Omicron Update: Thoughts From Columbia’s Infectious Diseases Chief

Just two months after omicron emerged on the scene, many of the uncertainties about the new variant are starting to become clear.

Does omicron truly cause less severe disease? Will vaccines and new antivirals work?

Magdalena Sobieszczyk, MD, Columbia University Vagelos College of Physicians and Surgeons

Magdalena Sobieszczyk

To get the latest answers, we spoke with Magdalena Sobieszczyk, MD, MPH, chief of infectious diseases at the Vagelos College of Physicians and Surgeons at Columbia University Irving Medical Center and the Harold C. Neu Professor of Infectious Diseases in the Department of Medicine.

Though the unprecedented growth in new COVID cases in New York City is giving many New Yorkers flashbacks to Spring 2020, when hospitals were overrun and close to 20,000 people died, we’re in a much different place today, Sobieszczyk says.

“The case numbers give you pause and that sense of doom and gloom, but it is not the same,” she says. “About half of the patients in the hospital with COVID are admitted for other reasons and found to be positive during routine testing, and of the patients in the hospital, about half are unvaccinated. Many people who do end up in the hospital are not as sick and the number of patients in the intensive care units is lower than before. We’ve also learned since then how to treat the disease, and more people who enter the hospital survive. Those are important things to remember.”

More thoughts from Sobieszczyk:

Early reports hinted that omicron is less severe than previous variants. Is that true?

We’re starting to see evidence from many different types of reports, and together they do suggest omicron is less severe. Data coming in from the UK and South Africa show that people are 30% to 70% less likely to have severe disease or be hospitalized with omicron than with delta. And among people who were hospitalized, people with omicron were less likely to go to the ICU or to be intubated. The pattern is dramatically different from what we saw with delta, and we’re seeing the same patterns in New York.

Really intriguing data emerging from animal studies also suggest that omicron replicates rapidly in the upper airways and airways in the lungs, but it’s slower at infiltrating the lung tissue.

It is also possible that part of the reason omicron is causing less severe disease is because it’s infecting more people who’ve been vaccinated, but also because of the unique characteristics of this variant.

Do our vaccines still work against omicron?

Yes they do. We’re seeing infections with omicron among vaccinated people, but the vaccines and the boosters that we have right now are highly effective at preventing serious illness, hospitalization, and death. That cannot be emphasized enough.

For people who are vaccinated but not boosted, data emerging from outside of United States show that the effectiveness of protection from severe illness and hospitalization was up to 70%. It appears even greater for people who’ve had the booster shot, with early data from the UK suggesting it is over 80%, though more data are accumulating. And while protection from symptomatic infection is low after only 2 doses of the vaccine, it is higher in people who have received the booster shot. We are definitely still learning about the duration of protection of the booster dose.

When people do become infected, the symptoms in the unvaccinated are definitely more severe, and unvaccinated are more likely to end up in the hospital than vaccinated people. In predominantly vaccinated populations, there’s a milder course of disease.

If omicron is milder, why should people still be wary of it?

Even if it's milder in vaccinated people, it is incredibly infectious, and just because of the sheer number of people that it infects, it will cause more hospitalizations. More health care workers are out, because they're positive, and it’s really straining the health care infrastructure.

On an individual level, even people who are mildly infected can develop long COVID, and with so many people being infected with omicron, we could see more long COVID cases in the future. And then those who are unvaccinated remain at high risk for severe disease.

High rates of transmission may also give the virus more and more opportunities to acquire more mutations that could make it more resistant to vaccines, antivirals, and monoclonal antibodies.

Many more children are being hospitalized now with omicron. Is omicron affecting children differently?

The increase in hospitalizations of children can be explained by several factors. It could be, for example, because we're seeing more cases in general.

Among kids hospitalized for the treatment of COVID, most are not vaccinated, because either they're too young, below the age of 5, or they haven't gotten vaccinated yet. And some children are also found to be incidentally infected, while hospitalized for other reasons.

Young kids’ airways are different than adult airways: They're narrower and a little bit more floppy. That means that during an infection that produces a lot of inflammation and mucus, kids don’t clear the mucus with coughing as efficiently as adults. Sometimes, they need to be hospitalized to get added oxygen and support to help them to clear the inflammation, but the hospital stays are usually brief. Still, most of these cases don’t seem to be life-threatening.

Will we need additional shots of the COVID vaccine?

The way I think about it, coronavirus and its variants are likely here to stay for a while. It is not clear yet, but we should probably start thinking about COVID vaccines like the flu shot. Which is also an important vaccine to get because people can get co-infected with both the flu and COVID. Whether we call it a booster or repeated vaccination, it's something that we may need to get periodically and becomes a normal part of our health care. And of course some people with weakened immune systems, who don’t make a good immune response to vaccines, are already recommended to get additional doses.

I think the wider population with intact immune systems may eventually need to get an additional shot and ideally with a vaccine targeting the newer variants; when is still to be determined. People who've gotten their boosters are doing really very well in terms of being protected from the severe effects of omicron. I don't think it's coming in the next month or two, but sometime in the near future. We are still learning about the duration of protection of the booster dose.

Do the two new oral antivirals that are now available work against omicron?

Right now, there is laboratory evidence that both new antivirals—Paxlovid and Molnupravir—work against omicron in preventing hospitalization and death in those at highest risk. But this will have to be monitored in the real world. These drugs could be a game changer in preventing severe disease in people who have a medical condition or other factors that increase their risk for severe illness. Unlike monoclonal antibodies, Paxlovid and Molnupravir are oral medications that can be taken without the need to come into an infusion center.

The tricky thing with these drugs is they must be given early, when symptoms are mild to moderate and have just started, not when people are in the hospital due to COVID. And the drugs are currently in short supply. Because of the shortage, we are following guidelines about who should get the drugs. Right now we're really focusing on people who are most at risk if severe disease develops: people who are moderately or severely immunocompromised, or those over 65 and not fully vaccinated with some additional risk factors for severe illness.

When the supply is no longer limited, we’ll be able to give them to more people who are at risk for developing severe illness. They will still need to be prescribed by a practitioner to make sure that there are no drug interactions with other medications that a person may be taking and that there are no other contraindications to taking them (e.g., pregnancy for Molnupravir).

How can people protect themselves from omicron?

Getting vaccinated and boosted is critically important in protecting yourself. The variant is much more contagious than previous variants, but masks, social distancing, those precautions still work. We need to be more vigilant about those practices at the moment.

We are in a much better spot than we were before, but this virus is still quite a formidable opponent.