Preliminary laboratory research by Pfizer/BioNTech finds that a third booster shot of its COVID-19 vaccine successfully neutralizes—that is, blocks—the omicron variant of the virus from entering and infecting cells. The researchers tested the new variant against antibodies produced by people one month after they had been inoculated with a third booster dose of the Pfizer/BioNTech vaccine. They report that the boosted level of antibodies "provides a similar level of neutralizing antibodies to Omicron as is observed after two doses against wild-type and other variants that emerged before Omicron. These antibody levels are associated with high efficacy against both the wild-type virus and these variants."
In the press release reporting their initial laboratory results, the company also notes that the antibodies produced after two doses are 25 times less likely to neutralize the omicron variant than they are for earlier versions of the coronavirus. Nevertheless, the researchers believe that two doses of the vaccine may sufficiently prime T-cells, the next level of immune response, that people may still be protected against severe forms of the disease.
This news follows on less happy preliminary research from South Africa reported earlier this week that tested the omicron variant against antibodies produced by one group of participants who had received two doses of the Pfizer/BioNTech vaccine and another group who had been previously infected with an earlier COVID-19 variant.
The researchers reported a 40-fold decline in the ability of antibodies produced by two doses of the vaccine to neutralize the omicron variant. On the other hand, five of the six people who had been previously infected by an earlier variant showed a higher ability to neutralize the omicron variant. "Previous infection, followed by vaccination or booster is likely to increase the neutralization level and likely confer protection from severe disease in Omicron infection," suggest the researchers.
Keep firmly in mind that these are very preliminary laboratory results that need to be confirmed by real-world epidemiological evidence with respect to breakthrough infections and disease severity. Nevertheless, these results corroborate that people who have already gotten two doses of COVID-19 vaccines or have already recovered from a prior COVID-19 infection should go get a booster shot and that people who are not yet fully vaccinated should delay no further.
In case these lab results don't hold up in the real world, vaccine makers are already working on tweaks to their inoculations that specifically target the omicron variant. The updated vaccines could become available as early as March 2022. The COVID-19 virus variant rollercoaster should spur vaccine makers to develop and deploy universal coronavirus and influenza vaccines and, despite all evidence to the contrary, one can hope for speedy regulatory approval of them.
Disclosure: I mixed and matched my earlier Moderna inoculations with a Pfizer booster dose in late October.