Dr. Shaun Grannis on the Robust Efficacy of mRNA Boosters in Protecting Against Severe Omicron

A recent CDC study found that mRNA booster shots are 82% effective in protecting against COVID-19 Omicron variant-associated emergency department (ED) visits and 90% effective in protecting against Omicron variant-related hospitalizations.

DocWire News spoke with the study’s co-author, Shaun Grannis, MD, Regenstrief Institute VP for Data and Analytics, about what this analysis means with respect to the ongoing fight against COVID.

DocWire News: Can you give us some background on yourself, and your role with Regenstrief Institute?

Dr. Shaun Grannis: Sure. I am one of the investigators in the Department of Biomedical Informatics and I also serve as the vice president for data and analytics at the institute. I also hold the Sam Regenstrief chair of biomedical informatics within the School of Medicine at Indiana University.

Can you talk to us about the recent CDC study that demonstrated the efficacy of mRNA vaccine boosters against Omicron?

So we looked at a number of different elements here. We wanted to look at the effectiveness of Omicron, the effectiveness of Delta, and we wanted to look at that effectiveness for preventing COVID related emergency department visits and also preventing COVID related hospitalizations. So we looked at a couple of different time periods. So we started by looking at just the effectiveness in the first six months of the vaccine. And for Delta, as many know, the effectiveness of the vaccine was quite good, it was about 86% effective in preventing COVID related emergency department visits and 90% effective with preventing COVID related hospitalization. That’s for Delta.

Now, for Omicron, in the first six months of receiving the mRNA vaccine, it was only 52% effective for the ED and 81% effective for the hospitals. If we look after six months, so after 180 days of receiving the two-dose mRNA combination, for Omicron, that effectiveness dropped significantly, it was 38% for emergency departments and 57% for hospitalizations.

But probably the takeaway finding and the good news here is that once you receive that booster shot, effectiveness for emergency department visits for Omicron jump from 38% to 82%, so it’s all the way back up to the effectiveness like Delta. Similarly, for hospitalizations, after the booster shot, effectiveness went back to 90% for preventing COVID related hospitalizations for Omicron related hospitalizations. So that’s a long-winded way of saying the boosters help to significantly improve the effectiveness of the mRNA vaccines, taking them back, effectively, to the effectiveness against the Delta virus.

Based on these data, what message would you give to people who are still vaccine hesitant, or have not yet received a booster?

I would say these provide, I think, pretty compelling and exciting evidence that the boosters do make a significant difference. And I would encourage people to take a look at that study, to talk to their healthcare provider, their public health official if they have any questions or concerns. But I think the evidence is increasingly clear and compelling. We’ve known for a long time that the vaccines are safe, we’ve known that they’re effective against a number of variants. And now we know that with the booster shot, the vaccines are very effective against Omicron.

Do you think we’re headed for COVID becoming an endemic disease?

Sure. I think, we want to be careful when trying to predict the future with COVID because it surprised us so many times. But I hope that one of two things happens and one is more likely than the other. The unlikely event would be, I would hope that COVID just goes away. I don’t think that’s going to happen. So my other hope would be that it does become endemic, does become much more consistently patterned like influenza is. But we’ll have to wait and see.

Are you involved in any other studies you would like to make our audience aware of?

We have some ongoing work. Results aren’t ready yet. But we’re part of the… The most recent results were published from the CDC VISION Network. And VISION is working on a number of other questions as well, questions related to waning, questions related to pediatric effectiveness, et cetera, questions related to immunocompromised individuals. So more results will be coming and I’d be happy to come back and share those results once they’re available.

Any closing thoughts?

Again, I think this is important and exciting information that the boosters do work. I think it provides great information for those people who are on the fence and just encourage people to make as well-informed decisions by taking in all of the information.