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Omicron can evade some antibodies.

Even before omicron began to spread widely, scientists were immediately concerned that it might be able to hide from some virus-attacking antibodies. Recent studies suggest that yes, the virus can evade parts of the immune system. But as our immune defenses are multipronged, it’s not all doom and gloom.

That worry initially came because omicron sports more than 50 mutations in various viral proteins. More than 30 of those changes are in the coronavirus’ spike protein, which helps the virus break into cells and is a major antibody target.

Since December 7, a slew of studies that have yet to be reviewed by other scientists has come out in support of the hypothesis that omicron can evade the immune response, showing that some antibodies don’t recognize omicron very well.

For example, among people vaccinated with two doses of the COVID-19 vaccine made by Pfizer and its German partner BioNTech, levels of immune proteins called neutralizing antibodies that stop the virus from infecting new cells were 41 times lower compared with antibodies against an older version of the virus that rose to prevalence in mid-2020, researchers report in a preliminary study posted December 11 at medRix.org. Previously infected people who have been vaccinated, on the other hand, have a leg up (SN: 8/19/21). The study showed that antibody levels against omicron were lower in people who had received two doses of Pfizer’s shot than in similarly vaccinated individuals who had recovered from a previous infection.

The findings are in line with those from multiple other studies that include other vaccines approved in the United States — Moderna’s and Johnson & Johnson’s — as well as ones used globally. The overall magnitude of the antibody drop differs from study to study, but all show the same pattern. Antibodies from people who had previously been infected but not vaccinated also perform poorly against omicron.

What’s more, omicron’s spike mutations may make treatments using lab-designed antibodies, called monoclonal antibodies, less effective, researchers report in a preliminary study posted December 14 at medRxiv.org. Out of nine monoclonal antibodies currently in clinical use, only two neutralized omicron in lab-grown cells.

The good news is that a different treatment, a yet-to-be-approved pill from Pfizer called Paxlovid, should still work against the new variant, the company said in a December 14 news release.