What to Know About the Updated COVID-19 Booster Shots That Target Omicron
An infectious diseases expert explains what's different about the new boosters and who should get one.
With Omicron BA.5 fueling COVID-19 cases in the United States, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) have approved and recommended an updated booster shot that targets this subvariant.
Individuals who are age 12 or older are now authorized to get the new Pfizer-BioNTech booster. Anyone 18 or older is eligible for the updated Moderna COVID-19 shot. People should wait at least two months after their last booster or completing the primary vaccine series before getting the new booster.
“The original promise of the mRNA vaccines was that you can update it very easily,” says Dr. Marcus Pereira, medical director of the Transplant Infectious Diseases Program at NewYork-Presbyterian/Columbia University Irving Medical Center. “All you have to do is modify the mRNA sequence, and this is exactly what we’re seeing now for the first time. It’s the upgrade.”
Dr. Pereira, who is also an assistant professor of medicine in the Division of Infectious Diseases at Columbia University Vagelos College of Physicians and Surgeons, spoke with Health Matters about the new COVID-19 booster shots that target Omicron.
The new booster is known as a bivalent vaccine. Can you explain what that means?
A bivalent vaccine means that half of the mRNA sequence is coding for the spike protein from the original SARS-CoV-2 strain and the other half codes the spike protein from the BA.4 and BA.5 subvariants. The Omicron subvariants are substantially different from the original strain, which is what’s causing these breakthrough infections and cases to rise, making them the predominant strains now.
The idea was not to have a purely BA.4/BA.5 vaccine because it’s tough to predict what may come next. It could be a newer variant that’s closer to the original virus or to the Delta variant, so the more diversity you can include in the vaccine, the better protected the population could potentially be.
Why did health officials decide it was important to upgrade the boosters and have them available before the fall?
They’re trying to prevent what happened last winter when Omicron caused the surge in cases. I think we all had that sense of despair when Omicron happened last year. It made people very sick and increased hospitalizations, and it was also an enormous disruption that caused a lot of frustration. And while there’s no guarantee, the best way to avoid that this year is for people to get vaccinated and protected against the Omicron subvariants.
For the general population (for example, low-risk individuals who may already have gotten the first booster and/or may have had a mild case of Omicron), why is it important for them to get boosted with the new shot?
Everyone should be encouraged to get boosted. Even for those without risk factors, it’s still worthwhile because they want to protect themselves, protect their loved ones, and protect those around them who are at greater risk.
What we’re seeing is that a variety of exposures, whether it’s through the mix and match of vaccines or the vaccines plus natural infection, does seem to correspond to a greater level of immunity. That’s what we experience for other viruses and infections — that prior exposure to certain infections generally confers immunity against that same organism when you get exposed in the future. Making a vaccine bivalent and keeping it broad offers a wide net of protection against what may come next.
“Everyone should be encouraged to get boosted. Even for those without risk factors, it’s still worthwhile because they want to protect themselves, protect their loved ones, and protect those around them who are at greater risk.”
— Dr. Marcus Pereira
For people who have already gotten two booster shots, should they get this third updated booster?
For those at high risk of severe disease — over 65 with comorbidities like diabetes, hypertension, heart disease, chronic lung disease, and so forth — as well as those who are immunocompromised and are most vulnerable to severe COVID, this booster is going to be highly recommended. We want to go into the fall and early winter as prepared and as protected as possible for what may come. Given that those populations are most vulnerable, they should take this recommendation seriously.
What about those individuals who have not been vaccinated yet?
The FDA was very clear that the bivalent vaccines are not meant for primary vaccination. Because the overall concentration of the mRNA material is lower, this formulation is meant to be only a booster. For the general population, it’s still recommended to get two doses of the primary series. For the immunocompromised population, the primary vaccine series is three doses. Then they can get the updated booster two months later.
How do we know that the new booster is safe and effective?
The United Kingdom had approved a bivalent vaccine that included the BA.1 subvariant, and we know from those human trials that it was quite safe with a similar set of side effects as the original vaccine, such as pain at the injection site, fatigue, and headache. Human trials are now underway for this new booster protecting against BA.4 and BA.5, but animal studies showed that it raised antibodies and mounted a good immune response. There is no expectation that this new product is going to be any less safe than the original vaccine.
Will COVID-19 boosters be reconfigured annually, like the flu shot?
Nobody really knows, but we do know that COVID-19 is not going away anytime soon. And many experts are thinking that it’s probably going to become something like influenza, that there will be seasons and variations, so we will have to be inoculated against whatever we think is coming our way. But with this mRNA platform, it’s pretty straightforward. They predict strains for influenza for the annual flu vaccine, and the same thing might potentially happen with COVID-19.
Marcus R. Pereira, M.D., MPH, is medical director of the Transplant Infectious Diseases Program at NewYork-Presbyterian/Columbia University Irving Medical Center and an assistant professor of medicine in the Division of Infectious Diseases at Columbia University Vagelos College of Physicians and Surgeons. Dr. Pereira is focused on infectious complications in patients with solid organ and bone marrow transplants as well as hematological malignancies, and provides care in both inpatient and outpatient settings. As medical director of the Transplant Infectious Diseases Program, Dr. Pereira oversees the development of infection prophylaxis and treatment protocols for immunocompromised patients. His areas of interest include multi-drug-resistant infections, including bacterial and fungal organisms in transplant patients as well as resistant cytomegalovirus infections. He is an associate editor of the American Journal of Transplantation and has led several studies this past year on the impact of COVID-19 in solid organ transplant recipients.