Researchers are fiercely discussing what led to the adaptation of corona vaccines to the BA.5 variant. While vaccine makers Biontech and Moderna are touting the benefits of the new bivalent booster vaccines, a new independent laboratory study by researchers in Göttingen and Hanover now suggests that while there is an additional benefit from the upgrade, it is relatively minor. Additionally, tube tests confirm the potential of the new BA.2.75.2 and BQ.1.1 variants to evade antibodies accumulated from vaccinations and vaccine advances.
Comparison: vaccine and recovered antibodies against variant BQ.1.1
For their study, published in The Lancet journal, scientists led by Markus Hoffmann and Stefan Pöhlmann from the German Primate Center’s Department of Infection Biology carried out a series of neutralization tests. The blood of the test subjects is compared with the viruses in a petri dish, in this case with the so-called pseudovariants. These are viruses spiked proteins of the current BA.5 corona variants BA.2.75.2, BJ.1 and BQ.1.1. they were planted. For comparison, they also used viruses with variant B.1 spike proteins. In this way, the researchers were able to observe the extent to which the test subjects’ antibodies bound to the mutated spike proteins.
The people tested in turn belonged to five groups.
- The first group had received three vaccinations and had not had any vaccination breakthroughs.
- Group two had received four vaccinations with the mismatched vaccines and had not had any vaccination breakthroughs.
- Group three had received a fourth dose of the matched BA.5 bivalent vaccines.
- Group four had vaccine breakthrough after three vaccinations with one of the BA.1, BA.2, or BA.5 omicron variants.
- And finally group five had a breakthrough in vaccination with BA1 after three vaccinations. or BA.2 and then finally got a booster vaccination with an adapted bivalent vaccine.
Stronger immunity: three vaccines, then Vaccine Breakthrough, then Omicron Booster
All tests showed that the BA.2.75.2 variant, which circulates mainly in India, and the BQ.1.1 variant, which is currently gaining ground in Europe, were the best at evading the antibodies of the vaccinated and the recovered. The researchers write in the study that immune escape was most evident here.
Group five was able to defend against stronger viruses with the vaccination breakthrough after three vaccination doses and the additional dose with the bivalent BA.5 vaccine. They had 17.6 times stronger antibodies than group one (three vaccinations, no infections). This was followed by group four (three vaccinations plus infection), which had between 3.7 and 8.5 times more neutralizing antibodies than group one. Finally, group three (no infection, fourth BA.5 booster vaccination) showed 1.9 to 2.2-fold higher neutralization than group one. However, the value fell only slightly better than in group two (four vaccinations with the original vaccine), where the neutralizing activity was about double.