As soon as omicron was discovered in December, the pharmaceutical companies Bayontek/Pfizer and Moderna began developing special vaccines against this variant of the virus. At the end of January, both companies started the first clinical trials.
There were good reasons for the rush, as it turned out that the new variant could significantly weaken the immune protection of previous vaccines, and even those who had been vaccinated three times became infected with the new mutant. Biologically, omicron differs significantly from previous variants.
Although patients who were vaccinated two or three times showed a much milder course of the disease, there was a risk that infected persons would spread the virus unknowingly, because the infection was asymptomatic. Therefore, it was considered necessary to develop a special vaccine.
Now that the omicron wave has almost reached its peak in many countries, and in some it has probably already passed, there are also the first results of animal tests with the newly developed omicron vaccines. But they are disappointing. The expert journal Nature writes that all studies are not yet final and are only available as a pre-publication.
Previous booster vaccinations are just as good
Four studies with different vaccines were conducted on hamsters, mice and rhesus monkeys. Three of them with mRNA vaccines.
Although the total number of animals tested was small, the newer vaccines work "no better than a booster shot with a conventional vaccine," summarized David Montefiori, director of the AIDS Vaccine Research Laboratory at Duke University in North Carolina.
Probably the most significant study was done with macaques and rhesus monkeys. The study comes closest to human reality because it takes into account that most people have already been vaccinated several times. In this sense, the researchers took a closer look at the effect of the supplementary, or third, vaccine. In addition, the study was conducted on vaccines already approved for humans.
Therefore, all eight tested rhesus monkeys have already been vaccinated twice with Moderna's usual vaccine against covid-19. Now half of them received the same booster vaccine and the other half received the new omicron mRNA vaccine. Both groups formed equally broad-spectrum antibodies that are also effective against omicrons.
White blood cells against omicrons
In addition, both test groups also developed cross-active memory cells. These specialized B-cells, which are part of white blood cells, are important in building the body's immune memory. These cells themselves release antibodies and thus act against a large number of variants, and possibly against other corona viruses.
Another study in mice used an mRNA vaccine specifically developed against the delta variant and compared it to the omicron vaccine. That study also showed a similar result, but with the limitation that the omicron vaccine no longer works well against the earlier variants.
It turned out that, as in other studies, with supplementary vaccinations, it did not make a big difference which vaccine the animals received. However, if only one dose was given, the special omicron vaccine provided better protection.
The uncertain future of the omicron vaccine
Although these results of the study are preliminary, they indicate that it may not be worthwhile to further develop a special omicron vaccine.
On the one hand, the rapid spread of the omicron wave has overtaken even the unusually rapid development of a vaccine and could stall before such a vaccine even reaches the clinical stage of human testing.
On the other hand, vaccines that have already been tested and approved have also been shown to be quite effective against omicrons. In such circumstances, the question will rather arise for pharmaceutical companies and researchers that it may make sense to initially observe the development of possible further variants and then, if necessary, enter the market with even more effective new vaccines. After all, good remedies are already available against the current relatively mild threat.
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