A pre-print study (not yet peer-reviewed) by U.S. Government researchers shows vaccinated people produce a less comprehensive immune system response following SARS-CoV-2 infection than unvaccinated people.
The researchers examined data from the Moderna Covid vaccine trial and found that, compared to unvaccinated controls, vaccinated participants produced far fewer N-antibodies. These are antibodies against the nucleocapsid protein inside the virus particle, in contrast to S-antibodies against the spike protein that the vaccines target. N-antibodies were detected in 40% (21 of 52) of infected vaccine recipients versus 93% (605 of 648) of placebo recipients. This means those infected after being vaccinated produced N-antibodies at less than half the rate of the unvaccinated.
The researchers found that N-seroconversion (producing N-antibodies following infection) was more likely for infections with higher viral loads. So they checked to see if the difference was due to the vaccinated having milder infections with lower viral loads owing to the vaccine. They found that it wasn’t: for the same viral load the unvaccinated were around 14 times (13.67, 95% confidence interval 5.17-36.16) more likely to have detectable N-antibodies following infection than the vaccinated. Look at the contrasting curves below: the yellow unvaccinated curve is much higher than the blue vaccinated curve, showing that for any given viral load (x-axis) the probability of detecting N-antibodies following infection (y-axis) is much lower for vaccinated than unvaccinated.