to accelerate over time.
(With apologies to Howard Cosell: Down goes efficacy! Down goes efficacy! Down goes efficacy! The area in yellow represents higher risk in people who received the fourth shot.)
In contrast, the Chinese researchers were looking at Covid vaccine effects at the cellular level. They injected mice with several doses of purified spike protein receptor binding domain (RBD).
The receptor binding domain is the most crucial part of the coronavirus spike protein. It attaches to the receptors on our cells that allow the virus to dump its payload into them.
BioNTech and Pfizer initially considered targeting it alone for their mRNA vaccine before deciding to make a broader version that would cause our cells to make the entire spike. (The RBD-only version was called BNT162b1, as opposed to BNT162b2, which ultimately became the version BioNTech and Pfizer sell.)
The vaccine the Chinese scientists used differs from the Pfizer or Moderna shots because does not cause cells in the recipient to produce the coronavirus spike protein. It is more like the Novavax vaccine, which is spike protein itself.
But both the mRNA and Novavax vaccines ultimately work by producing an immune response that is highly focused not just on the spike protein but its RBD portion. In this way they are very similar to the vaccine the Chinese researchers used.
The researchers found that after receiving three or four doses of the vaccine, the mice had an strong immune response, similar to the early response in people who received the standard two-dose mRNA regimen:
We found that the conventional immunization course could stimulate sustained levels of neutralizing antibodies and promote the antigen specific CD4+ and CD8+T cell reactivity.
But when the researchers gave the mice fifth and sixth doses, they found a paradoxical weakening effect in both antibodies and underlying parts of the immune system, including B-cells and T-cells.
Essentially, the mice appeared to suffer immune tolerance or outright exhaustion and to become more vulnerable to coronavirus infection. The researchers wrote:
When we administrated additional doses of the same vaccine booster, with the attempt to induce a similarly enhanced or at least sustained immune response, we observed an overt reduction of the overall immune responses.
(A lot of charts, all saying the same thing: more than four doses are not good for mouse T-cells.)
The researchers suggested that one potential solution to the problem would be to switch vaccine types for boosters, a strategy known as “heterologous” boosting. Unfortunately, neither they nor anyone else has offered any evidence that strategy will work.
The paper has so far received almost no notice.
I found it only because the French preprint about the second booster made a glancing reference to it:
“Moreover, it has been shown in animal model that repeated boosters induce humoral and cellular immune tolerance.”
But as governments around the world continue to press boosters on largely unwilling populations, this paper shows more clearly than ever the risks they are running – and why further Covid vaccinations must be suspended unless researchers can prove that the immune collapse found in mice will not also happen in humans.