What We Know About the Omicron Variant and Vaccine Efficacy

Deepta Bhattacharya, PhD, professor in the Department of Immunobiology at the College of Medicine – Tucson, has spoken often about COVID-19 — to local or national news media, health departments, and his colleagues at the University of Arizona. However, the reason for his popularity may be wearing on him.

“The reality is that every time I do this, it means that something isn’t going that great,” said Dr. Bhattacharya as he recently provided an update on the latest information on the omicron variant, COVID-19 vaccines and the best strategies for staying healthy and safe. 

Early in the pandemic Dr. Bhattacharya, who also is a member of the BIO5 Institute and UArizona Cancer Center, collaborated with other University of Arizona Health Sciences colleagues to develop an antibody test for the virus that causes COVID-19. It was approved by the Food and Drug Administration as one of the most accurate tests of its kind and is being used to study the immune response to infection and vaccination.

How well are the current vaccines protecting people against the omicron variant?

The best data, coming from the UK and South Africa, shows that people with two doses of a vaccine, or one dose of the Johnson & Johnson vaccine, are only about 44% effective at keeping you out of the hospital. After you get a booster, that number goes up to about nearly 90% — meaning you are 10 times less likely to land in the hospital than someone who has not been vaccinated at all.

Would getting vaccinated or getting a booster now help you fight off omicron, or is it too late?

Given that we are in the midst of this omicron wave, I think it is reasonable to expect that if you get a booster dose now, that may be enough to carry you through this wave. So, if you haven't gotten it, I would definitely encourage you to do so. It is preferable to build up your immunity through a vaccine than by getting the virus and risk serious illness.

Is omicron a milder variant?

Omicron is certainly milder if you have some degree of immunity already from getting a booster of an mRNA vaccine. When people ask if it is milder, I think it is important that we define what exactly they mean by that. It is probably a little milder than the delta variant, but because of the sheer numbers of people getting sick, it’s not really as mild as we would like it.

I don’t think we should assume that we should just get omicron and be done with it. If you are able to ride out these next few weeks taking all the precautions and not getting sick, it would definitely be worth it.

What can we do?

Image

The vaccines have clearly lost some ground against omicron. But as far as the tools in our toolbox right now, getting booster shots is clearly the most important thing we can do. If you haven’t gotten one, now is a great time to get it because it will likely help you ride out the rest of the omicron wave.

It’s probably not going to do a great job of keeping you from getting infected in the first place, but it will reduce the chances that you get really sick. The other tools are the same things that we’ve been talking about all along. If you have the option of doing things outside, we know transmission is much less outdoors.

Better indoor ventilation is a big thing — which our facilities team at UArizona has done a great job of really bumping up ventilation and filtration within campus buildings. High quality masks are becoming more important with the transmissibility of omicron. Cloth masks, or single-layer mask really aren’t going to cut it anymore.

Should people get a fourth dose of the vaccines?

There is not a lot of data on the effectiveness of a fourth dose. There has been some discussion about this for people who got their booster early on and thus the effectiveness will have decreased, but at this point I think we are running out of territory in terms of what we can expect the boosters to do. If you fall into a vulnerable group, you should talk with your doctor to see if it makes sense for you.

Will there be an updated vaccine?

I think it is definitely time to update the vaccines to match omicron. There is nothing intrinsic about omicron that makes it difficult to vaccinate against, it’s just that it’s different from what the original vaccines were made to protect us against. When the vaccines get updated, I’m really confident that they’ll return to their same high levels of efficacy.

Do the rapid antigen tests work as well at detecting omicron?

There is increasing data that shows that for the first couple of days in which you are positive, the rapid antigen tests may show negative while the saline gargle PCR test will show positive. One of the things we are seeing is that some people actually test positive through a throat swab and not by a nasal swab and some people are the opposite. So, there’s something unique about the omicron biology that probably means, depending on where the virus goes into the body, it kind of stays there for a little bit. We are looking at this data and working with the manufacturer of the rapid antigen test to see what the best way to make sure that we’re catching as many cases as we can with this test.

Have you seen any changes to the incubation period of infection for omicron compared to the previous variants?

Yes, it has shortened by about a day. Delta was somewhere in the vicinity of four days, and early data suggests that omicron is about three days.

So, now what?

There’s been a sort of emerging narrative saying that we’re all going to get it. And you know, over the course of our lifetimes, I think that’s probably true. But it doesn’t mean that you have to get it right now. I know it’s really hard. It’s not your fault if you get it, but to the extent you are able to avoid it, you should because there will be some better options coming. If you can hold on for just a little bit longer taking the precautions that we know can help us stay healthy, you might be able to ride it out and at least not get this variant.

Hear more from Dr. Bhattacharya in this recording of a webinar he gave Jan. 20, 2022.