Omicron has been with us for a few months, and it is only now that we are reaching a scientific consensus. The big science news is the discovery that omicron has developed a way of entering our cells that has never been used before by Covid-19 viruses. Because some types of cells allow this entry and others don’t, the course of the pandemic may be altered. I’ll give you an update on what we’ve learned about the risks with omicron and the changes in the regimens that must be used to treat it. But first, here’s the bottom line, with the details to follow.

Bottom line

We now know that omicron has figured out a new way of entering cells—this variant attaches tightly to their outside and then tricks them into protecting it with a layer of fat and pulling it inside. It does this best with the cells that line your nasal cavity—the very cells that are thought to release the virus bursts that infect other people. So it’s very contagious. Omicron can also be pulled into the types of cells that line the nasal cavity of some animals, so we will need to monitor this closely.

How many of us will get hospitalized or die? As with all forms of Covid-19, omicron is far, far more dangerous to older adults than to kids, including unvaccinated young children. Nonetheless, if all adults were vaccinated, the number of Covid deaths from omicron would likely be even less than deaths from the flu. But because so many adults are not vaccinated and omicron is so contagious, many will get sick and die.

Treatments that work against omicron

How protective are vaccines against omicron? The answer is very, very protective. The current data suggests that vaccines reduce the chance of dying by an astonishing 95 percent. It is much harder to estimate how well vaccines protect against being hospitalized. This is because the majority of people who test positive in hospitals are not there because of Covid-19. That is, they are hospitalized for other conditions and then routine testing gives a positive Covid result. This is especially true of young children, who rarely are hospitalized with a Covid diagnosis. So it is difficult to get data on the number of people hospitalized primarily due to Covid. Still, looking at the data overall, it appears that vaccines are more than 90 percent effective at keeping you out of the hospital due to illness caused by Covid-19.

But what if you are hospitalized because of serious Covid symptoms? Omicron has changed the treatment landscape. We defeat omicron with our biological memory systems, rather than with the antibodies that circulate in our bodies. Basically, antibodies triggered by vaccines or old infections do not recognize omicron very well. This is also true of the antibodies in treatments developed in drug company laboratories, so the two most common antibody infusions can no longer be used effectively. This is a serious problem because these infusions, from Regeneron and Eli Lilly, have been an important medical treatment, especially for the unvaccinated. It is not difficult to redesign the infusions to target omicron, but that will take time. Fortunately, pills, especially Pfizer’s remarkably effective Paxlovid, still work against omicron. But we will need to be patient as these become more available and we gain real-world experience in their use. Paxlovid supplies are very limited but growing, and the medical establishment needs to learn how to get them to patients in the few days after Covid diagnosis, when Paxlovid is most effective.

How omicron works, and why this matters

As mentioned, omicron has developed a way of entering cells not seen before with any variant of Covid-19. As far as the implications for humankind are concerned, there are bad and good aspects of this change. All other virus variants attach to the outside of certain cells, shape-shift and then shed their spiky coats. This leads to the release of virus m-RNA to the inside of the cells. The cell’s machinery is then hijacked and forced to make many copies of the virus, which then go on both to make you sicker and spread the disease to others. But omicron doesn’t work exactly like this. Instead, it takes advantage of how some cells capture useful nutrients to bring them inside. Omicron tricks some types of cells into “capturing” it and pulling it inside, coat and all. We don’t yet know exactly what happens next, except that more copies of the virus are made.

Not all cells are equally susceptible to being entered in these two different ways, and this is very important in understanding what omicron does to us. Omicron is very good at getting into the cells in your nose but not very good at getting inside the cells of your lungs. These two places play very different roles in Covid diseases. The nose is thought to be the main place where contagious respiratory viruses are released, and this helps omicron be very contagious. But since the presence of the virus in the lungs leads to the most dangerous Covid symptoms, omicron is somewhat less dangerous.

Omicron is also very fast. It gets into your cells faster, induces symptoms faster, and if you get really sick, this also happens faster. But like a sprinter who drops from exhaustion at the finish line, omicron has somewhat of a hard time keeping going. So the burst of omicron viruses appears to be smaller than bursts coming from existing variants that don’t use the new entry pathway. This may be fortunate for us, as it could possibly help minimize the spread of Covid to our internal organs.

What might an omicron future look like?

The changed way that omicron enters cells leads to new uncertainty about what will happen in the future. Covid-19 is believed to have started out in horseshoe bats, which are a natural reservoir that provides a place where mutant viruses can begin to be produced. The original mutant that thrived in human cells was so altered that it could not go back and easily reinfect bats. But now scientists have found that omicron’s use of the new entry pathway allows it to be captured and pulled into lab-grown cells isolated from some animals, including horseshoe bats, chickens, and mice. Whether this will cause infections in real animals is as yet unknown, but it is definitely something that needs to be monitored.

What about boosters and omicron? Boosters have definitely helped, and you should get one, but it is really getting your first shots that is most important. The Centers for Disease Control and Prevention just released updated data that underscores this. Two shots give 93 percent protection against death, and the booster raises it to 99 percent. But the emergence of variants such as omicron almost certainly means that we will need to redesign booster shots and take them periodically. The redesign of m-RNA vaccines is straightforward, and making an even more effective booster for omicron should not be a problem. In fact, booster shots for the flu have been redesigned annually for years, and perhaps an annual redesign of the Covid vaccine will be appropriate. Scientists are already designing a single shot that would deliver both vaccines. Right now, the Covid vaccines are more effective than the flu vaccines, so it may turn out that Covid will become the lesser danger of the two.

But there is one caveat here, and it’s a big one. If you’re not vaccinated, Covid, even in the form of omicron, is significantly more dangerous than the flu. And although vaccinated people can spread omicron, the spread is far worse from an unvaccinated person. So if you know someone who is resisting vaccination, you might send them this post. Or just ask them to sacrifice their personal preference for the sake of protecting their community and the nation from the spread of Covid-19.

Jay Gralla is professor emeritus of biochemistry at UCLA. He has published more than 140 scientific papers on m-RNA. For more on the science behind Covid 19, visit his blog, Covid 19: The Science Explained.